Rough idle & black smoke

[craigs]

I have a 96 3500 4 door dually. My problem is: on start up, it goes to 1500 rpms and when I tap the foot feed, the tach goes to red line and black smoke pours out. So far, I have changed the injector pump, fuel filter, air filter, and map sensor. When the truck warms up, it smoothes out on the idle. When I put it in gear and give it the gas, it power surges. While driving, it surges, runs right, then surges again.
What can I do next? There are no Chevy diesel mechanics when I am, so I'm on my own.
Thanks,
Kyle

[john8662]

Any codes associated with the truck?

Since you've got a '96, it's OBD-II computer controlled, so you will need a scan tool to retrieve the diagnostic codes.

Is the check engine light or Service engine soon light?

Since you've replaced the Injection pump, it could also be the APP module (Accelerator petal), since this truck is "drive by wire" copper wire that is.

We'll get it figured out!

P.S. Welcome to the forums!

J

[craigs]

I have an OBD ll and it currently shows no codes. I unplugged the APP to get a code, but the code went away when I plugged it back in.
Thanks for the welcome.
Kyle

[craigs]

bumping up for more help.

[craigs]

I just checked my truck for codes again and got three new ones.
PO 113 IAT sensor high <<------- What is an IAT?
PO 251 Injector pump meter control high.
PO 370 Timing is high.
Any ideas?
Thanks.
Kyle

[JohnC]

You said you changed the injection pump, but it sure sounds like the injection pump to me...

If there are no codes being set then it would seem something's telling it to do what it's doing. Plug the scannner in and see what's acting up when it goes hay-wire.

(OK, I see you just posted some codes.) When things are "high" it often points to bad wiring. Check all the connectors in the engine harness, all the grounds, etc. See the thread on stalling for more help.

[MTTwister]

IAT -= Intake Air Temp

I believe when the computer senses the Intake air temp too high it starts to cut back on the Boost, which would lead to an overfueling condition - ie: black smoke.

I think there a test for the IAT sensor, to see if it's out of spec.

Try searching the Member's Area, and also search the threads for any IAT references. Hopefully someone else will chime in.

Good Luck

[JohnC]

Generally when they use the word "high" in a code related to an electrical sensor they mean the voltage sensed is higher than the normal range of readings, not high relative to the desired reading, i.e.outside the range of the sensor. Wiring problems are the cause of choice when you have several.