SR Problem Stuttering when at boost

[sil180]

Hey guys, I have a strange issue.

When I'm at boost the car stutters. It seems like it still reaches max psi but the car shakes while doing so. If i drive the car regularly without boosting the car runs fine.

I changed the Turbo same issue so i dont think its a turbo problem. There is no smoke though the car back fires at times. So i think its an electric problem.

I tried to switch MAF's with a spear my friend had same issue. The idle is fine so can it still be Plugs or Coils? Can it be a bad or dirty O2 sensor? Can i just clean that stuff with some electronic cleaners? I tried to check the plugs, but the seem fine. Any help with be appriciated.

If this helps, I was on it... getting on the freeway when it happened.

Anyone have the same issue?

[Hijacker]

what fuel pump are you running? and if you changed it, how long ago was it? Also, how long has the motor been in the car? The reason I ask about the pump is that I was driving a CA powered car with a new turbo that hadn't had a new higher volume pump installed and it would stutter at boost under heavy loads once the pump had been running for a bit. Tired pumps FTL.

I don't see the O2 sensor causing a stutter like that. The O2 usually causes gas mileage to take a dive and you run pretty rich.

Another issue could be grounds. Check your main battery ground for corrosion and double check that the chassis ground on it is grounded as well.

The last thing I can think of is ECU. If you can have a friend loan you they're ECU, check it out to see if the stutter persists.

[sil180]

Thanks, is there anyway to test the fuel pump? When I did my swap i switched it out to a Walbro high pressure one. I've had it in the car for about 70k miles, I'll change the bat grounds. I know they are pretty bad. I have some friends with an sr. i'll c if i can try their ecu.

[nismonut21]

check your timing my car started to do that and my crank angle sensor went bad. Another thing it could be is a boost leak. get a bost leak tester and check for leaks

[sil180]

I tested the timming, i belive it was okay at 5 deg off Top dead center. I checked the IC pipings and vacume lines as well. I even borrowed an IC from someone cuz i thought mine had a leak.. still same problem.

Boost leak tester. hmm can ijust pick that up anywhere? where do I attach that? I will check all this stuff tonight.. thanks

[sil180]

nm about the boost leak tester. found this..http://www.vfaq.com/mods/ICtester.htmlshows you how to make one..

[Hijacker]

timing should be 15 degrees BTDC not 5

[sil180]

Okay i guess i Have to check it again. Thanks Bart.. i'll try the crank angle sensor

Can anyone please tell me where the crank ange sensor is located?

[sr20-thoj]

its the big round black thing on your engine head close the T.. it has a plug connected to it... kinda looks like a distributor.. but yeah im also having the same problem also.. im not sure what it is.. but it might be the clutch for mines.. because it started doing that for a bit.. then my rpm started going up when i floored it.. let me know what you come up with though ok..

[sil180]

Okay timing in okay at 15 deg.. i changed my main grounds.

I'll perform the boost leak tester today. I spoke to someone that had the same issue, they said it was the BOV. The spring went bad and it was leaking pressure. I'll keep you posted .. on what i find..

[sr20-thoj]

hmm.. now that i think about it.. it could be my bov also.. it was leaking before until i opened it a little.. ill check on that too..ill let you know what happens.

[sil180]

well worked on it a bit last night. I used that pressure tester and found I had a large leak in my bov. So i tried to hook up the stock bov from a z.. almost identical to the srs and I still had some issues. Its not as noticable now but i think its still leaking.

Hey does anyone know if having a leak in the valve cover wil play a large role in this? when performing that pressure test, i noticed that my vaulve cover was leaking. air / oil.. proly change out the gaskets for that..

[Blown240sx]

Sorry I didnt reply sooner I could have told you it was a boost leak cause thats what mine did.

The stock BOV leaks also so it wont fix your problem.

[sil180]

figured it out.. its a boost leak. that boost leak tester is a great tool.. my bov was leaking.. and some of my ic hoses as well.. i think i'm going fmic.. this old side mount has seen its last days

[sr20-thoj]

kool.. need to check my bov.. and pipings.. thanks..