Three or four days ago as I was leaving town my burb started cutting out. Cruise set or not, doesn't matter. Seems to happen more when the truck is cool, before it gets up to running temp.


I installed new fuel filter, air filter, and cleaned & tightened all battery connections and grounds, except for the braided one on the bottom back of the block (will do it, just haven't gotten there yet). Today it cut out again on our way home from a Sunday family dinner. Feels like a miss, but not sure. No SES light, and no stored codes.


Not sure on condition of injectors, timing set, etc... Harmonic balancer appears fine. Seems to start and idle normal, cold or warm. Fuel pressure at idle is 4.5 psi.


Any ideas?Edited by: w_huisman

Inectors, timing, filters,supply pressure,all would give you a constant complaint.


Optic sensor 'hiccup' normally trips the SES light, PMD does not.

.... Fuel pressure at idle is 4.5 psi.


Any ideas? When, where and how did you test the fuel pressure. This sounds like what my truck did and I finally find, by mistake, That my new lift pump was not operating. I jumped it where the fuel pump relay if and not a hiccup one. With truck running open your petcock on the stat housing for a few minutes and see if you get fuel running out and truck keeps running or does it die with no fuel coming out.

Truck runs fine if I open the petcock. OPS/Lift pump are fine.


TDG: I'm sure you can guess my next question... How far away are you from getting those PMDs sent out?http://www.dieselplace.com/forum/smileys/smiley2.gif


My PMD is a 30214. I thought those were the PMDs that just plain stopped working when they were shot, or were less likely to cause intermittant problems? I also thought that since it only seems to occur when the truck isn't up to operating temp, that the problem likely isn't PMD. But you guys know a whole heck of a lot more than me! Edited by: w_huisman

30214, honestly, its been so long since I've actually messed with those I really don't reacall, I was referring to the 34264 when I said normally either worked or didn't. Since you do have the old 1st gen driver that is certainly suspect right off the bat. 4½# @ idle is not a whole lot of supply fuel either, 7 pounds or more would be best, 4 under load minimum.


As far as shipping the drivers...I know I know, I'm dragging @$$, its just a matter of convincing my accountant that I won't get burnt.

(double post removed)Edited by: w_huisman

30214, honestly, its been so long since I've actually messed with those I really don't reacall, I was referring to the 34264 when I said normally either worked or didn't. Since you do have the old 1st gen driver that is certainly suspect right off the bat. 4½# @ idle is not a whole lot of supply fuel either, 7 pounds or more would be best, 4 under load minimum.


That's right. I remembered wrong. It was the 34264's that either worked or didn't and there was no inbetween





As far as shipping the drivers...I know I know, I'm dragging @$$, its just a matter of convincing my accountant that I won't get burnt.





At this point, I'll send you the money ahead of time. Then you're guaranteed not to get burned.


Any other possibilities?

OPS can appear to work and cut out on you, best to relay around it. Truck stalls or just sputters? I would check the fuel supply to IP first for greasy leaks on the fuel lines/filter housing.

OPS can appear to work and cut out on you, best to relay around it. Truck stalls or just sputters?


I went to the parts store the other day and didn't see the add-a-circuit menioned on this board earlier this week. I was going to do just that... relay around the OPS. Not sure what makes the add a circuit any different than a line fuse?


I would check the fuel supply to IP first for greasy leaks on the fuel lines/filter housing.


Will do. Good idea.

QM: Lines at the filter housing look dry. So does the line going up to the petcock, but can't see the one going into the IP. However, I can see a little bit below the firewall-facing side of the IP, and it looks fine.


Still curious about Bowtie's Add-a-circuit OPS bypass. Could you possibly post a pic of one not installed so i know what I'm looking at?


I'm still concerned about TDG's comment about 4.5 psi at idle is low. Looking at finding a Delphi replacement PN and a good price.

http://www.dieselplace.com/forum/uploads/bowtie/2004-10-10_182226_DCP_0481.JPGok here it is sorry for the fuzzy pictures, I had to remove it from my truck and take the picture outside. There maybe other products out there that will work, some even better than this but this was what the store had, If you need one still let me know and I'll make arrangement to get another one and send it to you.


http://www.dieselplace.com/forum/uploads/bowtie/2004-10-10_182145_DCP_0477.JPG

As far as shipping the drivers...I know I know, I'm dragging @$$, its just a matter of convincing my accountant that I won't get burnt.


let me know if the money is an issue and mine will be on the way pronto.

