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Forum nameTurbo/Nitrous Tech
Topic subjectStill mis firing.
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i8&topic_id=50594
50594, Still mis firing.
Posted by JustOne, Jun-15-03 08:05 PM
I have had this problem for a few and still can’t get to the bottom of it.

The symptom is a miss fire or surge at 1-6psi and 1/2 throttle. At WOT and ~8-20psi the car pulls normal.

I have checked or replaced:

Plugs - replaced
Wires - replaced
Coil pack - replaced
Crane ignition - checked
TPS - replaced
IAC - replaced
MAP - replaced
Volt clamp - replaced
Waste gate actuator - checked
DFI - checked in many many many ways, symptoms always stay the same
Fuel filter - replaced
Fuel pump - checked
Stock o2's (not in use)
DFI's o2 - checked
Lifters/rockers - replaced
Valves/springs - checked

This problem only happens in boost and at ~1-7.

So I still have to check crank sensor, cam sensor and the DFI map sensor.

Do you guys have any other suggestions for me?

TIA
Brian
50595, RE: Still mis firing.
Posted by MetalJim, Jun-15-03 09:18 PM
Is it individual misfiring or is it a drawn out stall situation? If it's just an intermittant individual misfiring thing then I don't know what to think. But if it's a drawn out(1/2 second or more) stall then what I'm thinking is, the only thing thats different here is "half-throttle". The thing about that is that the stock ECU strives for conservative(stoich) fueling at half throttle. It also has a more agreesive timing curve. With a DFI fuel system, the ECU will still push the timing - but is the DFI pulling enough fuel? Maybe your flooding it? There's probably a better way of testing this, but try running it into that situation, then when goes into "stall mode" shut it down immediately and pull a plug. Is it wet? I really don't know much about the DFI, so hopefully a DFI user can help you out more. If it's a drawn out stall kind of misfiring situation - or a "surge" - then it would seem to me like the DFI needs some tweaking for part throttle(stock ECU closed loop operation). This is strictly opinion, I don't have a DFI, I don't even have a turbo - just giving my .02


95 Eclipse RS : 5 speed
15.943 @ 86.48mph
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html