Wrong EGR-_Just discovered!

[ltmark]

Re: my 85' coupe. It has been off the road for 3 years while my wife whooped breast cancer. I just recently started going through it to fix some problems, including rough idle and overheating that my wife was experiencing just before we took it off the road.

I've now have the plenum and TPI all apart to clean, etc. Even though I replaced the EGR about 4 years ago (only 1 year of which it was being driven) I took the opportunity to check the EGR's function with my vacuum gun and low and behold, the diaphram didn't budge and would not hold ANY vacuum. I started doing some research and discovered that I had been given the "Canadian" model.

The FSM says that no egr will cause engine overheating and poor SMog test results.

Does anyone know what the difference would be in US vs. canadian EGR valves. I would think that even in Canada, the diaphram would have to move with vacuum with similar vacuum levels? The only visible difference is the actual valve that allows the exhaust gas by it extends down into the manifold about 1/2 inch on the US model and the Canadian one was level with the EGR valve base.

The correct US one that I just ordered is 65.00 The Canadian one that I got was 90.00? I guess Auto Zone put the double whammy on me?

I'm hoping my overheating will be solved when it's all back together!

 

[TedC]

ltmark, check out this thread...
http://www.corvetteactioncenter.com...rum/92886-vaccum-signal-unseat-egr-valve.html
You can read about the testing I did on my 1989 that has a negative pressure type EGR.
I could force engine ping by keeping the EGR valve closed. However, I don't remember seeing any significant increase in coolant temps when forcing these conditions.

 

[TWISTERUP]

I'm guessing the difference would be in the amount of exhaust gases that are metered to be reburned--in order to meet our EPA/emissions standards versus the Canadian version of the EPA. The EGR would need to open regardless when vacuum is applied. EGR lowers combustion temps which would also affect engine temps. Back in the day a inop EGR would also cause "spark knock"---nowadays we have knock sensors to retard timing when they "hear" knock--so there would also be a bit of a performance/economy issue which could go undetected since you wouldn't hear the knock while driving. my 2 cents

 

[CorvetteArchives]

Congrats on still having your wife around ...so now you have time to get back to "servicing the mistress", eh?
I know they did discontinue then change the part# for the EGR for the 84 so no big surprise you accidentally got a Canadian one as Autozoners are not much better than PepBoys....but that one should work too, eh!