The money itself is not the issue, rather that I'm married to my accountant ;)

Would a little influx of cash help to convince your accountant? I understand the feeling... my fiance is studying to be an accountant. I can't get away with anything. If you need to go "pre-pay" I am sure most people would have no problem with that. Maybe if you were asking for $500 they would, but the amount is relatively small.

I'll get Bowtie's version of the OPS by-pass installed today and re-check fuel line pressure at the petcock. But I doubt the by-pass will make a difference in fuel pressure at idle.


Still hunting the net for a good price on a Delphi 10-14psi lift pump, just in case that's where this gremlin hunt takes me.Edited by: w_huisman

Fuel shop is the best place, nearly all are Delphi diesel dealers, FP905 is what your looking for.

I got the lift pump relay jumped, just like Bowtie's, and also found the big Aux A was blown. I think it was Aux A, either that or Aux B, it was the top left BIG fuse.


I made sure the lift pump was running after I turned the key and before I turned the engine over. It was, so I fired her up. Fuel line pressure at the thermostat petcock was now 5psi. Unhooked the pressure gage and took her for a ride. Ran flawlessly for 15 miles or so, till I was back home and tried to shut her off. I turned the key off, but the engine kept running. Talk about a funny feeling!


I jumped under the hood and pulled the jumper wire and it died immediately. I figured this was odd, so I hooked the jumper back up and started it again, and again it wouldn't shut off. Hooked the jumper up to another fuse hot with ignition, and it did the same thing.


What the heck?


At least the "hickup" or cutting out is gone for the moment.

hum did you replace that fuse and what is connect to the aux post of that fuse. sorry to ask but just checking to see if maybe some got connected wrong or something

It was the AUX B fuse that I found blown. Nothing is connected to Auxilary post B, so I suppose it just accidentally got bumped and grounded out with a wrench or something.


I connected the add-a-circuit from pin 30 of the fuel pump relay to the fuel solenoid fuse (exactly like Bowtie's), and then to the ECM-I fuse. Engine wouldn't shut down connected to either fuse.Edited by: w_huisman

After further review I think mine is connected to the fuel sol Circuit breaker. maybe that has some thing to do with you truck not shuting down. Please try and post results as I am interested in why this is happening.

http://www.dieselplace.com/forum/uploads/bowtie/2004-10-07_220417_relay_bypass.jpg


After further review I think mine is connected to the fuel sol Circuit breaker. maybe that has some thing to do with you truck not shuting down. Please try and post results as I am interested in why this is happening.


Huh?


I can see from the above picture that you posted that mine is wired up EXACTLY the same way yours is.... from pin 30 of the fuel pump relay to the 20A fuel solenoid fuse.


Does anybody know why my fuel solenoid fuse continues to provide power after the ignition is shut off with this OPS by-pass wired in? And my ECM-I fuse did it too.

could it possibly have something to do with the AUX B fuse you replaced? Maybe there's a short somewhere else in the system that caused that one to blow.....I have seen weirder things....


my old 90 blazer wouldnt shutoff, I finally traced it to a short in the instrument cluster, unplugged one of the back lights and it worked normally!

The truck shuts off normally with the stock fuel pump relay in place. But when I put the jumper in place of the relay, just like the picture above, it won't shut off no matter which "hot with ignition" fuse I tie it to. So the problem is that the lift pump isn't shutting off with the ignition. A "switch" someplace isn't killing power to the ignition-only fuses on the fuse board.


Might have to try QM's OPS by-pass method of splicing into the gray wire going into the OPS instead. I'll see if I can dig up the specifics on that.


(BTW: TDG- Can you double check that lift pump PN for me? A lot of web sites say the FP921 is the model I need, not the FP905.)Edited by: w_huisman

HowieE has a wiring schematic on his website. It is not hard and no ignition wires to jump off of.

