Sometimes when I key on my car I get a pressure spike on my boost gauge, seen it go up to 1.5 bars, its quick.

My guess is the coils firing though I did the the Joe spark output mod and figured that it shouldn't be doing this

MS2 pcb v3

I will grab a pic of it soon

 

bump, no one knows what to look at?

 

sounds like the issue people would have back in the day...but never remember seeing any boost spikes...especially not that significant. Do you have a mechanical or electric boost gauge?

 

mechanical boost gauge, you can hear a sound at the same time, a puff\pop or something like that.

 

I used to have it even with the improved spark mod.

Replaced the injectors, issue went away. They were RX7 550's. Can only assume they were leaking slightly.

 

I know injectors are suppose to fire but I wouldn't think that would cause this issue without spark happening to ignite the fuel and cause the pressure spike.

 

I can only tell you what I experienced.

1) I have the improved mod.
2) It still 'backfired' into the intake.
3) Changing injectors fixed it.

 

Finally I got a log of it when it happened
Notice in there the wideband is effected, not sure if its noise, I doubt it, but if so I think the igintion is sparking off and any fuel left unburnt is being burnt.

thoughts?




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(Posting from my phone.)

What's odd is spark advance stays at zero and doesn't read off map.

This is with joes mod and spark output set to inverted?

 

Yes Joes mod and spark output set to inverted