ok so Ive been working on this 6.5 for a friend...1999 Suburban 2500.

He said it did the standard stall/shut off randomly while driving PMD thing. So he replaced it with a remote mount PMD from Accurate Diesel (I think???). Ran that for a little while, then it stalled a couple more times and wouldnt restart. He was going to take it to the junk yard but I said I would take a look at it.

My couple questions are (Ive searched, but a billion things turn up, and I havent found a cut and dry answer):

How can you diagnose a bad IP from a bad PMD? Going through SI (factory service manual), its pointing me towards a bad IP. But seeing as the DS4's really dont fail that often (9 times out of 10 it being a bad PMD), I find it hard to believe the pump is bad. But yet Im "sort of" ruling out a bad PMD because it has a new remote mount PMD.

The other question is, where does the ground go on the pump? The remote mount PMD kit put the ground wire to the remote PMD heatsink...everything ive read says it should still stay attached to the pump. Any of those torx screws on top of the pump ok??

heres the 'check list'. this thing is a little different than working on duramax's like im used to...



1. Describe the problem you are having in detail: Wont start...at all!

2. Year of truck/engine. 1999 Suburban 2500 6.5 "F"
3. Odometer reading (indicate miles or kilometers). 140,000 miles
4. Indicate the model number on the Injection pump (starts DS4 or DB2......). DS4, cant read the rest of the numbers without pulling the whole intake off.
5. Indicate if you know if it’s a 1500, 2500, 2500HD, 3500, 3500HD. 2500
6. Do you have an EGR on the engine? (An F or an S engine code 8th VIN digit) no EGR...its an F engine
7. Air Filter condition (visual check). Fine
8. Fuel filter condition (freshly changed, mileage since changed). Fine
9. Location of PMD/FSD (http://www.dieselplace.com/forum/showthread.php?t=39436)? (ex. on pump/remote over intake, behind bumper).Remote, over the intake
9a. If remote mounted, describe wiring harness (homemade or purchased from which vendor). I think its accurate diesel?? The sticker is rubbed off, picture attached
9b. Indicate the location and condition of the FSD/IP grounding wire. On the remote PMD heatsink, but I also tried putting it back on the pump
10. Outside Temperature (C or F). _____ ° room temp...

11. Service Engine Light while running?- on/off/intermittent no DTC's current or in history
11a. Service Engine light does glow during start/cranking/bulb check: Yes/No yep
12.Have you scanned for engine codes? Yes/No yep
12a. List exact results on engine codes (http://www.dieselplace.com/forum/dtc.php). none

13. Condition of Battery terminals (removed, cleaned and tightened). cleaned/replaced/tight
14. Known condition and age of Batteries. fine
14a. Are batteries a matched set of same age? yep
15. Condition of Major Grounds (http://www.dieselplace.com/forum/showthread.php?t=157085) (removed, cleaned and tightened) checked; cleaned; tightened

16. Does engine crank, or "turn over"? yep
16a. Does engine start and run? nope
17. If engine does not start- Crack injector line (http://www.dieselplace.com/forum/showthread.php?p=2188140#post2188140): do you have fuel? Yes/No nope
18. Does your Wait To Start light come on? yep, normal
18a.Number of seconds WTS light is lit. I dunno, 5 seconds maybe?
19. Engine Cranking speed (if you have an accurate tachometer). 180rpm according to the Tech 2

20. Are you experiencing Stalling? Doesnt even start
20a. Describe the event (upon startup only, down the road, hit a bump, etc...)
20b. Do you notice loss of dash or instruments?
21. Check turbo inlet and air filter for obstructions.
22. In a no-hot start, pour a bottle of room-temp water on the injection pump. Does it start now?
23. Lift pump test (http://dieselplace.com/forum/showthread.php?t=39350) - Describe results. Lift pump works fine; with the key on I have fuel coming out of the filter assy and the t-valve bleeder thing near the alternator

24. Upon cold start, does the radiator hose get hard quickly? Yes/No
25. Upon cold start, do you have excessive white smoke? Yes/No
26. Do you have excessive cranking time before the engine starts? Yes/No
27. Have you used the block heater? Does it affect engine starting? (only try for starting problems).
28. Are all glow plugs in proper working order (http://www.dieselplace.com/forum/showthread.php?t=39182)? Yep, tech 2 confirms this