HowieE has a wiring schematic on his website. It is not hard and no ignition wires to jump off of.


http://mysite.verizon.net/vze54tx9/sitebuildercontent/sitebuilderpictures/ops.jpg


yeah, but now I gotta go find a darn relay, and they wont have them in town either. What PITA!

There's gotta be a reason why the ignition circuit is still providing power after I turn the key off with Bowtie's OPS jumper in place.


There's a couple of electrical goo-roos (engineers?) on this forum (biampala, mdhorban, etc...). Maybe you guys have an idea?

All the electrical is tied together. Isolate the Ignition circuits with relays the same as the OPS. This will seperate the load.

All the electrical is tied together. Isolate the Ignition circuits with relays the same as the OPS. This will seperate the load.


While it's true all electical start at the same place, the switch is suppose to seperate it when turned off. My doesn't keep running so his shouldn't either. He has some other problem there, unknown at this time, thats is keeping the fuel shutoff valve powered up though the lift pump. I don't know where that valve pulls power from but it might have something to do with that blown fuse.


When you replace it does it blow again or the ither Max fuse under there still good.

I can see from the above picture that you posted that mine is wired up EXACTLY the same way yours is.... from pin 30 of the fuel pump relay to the 20A fuel solenoid fuse.


Does anybody know why my fuel solenoid fuse continues to provide power after the ignition is shut off with this OPS by-pass wired in? And my ECM-I fuse did it too.






Looking at my wiring diagram the the engine shutoff solenoid and the Fuel Solenoid Driver (PMD) are wired off the same power source. so remove the add-a-circuit and run a jumper (just for this test) from the battery OR another hot source to the 30 pin of the fuel pump relay and start the truck then see if it will shut down. ALSO while you have the add-a-circuit removed turn the key to the run position and see if you have power at the fuel solenoid fuse and if it shuts down when you turn key off. Also when in the run position but with out the fuel pump relay in place use a test light to see if you have power backtracking to the number 30 pin, other word see if maybe someone else bypassed the ops with another hot wire before you bought the truck. These are kind of what I would do in looking for the problem just to see wht to fix.

HowieE has a wiring schematic on his website. It is not hard and no ignition wires to jump off of.


http://mysite.verizon.net/vze54tx9/sitebuildercontent/sitebuilderpictures/ops.jpg


yeah, but now I gotta go find a darn relay, and they wont have them in town either. What PITA! YEA and you still got to replace the OPS which is a PITA and the reason I looked for another way around doing that.

Both the Aux fuses (A & B) are fine.


I don't think finding the Aux B max fuse being blown out has any connection to why my lift pump won't shut off. I'm pretty sure I simply bumped the Aux B post with a wrench when I installed a brake controller a while back.


Nothing else runs off those Aux fuses, except for whatever is connected to the adjacent Aux post, right?Edited by: w_huisman

What if the lift pump is still getting power from the OPS? Couldn't it go back up the grey wire at shut down and power the fuel shutoff through that jumper he installed. The OPS will stay powered through the OPS till engine shuts down, It's not an IGN. controled circuit.

Looking at this wiring diagram the fuel pump relay is tiggered by the Crank 10A fuse circuit that I believe come thru the OPS, it doesn't show that part, but the work load of the lift pump comes for the ECM-B fused circuit. It provides power to the L/P when the relay is closed. Kind of looks like this


http://www.dieselplace.com/forum/uploads/bowtie/2004-10-12_093400_Wiring3a.JPG

yes it could if that but where the ops getting its power from ? Thats why I mention doing some checks in the earlier post. something has to be amiss somewhere, or is my truck wrong.Edited by: bowtie

What if the lift pump is still getting power from the OPS? Couldn't it go back up the grey wire at shut down and power the fuel shutoff through that jumper he installed. The OPS will stay powered through the OPS till engine shuts down, It's not an IGN. controled circuit.


The way I understand the wiring diagram I looking at, The OPS closes the fuel pump relay, allowing power to the pump. Am I missing something here this diagram does not even show an OPS in the picture.

The ECM triggers the LP during the glows through the LP relay. Once the engine starts and builds oil pressure the LP i powered by the OPS directly no relay.

So the LP relay does nothing after the engine is running? Then the only thing Bowtie's jumper wire mod does is jump the lift pump when the key is first turned on, and after the engine starts power to the LP still goes thru the OPS?


