Ive been trying to track down this pesky code 36 for a while now. It started out intermittently and became increasingly more frequent. Ive replaced the coolant temp sensor, as I found some posts saying that a faulty one could cause a false positive 36. Started having a hard time starting so I recently replaced all my shot ssdiesel instant heat glowplugs with Delco 60g's. It starts a lot better but kind of stumbles for a few seconds before settling into the normal rhythm. The code 36 went away for a time, and now its back. I have noticed that it only happens when my RPMs read between 1400 and 1700. Under or over that the SES light goes off. Any ideas??

Oh...one more item.

At 1400-1700 RPMs i don't hear or feel any noticeable problems.

My truck stumbles when starting and occasionally I'll get code 36. I would also appresiate an explination of what causes code 36. It has somthing to do with the optical sensor, right?

Might try some Stanadyne additive.

Mine does the same thing...I would be nice to hear if someone has figured this out? Sounds like a common problem.

Might try some Stanadyne additive.

If it were something mechanical that needed lubrication, wouldn't it be happening at all RPM's?

The Optical sensor filter harness goes bad after a while.

The engine bay heat does to it, exactly what it does to the PMD.

Starting in '96 the OS filter harness was built into the ECM itself. Some 96's still have the OS filter harness in the engine bay(mine did as was the cause of the P0251, which is an optic sensor code).

replace the OS filter harness, if your getting codes. The 94/95 model years need them as they are not built into the computer.

A bad OS filter harness will cause the same problem as an optic sensor problem, as the computer and the sensor cannot talk, and the computer says "well something must be wrong with the sensor, as its feeding me garbage" and throws the code(s). The computer doesn't have the capacity to "think" that the sensor may be fine and it could be a connection problem(OS filter harness damaged from heatsoak).

had 36 till my burb died 75 miles from home....new Heath PMD kit and never have had 36 show up again...

btw when the code is thrown does your cruise control work?

Where can i find a new optic sensor?

I fixed my code 35 and 36 by using 2 stroke oil in every tank. I ran as high as 2% but found 1.5% worked good (1.5 Liters to 100 Liters of Fuel) it took over 3000 KM to clear it up and Now I use Stanadyne in every tank. (My truck had sat for 8 months before I bought and that might have been part of the problem) I had the same problem it would come on at Highway cruising speed but go out is I was passing. There is a possibility that you are sucking air in the fuel lines as well These trucks suck fuel like drinking from a straw so if you have a pin hole they will suck air in and the bubbles will mess with the optical sensor.

I probably need to replace all my rubber fuel lines in the engine compartment...

bump

did you look at post #8?...does your crusie control work when it throws the 36 code?

No i didn't see that question...I'm assuming no, but ill check it later today.

When the code happens the cruise control is disengaged.

so the CC dropped out when it throws the code?......sound like a PMD to me...

Its a brand new PMD...

i see in your sig you have a SSdiesel Heatsync.....is it mounted on the intake?

I had it there for a few weeks, but i got an extension cable and now i have it mounted under the front grill.

Could it be shot already? Should still be under warranty with SSDiesel...I think they cover it for 1 year...i hope

do you have access to a none working 1 to try?.....did you leave the ground on the IP?

Yes the ground is still on the IP. What do you mean by non working one? Non working PMD? What do you mean by try? plug it in and see if it works?

I think he meant "known working one" and yes plug it in and see if it works.

i spelled it wrong....known working 1.....1 from a truck that working with no codes to test....

No i dont...not unless i purchase a new one...

UPDATE:

This past weekend i installed a new IP/PMD wiring harness from SSDiesel. Installed new Biodiesel compatible tubing to/from filter and for injector return lines. I also installed a fuel pressure guage on the firewall for easy lift pump monitoring. The new harness fixed all of my issues. No more stumbling on startup, no more code 36!

glad you got it fixed!!!:)

Here is a shot of where i put my fuel pressure guage and filter housing drain.

http://img231.imageshack.us/img231/3384/fuelpressure.jpg (http://img231.imageshack.us/my.php?image=fuelpressure.jpg)
http://img231.imageshack.us/img231/fuelpressure.jpg/1/w320.png (http://g.imageshack.us/img231/fuelpressure.jpg/1/)