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engine dies - throws codes - what do they mean?

I'm thinking I must have a non-stock eprom. I've searched the net and it seems my code doesn't match with anything I've been finding.
 
BXPW chips came out in 1996 for the 1995 trucks, so your EPROM has at least been changed, but i dont know why there is a 5 after it on the chip itself.

I have a stock BPAA chip which BXPW replaced that I could send you to see if it works any different.

Have you done a high idle mod on this truck?
 
No high idle mod.

If I swap out the chip, does that require doing a relearn? If so, I'll need to purchase the full version of GMTDScan.
 
no relearn required for changing chips. What is your max fuel rate observed. If its only 60mm3 that would be stock programming, but 16 degrees is not for that chip code.

What is GMTDScan telling you that the engine coolant temp is? If that is reading really low could be the cause. And what is your idle RPMs.
 
Engine coolant temp in GMTD Scan is close to the dash gauge - maybe within 3-4 degrees. RPM right now while idling flips between 581 & 600.


Just put in some Seafoam & cleared codes. Sitting here idling in park, ECT is up to about 165 and step on the throttle to watch Fuel rate-maximum transient. At idle, it is between 35 & 37.19. As I floored it, it got up to 79.38, I backed off, then did it again. As it got to the 70s the engine died and coded: 98 - Cylinder balance fault #8 cyl - first time for that code.

Started it back up, checked codes and it had 19 & 98 in historic, nothing in current. Cleared codes.

Sitting here idling, temp up to 183, and it just died with a code 19 - crankshaft position reference error. Right before it died, it started idling rough for a couple seconds with fuel rate-maximum transient jumping around between 35 & 42.

After dying each time, I can start it right back up.

Just died again instantly when I put pressure on the throttle and gave code 18 - pump cam reference pulse error.

Started back up, cleared codes, let it idle, and after about 2 minutes died again with code 19.

Is this looking like multiple things or pointing to the one thing?
 
Another new code: 91 - cylinder balance fault #7 cyl.
This one appeared just now along with 98 - cylinder balance fault #8 cyl after idling for about 5 minutes, then I held rpm at 2300 for about 30 seconds then backed off, at which point it started idling rough and then died.
 
Its looking to me light a bad EPROM. If you PM me I can send you one I know is good you can try.

I experienced something similar with a bad EPROM program.

you fuel rate is waaaaayyyyyyy too high. I mean out of the ballpark. At idle it should only be around 8mm3.

Going back through I realized your desired timing is 16* at idle, so your stepper motor is doing what its told.

There are so many things wrong and the simplest explanation is the brains are out of whack.
 
OK, got your PCM & EPROM today and hooked it up. Started up fine, and sounded a lot quieter. Let it warm up to 185*F and took it on a drive. Started out fine - power was noticeably less which I expected. After a couple miles, the truck stalled - code 18. Started right back up, cleared codes, and then coded 18 & 54 right away.

Here are the readings while idling in Park after I got back home with ECT at 185*F (did not clear codes at this point).

TDCO: -0.26
Actual IP timing: 46 with an occasional drop to 4
Injection timing - measured: 9.8
Injection timing - desired: 9
Fuel rate: 11.88

Turned it off, started right back up, cleared codes, and checked readings again:

Actual IP timing: 46 occassional drop to 30-31
Injection timing - measured: 8.8
Injection timing - desired: 8.9
Fuel rate: 5.31

Idle RPM 600

So I guess it is not coding because of a bad PCM or EPROM. Is it looking like the injection pump?
 
You might not have a bad IP, but it may need to be retimed.

If you get the full version of GMTDScan you could set the timing and TDCO and see what the IP actually is at.

My PCM I set to -.26 TDCO and its stored from me, which wont be exactly what you have, but I wanted to see if it would help. My time set did bring you back into the right injection timing area though and better idle fuel rates.

I will hypothesize that some one monkeyed with the IP in the past, maybe even messed with the OS and didnt reset the PCM timing.

The PCM is doing what its been told to do as well as it can, but your PCM was whack with its desired timings. The actual injection pump timing being so wrong gives you a clue that the IP is not set right. The low fuel rate at idle 5.3 tells me perhaps the OS was messed with. You could turn the IP a little towards the passenger side and see if your actual IP timing comes down closer to 30degrees. Meanwhile my time set will still be applied and all might be better.

Otherwise it could be just a faulty IP.

You can try putting your EPROM in my PCM and see if you get any different results.
 
I ve been following this becuase my truck is acting the same as Gordy's. I dont have a OBD 2 reader. When the dies its upsetting to say the least. I was told that the remote pmd doesnt need to be grounded but Im thinking that it wouldnt hurt. Since march I've been through 2 pmds and now the stock pmd is acting up. I'm going to check for lose grounds. I replaced the lift pump and ops switch. Could my timing be off also? Thanks for the help.

Gunner
 
Not sure and probably out of my league but isn't there a filter harness for the OS on the OBD1 trucks that causes some sort of problem ?
 
The OS filter could cause some of the codes. I didn't think it actually caused stalling though. If there is a filter between the OS and the engine harness then it can be removed. You can also try unplugging OS all together and see how long it runs, in backup fuel mode.
 
I downloaded and paid for a license of the full version of GMTDScan Tech a couple hours ago. Waiting to get the email with the license info.

On another note, I looked and saw I have the OS filter harness. I pulled it out but the wires were too short to plug in without the harness. Not sure how to tell if it is the stock harness or aftermarket. I didn't see any brand names on it, but there were some numbers on the plastic.

Also, does the PCM have anything to do with the HVAC fan in Hi position? I haven't had Hi for awhile (even after replacing resistors and dash control panel), but today it was working. Only thing I can think of is the PCM was swapped or maybe I bumped a wire while pulling the PCM.
 
You probably just knocked something for the HVAC, all those relays in there.

The OS harness should reach, just need to find some slack from around the IP.

When you get the full version do the TDCO set procedure and see where it automatically put it. To do that follow the directions on Enghs website. I'm thinking it is beyond the -2.02 limit so that it is actually too far advanced. If so you'll have to adjust the IP.
 
buddy said:
When you get the full version do the TDCO set procedure and see where it automatically put it. To do that follow the directions on Enghs website. I'm thinking it is beyond the -2.02 limit so that it is actually too far advanced. If so you'll have to adjust the IP.
Click to expand...

I'm thinking the license process isn't automated and I'll have to wait till Monday to get the license so I can run the software. I've bookmarked the page on Engh's site with the instructions.
 
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