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-   -   Boosted 3.2 Carrera fuel injection woes.. (

raceman 03-15-2008 09:41 AM

Boosted 3.2 Carrera fuel injection woes..
l have a 1984 3.2 Carrera that l laid up over the winter. l just replaced the battery and fueled it and l now have super rich condition (19.0+ AFR`s) ,the idle hunts and of course black smoke from the rich running. Before l dive in l figured l should post. l have lots of guages and fuel pressure is about 30 at idle (l can adjust this) and the PLX wideband shows 19.0+ AFR`s. This PLX also sends a narrowband signal to the l`m thinking it`s possible the WB sensor is faulty and causing the trouble? anyone? l do have the factory test plans for 3.2 motronic diagnostics.
any and all help appreciated:)

NathanUK 03-15-2008 12:34 PM

It certainly would seem the sensor is the problem.

beepbeep 03-15-2008 12:36 PM

19:1 AFR is superlean...

NathanUK 03-15-2008 12:54 PM

Would it run that lean Goran?

jbrinkley 03-15-2008 06:50 PM

I don't know if it would run at 19/1 but high and low of the sensor is 19 something and 10 something.
I know my lm1 reads 19 something off throttle coasting in gear for a moment until icv and chip pick up idle conditions.
new WB on amazon is the cheapest place to get the LSU4.2 $55

I find it easier without using the NB signal. Narrowing down the fuel press at idle is easier without it. One less variable
I believe it should be higher than 30.... I want to say mine is around 40 at idle, 14.1 to 14.3 at warm idle, W/O any NB o2 sensor interference.
of course if you're using different injectors my pressure numbers don't mean ****

beepbeep 03-16-2008 09:02 AM


Originally Posted by NathanUK (Post 3830008)
Would it run that lean Goran?

Nope, probably not. Something is wrong...

I would start with disconnecting narrow-band feed back into ECU and see if it runs better. I believe it might be WBO2 sensor that is failing and sending wrong signals into ECU, which richens the mixture to compensate for what WBO2 believes is "lean condition" ... thus black smoke.

To wrap it up:

Your WBO2 believes it runs lean. But it doesn't. It commands ECU to richen to correct, but it only gets even richer.

Your WBO2 sond might be failing.

raceman 03-17-2008 07:17 PM

[QUOTE=beepbeep;3831160 Something is wrong...

To wrap it up:

Your WBO2 sond might be failing.[/QUOTE]

precisely what l thought:) l`ll keep you posted

Jeff Alton 03-18-2008 04:25 PM

My motor is NA but it may give some help for you. Off throttle down hill (big vacuum) I will 20:1 AFR's. I run 40PSI constant. When the tuning was still only roughed in at idle I had 10.5:1AFR and it was not smoking, it would smell rich, but no smoke. IF you are seeing black smoke at idle, it is reallllllllllllly rich!


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