concept11253

iTrader: (13)

I have recently been having an issue where the car begins to hesitate/break up above 3000rpm's. It occurs in both boost and vac. I can build boost no problem before 3000rpm but as soon as I pass 3-3.5k the car begins to violently break up. The car was working great a few days ago. I am currently running a 2.3L stroker on e85 with an aem c2di ignition system and aem ems. I recently changed spark plugs and I have already tried gapping them a 0.020 and at 0.028 and the problem persists. I am wondering if this is an ignition related problem? Any help/ideas would be greatly appreciated. Thanks.



EDIT:: Car works great again. Thanks for all the help guys. The problem was the Camshaft Position sensor.

cheez_it33

iTrader: (1)

Does the car run really rich? I had this problem, and it ended up being a huge boost leak.

concept11253

iTrader: (13)

Hrmm i will definitely look into that. The only reason I haven't checked that yet is because I can build like 18psi before 3k but as soon as I pass 3k it cuts out on me. My a/f ratio looks pretty normal under wot though on the uego. I am on a speed density setup btw.

SpecialNeeds

iTrader: (2)

what psi are you at at 3-3.5 k?

concept11253

iTrader: (13)

I can get to about 18psi but the problem happens in vac as well so it seems unrelated to boost. I am stumped on this one. Maybe a bad cam shaft position sensor?

TurboTim06

iTrader: (2)

no codes? how conservative is your E85 tune? any idea of your the current ethanol percent in the fuel?

concept11253

iTrader: (13)

I am on aem ems so the cel doesn't work. The e85 tune I am on right now is pretty conservative but I have no idea what % ethanol is in the fuel right now. I guess I will run through this tank and load the 91 tune and some 91 and see if the problem goes away.

SpecialNeeds

iTrader: (2)

sorry, to clarify though, past 3.5 k if you stay on it, does it still break up, or is it limited to that specific little range 3-3.5

concept11253

iTrader: (13)

It still breaks up and gets progressively worse with and without boost. It happens under all throttle conditions as well.

05VIII

iTrader: (17)

Check you sparkplugs. Check the gap. If needed, replace them. I have mine gapped at .024 running 30psi on e85 no problems. You could try that.

wtbEVO9

iTrader: (10)

most likely fueling. check pump.

SpecialNeeds

iTrader: (2)

I was thinking similar thing, although I cant see the car in person. Can you check fuel pressure while under load and past 3k? I would start there.

concept11253

iTrader: (13)

Thank you for all the ideas guys. I checked the Fuel pump and filter since it seemed probably that either was clogged/broken and they appeared to be fine. I then picked up a new camshaft position sensor and it solved the problem I appreciate all the responses I received here.