Anybody had this problem...
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Joined: Jun 2011
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From: New Zealand
Anybody had this problem...
Hi There Team,
We have a Rx8 here that has a problem after it is hot, it jumps from closed loop to open loop at idle & runs stupid rich (thick black smoke). It doesn't log any faults in the ecu though. Initally it logged some 02 error so we replaced both the front air/fuel sender & the rear O2 , now, as I say it doesn't log any error just all of a sudden starts to run stupid rich once warm & left idling....
We have a Rx8 here that has a problem after it is hot, it jumps from closed loop to open loop at idle & runs stupid rich (thick black smoke). It doesn't log any faults in the ecu though. Initally it logged some 02 error so we replaced both the front air/fuel sender & the rear O2 , now, as I say it doesn't log any error just all of a sudden starts to run stupid rich once warm & left idling....
Thread Starter
Registered User
Joined: Jun 2011
Posts: 4
Likes: 0
From: New Zealand
I've had two different diagnostics scanners pluged into her, the first was a blanket type that covers many different vehicles, it displayed all sensors real time read outs & what mode was currantly being used (open or closed loop) it would alternate from one to the other when the problem is present....thats the thing this only happens intermitantly after being run for about half an hour...
The second scanner I've used is the genuine mazda item, it actually wasn't as good as far as viewing in my opinion, anyhow it wasn't logging any errors before & after it started doing its thing. It has a function where it can perform a "test" we did this before the problem occurs, result nothing found & after where it came up with two errors code PO410 & PO172. I understand that one of these is the air pump & one is the O2. however I picking that this is a result of the issue - not the cause.
I had a thought in the middle of the night that it may be somehow triggering the secondary speed of the fuel pump hence causing the richness, so I'll try that I think. I can't see how else it could suddenly start randomly running that rich....
Open for surgestions though
Thanks
The second scanner I've used is the genuine mazda item, it actually wasn't as good as far as viewing in my opinion, anyhow it wasn't logging any errors before & after it started doing its thing. It has a function where it can perform a "test" we did this before the problem occurs, result nothing found & after where it came up with two errors code PO410 & PO172. I understand that one of these is the air pump & one is the O2. however I picking that this is a result of the issue - not the cause.
I had a thought in the middle of the night that it may be somehow triggering the secondary speed of the fuel pump hence causing the richness, so I'll try that I think. I can't see how else it could suddenly start randomly running that rich....
Open for surgestions though
Thanks
If the 02 sensor was faulty you would see the AFR flatline at 14.7 under all conditions
To check fuel pressure/pump you would need to put a guage in the line and monitor under both conditions.
To check the purge solenoid https://www.rx8club.com/showpost.php...3&postcount=24
If you live close to Hamilton I could take a look at it for you ....
Last edited by Brettus; Jun 24, 2011 at 08:32 PM.
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