1G Misfire > 4k RPM

[Awesomewheeldrive]

So, as a few of you know ive just got my engine in. I was trying to do the motoman break in. And well, first pull i was in 2nd flooring it and as soon as i hit 4k rpm and only at 7 psi (yes i have an aftermarket boost gauge) the car bucks and sputters. I know its not fuel cut because i have a 255lph walbro. I also have a 2g maf and 550cc injectors. Car runs flawless under 4k even in boost, but anything over i get misfire/sputter/jerky-ness. Ive got bpr7es plugs gapped at .029. I just replaced the ecu with a rebuilt ecu with new caps. I just want the car to run right..ive spent 6 months and all my extra money in this car and im just getting exhausted.

 

[bastarddsm]

You got a logger?

 

[Awesomewheeldrive]

No unfortunatly i dont have a logger, but i do have a brand new mitsu knock sensor thanks to the machine shop that ### my wires on accident. But i.installed the new maf, no differnece, new transistor no difference. Going to pick up my other coil pack right now and try that. If that doesnt work, im pulling the fuel pump.

 

[Awesomewheeldrive]

Its running fine now. 20% fuel on the safc. Swapped mafs, new coil packs, then i replaced the fuel pump. It ran good but still dropped a/f. Since i owned my dsms i kept reading and reading about the wally 255 with stock fpr. Now for anybody who doesnt believe, i will make you a believer. The 255 well over powered the stock fpr and broke my regulator. so i swapped regulators and now its fine.

Which leads me to this, for anyone running a 255 and no afpr, our cars are old, brittle, and fragile. One performance part can break a 20 year old stock part. And that is exactly what happened.

Thank you everyone for the advice and support. Keep the dsms running!!

 

[NHerron]

For some reason I was thinking you already had the FPR. Never even occured to me

Well glad you got it figured out !

 

[jed344]

Just caught up to ## thread was going to say my car did same thing with a wally 255 and stock FPR...

 

[Awesomewheeldrive]

Well my fix seems like it was all just luck.... Back to the drawing board. Lets start fresh. Ive got a 255 with a new strainer, new 550cc injectors, used 2g maf that i tested and it tested good. Also have a k and n filter, my ecu had the caos replaced. Fuel pump rewired. And now im a/f are spot on cruising. Same thing for WOT, until 5k rpm. Then it runs ridiculously lean. I replaced the fuel filter about a week before i replaced the strainer. And the strainer was covered in solid black tar like stuff. So should i replace the filter again because maybe it got clogged within that week of driving with the bad strainer? Also it is hard to start after its been sitting. Takes about 10-15 seconds feathering the throttle.

 

[NHerron]

You can easily pull the drain plug on the fuel tank to see what crud comes out

http://www.dsmtuners.com/forums/newbie-forum/318608-how-do-i-remove-gas-tank-plug.html

 

[Awesomewheeldrive]

Okay, i have no clue why my car it messing with me, but it just started running fine. And its been running amazing for the past week. I dont get it. I tried a launch. Slipped the clutch just like we awd'ers are suppose to and it started to break them loose. It feels great to be back in the boost game

 

[Awesomewheeldrive]

The car was running poorly way before i installed the afc so i know that is not the problem