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  #16  
Old 08-22-2011, 01:27 AM
Tapani Tapani is offline
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Re: stumbling idle and backfiring, PLEASE HELP!!!!!

My apologies if I sort of repeat myself, but one idea is to tap into the MAF signal wire at the ECU connector. See if it behaves logically. I did this on mine yesterday while chasing another issue. Very easy and you can monitor the MAF while driving.

My bet is still way too lean a mixture.

Tapani
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  #17  
Old 08-22-2011, 05:37 PM
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Re: stumbling idle and backfiring, PLEASE HELP!!!!!

List of things I've changed
1. MAF
2. Throttle bodies with all the sensors attached
3. Coil packs
Now it doesn't stumble, but it still backfires!!!!!!
Someone please help me or this car is getting scrapped, because I'm f*cking done.
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  #18  
Old 08-22-2011, 06:16 PM
oab_au oab_au is offline
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Re: stumbling idle and backfiring, PLEASE HELP!!!!!

Does it backfire out the inlet or exhaust????

Harvey.
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  #19  
Old 08-22-2011, 06:46 PM
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Re: stumbling idle and backfiring, PLEASE HELP!!!!!

It backfires from the exhaust. From a dead stop the car hesitates until 2,000 rpm when accelerating, and then drives normally.
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  #20  
Old 08-22-2011, 06:55 PM
oab_au oab_au is offline
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Re: stumbling idle and backfiring, PLEASE HELP!!!!!

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Originally Posted by 92_LSL View Post
It backfires from the exhaust. From a dead stop the car hesitates until 2,000 rpm when accelerating, and then drives normally.
OK that means that there is unburnt gas in the exhaust, that is being ignited. That would suggest that the ignition is being interrupted,(the spark missing for a couple of firings), igniting it when it returns.

As you have just done a trans swap, I would check all the wiring that you have touched, disconnected, or wriggled, including the ground wire at the rear of the engine that runs to the firewall under the engine steady 'dogbone).

One of them is not connected properly.

Harvey.
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  #21  
Old 08-22-2011, 07:55 PM
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Re: stumbling idle and backfiring, PLEASE HELP!!!!!

A disconnected ground can cause this!?!?!?
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  #22  
Old 08-22-2011, 08:07 PM
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Re: stumbling idle and backfiring, PLEASE HELP!!!!!

Yes.

Harvey.
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  #23  
Old 08-22-2011, 08:10 PM
92 SVX 92 SVX is offline
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Re: stumbling idle and backfiring, PLEASE HELP!!!!!

very much yes
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  #24  
Old 08-22-2011, 08:21 PM
oab_au oab_au is offline
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Re: stumbling idle and backfiring, PLEASE HELP!!!!!

If the engine block is not grounded to the body, spurious voltages can return to the body through the signal wiring carrying control information to the ECU, to change the signals.

Harvey.
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  #25  
Old 08-22-2011, 08:31 PM
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Re: stumbling idle and backfiring, PLEASE HELP!!!!!

The only ground I'm not too sure about is the one on the dog bone, It's connected but I'm not sure if It's bolted to the right place though.
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  #26  
Old 08-22-2011, 08:41 PM
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Re: stumbling idle and backfiring, PLEASE HELP!!!!!

When I did the swap I removed only two grounds, the one on the dog bone and the one for the starter. Also, when the car is flashing "power" on startup, is the code the same one that would be flashing if you were doing self diagnostics? Because on startup the car is flashing "16", which I believe is a faulty cylinder 3 injector.
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  #27  
Old 08-22-2011, 08:56 PM
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Re: stumbling idle and backfiring, PLEASE HELP!!!!!

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Originally Posted by 92_LSL View Post
When I did the swap I removed only two grounds, the one on the dog bone and the one for the starter. Also, when the car is flashing "power" on startup, is the code the same one that would be flashing if you were doing self diagnostics? Because on startup the car is flashing "16", which I believe is a faulty cylinder 3 injector.
power light flashing 16 times just means you need to check the trans codes. since you put a fwd trans in an awd car it could be as simple as (eh theres no power going to those rear wheels) but then again maybe not.

Your check engine light should tell you if there is a problem at the ecu, and stumbling and backfiring should set check engine light I would think.
I believe the way to read that is a connector in the kick panel on the drivers footwell, 2 blue wires but I dont remember the exact sequence to make it work.
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  #28  
Old 08-22-2011, 09:02 PM
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Re: stumbling idle and backfiring, PLEASE HELP!!!!!

Oh, well the car has had that flashing since I bought the car. The check engine light has came on several times but went off shortly after.
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  #29  
Old 08-22-2011, 09:13 PM
92 SVX 92 SVX is offline
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Re: stumbling idle and backfiring, PLEASE HELP!!!!!

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Originally Posted by 92_LSL View Post
Oh, well the car has had that flashing since I bought the car. The check engine light has came on several times but went off shortly after.
the new trans is 5sp right?

Probably the trans controller saying hey bud you got NO transmission.

the light coming on then going off can be indicative of a bad ground, light comes on when misfires are detected then go off when they clear up.
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  #30  
Old 08-22-2011, 09:21 PM
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Re: stumbling idle and backfiring, PLEASE HELP!!!!!

I wish I had a 5 speed!!!!!
It's a temporary fwd legacy swap until I can afford a five or six speed swap. Could the starter ground contribute to this kind of behavior?
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