29. During hard acceleration, do you have excessive black smoke? Yes/No
30. Do you have any unusual exhaust smoke issues?
31. Turbo check out (http://dieselplace.com/forum/showthread.php?t=39368) - Pass/Fail its fine
32. Indicate fuel that you are using: Bio-Diesel, #2 Diesel, SVO/WVO, other
32a. If running Veggie Oil fuel setup, indicate details of your conversion (homemade or packaged system).
33. Are you using any fuel additives? If so, please list.
34. Upon unscrewing fuel cap, do you have a large vacuum formed in the tank? Yes/No Nope
35. Do you have any service history available that might pertain to the problem you are having?
36. Please indicate any modifications to the vehicle that might help us diagnose better.

I have a Tech 2, what other advanced diagnostics can I do with it that would better diagnose it than just "old fashioned" testing/diagnosing??

I think I read somewhere to check the "C time" when cranking??? Tech 2 says its 0.00ms?

Im in CT, Stanadyne is in windsor, not too far from me, if I take the PMD to them can they test it any way?

thanks
ben

That torx screw on top of the IP is where the ground suppose to go, it is not there just for the sake of being there.

PMD on intake is actually much worst than the stock location.

Sign of IP going bad, is usually followed by SES. If there is no SES, then chances are PMD is bad.

First thing though, check all the grounds and electrical connectors a FEW times. Makes sure there are nothing loose. Also, check the battery, starter, alternator. I could not tell you how many times we tell people about this, a month later, they come back to say "there is loose connector at .....". After a whole month of wild goose chase.

That torx screw on top of the IP is where the ground suppose to go, it is not there just for the sake of being there.

ok yeah, I tried moving it back there, still wont start

PMD on intake is actually much worst than the stock location.

ah ok, ive been reading that...interesting. Why would accurate diesel do this I wonder? So maybe replace it with a Heath remote kit and new PMD??

Sign of IP going bad, is usually followed by SES. If there is no SES, then chances are PMD is bad.

ok good! I cleared the codes, cranked it a bunch, and the only one that comes back is the MAP sensor code (because its unplugged w/ the intake off).

I guess the PMD is bad then...

The suburban doesnt have a factory bumper; its an aftermarket HD winch bumper; so I guess Ill find some other place to remote mount the new PMD.

ben

oh, and when I unplugged the Accurate Diesel PMD, I noticed there was no resistor in the PMD under the plug??? Would that mess anything up? I mean, I know it wont run correctly, but would that cause a no-start condition?

the resistor is to fix tolerance issues in the manufacture of the IP

just get a relocate exstension harness and re use the heat sink and mount it out of the engine bay. in his case behind the grill

the resistor is to fix tolerance issues in the manufacture of the IP

Yeah I know what the resistor is for, Im just wondering if NO resistor at all would cause a no-start issue. Everything ive read says no, it will still start without a resistor in place.

just get a relocate exstension harness and re use the heat sink and mount it out of the engine bay. in his case behind the grill

ok so just re-use the Accurate diesel heatsink, and make an extension harness?

Ill still need to get a new PMD regardless; probably a stupid newb question, but where is the cheapest place to get one with a decent warranty?

Thats why im wondering if its worth while to get the Heath one...comes with the long harness, a new heatsink, and a 7 year warranty...for like 500 bucks??

ben

Have read that ObdI,s would default to a number 5 or maybe 1 ,if no resistor , & that ObdII,s after 50 starts or so would do a relearn & if no resistor discovered may not allow engine to start .

You won't find a warranty anywhere else like Heaths. Not sure how the competitors warranties compare though, probably most are a year... And I've had my PMD on my intake with the ground on the heatsink for over three years and no problems so far ;).

But Heath has the best warranty. If you want a cheaper way you can just buy a new pmd, an extension harness, and relocate your heatsink behind the bumper or anywhere out of the engine bay.

