High Idle Problem

[nitrofumes]

Hello all,

I have an issue that has recently popped up on my '92 Cummins.

The truck was turned up in early May (fuel pin, 1 turn on the pump, 366 spring & a timing bump) and has ran flawlessly until now – it has developed a random high idle issue. After driving it down the road and then coming to a stop the idle will stick high almost like a gas burner with the choke on. Even if you shut the truck off and fire it up again the high idle persists. I've found that a good WOT blast will mostly correct the issue.

Soon after I had the truck tuned the FSS died and I rigged up a manual shut down cable. So now I am wondering if the rubber tip off the FSS is causing the issue? Maybe the tip has gotten to the fuel pin and isn't allowing the pin to seat properly? I am at a loss and not really wanting to tear into the pump again...

Thanks in advance for the suggestions guys.

[RCCUMMINS89]

Sounds to me like your throttle return spring(s) or throttle linkage is sticking.

[nitrofumes]

That is what I first thought as well but everything appears to be returning correctly.

[Knoberman]

From what I've read read the rubber ends up in the dvs, if anywhere, I lost my shutoff but it seems it never caused any trouble, it is now gutted. I don't know what it could be otherwise, fuel pressure good?

[nitrofumes]

Seems to be ok - I haven't put a gauge on it to get any hard numbers tho.

The idle is always higher not lower and it'll still hit 30 lbs of boost so i'm thinking fuel pressure isn't the issue? Someone correct me if I am wrong tho as I'm new to the Cummins.

[Knoberman]

No probably not fuel pressure.