I have the dreaded Code 35 injection pulse too short but it only comes on during acceleration.

It started when the wife shut down the truck prematurely and I had to start on a little bit of cold veggie.

Funny thing is that it now runs fine once it switches to WVO. The code goes away completely and the truck has no issues on WVO.

I suspect there is some issue with the optical sensor from reading several posts here. I have tried the following:

Installed clear line and checked for any air bubbles-none present.
Run Lubro Molley diesel purge through the IP.
Run 1/2 tank of diesel with 2 stroke oil
Run Powerservice
Filled the tank with fresh new diesel

I am trying to decide between buying a reman IP or just the OS but I can't find anyone who sells just the Optical Sensor.
Any help is greatly appreciated.

Bumpity bump bump

Dtc 35 doesn't point to the optical sensor. Have you run the truck with a scan tool hooked up to see if the pulse rate fluctuates? Are there any other codes present? Other codes can cause dtc 35. Other codes must be fixed first. If your pulse fluctuates then there is a faulty fuel soleniod connection or faulty fuel solenoid. Something else that is suspect is the filter harness that connects to the optical sensor. they go bad from the engine heat and age.[heath sells new and improved ones]

I have the GM Scan Basic and the only code is 35 at this time. I have watched the pulse rate but wasn't sure what I should be looking for and what was considered abnormal. When the code 35 triggers the throttle response is overly sensitive and cruise cuts out. The transmission seems to lag as well. As soon as I run on WVO the problem goes away and all is normal. I have a fuel pressure gauge and fuel pressure is normal as well on both WVO and Diesel.

Optical filter is fairly new as well(2 years)

Ok . Here goes the troubleshooting tree out of the 95 gm service manual.
1. engine at operating temp
Does scan tool display injection pulse width of 1.95ms?
Yes
2.scan injection pulse width while depressing accelerater
Does pulse width fluctuate?
Yes.
faulty fuel solenoid or faulty fuel solenoid connection

If No to #1 dtc 35 is intermittent. If no other DTCs are stored refer to diagnostic aids

If no to #2 Open circuit 985 [red wire from ecm to fuel solenoid driver]
or faulty connection or faulty ecm

I hope this helps

Ok . Here goes the troubleshooting tree out of the 95 gm service manual.
1. engine at operating temp
Does scan tool display injection pulse width of 1.95ms?
Yes
2.scan injection pulse width while depressing accelerater
Does pulse width fluctuate?
Yes.
faulty fuel solenoid or faulty fuel solenoid connection

If No to #1 dtc 35 is intermittent. If no other DTCs are stored refer to diagnostic aids

If no to #2 Open circuit 985 [red wire from ecm to fuel solenoid driver]
or faulty connection or faulty ecm

I hope this helps

Injection pulse width fluctuates between 1.8 and 2.2 before the code appears. When the code appears the pulse width is 1.95 and stays there until I back off on the accelerator. When I back off the accelerator the code goes away and the pulse width fluctuates again.

I did notice the pulse width is 1.84-1.84 on WVO and goes back to 2.2ish when back on diesel after I purge. The code seems to be temperature related since after I purge and go back to diesel I still don't get the code.

Any more ideas? Based on the above I am leaning towards a fuel solenoid but I thought those were either on or off causing stalls rather than pulse width.

Is there a difference in fuel temperature? That Lubro Molly stuff I would not use, it has a solid lubricant in it, like graphite that could blind the OS, and have you checked your filter? It has a strong detergent probably picked up a lot of crap from the tank. The troubleshooting doesnt point to an OS, but what I think happens is the cloudy, or bubbly fuel screws up the timing through the OS and sends the fuel rates out of spec.

Normally not an issue, because it would stay in spec, but you have some mods that affects the system.

You have remote PMD, what value resistor in it and where did you get the extension? A higher resistance value in the PMD and a long extension increases the resistance which can increase the pulse width past the PCM commanded amount. You also have a chip from Heath, which allows higher commanded fuel rates, so as that increases the tolerances can get sloppier.

Did you have this issue even before you moved the PMD and upgraded the chip?

Did you buy a new PMD when you remote mounted it? Is it a D-Tech or Stanadyne?

If the fuel rate doesn't increase with throttle it could be in back-up fuel[back-up fuel stays at the same rate] or fsd isn't receiving signal from ecm. It just doesn't make sense that it runs good on wvo and not on diesel. Are all 3 app signals varying with throttle? Do you have a boost gauge? Possible de-fuel from over boost. You may want to call Bill Heath since you are running his chip. He is more than happy to answer questions especially if it concerns his product. At the least he could point you in the right direction.

Hi, i have a chevrolet silverado diesel 1996 6.5l. When it cold, start easily, but when i stop it during 15-20 minutes, long crank before start. He start with black smoke. I'm buying a new PMD and the samething.

What i can look now??

Thanks.