I had that heatsink mounted on the intake, seems like I went through a PMD every 2 years. I recently relocated it behind the bumper, using that very same Accurate heatsink. Sounds like behind the grille, but in front of the condenser sounds like the best place to mount it on this Sub. Ben, you're good at fabricating, save some dough and only buy the PMD, #9 resistor, and extension cable from Heath. Surely, you can find a way to make that old heatsink fit.

I just put bolt holes on my bumper where the heatsink is fastened. I don't have stock bumper either, you can see it in my garage pix.

Yes, no resistor can cause no start condition since it is looking for one. Nobody knows when it is starting to look for resistor, so yes, get a resistor. Get a new PMD and extension, put it outside, you should be fine probably lasting longer than the truck will be.

ok played around with it more today...

The 'burban had been sitting for about a year prior to me working on it, so there were some critter homes under the intake manifold. I tried vacuuming them out but finally just said NO STOP BEING LAZY DO IT THE RIGHT WAY and took the intake manifold off. Its nice (pulling the intake manifold), being a 20 minute job rather than the 2 hour job it is on a duramax. :)

There were a good couple handfuls of acorns, insulation etc...stuffed under there that I pulled out.

Also found one glow plug completely disconnected...the plastic wire loom for the glow plug wiring somehow turned completely brittle (even tho all the other loom on the engine is still normal?) and 'shattered' when I tried to bend it/take it off.

Also was able to carefully fish the resistor out of the original [broken] PMD that was still bolted to the side of the IP, that was kinda a PITA. Turns out Its a #5. Maybe ill put a #9 in, and make it a real hot rod. :D

Ill have the new PMD on sunday, so hopefully Ill be able to fire it up then. Ill have to get new intake manifold gaskets though.

One other question, this is an "F" engine; no EGR...are there different intake manifold gaskets for "S" and "F" engines? The gaskets that were on the truck had holes in them for the (what I assume is) EGR ports on the heads? But the intake manifold obviously didnt have the EGR ports...I would think the gasket shouldnt have the hole for the port there if theres a non-EGR manifold on it??? no?

ben

Hey Ben,

The intake manifold gaskets are different for the "S" and "F" engines. The "S" engine has an opening for the EGR passage, and the "F" engine has a little metal block off plate. The upper intake Plenum is the same as far as i know. The intake of an "F" engine is not cast with the EGR passages in it so you can use either the "S" or "F" gaskets really. I have a non EGR intake on my blazer with EGR manifold gaskets.

On another note, how bad are the gaskets? I've reused the same set of lower intake gaskets about 4-5 times now on my blazer and i've had no issues. However that's a non turbo so with a turbo you may get a leak with the boost pressure.

Also on the PMD, don't fire the truck up with the PMD not attached to a heatsink. The fuel flow through the IP is the heatsink in the case of a factory location. You'll get about 3 minutes of life out of your new PMD before it starts smoking if it's not mounted to a heatsink.

ok cool thanks dave.

Ill check the dealer monday for the gaskets; Im sure I 'could' reuse them, but after 10 years and 140k miles I might as well replace them while the intake is off. Does anyone have the part number for both S and F gaskets? Obviously Ill look for F gaskets but if the dealer only has S gaskets in stock, ill just use those...

ben

ok cool thanks dave.

Ill check the dealer monday for the gaskets; Im sure I 'could' reuse them, but after 10 years and 140k miles I might as well replace them while the intake is off. Does anyone have the part number for both S and F gaskets? Obviously Ill look for F gaskets but if the dealer only has S gaskets in stock, ill just use those...

ben


Ben,

you don't have to go to the dealer for the gaskets, unless you get them cheap or free there that is. That's a different story. :D

I don't have any part numbers for the gaskets unfortunately. I"ll look around and see if i can find anything for you.

A nice bit of info you should be able to find with the intake off is the 3 digit block casting number on the valley "walls". There were several different blocks. It's more so for personal knowledge as the only major difference is the 506 block with the piston oil squirters and the HO oil pump factory.

Ben,

you don't have to go to the dealer for the gaskets, unless you get them cheap or free there that is. That's a different story. :D

I don't have any part numbers for the gaskets unfortunately. I"ll look around and see if i can find anything for you.

