EGR problem or something else
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New User
Joined: Jun 2006
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EGR problem or something else
High guys. My 94 Lightning is plagued by idle surging and stalling these are the symptons:
- On start up with the engine cold there is no problem. The idle seems to be consistent if a little high.
- As the engine becomes warmer the she seems to be running a little rich with a pronounced smell of petrol.
- When the engine is warm the idle will surge quite violently and when in the down cycle will thow black smoke out the exhaust.
- Soon after that the vehicle will stall and have trouble starting. It seeems to be very rich.
Tuned
Joined: Jun 2006
Posts: 420
Likes: 4
have you checked your air filter? do you know if you have any codes? i'm not an expert on efi stuff, but check if your O2 sensor is still plugged in. it sounds like some sort of sensor fault because your motor runs fine when its cold. its in a loop mode untill it gets warmed up, then once its warm the ecu takes information from all your sensors in order to make your motor run its best. if one of t hese sensors are out of range, or not plugged in, the motor will most likely run like crap. i hope someone with more knowlage will chime in and point you in a specific direction. good luck.
Freshman User
Joined: Jun 2006
Posts: 28
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From: Ennis, Texas
it may be the temp sensor for the computer if it is reading -40 degrees it will run rich also pull the vacume line off the fuel pressure regulator and see it if there is fuel in it from a bad regulater, if thats dont help pull codes
Posting Guru
Joined: Jun 2004
Posts: 1,781
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From: Central NY
If your check engine light is not on, then I doubt the EGR is stuck. The egr valve has a position sensor on it...
The rich running could be many things, best advice has already been given: pull those codes
The rich running could be many things, best advice has already been given: pull those codes
Thread Starter
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New User
Joined: Jun 2006
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vacuum
I changed my oxgen sensor yesterday as a friend pulled codes a few weeks back and it apparently showed poor O2 sensor. THIS did not help.
While I was checking the EGR I found that the vaccum to it was weak and erratic. Will this make any differece to the idle. Wen I pull the hose it makes no difference to idle.
While I was checking the EGR I found that the vaccum to it was weak and erratic. Will this make any differece to the idle. Wen I pull the hose it makes no difference to idle.
Fleet Owner
Joined: Aug 2005
Posts: 23,667
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From: Easton,Ks
Originally Posted by dkatz
While I was checking the EGR I found that the vaccum to it was weak and erratic. Will this make any differece to the idle. Wen I pull the hose it makes no difference to idle.
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Mountain Pass
Joined: Feb 2003
Posts: 136
Likes: 3
Vacuum to the egr, has to go through either two or three solenoids, which are controlled by the ECM. To check the EGR itself though, you can hook a vacuum gauge/gun to the egr itself, then take the reading(Resistance) from the EVP sensor as you apply vacuum. There are alot of vacuum lines/trees going to the EGR, via the solenoids, so there are lots of potential areas for cracks/breaks.
Also, have you checked the Engine Coolant Temp Sensor? If it is stuck showing cold, then the engine will think that it is cold, when its really hot, and wont lean out like it should, to componsate.
Also, have you checked the Engine Coolant Temp Sensor? If it is stuck showing cold, then the engine will think that it is cold, when its really hot, and wont lean out like it should, to componsate.
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