71 replies to this topic

[p4cks]

Bit stumped with this one like.

 

Since having my VXR turbo fitted I've been having some problems. First of all was the AMM, which was replaced. Then it was the boost solenoid so that was replaced. I've changed the coil pack and plugs and I'm still having some problems with misfiring under hard acceleration. It's got a Pipercross cone filter on it attached to some uprated piping to the throttle body, and there are no air leaks.

 

I've searched and repaired where I can find anything remotely close to a misfire problem but to no avail. I now seek some assistance from the .org people...

[CocoPops]

I thought the amm blows with anything other than a paper filter?

[p4cks]

That's what I was thinking. I've changed everything other than the filter, so my thoughts were it could be that.

 

Fucksake.

[Crabash]

What about the wiring and plug to the coil pack?

[Ormes]

Plugs not gapped correctly...?

[P11 COV]

I thought the amm blows with anything other than a paper filter?

 

 

Yes, cone filters not recommended in the turbo. Can blow the AMM. Not necessarily going to cause the misfiring though. Might be worth a try though.

 

The standard filter box with some extra holes is fine for 300bhp so I would suggest theres no need for a cone. Also, isn't a cone filter going to pick up lots of warm air form the engine bay anyway so probably worse than the standard box.

[p4cks]

I'm gonna give the standard airbox a go and see how that fares, and report back.

 

Failing that, it must be the plugs. There's nowt left it could be!

[SteveA]

In my experience a dead MAF doesn't misfire, it gives you massive gaps in power. Unplug the MAF and give it some beans, it will default to a base map in the ECU for airflow and rule out the air filter and MAF if the issue is still there. My money is on plug gaps or wiring to the sparks.

[Crabash]

Mine did a similar thing that turned out to be nothing more than the coil pack plug was not fully clicked home.

[p4cks]

I've checked the coil pack connection and it's fine.

 

What plugs would you recommend for a (effectively) Stage 3 VXT?

[Ormes]

I *believe* ngk iridium 7s but depends on state of tune. I use 6s on a stage 2.

Edited by Ormes, 19 August 2014 - 05:09 PM.

[redvts]

Mines stage 3 and it has iridium BKR6IEX plugs in it

[redvts]

'7s' gave a flat spot in mine

[Parrappa]

Probably not the same problem, but I had an issue where the engine would violently cut out going up the rev range in 1st and 2nd gears. Changed out the MAF, coil pack, plugs, had all the wiring checked and it ended up being the ECU, there was a couple of faults on it.

 

Really wish I had just sent my ECU away initially as it all became quite costly, hindsight is a wonderful thing....

[p4cks]

Woohoo, fixed!

 

Got some plugs as recommended by redvts (NGK Spark Plug Iridium BKR6EIX 6418) and it seems to have done the trick!

 

For any searchers, I had the OEM Bosch ones in

[Ormes]

[redvts]

I win

[p4cks]

Not so fast - it's doing it again. Looks like a boost problem at 3.5-4k revs

 

I've lost patience with it so it'll be going somewhere to get it fixed (not Vauxhall or any other local garage or even Lotus Newcastle) which will more than likely be MMG as long as I can get it down there and I have enough £s.

 

Anyone wanting to mod their turbo past a stage 1.5 - don't bother. A remap and a pre-cat are sufficient. Worst thing I've done is get that fcuking VXR turbo fitted

[Tibbles Stryker]

Well that's put me off, stage 2 seems enough anyway 😍

[p4cks]

Ha I meant don't bother going from a stage 2 upwards!