A nice bit of info you should be able to find with the intake off is the 3 digit block casting number on the valley "walls". There were several different blocks. It's more so for personal knowledge as the only major difference is the 506 block with the piston oil squirters and the HO oil pump factory.

Yeah In all my reading over the years ive picked up little snippets about the 6.5's here and there, one being the block casting #...I knew about the block casting number but never knew where it was...then I pulled the intake off and "oohhhh! so thats what they were talking about...!"

I remember theres 506, 599, something about an International block??

This particular 6.5 im working on has a 506 block.

Where else can you buy the gaskets? Advance Auto? These ones that I pulled off, I kinda kinked them and they're a little nasty. If it were my truck Id say whatever and throw them back on, but seeing as Im working on someone elses truck I want to do everything "EXTRA correctly". :)

ben

Yeah In all my reading over the years ive picked up little snippets about the 6.5's here and there, one being the block casting #...I knew about the block casting number but never knew where it was...then I pulled the intake off and "oohhhh! so thats what they were talking about...!"

I remember theres 506, 599, something about an International block??

This particular 6.5 im working on has a 506 block.

Where else can you buy the gaskets? Advance Auto? These ones that I pulled off, I kinda kinked them and they're a little nasty. If it were my truck Id say whatever and throw them back on, but seeing as Im working on someone elses truck I want to do everything "EXTRA correctly". :)

ben

The other blocks i know of that you haven't mentioned are the 141 and the 929.

The Navistar block is a 506 block, but the way you can tell you have one is look in the valley and look for the navistar diamond logo in the valley.

I can't find a photo of the logo at the moment but i'm still hunting.


Advance auto, autozone, etc. Pick your poison when it comes to those stores. They can all get you the gaskets, but sometimes the headache they can also give you free of charge isn't worth it.

If you've got a decent Napa near you go for them. If there's any mom and pop run parts stores around you, go there. They'll work with you the best. I've found that out with a place called "Shelton Quality Auto Parts" down here. They can get pretty much anything in a few hours and at most a day.

Duro the intake gaskets for my van were 37 bucks at napa ( fel pro's ) but they werent in stock so i had to go to the stealership 73 bucks !!

since that burban had a rats nest in it i would check all the wiring inside the engine bay it could be as simple and a chewed wire them effing critters like to chew

after you get her fired up a good stiff mix of powerservice will help clean the crud out of her... run it like you stole it

The other blocks i know of that you haven't mentioned are the 141 and the 929.

The Navistar block is a 506 block, but the way you can tell you have one is look in the valley and look for the navistar diamond logo in the valley.

I can't find a photo of the logo at the moment but i'm still hunting.


Advance auto, autozone, etc. Pick your poison when it comes to those stores. They can all get you the gaskets, but sometimes the headache they can also give you free of charge isn't worth it.

If you've got a decent Napa near you go for them. If there's any mom and pop run parts stores around you, go there. They'll work with you the best. I've found that out with a place called "Shelton Quality Auto Parts" down here. They can get pretty much anything in a few hours and at most a day.

Awesome thanks for the help Dave. I didnt know if Advance Auto could get those things, thats nice; basically every dmax part is $tealer only. :rolleyes:

I actually got the new PMD tonight so Im going to try firing it up a little later on.

Ben

Duro the intake gaskets for my van were 37 bucks at napa ( fel pro's ) but they werent in stock so i had to go to the stealership 73 bucks !!

since that burban had a rats nest in it i would check all the wiring inside the engine bay it could be as simple and a chewed wire them effing critters like to chew

after you get her fired up a good stiff mix of powerservice will help clean the crud out of her... run it like you stole it

Yeah I checked all the wiring, there were no other codes and the Tech 2 said the ECM was happy with everything else so Im 99.99% sure its the PMD.

Thats not bad, I would have thought the gaskets (37 bucks) would be more expensive...that 37 bucks was for both right?

Ben

Yeah I checked all the wiring, there were no other codes and the Tech 2 said the ECM was happy with everything else so Im 99.99% sure its the PMD.

Thats not bad, I would have thought the gaskets (37 bucks) would be more expensive...that 37 bucks was for both right?