Here's the results from the tests Bowtie told me to run...


remove the add-a-circuit and run a jumper (just for this test) from the battery OR another hot source to the 30 pin of the fuel pump relay and start the truck then see if it will shut down.


truck runs and shuts off as normal.





ALSO while you have the add-a-circuit removed turn the key to the run position and see if you have power at the fuel solenoid fuse and if it shuts down when you turn key off.


No power at fuse before startup. Power while key is on. No power after I turn the key off again.





Also when in the run position but with out the fuel pump relay in place use a test light to see if you have power backtracking to the number 30 pin,


No power to the 30 pin with key on, but there is power to the 87 pin.Edited by: w_huisman

The ECM triggers the LP during the glows through the LP relay. Once the engine starts and builds oil pressure the LP i powered by the OPS directly no relay.


Show me that in a wiring diagram and I'll agree. I believe the L/P runs thru the relay all the time just from different power supplies. The ecm before start and the OPS after maybe.

So the LP relay does nothing after the engine is running? Then the only thing Bowtie's jumper wire mod does is jump the lift pump when the key is first turned on, and after the engine starts power to the LP still goes thru the OPS?


Here's the results from the tests Bowtie told me to run...


remove the add-a-circuit and run a jumper (just for this test) from the battery OR another hot source to the 30 pin of the fuel pump relay and start the truck then see if it will shut down.


truck runs and shuts off as normal.


ok then find another power supply even if you have to extend the wire end. This gets the truck running again while you look for the other problem.


ALSO while you have the add-a-circuit removed turn the key to the run position and see if you have power at the fuel solenoid fuse and if it shuts down when you turn key off.


No power at fuse before startup. Power while key is on. No power after I turn the key off again.


Cool this tells me that the Lift Pump is providing a ground to something else or another relay that keeps everything poweed up.


Also when in the run position but with out the fuel pump relay in place use a test light to see if you have power backtracking to the number 30 pin,


No power to the 30 pin with key on, but there is power to the 87 pin.


good this should indicate that there is no other power going to the L/P Edited by: bowtie

To get the truck running again, I threw the LP relay back in and removed the add-a-circuit. Back to square one. Guess I could just run a fused hotwire from pin 30 to one of the Aux posts, but I can't recall right now if they're powered with ignition on or powered all the time.


I'm probably a step behind you guys in understanding the flow of electricity here, but I have a blunt question I need answered...


Is QM saying that the power coming from pin 30 still goes thru the OPS after startup?Edited by: w_huisman

OPS is powered all the time by orange power wire from the fuse block switched on by the OPS sensing pressure. Fuel pump relay powered by the same orange wire switched by ECM. Both circuits when swiched, power a grey wire that goes to the LP. same wire. If you have power at both ends of that wire it will go back up the Ign circuit and power it with the key off.


On my '94 this is how it works. Other trucks could be different.

well the diagram I'm looking at the orange wire comes FROM the fuse to power the ECM with another wire going from that wire to the relay. It also shows wire going from crank fuse to power the relay marked as hot in start. a black/white wire going to ground. red going to fuel pump prime and gray going to the fuel pump. that may be the same gray wire that runs thru the OPS to the fuel pump, not sure right now.

one diffenence between 94 and 95 is that your orange wire gets power thru a fuseable link and 95 gets it from the ECM-B fuse. I still haven't made it to the dealer to look at their wiring diagrams to see if it is different from mine.

The truck died twice on the way home from work this afternoon (less than a mile!) running with the fuel pump relay in place. It wasn't doing that before! It died like someone turned off a switch and fired right back up again like nothing ever happened.


Once I got home I ran the add-a-circuit from the fuse box in the cab, and the engine shuts off just fine now. Took it for a 10 mile ride and it ran like a top.


If I unplug the OPS and the engine still starts and runs OK, does that prove that the lift pump is now running on the add-a-circuit?Edited by: w_huisman

I just went out to the truck, unplugged the OPS, and the truck fired right up and idled perfectly (except of course the oil pressure gage didn't work).


