[RESOLVED] Stutter problem around 4-4500k rpm

[95eclipseSlow]

I have a 1995 eclipse rs that i recently put a turbo on. My fuel system consists of a walbro 255, sfmu with largest disc and small hard spring, dsm 450cc injectors. I am running around 10-14psi i just havent really messed with the boost yet because of the stuttering problem. When at wot the car will hesitate and stutter at 4000-4500rpm. Right at the power band is when it stutters. I have new injectors, new fuel filter, the fuel pump was new,and new fuel return line. I just put plugs and wires in not too long before i installed the turbo. Where do i start to diagnose this problem?

 

[numlock666]

what are you using to control those injectors? FMU just control your fuel pressure, not the actual amount of time the injectors open.

 

[95eclipseSlow]

i just have an sfmu im not using a safc or anything.

 

[Defiant]

Are your plugs gapped for a turbo, or are you still running N/A gaps?
Set to .028", use NGK BPR6ES.

 

[95eclipseSlow]

ok, i will try that. I actually didnt even check what they were gapped at when i bought them. Arent you suppose to have them colder with turbo?

 

[kyleh]

ya after reading your problem I would say make sure you have the correct plugs and correct gap as a turbo dsm.
What plugs are you using right now?

 

[95eclipseSlow]

i have some ngk iridium BKR6EIX-11

i just bought those plugs and they dont even fit? They are too big. When putting them in the hole it doesnt even make it all the way in. They also required a 21mm socket to install and theres no way the plug and socket would fit in there. Should i just try the ones i had but just gap them a .28?

 

[95eclipseSlow]

i just installed NGK BKR7E plugs and gapped them to .32 The car is still doing the same exact thing. No difference it is still stuttering and losing power at 4000-4500 rpm.

 

[evileclipse909]

Make sure your wires are good. cheap aftermarket ones won't work. Try some NGK wires as well and dont forget to use a lot of dialectric grease on both ends of the wires.

 

[95eclipseSlow]

i have some blue ngk wires in there right now.

 

[jshuman]

Shouldn't your plugs be gapped to .028" as defiant said? At .032" I know my car would stutter.

 

[95eclipseSlow]

Defiant told me the wrong plug to use. I searched and found with the NGK BKR7E you are suppose to gap them at .32

 

[95eclipseSlow]

Im just so sick of not being able to drive my car to its full potential. The car only stutters at wot and its very annoying. Ever since i put this turbo on its been stuttering at the same rpm band. I have tried many things and so far nothing at all has worked. What are any other possibilities for this car to run right??

 

[wondabread]

Defiant told me the wrong plug to use. I searched and found with the NGK BKR7E you are suppose to gap them at .32

That isn't the plug Defiant told you to get. BPR6ES is what he said. And they should be gapped at .28

You could also go with the BPR7ES, and the gap is the same.

 

[peter535]

i had the same problem and it was my coilpack you might wanna check that out

 

[95eclipseSlow]

The plug that defiant told me to use wouldnt even go in the hole where the spark plug goes. It was wayy to big. I will test the coil pack and see if thats it but for some reason im starting to think that it isnt anything related to spark.

 

[95eclipseSlow]

its not the coil.

 

[Maranello993]

When I first got my car it would do a very similar thing. The biggest problems came around 5psi or more boost. I used the plugs for the 4g63 that defiant said to use (bpr6es) and problem was solved. I was so worried that something bigger was wrong with the car I had just bought. PLUGS solved my problem right away.

 

[Defiant]

Defiant told me the wrong plug to use. I searched and found with the NGK BKR7E you are suppose to gap them at .32

That's the NA gap. It won't work under the pressure of a turbocharger. .028"

 

[phunny]

Ehhh, BKR7E and BKR7E are the exact same size. But 6 is a colder plug. Like they keep saying, gap it at .28. And your running 14lbs on a stock NT block?

 

[95eclipseSlow]

no its completely rebuilt. i guess i will take the plugs out and try gapping them at .28 but i really doubt thats going to work. i know it may have worked with your cars but keep in mind im 420a your 4g63.

 

[thatblondechik]

I've been plagued with a similar issue. Except mine started when I added an SAFC to the equation. I was already tuning with a a MAFT and I decided to add the AFC just to make it easier to tune "on the fly."

I'm still using the Trans to compensate for injectors but other than that, I use the AFC. And no matter how hard I try, I always start to backfire rapidly/stutter around 3.5k-4.5k depending on how I play with the tuning.

I'll be interested to know what your solution is...I've been unable to fix my stutter for going on 4 months now.

 

[95eclipseSlow]

took the car for a quick test drive with the plugs gapped at .28 and that didnt solve my problem. what else guys?

 

[Plaser]

time to take it to a shop and pay out your ass...

 

[95eclipseSlow]

id rather not take it to a shop because absolutely no one around here knows anything about aftermarket cars. If its not stock they can't work on it, every shop around here is a joke. The only thing i can do is keep troubleshooting things and eventually i'll fix it. I replaced the map sensor, could the part that plugs into the map sensor be causing this problem? Is there anything in the ecu that would cause this to happen? Could the fuel pump be burned out and cant pump enough fuel?