Ben

That's somewhat expensive really. I was pricing a set for the blazer, while it's a 6.2 it's the same gaskets and i saw them for ~$15 for the pair from felpro. Also comes with a new IP gasket. That's a triangle shaped gasket with a hole in each "corner" of the gasket. you don't have to replace that unless your doing the IP, or the current gasket is leaking.

I just checked. I only paid $13 for fel-pro intake manifold set from napa. #9 resister is a waste of money. Very little gain if any from it. It makes people feel good though. They can add another 30 or 40 hp with ricer math.

Just went to advance auto, they had it in stock! Like 16 bucks for both gaskets, as you said dave.

The guy whos Burban it is also had a spare PMD which he dropped off. I put it semi-back together with the new PMD and still doesnt start. No fuel at the injectors.

If I command the lift pump on (with the tech 2), engine not cranking, I get plenty of fuel going into the IP but not much coming out...is it supposed to be like that?

I pulled the oil filler tube and the IP nut/gear seems to be turning OK.

When I check the fuel solenoid closure time when cranking with the tech 2 it sometimes says 0.00ms then after a few seconds of cranking it will jump to 50 or so, then fluctuate around there. So I guess that means the PMD is working??? Commanded vs. desired injection timing is around 17* when cranking for both, commanded fuel rate is 10mm3. TDCO is like .53* I think? Ill have to double check. Its not over 1* tho. I tried unplugging the optic sensor and it still doesnt start.

The IP is original I think, or at least the MFG date on it is late 1998??

I just wish it was easier to diagnose the PMD's and IP's on these things. From what ive read its sort of "well...replace it and see if it works". Arrgh I hate these "hybrid" fuel-injection system diesels, the 94+ 6.5, 99-02 cummins, etc... complete mechanical injection on a diesel makes sense, and common rail makes sense...but these "sort of electronic, but not" diesel injection systems are annoying. :rolleyes:

If I remove the IP and take it (and the 'good' PMD) to Stanadyne (probably 40 minutes from me), can they test it for a not-ridiculous price before I replace the IP???

ben

Ben where in CT are you? I"m down in Shelton.

PM me if you want and i'll give you my cell number. Maybe i can help.

No sense pulling the IP if you don't have to.

If you haven't, check your ECM fuses as well. those can blow and cause a no start.

A few basic things to check.

When cranking do you see any white unburnt diesel from the tailpipe? If so then you've got fuel. If not well you know.

I agree. i like the ease of cold starts on my 96, but i'll take the full mech injection of the 6.2s any day.

Well, you need to be sure that the PMD you put in there is still good to eliminate it as a culprit.

As far as testing, call them ahead of time to check their pricing.

Well, you need to be sure that the PMD you put in there is still good to eliminate it as a culprit.

As far as testing, call them ahead of time to check their pricing.

I Agree. There's no real way to test a PMD. That's why GM's response was "its the Injection pumps fault" since the PMD never threw codes, but the failure acted like a dead IP.

Ben if your sure the PMD is good i'd move onto check wiring to the Fuel solenoid in the center of the injection lines. Also make sure the ground wire for the PMD is on one of the little torx bolts on the IP. That's very important.

Dave you have a PM

How much fuel should come out of the pump if I unhook the return line? Same pressure/flow that (appears to be) going in? Will the return rate/pressure from the pump be different if its cranking or not?

no unburnt diesel smell; its definitely not even getting fuel. There is no fuel at the injectors if I crack one open.

no unburnt diesel smell; its definitely not even getting fuel. There is no fuel at the injectors if I crack one open.

Sounds like a classic PMD problem. Could also be the fuel shutoff solenoid i suppose. You can pull that off and put power to it and see if it works. It's the long cylinder on the top of the pump. It's more of a redundant setup. If you cut power to the IP turning the key off the engine will die. The shut off solenoid really isn't needed like it is on the DB2 IPs.

Also PM returned Ben.

hmmm ok so I just played around with it a little more...pulled the ESO solenoid out, that works fine when 12v is applied. Put it back in, double checked everything, etc..

Cranked it and noticed on the tech 2 that the closure time on the fuel solenoid is ~2.0-2.5ms, which is what its supposed to be I think...before it was like 60-70ms. Cranked it again for a little while, and all of a sudden it stumbled a couple times and ran for about 2 seconds then stalled. Tried starting it again immediately after it stalled and now it just cranks and cranks like before. WTF!!!

