Thread: car breaking up during first run :(

So I just swapped a w11 det into my b13 and it came out pretty good. Went to go drive it down the street and its breaking up bad. I'm running a jwt ecu programed for a 93 cobra maf and 50lb msd injectors. Just woundering if this set up is sending to much fuel and causing the car to break up around low to mid rpm's??? Any idea would be extemely helpful and any local broward county help would be even more helpful!

i would check your grounds and the maf..how much vacum is it pulling at idle? possible boost leak too.

breaking up during normal driving or under boost.

If under boost, what is your plug gap at. If you havent gapped your plugs down I would do so. I recommend .022 to .028.

If under regular driving you might have a leak somewhere causing it. We need more details on the setup. Are you running a Walbro 255 fuel pump and so on.

Also recommend getting a wideband to see whats really happening. You will get a much better idea of whats going on that way.

im with ash check the plugs and gap them down

My set up is a stock t25 on 7psi running off a jwt tuned for cobra maf, 3bar and 50lb injectors. I have the plugs gapped at .30 right nowbut had the same problem when they were gapped at .28. I've also been told the fuel setup is to aggressive for a t25. Could that be a problem??? Also it breaks up during regular driving. Starts around 2500 and kinda stops after 4500 5000.

fuel set up is awfully big for a t25 on 7psi, curious to know what it would do if you lowered your fuel pressure some. I'd say that as it enters boost it's dumping too much fuel and then higher up in the revs it's enough to run decent again. That is, if you know everything else is right, vacuum, no boost leaks, fuel pressure.

I'm puting my 370s back on and stock maf. Will see how it goes.

Why would you do this if your running a jwt ecu programed for a cobra maf ?
you say you just swaped this motor. start with the basic's ! check grounds, check tps, check for boost leaks, try another cobra maf if you have the means. Jus my 0.02 $ tho. sounds like a stupid fix to me..

let the car warm up to normal working temperature and see if it still misfires as mine does the same thing when cold

sounds like it could be going too lean or to rich, do you have a wideband to monitor the afrs