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Took out Filter harness SES light yesterday

P

pgguru

Recruit
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Location
Hamilton Ontario Canada
after replacing my PMD with one from Heath I still had codes 18 and 35.
I removed the filter on advise from here, cleared codes and all was well....
Until yesterday. I had a fish bite feeling on the highway and it stumbled and threw codes 18 and 35 again. After a restart it has been fine again.

NOTE: Sunday Night I had a tank of Diesel wax up and had to have the truck towed to the underground were I work for the evening. All was better in the morning and I added More Power service and 80L of Winter Diesel.
The lift Pump was still working in the Morning to re-prime the system but I am wondering if it was damaged from pulling on the clogged filter (I could really hear it chug that night)

Thanks for the help and advice.
 
pgguru said:
after replacing my PMD with one from Heath I still had codes 18 and 35.
I removed the filter on advise from here, cleared codes and all was well....
Until yesterday. I had a fish bite feeling on the highway and it stumbled and threw codes 18 and 35 again. After a restart it has been fine again.

NOTE: Sunday Night I had a tank of Diesel wax up and had to have the truck towed to the underground were I work for the evening. All was better in the morning and I added More Power service and 80L of Winter Diesel.
The lift Pump was still working in the Morning to re-prime the system but I am wondering if it was damaged from pulling on the clogged filter (I could really hear it chug that night)

Thanks for the help and advice.
Click to expand...

I just had a probably re-occuring fuel starvation problem also. I know my transfer tank (untreated) was frozen/waxed beyond pumping.
I add additive in my truck's direct tank, but it was cold. My truck lost fuel pressuer and I had to blow air in my tank to releave the more than likely clogged sock. Question is, clogged by what?

I've seen diesel wax, right out of my xfer pump before, I was like, ' WHAT THE HELL IS THAT?!?!??!?!?!?!?!?!??!?'

It looked like a wax ice-cream getting squished out of the xfer pump.

I always add additive anyhow, but after seeing it with my own eyes, i have a completely new view on what it looks like in the fuel system of our rigs. It's nasty....

Even worse, unlike water, it doesn't 'unwax' at the same temperature it 'waxed at' it can take a lot more heat to de-thaw it out. I'm not even positive that it is 'good fuel' again.

Anyhow, I'm back to the 10' hose n fuel pressure guage in the cab with me, wherever I go...

Perhaps you should do the same for a while. I had no idea i was even running low on pressure until my little fishbite before the 'puter' throws it in limp mode.

It actually may help save these pumps, as when fuel pressure is low, it limps it out, and shuts down great volume of fuel, along with power, but usually gets you home w/out too much strain on the IP.
 
You'll throw these codes with cloudy fuel. Or you can run the diagnostic I wrote the first time.

Also, DTC 35 is a short injection pulse width, less than 1.2ms, and the PCM will automatically set it to 1.95ms as a result of a constant SES condition. Engine coolant temp also has to be above 68F, so after warming a little. It can be caused by a faulty fuel solenoid, faulty PCM/E-PROM (not likely), or a broken circuit to the PMD, the red wire that ends up as pin E on the PMD, comes out of PCM pin PC2, which is the 24 pin pink connector pin C2. You can try testing continuity from that pin PC2 to the PMD harness that goes to pin E of the PMD.

Do you actually get stalling? You put yes, which maybe your fuel solenoid is faulty, not the Fuel Shutoff Solenoid, but the solenoid where all the fuel lines come out of and the electrical connector for the IP is.

You could do more diagnostics if you got a USB to OBD1 cable and got the free software or the pay one from Engh Motors on a laptop. Then you could read the injection pulse timing to see if it actually out of spec. Otherwise its just something interfering.

DTC18, cam reference pulse error, which is to control timing and start of injection.

For the 18, could be interference too, but to check it out, pull optic sensor harness off, turn the IGN to ON, and make sure there is 5V on terminal A (grey wire) of the harness. If youre missing that 5V then check that the PCM is outputting 5V on grey wire PD10, which is the Pink 24 pin harness pin D10, and if so then you have a break somewhere between there and the optic sensor.

If you have the 5V then make sure the ground to the PCM is good which is the white wire to pin D of the sensor harness. So there should be 5V across pin A and D of the harness, or check using a test light to positve battery.
 
I have not had stalling since removing the harness gust the fish bite and the codes the one time.
The Filter is $122 at the stealership I was thinking of remaking it and trying that?>
 
Just open up your old one and see whats inside, then make your own using the connectors on that harness. Probably cost you like $5 and an hour including the drive to radio shack. I'd be interested in knowing just what inside, there wasnt one on my truck when I bought it.

Or it costs $19 less at SSD even.
 
Now I know why I could NOT find one on MY truck! Heath only shows it for the 94-95 trucks and mine is a 96 so the factory must have eliminated it when they went to OBDII or it was taken off by the original owner or his mechanic.
 
