Ok, I posted previously that I thought I had a cold start problem. I was wrong.

After about 45 minutes it will begin to run right, no missfires. most of the time, except for today, It would get better, but not go away.

Today I decided to try to isolate the problem. I found out it's cyl 1 (closest to the radiator). I swapped out the spark plug, coil pack and injector to see if that would solve the problem. It didn't, I swapped out the EMS for my stock ECU and the car idled fine, no more missfire.

Ok so now for some questions, can the problem be faulty programing for either fuel or ignition in cyl 1 or a bad EMS?

I don't know if this matters, but here's the info.
S2000 Year 2000
Stock Vortech kit
no FMU
stock injectors
test pipe
everything else stock.

Tell me what you guys think, Thanks.

 

have you gotten a dyno?

 

yea. 308hp @ 8000 rpms. Stock injectors couldn't hold up against the boost. I wish I would have known that before I dynoed.

ok, back story.

I got the EMS from a member that was running a N/A AP2. It was tuned by church. I plugged it in my car to make sure the EMS worked.

After I installed the Vortech and new sparkplugs is when I got the missfire (still N/A tuned) I took it to get tuned (flatbed tow truck) and they ignored the problem (I guess) and the warmed up and ran fine. It got tuned like normal.

I have to take it back to get tuned again with the new injectors and smaller pulley (might as well). But I would like to get this solved before I take the trip back to the Dyno.

hope this helps.

 

when was the last time you changed out your spark plugs?

 

I put new plugs when I got the car tuned. I used the NGK 7's. I think I have about 500-600 miles on the car since I installed the blower and tuned it.

 

they should be gapped between 0.030" to 0.035".

 

gapped to 30. I don't think it's the plugs. The missfire seems to be coming from cyl 1. I put a new plug, coil pack and injector in cyl1. still the same, no change.

 

hum...it could be that you're running too rich.this may cause a misfire aswell.do you have an A/F gauge hooked up?

 

that would explain why under boost it goes away.

I pulled the plugs, they seem clean. the way they should be. And like I mentioned, If I disconnect injector or coil pack on cyl 1, the misfire remains the same. If I disconnect any other injector or coil pack the misfire get's worst. leads me to think it's cyl 1.

 

are you using a resistor plug? - i know aem ems sometimes is picky on that! we also had a car that had a bad battery, with poor grounds cause the same problem, replaced battery and upgraded battery to frame and frame engine grounds, car started easier, idled smoother and mirfires were a thing of the past. Everyone tends to overlook the grounds.