check engine light after EGR cleaning

[color=#0080FF]hi all,

So my 88 truck failed smog but not by much and smog technician I had it done at said that its possible that the EGR valve maybe the culprit since the catalytic converter on the truck is brand new. Took out the EGR valve last night man it was black as hell!! cleaned it up with 2 cans of carb cleaner and used a small flat head to scrap up gunk around the valve and inside the housing. I took out the sensor on top as well and sprayed carb cleaner inside to clean the springs. installed the whole piece back and check engine light comes on after 4-5 seconds ..... Drove it around the block anyways and felt a definite change in performance, its like cleaning that little part freed up some hp. checked all connections to the EGR and seems to be all intact, not sure why the check engine light came on. Any suggestions why the lights come on? I didnt change the metal gasket behind the EGR since it still looked good when removed, could it be possible that i had damaged the EGR while cleaning? or is it normal for the light to come on after EGR clean may need to be reset? let me know guys Thanks



Jun[/color]

The light comes on at regular intervals and is re set by unplugging one wire unger the dash, and plugging in the other one that wasn't plugged in. it's on the driver side, above the relay bank, and easily reached from the driver foot well. You'll see one un plugged wire, and a pair that is connected, you disconnect those, and plug the one that wasn't plugged in to the only one it can connect to. Takes about 45 seconds and the light will be gone. You can even do it with the engine running.

Thanks 91extcab. Ill go ahead and try it tonight, I will let you guys know what the out come is.

Update, tried to reset by changing plugs under dash. Still no change. Still a bit puzzled

Are you sure you got the right ones? You only switch them once, you dont change them back until the next time the light comes on..

It's these wires near the main bundle, driver side, near the firewall under the dash.



Were these the ones you messed with?

yes those were the ones i switch, but I solved the problem just a few minutes ago. What i did was use my compressor to spay some air into the EGR hose nipple as well as the no.2 air control valve. started her up and engine light gone

thanks for helping me diagnose the problem 91extcab

Weird. I've not heard of the light being associated with anything other than key on time with these trucks. when guys swap to weber carbs and remove the factory emissions computer and the emissions crap that goes with it they dont run into a problem with the light being on because the computer isn't getting bad readings from sensors as all that stuff gets pulled.

Yeah, I don't think the "Malfunction Indicator Light" (MIL) is that sophisticated. My factory manual says that it is only a mileage-indicated signal, so "hopefully" one takes it to the dealer for a check and leaves with a factory installed timing belt, etc.

It's not an intricate check engine light like 1996 and later vehicles have with ODB2.

At least on mine ('88 B2200) a malfunctioning or missing EGR has zero effect on the MIL. It's only come on with with mileage in the 18 years I've had it. Even when the distributor modules were bad and the truck barely ran, no lights came on.

Just for "fun", what is your odometer reading exactly?