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Trouble Code and Head Gasket Questions

Sorry for the slow response. I used the Felpro kit and it was mostly metal. I really have no idea on the cometic gaskets.
 
HMF said:
Andy,
Now that the Suburban is running again, are you having the transmission error still?
Click to expand...

OK, the transmission error is back and I am unable to clear the error. Secondarily I've replaced the computer and we are getting rough idle at times and also the injection pulse width error. I've gone through the grounds and believe that I've got them all, but not positive. I did use the sheet included in help section of the forum to locate the grounds. One thing to note is that I am missing the ground on the drivers side rear of block on head. There wasn't a ground there. The IP is timed correctly. At idle the fuel pressure says 12.xmm.

Any thoughts on the tranny and pulse width error?
 
When you replaced the PCM, did you also change the PROM (chip) or swap yours over to the new PCM, and what is the 4 letter code on the chip? Did you run the timing procedure after you replaced the PCM?

Do you have the scanner? Is that 12mm3 fuel rate at a warm idle or cold? Also if you have the scanner I would check the reported pulse width value. Which DTC do you have 35 or 36?

And which tranny DTC is it?
 
1. PROM from old PCM into new PCM
2. 4 letter code: BXRL (16244877)
3. Timing procedure run and approx -1.3-4
4. 12mm3 at 190 degrees
5. DTC: 36
6. Tranny DTC: 28 - trans range pressure switch circuit
 
The fuel rate is high, that could be from an uncalibrated OS inside the IP. Although that fuel rate shouldnt really cause a problem if just due to the OS being positioned a little off.

Rough idle and DTC36, could be you need a good PMD, or PMD extenstion, or the actual IP. You have not swapped the IP since buying it right?

Check what the injection pulse width on the scanner shows, then try a different PMD and see if it changes, or without an extension. If nothing changes it could be the IP is worn a bit.

The scanner should show a pulse width of about 1.8ms, and if yours is over 2.0 then its showing an issue. This is the time the computer is measuring from when it cut power to the fuel solenoid to open the metering valve and when the valve actually fully seated. There is a spring that puts the valve back seated in the fuel solenoid, and scoring on the valve can slow it down, and sometimes a faulty PMD will not cut that power to the Fuel Solenoid as fast as the PCM drops the signal to the PMD to power the fuel solenoid.

You may also get more life out of a PMD by tightening the transistor nuts after popping off the transistor covers, and also sanding the annodized surface of the PMD's own heatsink plate surface so that you can ground it could help.
 
New PMD kit from Heath, new IP, new injectors, new computer, all the grounds I could find cleaned.

Pulse width showing 2.28 at idle. At approx. 1800 rpm PW shows 1.99.
 
Where did the IP come from, was it a rebuild? Just because the PMD and IP are new doesnt mean they aren't bad, which is very unfortunate.

That pulse width over 2.0 at idle shows something is wrong with either the PMD or IP. rebuilt IPs dont necessarily have new Fuel Solenoids, probably just an OS replacement and they didnt calibrate it either. I have seen that from Badger diesel a couple times. You can try calibrating the OS yourself if you want to, and if might bring the pusle width down, not sure about that though, but if you try a spare PMD and there is no change I would probably get a replacement IP from the vendor. If you want to try performing the "optic bump" to get it back to correct location there is info about that in my recommended maintence file, on the first page.

The tranny code I will actually have to research.
 
The PO had the IP installed right before I got the burb. I believe they sold it to me as they had quite a few issues with it still...like the PMD and the head gasket. I have no idea if it was calibrated or not. At this point I'd suggest not, as timing wasn't set correctly when I purchased it, but can't be certain.

I've read the notes on adjusting the OS but didn't see exactly how that was accomplished. If it was your decision would you take the IP to a good injection shop for calibration or try to adjust it yourself? How does one actually accomplish the adjustment?
 
Well, I trust my own work more, but this IP may need a new Fuel Solenoid anyway. To calibrate the IP takes a knowledgable technician and a $150,000 machine. The driveway adjustment is done with the engine off, taking the top of the IP apart, loosening the OS and nudging it a bit, in your case to bring the fuel rate down, ever so slightly towards passenger side. Then tighten it all back up. Start the truck and verify you have about 7-9mm3 fuel rate at warm idle, if you overshoot too much you can redo it to correct. Although, first thing to do is try that spare PMD, and eliminate the extension cable as a problem as well. The PMD is directly related to pulse widths.

I can also resolve the OS being positioned wrong in the software, but since you also have a pulse width issue, I think a mechanical adjstment could prove more useful. Although the two things are not directly related, so I cannot say exactly if correcting the OS will help the pulse width issue.

Can you also check to see what the warm idle desired timing is? If its really low like 5 degrees that could be an issue too.
 
I unfortunately do not have a 95 anymore so I can't go look for you and my 98 could be different and I am sure my 93 is but if you suspect a ground wire is missing, I would address that first. The stuff Buddy is telling you may not be for the faint of heart...aka the Optic Bump. Once you are SURE the ground issues are addressed then move forward. I don't remember having a ground on the drivers side but I am not going to swear to that as my memory is probably tainted from rotating my herd so much...:D
 
The optic bump isnt real difficult if patient, I've had a couple relative newbies pull it off, although they were doing it because the fuel rate was like 0mm3, which is worse that a little too high. You just dont want to actually have the results of what people typically call an "optic bump", you would just be bumping it back to where its supposed to be. A lot of people want to bump it to get more throttle response, which happens when you make the fuel rate too low at idle, and it can cause other consequenses, because they didnt realize what it was actually doing. With the scanner feedback you can set it up correctly.

This site shows you how to get to the OS. http://www.mamut.net/royh/newsdet9.htm
 
Just checked with old PMD. Injection pulse width error still there...but the old one introduces other DTC's. One thing I'll mentioned...ever since we replaced the computer module, getting it to connect to the software has been a major challenge. Testing the connection proves successful, but connecting...we get an error code. Sometimes it will connect and other times it won't. It makes troubleshooting challenging. Additionally, we had the USB cable connected to the burb and used the PIN to help with manual reset of codes, as if you recall we were unable to get the tranny code to go away with the software. We have now been able to remove the tranny code and will watch for it again. I'm thinking that the new IP hasn't been calibrated properly. What else could it be?

Oh, the ground that I thought was missing was on the front of the driver side head stud...that was the drivers side negative batt connection.
 
Purple wire...

Can anyone potentially identify this spliced, but unterminated purple wire?
 

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With the other PMD, what was the injection pulse width while idling? What other DTCs did the older PMD cause?

Have you checked your LP fuel pressure lately? I wonder if lack of fuel pressure could be causing this recent rough idle and spout of pulse width codes.

Do you still have the old PCM, did you replace it in attempt to resolve some of these problems? Tomorrow I will see if my truck has the same purple wire under the dash.

For the DTC28, do you have the diagnostic manual for that? It shows what causes it and what you could check. Basically, although you may have the transmission shifter in overdrive its getting a signal back to the PCM that is not valid, showing the lines are grounded that should be when selecting 1st, and when selecting a higher gear. So something wiring related is possible.
 
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