92 240sx EGR Control -BPT Valve - testing

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alexh
Posts: 48
Joined: Fri Jul 14, 2006 12:44 pm

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The manual is not real clear on testing this valve. It says to plug one port and apply pressure to another port and verify that there is no leakage. Problem is, there are 3 ports, one on the bottom is connected to the exhaust manifold and the others are the EGR vacuum supply and source.

I can pass air freely through either of the top 2 ports when I plug one of them. The air appears to be escaping through the air mesh filter.

I believe the purpose of this valve is to block the EGR vacuum when there is insufficient exhaust pressure. In that case, when the car is off, is does not seem that I should be able to pass air through the valve and in no case should the air from the ports escape from the filter area. It also seems it might allow a vacuum leak when the EGR is turned on.

Could this cause occasional hesitation? Whatever the symptoms are, it seems they would appear to be intermittent since the EGR would turn on when it's not supposed to and/or at the same time there would be a vacuum leak.

For now I just disconnected it thus disabling the EGR
Modified by alexh at 9:17 AM 8/18/2007


180fan
Posts: 7799
Joined: Sat Dec 14, 2002 12:16 pm
Car: 89 fastback

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yes, it can cause rough idles and bogging if not doing it's job.

alexh
Posts: 48
Joined: Fri Jul 14, 2006 12:44 pm

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So far car seems to be doing much better. Idle is rock solid.

I have a continuous check engine light and I didn't bother pulling the code - I assume the ECU is sensistive enough to detect a disabled EGR?

Any idea if the EGR control valve is a dealer only item?

Thanks

180fan
Posts: 7799
Joined: Sat Dec 14, 2002 12:16 pm
Car: 89 fastback

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I'm sure you can find that part aftermarket since the emissions testing business is pretty big and I'm sure someone else would try to cash in on it.

Yes to the ECU/EGR deal.

pr240sx
Posts: 1005
Joined: Mon Mar 03, 2003 7:43 am

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Nah... if you want to retain EGR function, remove the BPT and related crap and ran a line from the EGR valve directly to the manifold


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