I think my EGR valve is dead. Supplying a vacuum to it does nothing. I have looked online and learned that a replacement costs around $140. I think that price is outrageous. Is there an equivelent available at a more reasonable price?
In the past I’ve tested my EGR valve (vacuum type on a 1990 XJ6) and found that they do not hold vacuum. They are apparently designed to open when vacuum is applied but only stay open when continuous vacuum is applied. There is a sort of measured continuous bleed down feature. At least that is the way mine worked and always has. Others may be able to confirm. Mine has a long number on it preceded by “GM”. There is also a stamping on it that says Made in USA. Therefore this may be one that was used on some GM cars of the era as well. Worth checking with some good parts stores for a better price.
Hi John,
Mine doesn’t open at all, even with continuous vacuum.
Bob (motorcarman) is the EGR guru 'round here -
I remember him saying once that the EGR will not hold a vacuum by itself as it needs to have exhaust back pressure to operate properly.
Don’t know if that’s any help but thought I throw it out there.
Hi Larry,
I’ve read that also. It’s hard for me to tell. I read the troubleshooting guide for the EGR code. The instructions are for to apply 10hg vacuum and if the valve doesn’t move, replace it. I did that and there was no action from it. I’ve also opened the valve by hand and blocked the vacuum port; the valve doesn’t hold a vacuum. Moving the valve rapidly does not give a puff of air out of the vacuum connection. Yet there is no code 39 or any MIL glowing.
Will, I guess you’ll have to replace it. On my car the operating solenoid for the vacuum operation once failed many years ago and my car threw a code. I believe (but not absolutely sure) it was due to not sensing a proper temperature differential at the port near the throttle body when the EGR opened and closed. Replaced the solenoid and all was well.
John Quilter
Eugene, Oregon USA
Many auto parts houses sell a multi-fit EGR for similar era GM’s that work well and are very affordable.
Vacuum port is clocked differently so the aesthetic is a bit off but that won’t effect function.
I usually swap my 1988 Chevy Pickup EGR when I think I have a fault.
The orientation is slightly different but longer vacuum line will reach if needed.
The way to test is…
Warm engine and shift to D with a FIRM hold on the brakes!!!
Rev engine slightly (1200 to 1500 RPM) until the diaphragm under the EGR valve moves.
I usually have a helper rev the engine (AND HOLD THE BRAKES) and I place my fingertips under the EGR to feel the diaphragm movement
If you place a vacuum gauge in the EGR hose you will see the gauge jump to some vacuum reading.
If you get a vacuum reading but NO diaphragm ‘lift’ at the same RPM then the valve is faulty.
Try substituting a GM TBI engine EGR.
The gearbox must be in DRIVE for the EGR to operate as commanded.
good luck
bob
If you have a FF37 then the EGR operating solenoid or circuit is faulty.
The EGR solenoid should ‘click’ when the EGR is commanded OPEN.
bob
I’ve bypassed the vacuum solenoid and revved the engine-no movement from the valve at all. Thanks everyone for the information on generic valves. I think I will do that.