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Discussion Starter #1
My most recent attempt at fixing the hiccup issue hasn't worked. I thought it would be the FSD if all the other R&R's hadn't worked. So I snuck one onto the M/C, put it on the cooler (now mounted out of the engine compartment) and off I went on a hard 9 hour run through the mountains. Sure enough the hiccuping strted after a few hours. I will say it seemed to running nice and strong. I also fixed the leaky filter lines and replaced the gaskets on the fuel filter. Definitely not pooling in the valley anymore. The problem is fish bite/hiccupping. It always comes when the engine warms up, sometimes an hard uphill runs, sometimes when I'm cruising at 110 KPH with a strong tail-wind. Since the FSD replacement it actually seems a little worse. Here's the checklist....

1.Lift pump test - Lots of flow from filter and t-valve. New kennedy harness and LP
2.Service Engine Light - off
3.1997
3a. Odometer reading 270,000 Km's
3b. Miles on major engine components if been replaced
4.Do you have any engine codes? No.
5.If you do have engine codes N/A
6.Air Filter condition (visual check) CLEAN
7.Fuel filter condition (freshly changed) NEW
8.Condition of Battery terminal connections NEW
8A.Known condition and age of the batteries. NEW
8B.Are batteries of differing age or are they a matched set? YES
9.Upon cold start, does the radiator hose get hard quickly? NO (will recheck)
10.Upon cold start, do you have excessive white smoke? NO
11.Do you have excessive cranking time before the engine starts? 2-3 seconds in warm weather, or when double plugged with block and circulater. Won't start when cold out.
12.Have you used the block heater, and does this effect engine starting? See #11
13.During hard acceleration, do you have excessive black smoke? NO
14.Do you have any unusual exhaust smoke issues? NO
15.Turbo check out - PASS
16.Do you have an EGR on the engine? (An F engine code) NO
17.Indicate if you know if it’s a 1500, 2500, 2500HD, 3500, 3500HD. 1500
18.Indicate fuel that you are using: Bio-diesel, #2 Diesel, #1Diesel, SVO/WVO, other WINTER DINO
19.Are you using any fuel additives? If so, please list. MYSTERY OIL and/or REDLINE 85
20.Please indicate geographic region you are in: (example: Texas or Canada) CANADIAN ROCKIES
21.Do you have any service history available that might pertain to the problem you are having? NO
22.Please indicate any modifications to the vehicle that might help us diagnose better.
23.Upon unscrewing the fuel cap, do you have a large vacuum formed in the tank? NO
24.Location of PMD/FSD? On the pump/remoted over intake/remoted out of engine bay (please specify specifically) OUT OF BAY, IN AIR FLOW
25.Are ALL glow plugs in proper working order as per this thread? YES, NEW THIS SUMMER

I have R&R'd every sensor I could reach and then some. I've cleaned and tighened every ground I could find. What I haven't done is the Optic sensor, blown out the sock in the tank or vinned the truck to see if IP is original.

Any thoughts?
Thanks
Dan
 

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Certainly no expert and even worse with PMDs:rolleyes: So here is my stab in the dark. I know you checked your lift pump but the first thing that comes to mind is fuel pressure. You may want to check that. I believe fuel pressure gauges can be had for under $30. Some even hook it up and leave it under the hood.:)

Now let's see if somebody else agrees or am I pointing in the wrong direction........ again:eek::
 

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No, that's a good area to investigate - fuel pressure can reveal a number of things.

Just heard about the Immobilizer - got one o' them on yer truck?

Where is the Fuel Solenoid ground wire, the one that's s'posed to be on the injection pump?

Did you waterproof the FSD when you remote-mounted it?
 

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Hey Fysh ... have you tried the filter harness trick yet? It's the 'other' wiring to the IP ... has 4 connectors on each end, connects between the IP and something else ... probably the PCM, about 6" long. You can take the darn thing right out, and hook up the IP directly, to try and get rid of the fishbyte...

