Cutting out under acceleration

[Turboquad4]

Hi all. I've been racking my brain over this weird problem I'm having with this car I tuned last week. Vehicle info: 2000 Oldsmobile Alero 2.4L, auto trans, with a turbo kit the owner pieced together. I tuned it on our DynoJet last week and everything seemed fine while it was on there. When I took it off and tried to go on a test drive it cut out a second into accelerating. It doesn't totally die though; it goes lean, engine cuts for a second, comes back for a second (richens up), dies again, comes back... You get the idea, foot on the throttle the whole time. It acts like it's cutting fuel or ignition, but it's not showing on the logs. I've tried turning off closed loop, torque management, any limiters, and it still does it. Has anyone ever come across something like this?

I attached a couple logs of it doing it. You can see it doing it when the O2 goes lean when on the gas.

Thanks for any help!

[Iam Broke]

Can't really view your log here without the .cfg file, but can you log fuel pressure to see if it's starving out? If IDC is going way high, I'd suspect that. Just a thought.

[Turboquad4]

oh, sorry. I'll attach that here.

Unfortunately, this vehicle doesn't have a fuel pressure sensor. I'd have to find a way to hook a mechanical gauge to where I can see it when driving (GM didn't make this one very easy to do that on).

I don't think going lean is the cause, I think it's an after effect. If you can see the logs now, IDC isn't going high, and the pulsewidth stays the same whether it goes rich or lean. It doesn't drop out either, it follows the fuel map. That's why I think something is cutting out, I just don't know what. And it only happens when driving, it'll idle and rev up fine in neutral all day long. So it seems speed related in some way, but there's no unusual readings there either. Idk...

[Iam Broke]

Still can't get all the info displayed from your log, I'm sure it's an issue on my end. My HPT setup is a real kludge over the years.

I don't have any other ideas right now, hopefully someone experienced with your setup can chime in.

[Leafy]

Issue is, that computer is using alpha-n and on your dyno jet your rollers were most likely lighter than the car, so it didnt simulate the actual loading of the car and the turbo didnt produce the same amount of airflow/boost that it does on the street. Since its alpha-n is give basically the same amount of fuel at wot no matter what the manifold pressure or air flow it. Its what makes tuning one of those computer for a turbo cars a complete pain in the dick.

[IDRIVEAG8GT]

If it's going lean, you could have several different issues. I'd start with fuel filter. If not then fuel pump, if not that, then I'd head straight to spark plugs.

[stromboli86]

If im reading the logs right it almost looks like the crank signal is dropping out.. that could cause some big issues

edit: the tps sensor also goes to zero when the crank signal drops so unless you are stabbing the pedal repeatedly id say look for a loose connection somewhere... hope that helps