So I guess because it ran for a second or two the IP can be considered good???

If you disconnect the return line off the IP and run the lift pump, how strong should the flow be out of there??

Does the case of the PMD have to be grounded? I just have the heatsink (with the PMD bolted to it) sort of dangling there, but the ground wire is tight on the IP.

Maybe this PMD is funky too??? I dont know........

ben

hmmm ok so I just played around with it a little more...pulled the ESO solenoid out, that works fine when 12v is applied. Put it back in, double checked everything, etc..

Cranked it and noticed on the tech 2 that the closure time on the fuel solenoid is ~2.0-2.5ms, which is what its supposed to be I think...before it was like 60-70ms. Cranked it again for a little while, and all of a sudden it stumbled a couple times and ran for about 2 seconds then stalled. Tried starting it again immediately after it stalled and now it just cranks and cranks like before. WTF!!!

So I guess because it ran for a second or two the IP can be considered good???

If you disconnect the return line off the IP and run the lift pump, how strong should the flow be out of there??

Does the case of the PMD have to be grounded? I just have the heatsink (with the PMD bolted to it) sort of dangling there, but the ground wire is tight on the IP.

Maybe this PMD is funky too??? I dont know........

ben


Since it coughed it could be air in the lines which is now causing it to not start where as before it could've been something else(PMD,ESO, etc).

They aren't that tough to bleed out. Crack the lines and crank it over for about 10 seconds, let the start cool for about 1 to 1 1/2 minutes then repeat.

That PMd could be funky but usually when i PMD is starting to go it's stalling when up to temp and hard starting when up to temp. Cold starts not so much, unless the PMD is totally fried.

well after a few more hours of messing with it, still nothing. I think the IP is bad. The Tech 2 shows the CTIME is ~2-3ms when cranking, so I think thats a pretty good indicator that the PMD is doing its job.

Also, I only get the slightest trickle of fuel from the return side of the pump. Shouldnt it be a steady stream? The lift pump has a steady stream of pressure going in...

hmmmm........

Could be the IP but i'd try a few other thigns that won't cost the owner first. Did you try unplugging the optic sensor on the top of the IP to see if it will run in "limp" mode.

Anything strange or out of spec on the tech II? This continues to point towards a bad IP but being the cheap-o that i am i do the free stuff first. ):h

If you do need an IP send me a PM. The guy i got my reman DB2 from gave me a very good price.

If you still want to test that PMD you have let me know.

hmmmm........

Could be the IP but i'd try a few other thigns that won't cost the owner first. Did you try unplugging the optic sensor on the top of the IP to see if it will run in "limp" mode.

Anything strange or out of spec on the tech II? This continues to point towards a bad IP but being the cheap-o that i am i do the free stuff first. ):h

If you do need an IP send me a PM. The guy i got my reman DB2 from gave me a very good price.

If you still want to test that PMD you have let me know.

Yeah I tried unplugging the optic sensor and cranking for a while...then plugged the optic sensor back in and tried unplugging the CKP sensor and cranking for a while...no change.

Im going to pull the IP off tomorrow and see what Stanadyne wants to test it, and if you are around Dave I might stop by.

ben

Yeah I tried unplugging the optic sensor and cranking for a while...then plugged the optic sensor back in and tried unplugging the CKP sensor and cranking for a while...no change.

Im going to pull the IP off tomorrow and see what Stanadyne wants to test it, and if you are around Dave I might stop by.

ben

Well i'm stumped Ben. :confused: In one hand i hope it's not the IP as they aren't cheap, but on the other hand i can't think of anything else since you've gone over everything and nothing's helped.


Not sure which Stanadyne shop is nearest for you. There is Gaspar(i think i spelled that right :o:) in Fairfield. I've been there once, but their price for rebuilding an IP would be higher than if you just purchased a reman from a vendor here, of from the guy i bought mine from.'

Give me a call if your in the area, i should be swapping that collapsed lifter in my 6.2 tomorrow so i'll be home save for a parts run tomorrow morning.