This proves that the lift pump, powered from the add-a-circuit, will run the engine just fine. Now if there was only a way to tell whether the lift pump is getting it's power from the OPS or from the add-a-circuit now that I have the OPS plugged back in again.


And I still wonder why the darn thing wouldn't shut off when I had the add-a-circuit plugged into the under-hood fuse box.

OPS is powered all the time by orange power wire from the fuse block switched on by the OPS sensing pressure. Fuel pump relay powered by the same orange wire switched by ECM. Both circuits when swiched, power a grey wire that goes to the LP. same wire. If you have power at both ends of that wire it will go back up the Ign circuit and power it with the key off.


If I cut the gray wire, then is it guaranteed that the LP is being powered by the add-a-circuit?

affirmative. The OPS won't power the LP if you cut the grey wire at the OPS connector.

What if I DON'T cut the gray wire at the OPS plug. Is the LP being powered by the add-a-circuit or the OPS?


My guess, based on what I've heard here, is that the LP is being powered by the OPS. But if the OPS fails, as it typically does, will the add-a-circuit kick in and power the LP without me even realizing it?

Wade, the FP905 is the correct lift pump rated for 10-14psi used on all electronic 6.5s.

Thanks TDG. I'm gonna get one ordered asap.

Wade, the FP905 is the correct lift pump rated for 10-14psi used on all electronic 6.5s.


What brand pump is that TDG ?

IIRC he said Delphi

Ok QM I got a dealer wiring diagram here in front of me and from the ECM-b fuse an Orange wire goes to the OPS, the Fuel Pump Relay, and the PCM. The Relay is tripped by powe from the crank fuse, that allows the relay to complete the circuit to the lift pump. It looks lke the relay is relaxed when not in the crank mode. the gray wire from the OPS and a gray wire from the relay connect to go to the fuel pump. I still haven't figured out why his truck keeps running but it sounds like it don't matter anyway anymore, he's going a differdnt way now I guess.

Thanks QM but I didn't see Deldhi in his response and still don't. ALso What is IIRC anyway

Any of you guys ever hear of Blue Ridge Diesel out of Salem, VA? Cheapest LP (Delphi FP905) price I could find.


IIRC = If I Remember CorrectlyEdited by: w_huisman

Thanks i was making sure I was reading correctly. How much for the pump?

found them searching for 6.5L parts. They have $84 vacuum pumps too.


Bow, on page one of this post, tdg's last post mentions delphi dealers and the part# . I just extrapolated that it was a delphi.

You got a webpage link to them


Sorry I forgot what happen on the first page LOL


Thanks

This morning I think I've confirmed my suspicion.


I fired the truck up and went to work (less than a mile). It was cold (32F) outside. Both the add-a-circuit (OPS jumper) and the OPS were plugged in.


When i got to work and shut the truck down, I could still hear the lift pump running for a couple of seconds, as usual (before the add-a-circuit was installed), until the cold thick oil dropped pressure.


This proves that the LP still runs thru the OPS with the add-a-circuit installed. Any arguments?


I may just have to cut that gray OPS wire. Good chance that doing so would get teh truck to shut down when I turn the key off with the add-a-circuit hooked up in the underhood fuse box. One less wire running into the cab.


New Delphi pump is ordered and on it's way. Should have it in a week or so.Edited by: w_huisman

Where did you order your lift pump and how much $ ?

This proves that the LP still runs thru the OPS with the add-a-circuit installed. Any arguments?


I was kinda hoping for someone to tell me whether I'm right or not.http://www.dieselplace.com/forum/smileys/smiley5.gif

Your right, your have not replaced the original circuit, only added an additional one, so either one being in place and operational will run the LP.


and YES, that was DELPHI PF905.

I unplugged the OPS and put the add-a-circuit back in the fuse box under the hood. What do ya know? She shuts down now when I turn the key off!


