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View Full Version : EGR valve problems, vaccuum?


fleaf
02-12-2004, 05:23 PM
Hi, my car is failing NOX for emissions (gross polluter). Iginition timing was off and I fixed that, but I think my EGR valve is the main culprit. I hooked up a vacuum gauge to the EGR valve and went up to 3000 rpm with load and it's barely reading any vacuum. The needle jumps up when I accelerate but quickly falls down.

About How much vaccuum should I be seeing? How should the needle be acting when im accelerating? I don't want to replace the whole unit if all I have to do is clean it. Seems like this subject is pretty common among nissans as I found a lot of result from searching, but i want to know if there is alternative way to replacing the unit since I don't have much money.

Thanks
:hs:

Var
02-12-2004, 07:07 PM
get a vaccum hand pump and pump the egr at idle. the engine will stumble or turn off if the egr is working properly. If the idle doesnt change at atll, the egr is bad. If your car is a gross polluter, *most likely* you will need a new cat alonf with whatever else you get done. Another guy on the forum was barely failing so they ran his car in first gear for the 15mph test and it barely passed.

fleaf
02-12-2004, 07:11 PM
get a vaccum hand pump and pump the egr at idle. the engine will stumble or turn off if the egr is working properly. If the idle doesnt change at atll, the egr is bad. If your car is a gross polluter, *most likely* you will need a new cat alonf with whatever else you get done. Another guy on the forum was barely failing so they ran his car in first gear for the 15mph test and it barely passed.

I thought our cars only had two stage cats, so NOX is not affected by our cat. converters. Also, isn't the EGR valve driven by a solenoid? What if the valve is fine but the solenoid is broken? I don't have a vacuum pump, but I did press the EGR valve diaphragm and the engine started to flutter so I'm sure the pahtways aren't clogged.

Var
02-12-2004, 07:20 PM
On 240's it's not solenoid operated, it's vacuum operated. There is also a vacuum tranducer which controls the vacuum that the egr gets and maybe that's not working. Not exactly sure how to test it though. And we have three-way cats so they do affect NOx, in fact that's the gas it has the most effect on.