Bill Heath writes about it on his blog: do a search on google for heath fishbite blog ... it's about the 6th item on the list. Look on the right-hand side of the blog.

Aw heck, I'll PM you the link.

It looks like this:
 

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That filter was for OBD1 '94-'95, may be on early '96 OBD2 , so don't be perplexed if you don't find it - there is a TSB for removing it.
 

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When did that TSB come out, gmctd? I know a buddy of mine had a harness on his 96 - because it went bad on him. He had an OBD-II.

The GM guys just removed it ... he was a little freaked about that, at the time. "if ya don't need it, why was it on there?" is what his question was.

The tech just shrugged. But the truck ran fine after that.:wtf1:
 

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I have also been experiencing the occasional hiccup & twice it has set a code for crank position sensor. I have a new sensor but havent had time to install it yet. Mine is getting pretty bad so i will probably do it soon. I will report back on results.
 

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My 95 has no problems now without the filter.

I do have an upgraded OS which is supposed to have a better encoder.
 

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It'd hafta be the end of the 5067\5068 era, sometime in '96, when the upgraded 5288 hit the production line.
 

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So if i have a 5521 pump, then i am prolly ok to remove the filter harness??
 

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Okay...I have to ask. This "fishbiting" you're getting.

Are you using braid, florocarbon or mono?

BwaaaHaaaa I kill myself.

Just a little fishing humour.

Dave
 

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It's ok to try it - if you get the symptoms, back in with it.

I'd store the filter in the cab, somewhere, as a security blanket.

TAG, I'd make the chance to install the CPS - the truck will run in Backup Mode without the Optic Sensor, but most won't run without the CPS.
 

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DOH!

Dave12;1595417; said:
Okay...I have to ask. This "fishbiting" you're getting.

Are you using braid, florocarbon or mono?

BwaaaHaaaa I kill myself.

Just a little fishing humour.

Dave

Throw that puney (sp) joke back! You missed the rebound as well!:p:

"Just fishing for humor"
 

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Discussion Starter #14
I don't have an immobilizer, let alone know what it is. Fuel pressure seems good, as when I open the air bleed on the filter, fuels shoots out. I don't know what the pressure is like on the highway. I do have a new LP and the Kennedy Harness. I can certainly here it when starting up. It seems to rattle when I turn on the ignition sometimes. I'll check and see if there is a harness off the IP. I did silicone around the base of the PMD for waterproofing.
I use sinking tips, flourocarbon (3X) and buggers and get lots of fishbites, but somehow those ones feel so much better....:rolleyes:
 

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The louder the lift pump runs, the closer to failing - loudest is when the valves fail, with no pumping resistance.

Bubbles in the fuel give same symptom, where it cannot pump any head pressure

The Immobilizer is a Canadian anti-theft device - one member's Inj Pump problems started soon after installation
 

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beter psi lift pump

hey fish byte i had same preoblem on my 96 gmc checked and played with and tryed just about all the advice on here and when i installed a new lp i decided afew more pds of pressure would not hurt after reading some of the replies so i went to advance auto and matched up lp that runs 8 to 12 pds an e3540 installed it and no more problems no more codes starts and runs beter so if this is any help your very welcome >
 

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Does that pump take the oem fuel pipe fittings, or do you cut and splice it in?
 

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When I check the Advance Auto website for that part number they have 2 different pumps that come up.

One is $97 and the other is $54, 2 different manufacturers and no specs on output etc.

Which one did you get?

Thanks,
Dave
 

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gmctd;1597339; said:
Does that pump take the oem fuel pipe fittings, or do you cut and splice it in?
If you have a look at the Auto Advance site and do a search for the part number. It appears to be a direct replacement.

Dave
 

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Yep - but are those fittings metric or english diameter & threads?

I installed the complete '95 fuel system on my old truck, metric pipes and everything, without any cutting and splicing - I'd try that LP if it requires no modification.
 
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