I decided to run with the OPS unplugged because my original problem, the "hickup", reoccured on the way home the other day when both the OPS and the add-a-circuit were hooked up. After unplugging the OPS I thought "Now I wonder if she'd shut down when I turn the key off with the add-a-circuit in the underhood fuse box." I pulled the line outta the fuse box in the cab, plugged it back into the underhood fuse box, and now with the OPS unplugged and the add-a-circuit under the hood it actually shuts down when I turn the key off. Amazing.http://www.dieselplace.com/forum/smileys/smiley24.gif


I took it for a 13mile ride this morning, now with the OPS unplugged and the add-a-circuit in the fuse box under the hood, and no hickup. I'm going to run it this way for a few hundred miles and see if the hickup is gone for good. The new Delphi LP should be here by the end of next week or so too. Maybe by then, if the hickup doesn't resurface, I snip the gray OPS wire and plug it back in so I can have my oil pressure gage again. I don't like snipping the factory wiring though.

The hickup is back. OPS unplugged, running the lift pump thru the OPS jumper (add-a-circuit).


When I'm driving down the highway, it's like someone turns the key off for a second, and then turns it back on. Engine was at about 185 degrees, about 10 miles into a 14 mile trip. At first, a couple of weeks ago, the hickup only seemed to happen before the truck was up to operating temp. Guess that's not the case anymore.


I've got that new lift pump coming towards the end of this week, but I'll be suprised if that solves the problem. Maybe I should run a hot wire directly down to the LP just to completely rule out the LP or the circuit that's powering it.


Edited by: w_huisman

I've been having a little trouble with mine lately. It get's air in the fuel filter housing and if I don't bleed it out after a few hundred miles it will start causing the engine to miss and eventually stall. I just bleed it and it starts right back up. Edited by: quantum mechanic

I've been having a little trouble with mine lately. It get's air in the fuel filter housing and if I don't bleed it out after a few hundred miles it will start causing the engine to miss and eventually stall. I just bleed it and it starts right back up.


I wish mine was that simple. Does it throw any codes when that happens to you? I still get nothing from my SES light. No codes.


The way it's acting, like someone flipping an on/off switch, I think it's gotta be an electrical problem.


Can you PM me instructions on how/what you built your PMD extention harness? At this point I'm thinking I'll end up buying a new PMD. What else could cause my symptoms and not throw a code?

Well, since it has to energize the F sol from 3.5' or more away, you should use 18awg and perhaps 16 awg wire to lessen resistance from the wire itself. It takes 6 equal length wires, a wireloom, sodering kit and some wire pliers. take it a wire at a time so you don't get lost.


Pretty basic really.

Thanks QM.


On the way home from work this afternoon (less than 1/2 mile) the truck died about a half a dozen times. Shuts off like like someone flipping a switch. I put it in neutral, turn over the key, and she fires right up again like nothing happened.


The truck was stone cold. 50 degrees outside and the truck hadn't run in 5 hours. I made it a 1/2 a block before it died the first time, and it died about 5 more times before I made it home. NO CODES.


Went to the dealership and ordered a new braided ground cable for the back of the engine block ($11). And I'm just about to head outside and start looking under the hood for other possible suspects. It's gotta be a wire somewhere, don't you think?


Any ideas?Edited by: w_huisman

Sounds like PMD to me, notorious for doing what you descibe and not setting any codes.

I tried taking the truck across town the other night and it cut out and died every half a block or so. So it's gotten to the point where I can't hardly drive it anymore.


After that frusterating trip to the hardware store I checked the tightness of the PMD mounting screws. They seemed pretty loose to me. I tightened up the two screws I could reach at least one-and-a-half turns if not two! Took her for a ride afterwards and I put on 15 miles with only one little hickup, but it didn't shut down. Quite an improvement.


Tonight I'm gonna get the new FP905 lift pump installed and make a little torx tool for tightening up the other PMD screws and get them tightened. If it works, hopefully it'll buy me a little more time with this PMD while I work on getting another one mounted to a heat sink in front of the radiator.


BTW: Can anyone tell me what size the four bolts are on the flange between the downpipe and the cat? Thanks!Edited by: w_huisman

I'm just now catching up to all of this Wade, and just posted to the other place where you asked the question. When you said that you tightened up the mounting screws to the PMD, are you talking about the four allen screws to the pump, or are you talking about the nuts on the transitors on the back of the PMD?

I'm talking about the four allen screws that mount the pmd to the pump. It's definitely helped since last week's 1/2-a-block-at-a-time episode. I don't think I want to try tightening up the transistor nuts. I don't want to go thru the effort of removing the pmd from the pump if I don't have to.