- Dave

One more thing i forgot Ben.

When you remove the IP, scribe a line on the timing case and on the IP. my 6.2 has the lines cast into the timing cover and the IP, but i'm not sure about the 6.5. I've never had to replace a 6.5 IP yet.

Any luck with the IP Ben?

yeah I got the IP out. Wasnt actually that bad a job as I thought it would be, about an hour and a half from start to finish.

Im taking it up to H&L Diesel in deep river and they are going to test it but seeing as the pump barely returned any fuel Im thinking its bad.

ben

ok forgot to update this....

got it running a couple days ago. Had to redo all the grounds and some wiring. Bunch of other little gremlins as well that were also problems. And of course replace the IP as well.

Now it seems to run great! I set the base timing to like 3.6* according to the Tech 2, which is what GM specs call for. Any advantage to setting it differently??? TDCO was like 1.xx something, I forget...Ill have to double check it.

I also did a custom PMD remote mount.

How long do these things take to get to operating temperature when the outside temp is ~25*??? After a ~7 minute drive it wouldn't really get above 160*. It seemed to heat up quickly to ~160*, but when it got there it didnt seem to heat up any more than that.

On the test drive (first time the thing has moved under its own power in over a year), I got about 5 minutes from my house and a car pulled in front of me, so I hit the brakes kinda hard and weee, pedal went right to the floor. Rusted out brake lines, awesome, I win. I drove it back home in 2nd gear while holding the "parking brake release" and using the parking-brake pedal with my left foot as if it was the service brake pedal. :D

I put it back up on the lift and the rear brake lines are shot, driver side front brake hard line is shot too. So I need to go to advance auto and get some brake line and bend it into place. The brake lines between the master cylinder and EBCM look OK.

Ben

You could set the TDCO to ~ -1.5. That should give a tad more power but still result in decent mileage. TDCO at -1.94 is whats considered to be the best place for power but on a cold start it will sound like the engine is coming apart at the seams.

The truck should've warmed up in that time. Could be bad t-stats. Does this thing have Dexcool in it? The Dex in mine sludged everything up and caused the stats to stick open and the engine ran at just a hair over 160. I replaced the stats and flushed the system and put in regular ol green coolant and it's been fine ever since.

Just idling they won't heat up, but after a minute or so on the road mine heated right up to operating temperature. If it has dual thermostats, one could be stuck open, or be cracked. I agree with Dave too, -1.94 is supposed to be the best for mileage/power. It is loud on a cold start, and overall nosier, but I was happy with it :D

Had no idea you were messing around with a 6.5.

I guess when you are used to the Dmax, these things don't get too hot. I gave mine to Fingers to go to the PUSU; he came back from Wisconsin with a redneck winter front made out of Coors beer cases.....:D I actually liked it and left it on until it dissolved...

If you lost the brake lines I would suspect that the fuel tank and/or sending unit lines are not far behind. When the sending unit supply line goes, it will give you almost the same symptoms you were having in the first place...

ok got the brakes more or less bled. I had to replace almost every line.

The only lines that were ok to keep was the one going from the driver side wheelwell to the passenger side front caliper, and the lines that go directly between the master cylinder and EBCM.

Seeing as I had to open up ALL of the brake lines I was worried it was going to be a bit tricky to get all the air out, but luckily doing the 'automated bleed' with the Tech 2 worked perfectly. :)

I still have a little bit of air in the rear brake lines though. I want to know WHO at GM designed the friggin rear wheel cylinders/drum brake setup??? Man im spoiled by the rear discs on dmax's and how easy those bleeders are to access...the bleeders on 14-bolt drum brakes are positioned so its almost impossible to get a wrench on them, and even harder to get a hose on the bleeder nipple. Luckily they werent rusted and I didnt round over the bleeder screws. :eek:

Also, im pretty sure the glow plugs arent working because it really didnt start that well being left outside all night. Took quite a bit of cranking and stumbling before it finally ran. Once it actually got running on its own without me holding the starter, it ran fine and didnt stall or need to be restarted...so I think its just a matter of crappy glow plugs.

The thermostat(s) are stuck open too I think??? The upper rad hose gets warm, but the thing refuses to get above 160* or so.

