missfire sometimes, data log included

[datman]

I've been driving my car for a while now but the last few days I have used it on the track and had some problems. When I am accellerating out of a corner it cuts out for a split second then goes then cuts out again. It doesn't backfire just dies dead for a spilt second.

I have 2 fuel pumps and a swirl pot, fuel is staying cool, I'm running an F54/p90 combo with MSII and EDIS. I will zip the lastest log which you can see the problem at 79.6 seconds. Any ideas? injector drivers getting hot? I'm using low imp 680cc injectors.....it doesn't do it all the time which is making it harder to find.

 

Thanks for looking

msq and log.rar

[datman]

I think I have found the problem. When I wired up the EDIS to the VR sensor I used a single core shielded cable using the core for 1 wire and the shield for the other..... It must have been a late one. Anyway I changed the wire to a 2 core shielded type, connected the shield at one end and the missfire has gone.

[mobythevan]

good find and thanks for the update.

[datman]

Update on this.....I found the true cause of this today..it seems a few areas of my fuel map were causing a rich missfire .Only happend in 1st or 2nd at high revs....3rd and 4th never fell in the same cells. I lowered the numbers and now its fine.

[X64v]

Update on this.....I found the true cause of this today..it seems a few areas of my fuel map were causing a rich missfire .Only happend in 1st or 2nd at high revs....3rd and 4th never fell in the same cells. I lowered the numbers and now its fine.

 

So did the 2-wire shielded cable help at all, or was the fuel map the sole cause of your misfire? I'm having a misfire similar to what you describe, except mine's misfiring at high rpms in 4th and 5th only (i.e. high speeds, 100+ mph). I have a vr dizzy wired up like you had your vr sensor wired with the single core shielded cable.

[datman]

I think it did cause a bit of noise on the ignition....I'm still getting the odd 11,000rpm spike but typically only 1 spike in 10mins of driving.... Yesterday I was watching the laptop screen as the car started to missfire you could clearly see the mixture was too rich....I turned off accell enrichment just to make sure it was the fuel table. Going to try power filters on the megasquirt supply to get rid of that random spike, although its not really much of a problem now. Cutting out coming out of every corner on a race track is much more annoying

[datman]

Car is running the best it ever has now....I have an profec A boost controller whic works really well but I want rpm based boost control so I'm going to use this :

http://store.autospeed.com/Items/14440?sck=5911623&caSKU=14440&caTitle=Independent%20Electronic%20Boost%20Controller

 

and this

http://store.autospeed.com/Items/14461?sck=5911623&caSKU=14461&caTitle=Hand%20Controller%20for%20Digital%20Adjusters

 

this way you can program boost levels at given duty cycles....looks like just what I've been looking for. I will do a write up once it's installed.

[mario_82_ZXT]

MSnS-E can be set to do that.

 

The volvo guys sell (or used to) a kit that came with a boost solenoid and all the little bits and parts to wire it up.

Mario