Help please

[vaughn8993]

1995 c3500HD 6.5L TD

when I start the truck it immediately high idles up to 2200 RPMand doesn’t come back down. When you attempt to hit the accelerator more than 1/2 way it chokes and sputters and falls on its face. You can disconnect the optical sensor and it stops high idleing but then it only idles at about 800 RPMs and it kinda bounces and surges. I guess what I’m asking is would this be the PMD or the injector pump ?

 

[ak diesel driver]

Try disconnecting the CPS

 

[dbrannon79]

Welcome aboard! Reconnect your OS and disconnect the CPS like Ak says. Also if you can pull codes and post them that may help us diagnose it. With a 95. Obd1 system you can short the two pins in the pcm connector and count the SES light flashes. Code 12 will be one flashes followed by two flashes pause then it flashes more codes. It will repeat once it goes through all the codes

 

[vaughn8993]

What is the CPS and where is it located ? Sorry I’m very new to the 6.5. Thanks for responding and I will pull codes first thing in the morning

 

[dbrannon79]

Crank position sensor. The connector should be on the driver’s side of the engine harness runs from down by the crank pulley up the block near the IP (injection pump)

 

[vaughn8993]

Crank position sensor. The connector should be on the driver’s side of the engine harness runs from down by the crank pulley up the block near the IP (injection pump)

Fantastic thank you so much I’ll check do it in the morning

 

[dbrannon79]

The engine will run with one or the other failed but not with both failed. It’s possible one of them is sending the pcm a bad signal

 

[MrMarty51]

Welcome to the forum Vaughn

 

[vaughn8993]

Update : I disconnected the CPS, found it running up the block kinda right behind the tensioner and it wouldn’t start at all

 

[vaughn8993]

Welcome to the forum Vaughn

Thank you … so much knowledge to absorb!

 

[dbrannon79]

Update : I disconnected the CPS, found it running up the block kinda right behind the tensioner and it wouldn’t start at all

You did reconnect the optical sensor right? It should start up but will have a slightly longer crank time

 

[dbrannon79]

On another note do you still have that problematic noise filter connected inline with the optical sensor connector?

 

[dbrannon79]

What all has been done leading up to the problem it has. Any other prior work or was this just a sudden change where it was running and driving normal. Has it been sitting any length of time or been a daily driver

 

[vaughn8993]

So I checked the codes since I have no patience and it is throwing 24 different codes …

 

[dbrannon79]

List them and I’ll look them up tell ya what they are. Unless you have the scanner to do that

 

[vaughn8993]

What all has been done leading up to the problem it has. Any other prior work or was this just a sudden change where it was running and driving normal. Has it been sitting any length of time or been a daily driver

So the noise filter is still in line with the optic sensor and I did plug it back in and I just bought this truck was only 900 figured I’d give it a shot.

 

[dbrannon79]

Pull that noise filter and toss it! Just plug the harness directly into the OS

I had a random missing going on and traced it down to that noise filter. If simply touch it and the truck would die

 

[vaughn8993]

List them and I’ll look them up tell ya what they are. Unless you have the scanner to do that

13,17,18,19,22,25,29,35,37,39,43,46,49,57,62,63,78,84,91,92,94,95,96,98

 

[dbrannon79]

Holy . You might wanna disconnect the batteries and clear them. See what comes back. Hang tight I’ll list what they are

 

[vaughn8993]

Pull that noise filter and toss it! Just plug the harness directly into the OS

I had a random missing going on and traced it down to that noise filter. If simply touch it and the truck would die

Pulled