'05 GXP - Problems again!

Discuss your Bonneville GXP and/or any other Northstar powered Olds or Cadillac... Including the Intrigue / Aurora 3.5L Twin Cam V6 (Short Star ) , 4.0L and 4.6L Northstar V8's. Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.
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CMNTMXR57
Certified Bonneville Nut
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Re: '05 GXP - Problems again!

Post by CMNTMXR57 »

It could. I don't know of a way to really "test" one though. If you can monitor it, it measures are in volume (lbs//hr) and in speed (Hz). So if you're monitoring it, and you're play with the throttle and you see volume increase/decreasing as well as speed increasing/decreasing as you actuate the throttle, it tells me the MAF is working.

A good cleaning with some MAF cleaner (or other electronics cleaner) would never hurt it either. Just spray it. don't try to brush or wipe those thermistors in the vane section. They're fragile and will break, and THEN you have a MAF problem. :)
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rwebb616
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Posts: 123
Joined: Fri Jun 10, 2011 9:16 pm
Year and Trim: 2005 Bonneville GXP

Re: '05 GXP - Problems again!

Post by rwebb616 »

Ok so reviving a somewhat old thread - My car was running ok enough that I hadn't gotten around to troubleshooting the issue - now I am forced to as it is running badly at idle. I'm also getting some throttle sticking which I assume is the throttle body butterfly sticking. I began monitoring my fuel trims and they are at about +30% at idle and while going down the road they stay around +40% when the TB seems to be sticking and I feel a somewhat subtle deceleration like it just unstuck and the short term trim drops to zero.

I'm thinking this is confirming your suspicion that I have a (probably large) vacuum leak. I am suspecting the TB to Intake coupler since a lot of people show videos on YT on how to replace them so it must be fairly common. I also plan to check the 90 degree elbow underneath the intake as I have heard that has a tendency to break as well.

My question is, looking at these fuel trim numbers would you say that is what I should be looking for?

Also is carb cleaner sufficient to spray around the coupler to verify my suspicion? I plan to watch the trims at idle while spraying around and looking for the values to drop. Is that a good test?

-Rich
rwebb616
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Posts: 123
Joined: Fri Jun 10, 2011 9:16 pm
Year and Trim: 2005 Bonneville GXP

Re: '05 GXP - Problems again!

Post by rwebb616 »

Ok yay finally fixed. It was the coupler between the TB and the intake - large crack and hence vacuum leak. Cleared codes and purring like a kitten now.

It went into a shop today for the alternator and they tested it and it was bad so I think that will resolve my electrical issues - not sure how it went bad so quickly considering Jake from N* Performance was supposed to change it when he did the engine.

Not sure if anyone is still reading these - kinda sad. There has to be still a lot of bonneville nuts out there...

-Rich
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