New lift pump didn't make a difference with the hickup/stalling, but I've got just over 6psi at the thermostat petcock at idle now.


Also installed a Flowmaster 3" downpipe this weekend. Spent most of Saturday afternoon working on it, and then a little more time Sunday morning trying to cure an exhaust rattle. There's no more rattle, and that new pipe seems to let that turbo sing just a little louder.


A pmd, heat transfer pad, and wiring harness are on the way, but it'll likely be next week. Hopefully I can round up a heat sink by then. I plan to make my own extended pmd wiring harness and mount that thing up in front of the radiator.


Tonight I gotta make a 70 mile round trip to go pick up a bombey, which is wife-talk for expensive lamp stand. I got my fingers crossed.Edited by: w_huisman

I had the same symptoms and resisited the idea that it was the PMD since it was new just weeks before I bought the truck, also that it is so hard to get to. I figured somebody blamed the PMD since it is the most commonly blamed suspect for those symptoms and that the problem was not yet cured so I figured I better look elsewhere. After months of fiddling around with everything else I finally broke down and replaced the PMD and it hasn't missed a beat since.

I had the same symptoms and resisited the idea that it was the PMD since it was new just weeks before I bought the truck, also that it is so hard to get to. I figured somebody blamed the PMD since it is the most commonly blamed suspect for those symptoms and that the problem was not yet cured so I figured I better look elsewhere. After months of fiddling around with everything else I finally broke down and replaced the PMD and it hasn't missed a beat since.


Good.http://www.dieselplace.com/forum/smileys/smiley32.gif I like to hear that. Reassures me that I'm on the right track.http://www.dieselplace.com/forum/smileys/hihi.gif

Updates?


How did tightening the 4 screws work for ya? Have you replaced the whole PMD yet?

Earlier this week I installed my home-made pmd extension harness (had to pull the intake off to connect the harness to the IP, quite the PITA) and ran it up in front of the radiator. The last idiot used some gasket goop on the lower intake that was another PITA to get off, but with the intake out of the way I easily removed the pmd from my IP. When I lifted the pmd off of the IP, one of the transistor caps fell right off and a couple of the transistor nuts seemed pretty loose. I retorqued them all and threw it in the glove box for a spare.


I cut a 6"x8" hunk of aluminum from some scrap and made a temporary pmd cooler out of it. I attached a pmd that came on a used IP I bought from Ebay to tinker with, and mounted this pmd/heatsink on the tranny cooler brackets.


The truck is running, but this pmd has a hickup in it too. I have a Kennedy heat sink coming. Should be here today or tomorrow. I also have a good pmd coming from Texas Diesel Guy (Travis) that hopefully will also be here today or tomorrow. This weekend I hope to get Travis's pmd mounted to the Kennedy heat sink and get it put in the truck and make this problem go away for good.


I'm still kicking around the idea of buying a brand new pmd from the dealer here. He quoted me $225, which isn't much more than you'd pay for one on Ebay when you figure shipping. I'd throw it in the glovebox for a rainy day.Edited by: w_huisman

What do you mean a hiccup?


I noticed when I changed my PMD/FSD that it now has a slight random clatter of advanced timing just off idle. I was going to ask TDG if that is possible, I mean is it possible that it could be the FSD.

By "hickup", I mean the truck will randomly die like someone flipped a switch, or else it'll miss. Most likely the miss is the same as it dying, except it's so short in duration that the truck keeps running.


Seems to happen more when the truck is cold. After it's up to running temp it seems to run down the road pretty well.


Still don't trust it much more than a few miles out of town.

hmmm ours right now is doing that but only when warm....lol Never cuts out, just acts like one of the cylinders failed to fire. Does it at idle after full warm up only. Once about every 30 seconds or so I havent located a fuel pressure gauge for somewhat cheap yet, but the lift pump is workin and fills up stuff FAST when I bleed the system... New fuel filter too, so I think we are in the same boat....

My bad FSD most often caused it to stall when cold.

Thanks Bob. It's good to be reassured I'm on the right track. Hopefully today I'll get the new FSD and heatsink installed and the stalling will go away.

One thing I should mention since it points my problem directly at a computer/electrical issue...


