HELP VS misfireing

[low-n-slow]

Hey all,

New to this forum, though y'all may be able to help me..

Recently purchased a vs , and its got a miss when revving it. have replaced coil packs,crank angle sensor, plugs, leads, fuel pump etc, doesn't miss at idle, or if you rev it slowly,

So today, thought I'd try a different air flow meter,, didn't change, but then i unplugged air flow and it was running heaps better, but still a slight miss..

its got me stumped.. Any info or ideas greatly appreciated.

Chris

[97VSV6]

Injectors?

[low-n-slow]

will check them now, thanks.

[VS_Pete_1]

Check for codes mate.
Checking error codes VR/VS (Revised)

[EVL-087]

Car dont show any codes
Just 12 system ok

Was my old car :-P

[low-n-slow]

as he said, don't show any, checked again today

[hako]

Try gapping the plugs down to 1.0mm - this can fix an elusive miss.

[low-n-slow]

cheers buddy.

[Brett_jjj]

If you find the sparkplugs have to be gapped down to 1mm instead of the proper 1.5mm before the engine stops misfiring and runs properly, then theres definitely a problem elsewhere in the ignition system that needs to be found and fixed. Seeing as youve replaced a few things already with no luck, next Id try replacing the DFI module, which is located directly under the 3 igniton coils, they actually bolt to it. Id replace that and see what happens as this can cause all sorts of problems if it becomes faulty. Its also worth checking the DFI wiring connector pins ,these pins or "contacts" inside the connector can become corroded and cause all sorts of problems.

[EVL-087]

The DFI was replaced also, by the previous owner before me

I replaced plugs leads coils fuel pump and filter cas cam sensor
Trying to chase the issue, only to come up with nothing

It used to do it on the odd occassion when i first owned it
Sold it to a mate and it became progressivly worse

He replaced the dfi while he had it
And it still ran like it

I brought it back and it was pretty much running like it all the time

[Brett_jjj]

If the DFI module has also been changed, then Id be going through all the main wiring harness and the engine harness, and checking their connectors and earth points etc, check for any dodgey connections etc. Also unplug and replug any of the major harness connectors a few times, just to make sure that they have a good connection where they join. If nothing out of the ordinary is found with the wiring, then it doesnt leave much else to check except the ECU, so try another ECU to see if that makes any difference. It can only be the plugs, leads, coils, DFI module , CAS or ECU, or the wiring between them, so its gotta be one of them..to a lesser degree, It could also be the fuel injectors, but usually when these block up, they will just cause a constant misfire, not just at certain times, or at a certain part of the rev range, or at certain engine loads etc. You can replace the injectors cheaply and easily enough, theres brand new injectors for the V6 available on ebay for $160.

[low-n-slow]

looks like its injectors next.. will chase up some new ones and see how that goes, cheers

[UW1SH]

it could be normal because the ecotecs seem to have a little miss in them when you suddenly open the throttle to much from idle.. idk why this is but iv owned 2 vs and both did it.. try hold it at 2500rpm and then give it a gutfull and if it still miss then theres a problem..

[drewins]

Hi I have a similar problem but it only misfires after then engine has been running for about 30 minutes. I have replaced the leads and the plugs are fine. Just thought it could be narrowed down because of the fact that it only happens when hot???

Any help would be appreciated.

Thanks