I need to know if I can clean my EGR valve and how to if so. Thanks.

 

Well, to answer that, you would have to report which model you have. An 4.0 XJ8 NA has no EGR valve... But if I assume your signature means you have an XJR, I would ask why you think you should clean it? It is a major PITA to get it off from behind the throttle body.

 

My check engine light has been on since I bought it one year ago and the code for the light reads back EGR valve; I can't remember exact code number but the part is the valve. And the car is a 1998 xjr v8 supercharger.

 

OK; well there is not a code I know of that reads "EGR valve", but I understand that you mean your codet implies a problem in the EGR system. Assuming you checked to see that the vacuum line to the EGR is intact, then you might consider removing the EGR valve and cleaning it. I THINK the function of the EGR is checked by the ECU monititoring engine speed and lambda sensor reactions when the valve is actuated, so there are a number of other sensors and systems that might cause a EGR system fault besides the EGR itself.

 

Thanks. Are there any links with steps on how to remove and clean EGR?

 

The JTIS manual has a technician level step by step, including drawings. Look at the "Stickeys" for it. I could reproduce it, except there are many hot links to drawings that would get lost in the copy.

If you download the JTIS and have problems searching for "EGR" ( it does not search easily) check back for some tips!

 

The EGR's function is checked by the MAP sensor, which mounts on a bracket high up on the firewall on the LHS. If the EGR is closed, the MAP sensor should agree with the MAF sensor about how much inlet airflow you're getting, if it's open they should disagree. The difference being that if the EGR's open the MAP sensor is seeing some exhaust gas flow that the MAF sensor isn't.

Check the electrical and vacuum connections to the MAP sensor if cleaning the EGR doesn't fix the code.

Disconnecting the MAP may fix the code too, since cars for some non-smog-sensitive markets didn't have MAP sensors, so presumably the software's smart enough to recognise "no MAP signal" as "I don't know or care if the EGR's working". Won't fix the underlying problem though, unless the problem's the sensor not the valve.

Removing and cleaning the EGR is pretty easy, though access isn't the best. The EGR sits beneath the throttle body, so you need to get that off first. Remove the air inlet tube, disconnect the water hoses, vacuum tubes, and electrical connectors from throttle body and EGR, unbolt the throttle body (4 bolts on top), unbolt the EGR (2 bolts on the back, 2 on the tube down to the exhaust pipe), and voila!

The EGR can be partially dismantled to allow easy access to the valve seat (pretty obvious how when it's off the car). Clean the air passages with carb cleaner, paying specal attention to the plunger and seat. Also while you're at it, decoke the inside of the elbow under the throttle body - there will probably be a bunch of carbon buildup on the air inlet from the EGR. Easily enough done with a scraper and some carb cleaner, but be careful to not let any of that carbon get further down the inlet tract: you don't need it in the supercharger or cylinders.