When the truck dies while driving, if I shift into neutral and try to restart, it will turn over but won't fire. But she'll fire right up if I momentarily turn the key off and back on again before turning it over.


Guess the pmd/computer needs a reboot.

Intermittent ground or shorting out an ECM harness wire to ?. A fuel supply problem wouldn't require you to turn the key off firstto restart.

Well, I guess we'll find out now. I got my parts from HowieE and TDG (thanks guys!) today, so hopefully I'll get this stuff on the truck tonight. If it's still cutting out afterwards, I'll start looking for a shorted wire (man, I hope not!)

I got Texas Diesel Guy's pmd mounted on HowieE's Kennedy cooler, and the truck runs smooth as ever. 30 miles without a glitch.


I ended up mounting the cooler/pmd on the upper intake bolts, per Kennedy's instructions. I just don't have the materials here at home to fab up brackets to mount it in front of the radiator. I'll have to do that when I get out to the farm shop again. Maybe tomorrow.


If the truck continues to run without problems, I think I might buy a brand new pmd and use the one from TDG as a spare.


Thanks everyone for all your help. When I get the cooler/pmd mounted up front of the radiator, I'll try to remember to post a pic.Edited by: w_huisman

It really makes me glad to have members offer to help me with parts and it's good to see I'm not the only one.

I think I found a permanent home for my pmd/kennedy cooler this morning.... inside the front bumper.


http://www.dieselplace.com/forum/uploads/whuisman/2004-11-07_104800_PICT0002a.jpg


http://www.dieselplace.com/forum/uploads/whuisman/2004-11-07_104902_PICT0003a.jpg


http://www.dieselplace.com/forum/uploads/whuisman/2004-11-07_105013_PICT0004a.jpg


http://www.dieselplace.com/forum/uploads/whuisman/2004-11-07_105057_PICT0006a.jpg


And after the front end is put back together... a peek inside the passenger side bumper hole....


http://www.dieselplace.com/forum/uploads/whuisman/2004-11-07_105214_PICT0007a.jpg


So what do you think? Pros and cons of this location? I just can't find a place between the grill and the radiator that has enough room for this cooler/pmd.Edited by: w_huisman

Wade, good to hear the PMD finally made it there and works!

My only concern with this mounting location is the potential for thermal shock if the PMD gets hit with splash water or slush thrown up from the road. From my limited experience, these babies get mighty hot (250 deg+) in a matter of seconds. I'd be concerned with stressing the junctions on the internal Darlington circuit if it gets quenched too quickly. On the other hand, I haven't cut a PMD apart yet...and if it's fully potted (electronics seated with fully poured-in compound), quenching will probably not be an issue.


Thanks,


Jim

Thermal shock...


Good point. But in avoidance of that, it's behind the center of the front bumper, so it won't get any spray directly from the road ahead. It'll have to deflect off of the black air deflector inside the bumper nostril first. And after a 70 mile one-way trip last night and after a 45 mile one-way trip today both the pmd and the cooler were cool to the touch. Of course that wasn't pulling any load, which I don't do a lot of anyway.


My main concern is ice build-up in the winter, especially after going to the car wash. But as you can see, the pmd isn't directly in the path of any stream from the car wash wand, unless I really try to aim at the pmd up the bumper holes. And maybe the heat from the engine will keep the ice from building up there.


Edited by: w_huisman

yeah, ice formations will definitely void your warranty. http://www.dieselplace.com/forum/smileys/smiley2.gif

Smart a$$.


(Thanks again, Travis!)

You know, for all the guys that complain about the OEM placement of the driver on the pump, its a good thing you guys don't own PowerJokes, you think GM was on glue, Ford stuck the IDMs inside the wheelwell right behind the front left tire, perfectly placed to get soaked and hit with rocks, not to mention pretty tough to get at.

Did you ever test out the old PMD with tightened up nuts on the transistors? That may be the only problem with the old one. I bought a spare PMD for the Mrs. of the house, just for peace of mind because I bar-b-qued the first one.

After I pulled my old pmd I retorqued the transistor nuts (two were pretty loose, IIRC) but never tested it. As of now, it's sitting in my glove box marked "original".