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82 244 turbo weird stuttering under boost

ogamer777

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Joined
May 22, 2016
Location
New North Winchestersonville (PNW 425 gang)
I'm driving right now and when I get the car in any boost it feels like the engine is misfiring. It feels like a flat spot in the power band. I set the car up with a manual boost controller and set it to 12-13psi. Lately it's maxed out at 10psi but I have not adjusted the controller since I last set it. Also my mpgs are trash at around 9-10mpg. I don't currently have an oxygen sensor installed and I know that's contributing to the poor fuel consumption but idk about the intermittent stutter in boost. The engine also has an intermittent high idle after driving a little ways. I swapped out the idle air module(?) the thing below the ecu in the passenger footwell. Didn't seem to make a difference.

Also I have a v16 cam so I know the powerband is higher up but this is all occurring in all rpms

All my windows and sunroof are fully open and I'm on the freeway but I don't think the wind resistance would cause that

So I'm at a loss. Mystery boost leak?

Info about car
Stock k jet
15g turbo
Enem v16 camshaft
Do88 intercooler
242000 miles

Thanks for your advice

edit: i just checked the spark plugs and they were tight, but the tip (part that screws on/off and what the boot makes contact with) was loose so maybe it had some bad spark because of bad contact? They weren't about to fall off loose but I could undo them by hand with virtually no effort.
 
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Can you smoke test the intake piping? Hidden slice in a coupler, leaking intercooler, etc. Once I swore up and down I had no leaks in my piping, then found it when a tiny bit of oil came out of the small slice on the bottom of a coupler.

When that happens to plugs, in my limited experience with that issue, they never stop coming loose. I had to get new plugs to stop that problem...the only reason I noticed it was a misfire, the wire was bouncing around with that tip still in the boot haha.
 
I don't have a smoke tester perse, but I have a vape pen haha maybe I could use that

Can you smoke test the intake piping? Hidden slice in a coupler, leaking intercooler, etc. Once I swore up and down I had no leaks in my piping, then found it when a tiny bit of oil came out of the small slice on the bottom of a coupler.

When that happens to plugs, in my limited experience with that issue, they never stop coming loose. I had to get new plugs to stop that problem...the only reason I noticed it was a misfire, the wire was bouncing around with that tip still in the boot haha.
 
A couple things come to mind. The plug gap could be too big causing spark blowout. Also the boost enrichment switch on the firewall may not be grounding pin 7 in the lambda controller. So there isn't any extra fuel under boost. The enrichment switch grounds at about 2.9 psi so it's supplosed to be there when in almost any boost.

To test the function in the ecu you can connect a dwell meter to the test temrinal on the left inner fender. The red wire. Then plug up the vacuum hose going to the switch. Now put a small hand pump like used to testing cooling systems to the switch. Pump it up and observe that the dwell goes to about 75 at about 3psi. Going from memory. But it rises very high. If that doesn't happen. Ground the wire going to the switch and if that works. Then the switch may be bad or has a bad ground connection.
 
I didn't mention spark blowout because it happens at any boost level, the gap would have to be really bad to blow out even at the max boost of this car. I haven't had that under 20 psi, but who knows, I haven't seen it all.
 
Is there an oxygen sensor still installed? Stuttering could also be caused by the car running rich enough to foul the plugs, if it has been running open-loop for a while.
 
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