Final question...I dont mean any offense to the 6.5 guys...but how slow are these things when they are running well/correctly?? This suburban runs really smoothly/well/sounds great...it more or less gets out of its own way, but not much more than that. How much slower are they than a stock dmax?

Dave- when I get the odds and ends fixed up on it (pitman/idler is going to need to be replaced too) tomorrow I might take a drive up to your place if you're going to be around...just so you can drive it and say "yeah thats a normal 6.5" or "something is plugged up, it should move out more than this"

ben

ok new pitman arm, new idler arm, new glow plugs, this suburban is basically brand new now.

But. The damn thing wont warm up!!!!! When driving normally it runs 154-158*. If I really beat the crap out of it up hills, WOT highway passing etc. I can get it up to like 165* but then it cools back down. I pulled the thermostats out and put them in a pot of water on the stove and they seemed to be working properly.

This doesnt make any sense; there are a million things that could make an engine run HOT, but basically only one that could make it run cold; stuck-open thermostats, and as far as I can see they work normally. :mad:

Its not the senders because the dash gauge agrees with the ECM's reading according to the Tech 2. (they are separate sensors no?)

ben

do you have good heat in the cab??? get a temp gun on the rad hose.

do you have good heat in the cab??? get a temp gun on the rad hose.

the heat is "ok"...like ok as in the kind of heat output you would expect at only 160* coolant temp... ;)

(so no, its not the heater core; the engine literally isnt warming up)

I can easily hold my hand on the upper rad hose after its been driving for a while. When my dmax is up to operating temp (~180*, basically same operating temp as a 6.5), I cant hold the upper rad hose. I havent tried using my infrared thermometer on it yet, but ill do that later.

So clearly something is preventing it from heating up. I clamped off the upper rad hose (not completely, but mostly pinched off) and it didnt really make much difference...so Im just wondering if this is normal for not running a winter front and it being 12-15* outside?

I dont have a winter front on my duramax but it will still (eventually) get up to temp when its this cold. Do 6.5's run that much cooler...?

A little later on im gonna put a piece of cardboard in the radiator and see if that does anything.

Does anyone have a pic of the thermostat orientation? I put them in the same way I took them out (when I checked them, I didnt replace them though), but maybe someone before me replaced them and put them in backwards?

ben

My 6.5 got plenty hot on the coldest days here, I love driving around with the windows down and the heat cranked in winter time.

IIRC, the pointed ends on the thermostats point towards the back of the truck. Been a while since I've seen them, but this is the way I remember it.

ok maybe the thermostats are indeed bad? Or leaking? Or something? argh.

Ill try a piece of cardboard over the radiator and take it for a drive.

The stats i replaced on my truck 2 winters ago would open a tad late, but would stick open randomly. Some times i would be fine, other times it would sit right at the 160 mark on the gauge. Even running it hard it wouldn't warm up.

If it's running that cold i'd say change the stats. See if that works. Like you said there's only one thing that'll make it run cold. My blazer runs cold(~150-175) in this weather sometimes but that's due to not having the added heat from a slipping 700R4 anymore.

but that's due to not having the added heat from a slipping 700R4 anymore.

:D

Just added a nice winterfront. It was a two minute job; ripped up a cardboard box to fit across the grille openings, folded it over and slammed the hood shut. Didnt even need tape or anything, how bout that.

Whats the deal with thermostats for these. Does one open a little earlier than the other, like the 'stat setup on a dmax?

Are there different mfg's for the stats? Are 'whatever they give me at advance auto' any good???

ben

AcDelco or Robert Shaw thermostats are the only good way to go. They should open approximately at the same time, provided they are the same temperature rating.

if I go to advance am I going to get those thermostats? Or is it dealer only?



nvmind I suppose thats a dumb question....I can always just go to advance to find out... :)

:confuzeld

I put Napa stats in mine over 2 years ago. two 195*F stats and it's always run at the correct temperature. Guess you could put a 180*F stat and a 195* stat in. Is that somewhat how the dmax setup works? I'd just go with dual 195*F's if it's just a kid hauler/DD. It's obvious the cooling system works too well. No sense running a lower temp stat if it works that well IMO.