Egr Valve Problem?

[dualscoopinchevy]

Hey Guys,

I've posted a couple of questions on here the last couple of weeks about problems i've been having with my truck, many of you have tried to help, thanks again.

 

Without going into all of the problems again, I'll ask this question in a more broad sense....

 

If you are encountering EGR Valve (or solenoid) problems, what would would be happening?

If the valve were stuck open, what would happen. Also if it were stuck close what would happen?

 

Could either of these cause slight random misfires and even have a slight backfire sound when letting off the gas at higher speeds (the transmission has not downshifted at that point)?

 

Thanks

[luminaapv3]

Hey Guys,

I've posted a couple of questions on here the last couple of weeks about problems i've been having with my truck, many of you have tried to help, thanks again.

 

Without going into all of the problems again, I'll ask this question in a more broad sense....

 

If you are encountering EGR Valve (or solenoid) problems, what would would be happening?

If the valve were stuck open, what would happen. Also if it were stuck close what would happen?

 

Could either of these cause slight random misfires and even have a slight backfire sound when letting off the gas at higher speeds (the transmission has not downshifted at that point)?

 

Thanks

 

I thought I was having an egr problem myself, but I believe it is a TBI problem (was all clogged inside). Not sure what kind of truck you have, but mine is a 93 Burb. You can check out my post in this forum.

Anyways if the valve was stuck open you would most likely be stalling within a few seconds after you started your truck, so i doubt that is your problem. When the valve is stuck open it lets the exhaust recirculate back into the intake manifold to be burned again, hence the e-exhaust g-gas r-recirculate valve, this is only suppose to happen when you are at cruising speeds, mainly highway.

 

If the Valve was stuck closed you would only probably know this problem existed when the "engine light" comes on when you hit cruising speed and the ecm finds it stuck. You may also notice your truck smells a little bit rich (gas smell) coming from the exhaust.

 

A misfire is usually something to do with your timing (distributor cap, rotor, plugs, wires, ignition, relays, etc...) Have you checked your timing? If you have a timing light it's simple, depending on your model and year of truck.

 

A backfire could also be because of bad timing, ie your exhaust valve opening too soon.

More commonly though a backfire is usually caused by a "hot spot" ,which could be too much carbon on the top of your pistons ,getting red hot and causing the mixture to prematurely ignite or ignite left over gases still in the cylinder, kind of like a double ignition, your cylinder firing twice instead of once.

Another hot spot source can be your exhaust (pipes, muffler and catalytic converter), the hot spot in any of these locations will cause the unburned fuel leaving the car to ingite again causing a backfire out the exhaust. I found that most of the time it comes from the cat.

To be on the safe side check your TBI vacuum ports. Also not that just because there some suction coming from them doesn't mean they are not clogged!

Well I hope I helped out some, if I missed something maybe some of the other guyes on here can pick up my slack