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1997 6.5 TD - no acceleration

Jetfrank

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Hi folks, I've been lurking on here for knowledge so this is my first post. '97 GMC Sierra, used infrequently and parked in the Fall and everything was fine. Started it a couple of weeks ago and basically all I have is a smooth idle but will not go beyond around 1000 rpm when you hit the accelerator. Basically idle slows and it starts piston slapping or dieseling. Does not seem to be getting 'fuel? perusing the threads I see a lot of problems can be traced to the PDM or the lift pump - replaced both and no change at all - idles smoothly but when you press on accelerator pedal same thing happens. I did OBD reader on it and no codes at all - what's next before I throw in the towel and have it towed to the local shop. Thanks for the help. Frank
 

Jaryd

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Put a clear hose on the IP return. It’s about 6” long. That lets you know if air is getting in the fuel system. When the engines running if you have 1 little bubble sitting there then you are ok. if there are several bubbles then there is a leak somewhere in the fuel system.
 

Jetfrank

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Put a clear hose on the IP return. It’s about 6” long. That lets you know if air is getting in the fuel system. When the engines running if you have 1 little bubble sitting there then you are ok. if there are several bubbles then there is a leak somewhere in the fuel system.
thanks for the quick reply-was rereading other posts and realized I haven't done that. I'll give it a try. FD
 

Husker6.5

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That is a possibility, a long shot, but a possibility. But I've never heard of a bad TPS not throwing a code, and he says he's scanned and it was code-free. That leans towards a mechanical issue. The truck sat for 6 months. Possible that there's corrosion internally in the IP from moisture in the fuel and that's causing mechanical issues affecting fuel delivery.
 

Jetfrank

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OK folks - threw the towel in and had it towed to a local shop. Verdict (not 100%) is bad IP. Cost installed approx $2500.....again - it idles but that's about it. Truck is a 96 K2500 4WD with 160K miles....so not sure if its worth dumping more money into although replacing it will cost pretty big bucks - thoughts? I need to get back to the guy by Friday. Thanks for the help!
 

Husker6.5

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$2500??? Do you get 10 reach arounds free at that price? As we used to say in the Army, BOHICA. A decent reman IP is about $900, new $1400. If you have any mechanical aptitude and a decent set of tools, R&R of an IP is definitely a DYI-able job in one good day. There are multiple threads on here for installing an IP and setting the base timing and doing the TDC learn function for the computer.
 

Jetfrank

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I'm lazy! but yea, I could DIY but a thousand other projects.....gonna check with another shop and see what they quote......
 

Husker6.5

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Ask the shops if you bring in the new (reman) IP if they will install it. Willing to bet that some of those quotes are for getting a reman from a source like Dorman, that's of questionable build quality and may or may not make it to the end of the warranty period, and then adding 50-100% mark-up to the price of the part. At $100/hr labor (I can't remember the flat rate hours for an IP, help, members) but it's around 8-10 hrs.

Again, lazy = serious dent in the wallet.
 

Will L.

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If you intended to own this truck for 5 years- I strongly suggest getting set up to diy and learn it. You will have problems in the future and working them out will cost.
His statement above about you stand a good chance of getting poorer quality ip out of this is very high and the shop will just charge a ton in labor for them to learn it. We wouldn’t push this if we haven’t seen this story play out many times before.
 

Husker6.5

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And for goodness sakes, DO NOT get an IP off of Flea Bay! Use ONLY a trusted IP specialist that is Stanadyne approved and uses ONLY genuine Stanadyne parts that are of the latest specs for ULSD use.
 

Husker6.5

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FWIW there are no hardened IP parts for ULSD for the DS4 only the DB2. I can change mine out in 5-6 hours. I'd check and see what flat rate time is.
In other words, Stanadyne said, "Screw the Civilian market, only ULSD-hardened parts for the Military's mechanical pumps."
 

Will L.

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yeah, I just cant imagine someone owning one of these old rigs and not diy. So few shops that don’t mess them up worse...

The first db2 hardened parts were in use before low sulfur diesel was out- I was running them. The hardened parts weren’t initially designed for ulsd, they were for multi fuels that were ultra dry like third world kerosene, and the different jet fuels. The fact that it solved the ulsd issue was a Bonus and stanandyne never misses a marketing option - a well ran company.
by time the ulsd came out mandatory in all USA, the second gen duramax was coming out.
 

Husker6.5

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That's right, multifuel military engine. Does the Mil Spec DB2 have compensation for fuel density like the old Deuce and a Halfs and Five Tons did, @Will L.? I remember one time, back when I was just a Private fresh out of Basic and AIT, the Battalion Motor Sergeant demonstrating how a Deuce could burn anything from #2 Diesel to ATF, used motor oil, JP8, differential lube, MOGAS, JP4 and vegetable oil. He had a hose attached to the suction side of the lift pump and just switched the hose from bucket to bucket for about 30 seconds per. The demonstration was to show how in emergency combat situations we could run them on pretty much anything we could find that was burnable.
 

Will L.

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Nope. It just burns it poorly. I ran an old 6.2 on straight unfiltered motor oil once just to see. SMOKE SHOW! No power- it was a turbo but acted like a worn out n/a 6.2.

Won’t run on anything like the real multi fuel set ups with full power and clean, but runs. Also the military was seeing db2 deaths early from running on jet fuel (dry as kerosene), they worked with stanandyne on the hardened parts. Also the extreme cold climates had issues from the thinner fuel wearing them out sooner.
 
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