Problems with boosting and stuttering

[simace]

I have the exact same problem and never really did anything - as I thought I was overboosting, hitting ~14.7.

I'm going to do some work now. One thing that I've noticed on my car; if I go from whatever throttle to WOT, I'll get that bad studdering as soon as boost climbs past 8psi. If I slowly press the throttle down until it's WOT (kind of matching the peddle with the RPMs), I won't get the studdering and the car pulls very strong (boost will be around 14.x).

Anyhow, time for me to get to work.....thanks for this thread....it is definately an eye opener for me...

[Mad Dog Bodine]

Originally Posted by simace

I have the exact same problem and never really did anything - as I thought I was overboosting, hitting ~14.7.

I'm going to do some work now. One thing that I've noticed on my car; if I go from whatever throttle to WOT, I'll get that bad studdering as soon as boost climbs past 8psi. If I slowly press the throttle down until it's WOT (kind of matching the peddle with the RPMs), I won't get the studdering and the car pulls very strong (boost will be around 14.x).

Anyhow, time for me to get to work.....thanks for this thread....it is definately an eye opener for me...

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

[Mad Dog Bodine]

Here is a copy of a recent log I did. Excuse the size and amount of data.....not quite sure how to edit it except manually which will take forever......

[BlackStealth]

Next time include the HHH datalog, some of us prefer that.

Anyhow, not surprisingly is your o2 numbers are indicating lean during WOT; this is expected if the engine is not igniting the fuel.

[Mad Dog Bodine]

Originally Posted by BlackStealth

Next time include the HHH datalog, some of us prefer that.

Anyhow, not surprisingly is your o2 numbers are indicating lean during WOT; this is expected if the engine is not igniting the fuel.

Alright....so I am running lean WOT....but now is this caused by the fuel filter not flowing enough....or my ignition not igniting the fuel? I am ordering a Fuel filter but I won't get it probably until next week

Should I look at gapping down the plugs?? Could this be spark blow out??

MDB

PS.
What did you mean by the HHH datalog, like the actually file I logged itself?? And not a CSV file??

[BlackStealth]

When there's a misfire it will show up artificially as lean, so no surprise here since that's what you're feeling. I don't believe it's a fuel problem.

Stock gap was good for about 14psi, but I've regapped them to .028. I don't think it's spark plug blow out at this low boost, assuming the plugs are good.

I have HHH, so yes the normal HHH datalog would be fine.

[Mad Dog Bodine]

Well here is the log file I did on Sunday......I am very confused....this is the first real bit of "tuning" I have done. Never had a problem until recently.
Thanks for all the help and suggestions.....

[Patch]

I'm having a similar problem Mad Dog Bodine.. except I can boost until around 10psi then the mambo begins... I'm starting with EVO bov and new plugs. Keep us posted!

[Mad Dog Bodine]

Originally Posted by Patch

I'm having a similar problem Mad Dog Bodine.. except I can boost until around 10psi then the mambo begins... I'm starting with EVO bov and new plugs. Keep us posted!

Yeah I won't be able to do much until the Filter and Caps arrive. Can't get them in town anywhere. So I have to order them. Going to check my plugs and wires this upcoming weekend as well....just don't have time during the day to do it.....

PS.
Your sig pic is hilarious....LOL

MDB

[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.