Problems with boosting and stuttering

[simace]

Originally Posted by Mad Dog Bodine

Well I am happy to hear I definitely am not the only one with this problem LOL.
My car though at any throttle, wide open or partial, if I get into boost and it passes 6psi (WG pressure) it stutters. For example, on my way home yesterday from out of town, with cruise on, and going up a hill, boost climbs, hits 6psi, and then stutters and shakes. The boost still tries to go to 10, but it doesn't pull like it should from 6-10psi.
I got some work cut out for me this week....good luck with your car!

MDB

Thanks!

So, I went out and started by cleaning all coil pack connections to the point where they were shinny inside. Got in and immediately noticed the stutter doesn't come on so easily now. I can go from whatever throttle to WOT and sometimes it won't stutter - and if it does, it's not as obvious as before.

Gonna continue. But just so you know, I like to make one (1) change, drive and record the outcome so that I KNOW what is going on and not guessing as to what I did to cause XXXX. I think others should do the same, yes it's time consuming, but imagine if others would have done this - we'd have a very serious library, here at 3si, to fix our cars......IMHO.

Good luck and I'll report back with whatever I do....

Eddie

[Mad Dog Bodine]

Originally Posted by BlackStealth

That HHH session file makes it much easier to read and visualize now. Your o2 sensors are cycling like normal and then suddenly hits zero during WOT. It's a little difficult to pinpoint what's going on as your throttle is not steady during those runs.

It's gonna take a week to get my PCV order to come in...not certain if that will cure my problem.

I will pull some more logs tomorrow. My laptop I use is at work currently. My throttle isn't steady cause I get out of it quickly once it starts to stutter.
I am not getting any knock though when it stutters, so maybe I will just try make a few pulls, and see if we can't figure out what is going on. I will "try" stay on it longer.....its just a little nerve racking.....

Should I WOT (stomp on it) or gradually accelerate to WOT??

[Mad Dog Bodine]

Originally Posted by simace

Thanks!

So, I went out and started by cleaning all coil pack connections to the point where they were shinny inside. Got in and immediately noticed the stutter doesn't come on so easily now. I can go from whatever throttle to WOT and sometimes it won't stutter - and if it does, it's not as obvious as before.

Gonna continue. But just so you know, I like to make one (1) change, drive and record the outcome so that I KNOW what is going on and not guessing as to what I did to cause XXXX. I think others should do the same, yes it's time consuming, but imagine if others would have done this - we'd have a very serious library, here at 3si, to fix our cars......IMHO.

Good luck and I'll report back with whatever I do....

Eddie

Very good information, and I agree about doing one thing...then testing. Can't lock it down if you do 5 different things to "fix" the problem...then the problem goes away. You dont know what was the solution.
I might just have to go out and clean my coil pack connections. Its free....lol and I don't have to wait for parts

[Mad Dog Bodine]

More information to fuel this fire.

I was just out driving around (not logging) and decided to fool around with my MBC. I turned the controller all the way out to almost the last thread (decreasing boost) and it had absolutely no change on my boost settings. If I stepped on it, it would boost to 6psi as per usual, then stutter on its way up past 10. I think I even hit 13-14psi once....stuttering all the way before I let off the gas. Could my MBC be causing some of this problem, or be attributing to it?? This controller has worked ever since I got it....but I haven't played with the boost until tonight. I had it set to ~15psi....and have left it there.

MDB

[BlackStealth]

Originally Posted by Mad Dog Bodine

Should I WOT (stomp on it) or gradually accelerate to WOT??

You were at 30% throttle most often so it's hard to decipher if that's considered WOT or not from the ECU's perspective. Get at least 50% or higher and try and hold it steady through 1st and 2nd gear. We only need to datalog one good run.

[Mad Dog Bodine]

Originally Posted by BlackStealth

You were at 30% throttle most often so it's hard to decipher if that's considered WOT or not from the ECU's perspective. Get at least 50% or higher and try and hold it steady through 1st and 2nd gear. We only need to datalog one good run.

I will see what I can do. Its hard to stay at WOT when the car is stutter though. Very very disconcerning. Also when its stuttering, the exhaust is popping and almost backfiring. It doesn't actually backfire.....but it pops and makes a lot of weird sounds when I try to stay on it while its stuttering. Thats why I get off the pedal so quickly.
I hate only having a partially running car.......

[Mad Dog Bodine]

I logged another run.....I will post the log tomorrow....but I cannot stay WOT for long because when the car starts stuttering and hesitating it starts to backfire almost....and it really starts to buck and so on.
I cannot get it past 4500RPMs WOT....the car runs like absolute crap while under boost. Hopefully we can decipher more from my log I will post in the morning. Its just saved on my laptop....and I am too lazy right now to transfer to my desktop.

Peace!

[Mad Dog Bodine]

Well here is the log from last night. I will post both CSV and the HHH log for anyone who wants to take a peak. I really don't know what it could be. I am hoping when I replace my fuel filter and caps....it goes away or at least improves.....this car is really no fun at only 6psi and no WOT driving.

[BlackStealth]

If your throttle was steady, then your TPS sensor is broken.

[Mad Dog Bodine]

It was as steady as I could keep it. I mean...I wasn't constantly on and off it....but its hard to stay on it when the car is stuttering, bucking and popping like it does. So I tried to get on it...and stay on it for as long as I could.

So....first things first....until I get my other "parts" I guess I should looking into my TPS sensor......

Thanks BlackStealth for all your help thus far!!