How much boost are you running and what is your AFR?

24-25psi on a 50trim ...AFR's around 10.3-10.9 (yes i know rich but i didnt think it would make it break up this bad)

What is your spark plug gap. Im guessing higher than .024. If its higher than .024 bring it down a little bit.

I think you answered your own question

what brand of sparkplug wires did you buy?

JayRolla said:

What is your spark plug gap. Im guessing higher than .024. If its higher than .024 bring it down a little bit.

Click to expand...

I agree. Also definitely needs to be leaned out quite a bit

Gap is at about .026 right now, plug wires are taylor 8mm wires...

I know its rich but at 19psi I was running in the 9's AFR (with less timing from a diff. tune) and it didnt break up like this, which is why I didnt think leaning it out to the mid to high 10's and increasing the timing a bit would make it run this much worse...

Anyone else have thoughts about what it can be? Im changing the ignition to the COP setup since I cant see the coil packs and if they are arcing under high load or at all(mounted under the SMIM).

That will probably make it worse if it is ignition related. Unless you get an ARC-2 or similar to control it then you will end up with an inferior ignition system by "upgrading" to COP.

Maybe just get another set of stock coils?

You can probably run 7ES at that boost level. I am running them at 28 psi right not.

BTW, your car looks bad ass!

Do you have a datalogger? It would be interesting to see where the timing is at in the high RPMs it sounds like your losing alot of timing uptop and the rich state along with boost levels could be causing the breakup.

rush2252 said:

Do you have a datalogger? It would be interesting to see where the timing is at in the high RPMs it sounds like your losing alot of timing uptop and the rich state along with boost levels could be causing the breakup.

Click to expand...

I log from Evoscan, the last log file mI took was before this new tune. I didnt have a chance since I blew my front diff apart so its sitting. Im trying to get some contructive ideas so I can fix it between. The last log had about 3-4 degrees at its highest load so we threw in another 3-4 degrees. It ran great for about week then started this. Thats what led me away from the tune more. After I cleaned the injectors the breakups almost disappeared but came back shortly after. The fuel filter, Im about 90% sure was the original one (sister had the car before me) and the car has 144k on it so all the gas poured out brown which is why I figured it was a clogged injector...it still may possible be an injector

ok got a question, i have 90 gsx 4g63t and i am having the same problem , car seem to breaking up above 4500rpm i have changed the coil plugs, wires, also installed gm maf and translator, none of this has helped, running 9psi of boost on stock turbo and injectors not sure were else to go is it posable to be a throttle position sensor issue? still kinda new to the dsm world any info would help u can txt me at 3308021225 if any ideas thanks