VY Commodore 3.8l V6 Backfire on Idle

[Halon]

Hi Guys

My VY commodore 3.8l V6 Has a Backfire on Idle issue. I have changed Fuel Filter, Plugs. Coil pack is working fine, but have not changed leads as yet.

However while checking i found that When the car is in Idle & Backfireing if i dissconnect the MAF sensor there is NO change..... The car still runs ....not even a slight change in revs.... is this a Faulty MAF? & is this issue consistant with the backfireing fault ?

Any Help will be much appreciated.

 

[Halon]

Hi Guys

My VY commodore 3.8l V6 Has a Backfire on Idle issue. I have changed Fuel Filter, Plugs. Coil pack is working fine, but have not changed leads as yet.

However while checking i found that When the car is in Idle & Backfireing if i dissconnect the MAF sensor there is NO change..... The car still runs ....not even a slight change in revs.... is this a Faulty MAF? & is this issue consistant with the backfireing fault ?

Any Help will be much appreciated.

PS: went to a mech..... he wants $180 just to put it on a machine to read Fault code & he cant do that for a month..... too busy

 

[losh1971]

Kmart scan the PCM and BCM for $45 and they normally get you in, in day or two.

 

[Halon]

Kmart scan the PCM and BCM for $45 and they normally get you in, in day or two.

Was going to get this with SRS Software for $110

https://www.envyouscustoms.com/diagnostics/diagnostic-kits/aldl-cable/

 

[losh1971]

Was going to get this with SRS Software for $110

https://www.envyouscustoms.com/diagnostics/diagnostic-kits/aldl-cable/

Great idea, I have the kit and it's a great tool to have. Reads engine and trans running data as well as names error codes. You will be happy with it.

 

[greenacc]

Can't you check a VY without a scanner?
You might have a faulty TPS. My Ecotec used to backfire when trying to accelerate when the TPS was stuffed.

 

[Halon]

Update:


I re-set Fuel consumption average & drove the car for 20mins. On completion the reading was 68L/100km… before it was 11.5L/100km… so running very Rich. Then I set the dash display into Diagnostic mode to check Instantaneous fuel consumption…. That reading was over the roof…. So yep… she is running Rich.

There could be many issues. I suspect the MAF….. The computer not detecting correct airflow & is running the car rich which is its Protection mode. Ordered new MAF, new Leads, Plugs & O2 sensors…. Will see how that goes.

 

[Halon]

Update:

The new GM Plugs will be in today so i have loosend the plugs on the car getting ready for the new ones. I removed 2 plugs just to check them as i had Cleaned & gapped them a few days ago. And Yep.... the plugs are wet & you can smell the fuel on them.

So the issue with the car is that it is Definitely running Rich. New Plugs & leads won't Solve that issue, But the new MAF & O2 sensors might fix it hopefully.

Any Ideas ?

 

[Halon]

Can't you check a VY without a scanner?
You might have a faulty TPS. My Ecotec used to backfire when trying to accelerate when the TPS was stuffed.

If you set the dash on the VY into Diagnostic mode you can get some information & work from that…but in general they would need Scan tool & software. SRS codes need Tool & software to Clear them after fixing any issues.

 

[Halon]

Update:

The MAF & new plugs arrived, installed them. but issue is not Fixed still running rich.will waiting for the O2 sensors & new Leads. I don't think that will make any deference. so back to Square 1.

apart from the computer what else can make the car run Rich ?