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EGR valve location

13K views 5 replies 4 participants last post by  Gacob 
#1 ·
Kinda new to the vehicle maintenance business. I recently got my hands on a 95 caprice from a salvage yard yard and when he started it after 3 years the car would idle rough. After about two weeks of trouble shooting he realized that it was the EGR valve, he said that he sprayed it and the problem went away. Could it be the EGR valve again? I've had it for about 3 weeks now and yesterday when i was at a stop light i felt the car rock a few times, Please help. I'm about to take a long drive to GA before heading to Iraq. Trying to get it takin car or before then. Thanks in advance
 
#2 ·
Sprayed the EGR valve ?! I guess it could be sticking it is located on the back side of the intake towards the driver side, with the car idling you could push on the diaphram and see if the car starts to die, and see if the diaphragm still has movement to it. What you me rock, surging, hunting idle?
 
#3 ·
I'm not sure if it's considered rocking but i felt a slight hesitation or stall while i was at the stop light. When i am driving all is fine but when i at a stop light that's when i feel the hesitation or knock. I'm probably not describing it to well but thanks for the help i'll go and try that now.
 
#4 ·
If you live in a non-emissions state you could get a cheap block-off plate for it and have PCMFORLESS tune your computer to forget about it all together.

If you already have a tune from them then you'll actually save money going this route...if not, then it'll cost a little more more for the initial tune but you'll get hp and mpg in return.

As each of my emissions components died I simply got rid of them. Now I have none left and have that many less things that will fail in the future.
 
#5 · (Edited)
If you already have a tune from them then you'll actually save money going this route...if not, then it'll cost a little more more for the initial tune but you'll get hp and mpg in return
I don't believe this claim one bit. Replace the EGR with a M6 F-body unit. Cost is under $100. Here's the real skinny on EGR. There's only benefits to keeping EGR on a stock engine (if you have an aftermarket cam, its another story):

From Car Craft mag August 2004, Whats Your Problem help column

Increased Efficiency Through EGR?

I enjoy reading your column and just wanted to pass on some additional info on a question I saw in the May issue entitled "Pinging Imp". While I dont disagree with your response, there is something involving the EGR and spark knock that is far more influential than any impact the slightly lean condition due to lack of EGR flow would cause. EGR is added to the intake charge as you describe to lower the combustion temps to reduce the formation of NOx. Older systems that just had EGR tacked on without any electronic controls caused driveability and fuel economy penalties with EGR and gave EGR a bad rap. Later systems, like the one on the Impala SS described, actually used EGR to improve economy by adding a lot of spark advance when EGR is enabled. A very rough rule of thumb is that for every single percent increase in EGR, the spark calibration is increased 2 degrees to offset the slower burn due to the dilution effect of EGR on the charge. So, if an engine is running 10 percent external EGR thru the EGR valve, then the spark is increased 20 degrees roughly to compensate. The engine will actually be more efficient like this than without EGR, as the EGR is "throttling" the engine and reducing the pumping losses slightly by reducing the intake vacuum. It works- trust me. In any case, there are multiple spark calibrations and tables in the OEM PCM for "EGR on" and "EGR off" spark operation. So, if the EGR is supposed to be on, the spark advance is increased dramatically over the "normal" "EGR off" spark levels. If the EGR is not flowing because of a failed valve, restricted EGR feed port, loss of vacuum signal, or so on, the engine will likely detonate or spark-knock heavily due to the fact that the spark advance is being advanced considerably by the PCM, although there is no accompanying EGR flow to dilute the charge and slow the burn rate. That is why the Impala SS is likely detonating, not just because of the slight lean condition caused by the EGR fuel compensation and lack of EGR. At part-throttle, the closed -loop control will pretty much correct for the fueling difference anyway, so I suspect that the reason the detonation is there is because of the extra EGR spark advance in the calibration without the accompanying EGR flow.
Al Cline
General Motors Powertrain
High Performance Vehicle Operations
Pontiac Engineering Center
Pontiac, MI
EGR is on only during steady-state cruise conditions. It will be off when accelerating and at high engine load. Therefore, it is not a power issue. As stated above, it actually increases fuel economy a little. I invite you to provide proof to the contrary.
 
#6 ·
I was referring to the power you'd get from the tune from PCMFORLESS, not power from removing the EGR. And if he's already got a tune from them, it'd only be $50 for a retune.
 
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