Weird boost problem

[Marky]

Went for a run today and this popped into my head, I had a similar problem years ago.

It was on a VR4 I had, basically it started cutting almost at random, like sometimes perfect other times just as it hit full boost, sometimes halfway throug the revs, no real pattern to it

Replaced plugs, coils, fuel filter, fuel pump, no intake leaks, different AFM, ECU, really scratching my head, gapping plugs close improved it for a while but not for long.

Felt exactly like a fuel/boost cut - ended up being the ignition module / igniter pack whatever its called, basically spark on all 4 was getting that weak it was just blowing out at random. It was like a headbutt the steering wheel kind of cut, not like a stutter or something, it'd just cut outright then kick back in, so I fully thought it was fuel cut (mitsi's don't have a boost psi cut, just if you overload the AFM at given revs they cut fuel)

I'm still thinking it's all spark related, or maybe intake mani gasket leaking once things get hot only? It really sounds like a fuel cut (like outflowing what the AFM / ECU thinks you should have at given RPM) something the ECU is doing on purpose not a fault, or just a problem with ignition. Just me though - it might give ya another thing to think about?

[tydon]

 Marky said:

Went for a run today and this popped into my head, I had a similar problem years ago.

It was on a VR4 I had, basically it started cutting almost at random, like sometimes perfect other times just as it hit full boost, sometimes halfway throug the revs, no real pattern to it

Replaced plugs, coils, fuel filter, fuel pump, no intake leaks, different AFM, ECU, really scratching my head, gapping plugs close improved it for a while but not for long.

Felt exactly like a fuel/boost cut - ended up being the ignition module / igniter pack whatever its called, basically spark on all 4 was getting that weak it was just blowing out at random. It was like a headbutt the steering wheel kind of cut, not like a stutter or something, it'd just cut outright then kick back in, so I fully thought it was fuel cut (mitsi's don't have a boost psi cut, just if you overload the AFM at given revs they cut fuel)

I'm still thinking it's all spark related, or maybe intake mani gasket leaking once things get hot only? It really sounds like a fuel cut (like outflowing what the AFM / ECU thinks you should have at given RPM) something the ECU is doing on purpose not a fault, or just a problem with ignition. Just me though - it might give ya another thing to think about?

thats the kinda cut it feels like.

i havent replaced sparkplugs or igniter yet