Hi, guys.I did not pass smog and I was going to replace the EGR valve and picked up a used one from a wrecking yard that the owner says was good. It's a Jeep wrecking yard and they do repairs, so i'm assuming it's going to work. In any case I want Is to check my old EGR Valve and check the used one I purchased
I don't know the best way to check them. And there's not much information on a 1990 Jeep Cherokee EGR valve. I scraped the old gasket off and i've been Spraying it full of carburetor cleaner And the insides actually look pretty good with very little build up. I live in California so I need the EGR valve so no I cannot plug it off. I appreciate the help.

 

There are others on here that know more about that year than I do , but I would start here:


https://cruiser54.com/?p=119

The bottom line is that there's a lot more to the egr system than the actual valve. Also there are other causes of high Nox: running lean, high engine temp, combustion chamber deposits, ignition timing, come to mind

 

What were your smog numbers? Did the EGR fail the functional test?

 

I have checked all lines, sprayed everything with brake cleaner AND starting fluid to check. I have replaced every sensor and accessory that can be replaced. New fuel tank, pump, regulator, injection, filter, spark, distributor. Cleaned throttle body. Etc. Untouched engine with 260k sat for 22 years. Bought new by my parents and was a commuter. Runs smooth, drives good.
Smog said I had wrong cat. New cat was CA legal but was one of two cats (supposed to be a pair). I just installed verified CARB approved Magnaflow. Smog said fuel cap was not sealed, Bought new cap. That was it from Smog. I thought maybe my EGR was not working right. Looked like one diaphragm post was bent. So I was going to pull and check.
I just don't know exactly what to do to check function and clean. I sprayed a lot of throttle body cleaner in the used one and seems clean. That is where I am at.
Thanks.

 

I'm totally confused.
you started the thread saying you failed smog and asking about the EGR valve. Your recent post shows you very badly failed HC and CO, which not an EGR issue ( maybe HC if stuck open at idle but very unlikely)

Seems like you're either running crazy rich and/or have a catalyst problem. Based on the very low NOx I'll bet on the running crazy rich.

 

Hello
Yes i'm running around like a chicken with its head cut off. I'm an old farm mechanic which means Bailing wire and lots of hydraulic lines. But i'm not quite up on everything else. I've read and also watched a lot of Is articles about bad e g r valves It was recommended that I go ahead and check Or replace my e g r valve. I have a spare but I want to check both of them and I don't know how to Go about it.

I have a brand new cat in and i've checked for Vacuum leaks.
If i'm running rich , then I need help going about correct in this. I have a new fuel pressure regulator And new injectors and new fuel filter A new fuel pump and new fuel tank. Could I have the wrong injectors or some other part? At this point I am lost.
again thank you

 

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All good now?

 

No, I put it on hold as I replace a suspension on a ford ranger. But what I was trying to ask originally is how to clean and how to check the function of the EGR valve.
Also one member mentioned that he thinks it is not the EGR but I have rich fuel. So I am not sure what to check or do on that. Is it a fuel pressure issue, injector or something else?
I am limited on what I know and don't know. So all the help I appreciate. Once I check the EGR and if there is anything within my ability to check, I will make an appointment to re-smog with a shop that does XJ repairs and builds. So I wont mess with it after that and have the "pros" fix it.
Thanks again.