MAGNUM SERVICES said:
Now I know why I could NOT find one on MY truck! Heath only shows it for the 94-95 trucks and mine is a 96 so the factory must have eliminated it when they went to OBDII or it was taken off by the original owner or his mechanic.
Click to expand...



My 96 had one. In fact its still sitting in front of my keyboard right now as i type this. Many 96's had them according to Todd at Heath. Mine was worn out and causing a P0251. The OBD I trucks(94-95) require the inline filter, the OBD II trucks have the filter built into the ECM(again i heard this from Todd at Heath). The inline filter in the 96 was a redundancy. My guess is GM had them left over after the switch to OBD II and used them until they ran out, which explains why some 96's have them and some don't.

The biggest reason for the change out was similar to the PMD issue, I believe. The filter's failed because of heat soak from engine bay heat, which is why when moved to the ECM they no longer had issues, as they were away from engine bay heat. Again, this is just my take on things, from what i heard at Heath.
 
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iamdave0887 said:
My 96 had one. In fact its still sitting in front of my keyboard right now as i type this. Many 96's had them according to Todd at Heath. Mine was worn out and causing a P0251. The OBD I trucks(94-95) require the inline filter, the OBD II trucks have the filter built into the ECM(again i heard this from Todd at Heath). The inline filter in the 96 was a redundancy. My guess is GM had them left over after the switch to OBD II and used them until they ran out, which explains why some 96's have them and some don't.

The biggest reason for the change out was similar to the PMD issue, I believe. The filter's failed because of heat soak from engine bay heat, which is why when moved the the ECM they no longer had issues, as they were away from engine bay heat. Again, this is just my take on things, from what i heard at Heath.
Click to expand...
Maybe mine does have one and I have just not found it yet and IF it is there it has NOT caused me any problems. Yet!
 
The OS Filter is just an inductive Emi\Rfi filter, required because the IP harness was a crimp-only assembly, OS wiring inclusive - Stanadyne upgraded the OS assy and released a new IP harness in '97 consisting of Teflon-insulated silvered-copper multi-strand instrument-quality wiring with crimped and soldered connectors - Stanadyne issued each new or rebuilt replacement IP with the new wiring harness to be installed at time of IP replacement, but some aftermarket vendors just kept them, selling them as extra only if customer asked - thus, lots of '94-'95-'96 trucks are still out there with the original defective IP harness, even after multiple IP replacement events - the oem harness is dull-colored silicone-compound insulated, 7-9 strand tinned wire, crimp-only - upgraded harness is smaller-appearing brightly-colored teflon-insulated, larger-awg 20-30 strand silver-plated copper instrument wiring, all connector terminals are crimped and soldered - works fine, lasts a long time, as evidenced by no more OS Filters

Around that same era, Stanadyne also released a new and improved OS Filter with crimped and soldered connectors for those early systems that required a filter - the early unsoldered filters would lose the 5v Ref supply to the OS, required by the Hi-res and Cam-ref IR LED's and the Fuel Temp circuit

My hand-built NoBD-to-OBD1 truck didn't require the OS Filter after replacing the as-equipped IP harness on the 5288 - later switched to the 5521, again with no filter and no ill effects, still OBD1

The IP harness can cause DTC 35-36-56-88 - the OS harness and filter can cause DTC 17-18-42-43-54-88-91~98

The basic engine harness can cause any of those, also DTC 13-19-34 - intermittent connection gives same symptom as failing sensor or module

If ya got'em, clean'em....................
 
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Update..
Today (a rainy day) I had to tow a friends car to the Transition shop; as soon as I got on the road it hesitated and turned on the SES light.. Then had no power (I think my Wifes Jetta TDI could have pulled it as well)
 
I have a fishbite in my truck....I have tried everything to trace it....

Todd figures installing the harness will fix it.....I'll let you know how it goes (truck does not have a filter as of now - didn't have one when I bought it)....
 
PCM drives the line pressure regulator to full output every so often to prevent the shuttle from sticking in it's bore - this repeating pressure spike can feel like a fishbite - all 4L80E's do this thing, is more discernible in cruise on flat hiway, moreso with lower-geared trucks, like 3.73, 4.10 - however, replacing the not very well aged oem silicone IP harness with the new and improved gaily-colored teflon IP harness will certainly brighten up the engine bay, if nothing else - if ya got'em, swap'em...........................
 
gmctd said:
PCM drives the line pressure regulator to full output every so often to prevent the shuttle from sticking in it's bore - this repeating pressure spike can feel like a fishbite - all 4L80E's do this thing, is more discernible in cruise on flat hiway, moreso with lower-geared trucks, like 3.73, 4.10 -
Click to expand...

Interesting you mention this...I started feeling the fishbite just after doing a trans fluid change...

I'll try the filter harness and go from there....:mad2:
 
The new IP harness is good upgrade for any '94-'96 6.5 with the oem harness - don't leave home without it...............
 
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