looking at buying a slightly used ip. but the place says it will require ID prom change. what does this mean?Edited by: scottysanderson7

Sounds like they want you to change the PCM too. TDG knows alot about these pumps he can set you straight about whatever problem it's having.

Its probably a 5068 pump and they are assuming since they are so rare that it won't work in your truck. All other pumps are interchangeable without changing the prom.

here are the part #


k3 ds4 831-5521


p/n 12561307


model# 10632638

DS4831-5521 is the Stanadyne model #


12561307 is the GM P/N


10632638 is the Serial, and judging by this alone, the pump is basicly brand new. I would be very curious as to how they acquired such a late late SN pump, 105 series is already '04, and this is a 106! My only guess is it was on a vehicle, they had problems with it, removed the pump for warranty, and someone somehow put it in the wrong truck, like theirs instead of UPS's and sold it to this guy as nearly new, which it is, but well.... I was going to say nobody pulls a pump off unless there's a problem with it, but it could have been a misdiagnosis and the pump somehow just dissappeared after they took it off, all speculation.


How much are they asking for it? How much for the PROM? How long are they going to warranty it for you? Might be a good one, might not. I'd say don't buy it if they won't warranty it for a year and won't let you buy it without buying a PROM.

Early '94s need a prom change to run most any of the later pumps - shop can determine that requirement from your original pump #.


Just get a '95 PCM from a local boneyard for around a hundred bucks, and you're over - OBD-I PCM's are identical, only proms change for 1500\3500, auto\manual, etc, once you're past the early '94 prom.


OBD-II PCM's are identical, flash data changes per useage.Edited by: gmctd

ONLY those trucks that came with a 5068 pump need a prom change to run 5067-5521 series pumps.

hold up.


I just switched out a 5068 for a 5288 without a pcm change. Is this why I'm getting code 36 at start up?


if yes, could i get a performance PCM for a 95 and make it work?Edited by: quantum mechanic

5067 or 5068? I'm sure you posted earlier that it was a 5067. If it was a 5068 then the truck would run very poorly if at all, but not set a code 36.

I went and unwraped it and looked again 5068 on the old and 5288 on the new. I did post that it felt like I dropped 50 hp when I installed it.

well that would explain it...ouch. Looks like you got to swap pumps again, using the optic off the 5288 pump. Sorry about that, I must have missed/misread your post on that.

Only problem there is something made it start racing. All you had to do was touch the pedal and it was like you floored it. What component would make it rev up to 11 degs advance and 11 deg desired adv. at 15% APP. advance piston worn? stepper?


This guy's teaching 6.5


www.geocities.com/MotorCity/Show/3753/6_5_litre.htm (http://www.geocities.com/MotorCity/Show/3753/6_5_litre.htm)


Edited by: quantum mechanic

Only two things can cause runaway/surge condition, optic sensor hi res sensor or broken fuel solenoid, which would be consistent with your code 36.


Desired and Actual advance tracking together like that means that everything is working, not that there is a problem. Its when they are slow or unable to sync that you have a problem.Edited by: Texas Diesel Guy

I'll tell you this, I tried retarding the timing and adv on th 5068 and it still surged. I drove it home racing like that and swapped pumps but used the same optical though as it had come from the 5288.


Did you read that link, it would have been all new to me two months ago. Edited by: quantum mechanic

So were trying to fix a timing problem on the old 5068, which you knew to have optic sensor problems?

Had. Untill I switched pumpcovers betwix the two. at that time I was trying to tune it down so I could get it home.

OK, lets start over...your truck had a 5068 pump, the optic sensor failed, GMCTD sent an old 5288 pump and you put the optic sensor on your 5068 pump and you had a runaway problem, so you swapped in the 5288 and tried both optic sensors but we know now you will never get that pump to work because its incompatible with your 5068 truck and its throwing a code 36 anyway, right? so you need a new optic sensor to put into your old 5068 to make your truck go right?

never used the old optical in the 5288.


I had trouble starting the truck first time with the 5288 installed, so I bumped the optical till it ran but with code 36. It will start with a little hesitation throw code 36 and then idle settles down and MIL lamp goes out. the truck drives underpowered but it atleast i can drive it.


At this point i'm not exactly sure what to do.Edited by: quantum mechanic

any ideas where to get new/rebuilt pumps at good prices?????

Around $600 for a rebuild. There's a link somewhere. i'd like to hear a better deal.

had my mech take a look at it. hooked up snap on scanner and sensors were say that they were at 100% + and we notcied very little to no vac at sensors. ecm was giving all kinds of wierd readings. told me to replace ecm.... that was the problem..

Vey little to no vac at sensors? I'm not awarwe of any vacuum 'cept the WG control. and the only thing close to that is the MAP which reads in psi and will screw everything up if not working.

map was fine. was no vac at turbo and very little at egr. now after replacing ecm works fine.. except for ip code....

Did you check your vacuum pump and lines too?





Which IP code? 036 response too long?


I'm going to try and fix the fuel solenoid on my old pump, received all the necessary parts yesterday.Edited by: quantum mechanic

QM, did your 'necessary parts' include a new armature and a H&R mount with a dial indicator mounted on it? I'm not doubting your ingenuity or mechanical know how, but this is not one of those things you can fake, need the proper parts and tools.

checked vacuum pump and all linesno leaks at all. yes its code 36 i've had this code probally for the last year and alf or so.. will probally baby it along untill it goes..

I'm going to find one. I have a new armature, gaskets, cap and optical. I'm going to ask blalley if he has one, he's mentioned rebuilding pumps in his nearby diesel shop. I'm going to ask for his help and go from there.