At 6500rpms in first gear ONLY, I have a misfire then the rpms go up to 7500rpm. At any other gear, there isn't a hint of any misfire. My VTEC is set at 5000rpm, I have a colder thermo and my needle is just below the halfway point, like a 16th of an inch lower on the outer end of the needle.

It is always at 6500rpm on the tach in first gear. I have an MSD BTM, VAFC, turbo and no IAB hardware. I've tried reconnecting the solenoid for the IAB since that is the rpm the IAB supposedly opens at full load. I've gapped the sparkplugs smaller, bigger, new sparkplugs, old sparkplugs.

My theory is that my colder thermo may be keeping the ecu in the cold-start-up mode where the vtec and revlimiter is held back?????? It misfires once or maybe twice, enough to lose power like hitting the revlimiter at redline but at only 6500rpm in first.

Help please, Gabe.

 

I haven't tried part-throttle in first at 6500rpms moving. Actually, it does it when revving in neutural. I did test it and it does misfire without a load. I guess I could switch thermostats. But, it runs cooler with the lower temp one. I'll give it a try when I get to my car. Just to know why would satisfy me.... Thanks for the response....

After the misfire, it climbs straight up to redline though, strange....


[Modified by G, 9:33 AM 3/29/2002]

 

Well, they are supposed to missfire at 6500 without a load, mine always has. Definitly sounds like your ECU isn't getting the signal that the car is warmed up, you might want to swap ECU's first and see if that fixes it, Wait, can you do that on a 5th gen?

 

Not easily, hehehe. Actually, I haven't had this when I had the turbo and FMU set-up. Since then, I've gone through at least 6 different fuel and minor deletions of OEM parts.

 

Does this only occur during spirited driving or can you slowly bring the engine up to 6500 in first and get past it smoothly- what are you describing as a misfire?Does it stumble or does it lose power in a smooth way?

 

I haven't brought the revs up slowly in first, but it does happen in neutral. It feels exactly like the oem rev-limiter then catches and continues up to redline. If I am up in 6500rpm, it is always spirited driving. I actually do it once in a while to see if the problem fixed itself. So far, it hasn't. Always and only in first, strange isn't it? I have a friend with a digi-vid-cam. It will be best to show you. I do have an MSD ignition coil, I'll try an OEM one then change the thermostat. All my electrical connections are soldered, heat shrinked and tested by me pulling on either end of the joint, all connections passed. If anything ignition or fuel aftermarket parts related, I would think it would fail under the most load, WOT in 5th gear going uphill (I have done this test to 130-140mph in the desert where there are no cars). I can't figure it out without replacing all my modded parts......

 

Your VAFC probably modifies the ECT (coolant temp) signal that the ECU sees- this can cause your rev limiter problem. Also, in neutral (depending on the year) some models lower the rev limiter if the vehicle is under a certain speed- hope this sheds some light .

 

I will remove individual mods until I find it. I am rarely up there in 1st, but I know when I really need to get on it, it will embarrass me, hehehe... Thanks all!