DaveDSM
20+ Year Contributor
- 294
- 0
- Mar 12, 2003
My car has been having problems under boost. In 1st gear, I will floor it, and the boost will go up to 16psi, then drop straight back to 7 psi. In 2nd or 3rd though, it will go up to 16psi and hold it until the car starts to buck and hesitate around 4k-5k. I've tested for boost leaks and datalogged this, here is what I've found:
My Hallman ES has a copper fitting in the hose to the wastegate that has a hole in it. This leaks a lot under intake leak testing. Is this supposed to be there? I couldn't get past 7 psi without covering that hole on the testing.
My plugs are gapped correctly, and the plug wires are on tightly(2 year old Magnecores).
After getting rid of leaks in my intercooler piping, and taping off the hole in the wastegate hose fitting, my car only goes up to 16psi. I found leaks at the dipstick and the oil cap.
On the datalog, in first gear I floored it, but my TPS reading only hits above 90% once. The rest of the time it was showing only 77%. At idle, my TPS shows 10% when I'm not even touching the pedal.
First gear datalog shows 29 counts of knock at 36xx, then goes down to only 2 counts by redline.
Third gear (where it holds the 16psi til 4-5k) shows TPS at only 77% and 20 some counts at the same spot, then it drops.
Fuel injector pulse doesn't exceed 16.8ms in any of this. Fuel trims are showing 118% for low, mid, and 119% for high. o2's are .85-.89v at 77% tps, but at 99% tps they're .76v
I don't know where to start with this. My base fuel pressure is set at 50psi on 450 injectors. I have a 90 AWD, 14b with Stage 1 mods, a walbro 255, and a 5 knob afc currently zeroed out.
Under boost it sounds like I'm hitting a rev limiter in 3rd or 4th. Yet my TPS isn't showing that I'm flooring the car when I am.
What all should I look for and check into? It looks like boost spike in 1st, but then in 3rd it goes to 16psi and holds. Fuel trims say I'm running lean, o2's and injector pulse look o.k. I'm confused.
My Hallman ES has a copper fitting in the hose to the wastegate that has a hole in it. This leaks a lot under intake leak testing. Is this supposed to be there? I couldn't get past 7 psi without covering that hole on the testing.
My plugs are gapped correctly, and the plug wires are on tightly(2 year old Magnecores).
After getting rid of leaks in my intercooler piping, and taping off the hole in the wastegate hose fitting, my car only goes up to 16psi. I found leaks at the dipstick and the oil cap.
On the datalog, in first gear I floored it, but my TPS reading only hits above 90% once. The rest of the time it was showing only 77%. At idle, my TPS shows 10% when I'm not even touching the pedal.
First gear datalog shows 29 counts of knock at 36xx, then goes down to only 2 counts by redline.
Third gear (where it holds the 16psi til 4-5k) shows TPS at only 77% and 20 some counts at the same spot, then it drops.
Fuel injector pulse doesn't exceed 16.8ms in any of this. Fuel trims are showing 118% for low, mid, and 119% for high. o2's are .85-.89v at 77% tps, but at 99% tps they're .76v
I don't know where to start with this. My base fuel pressure is set at 50psi on 450 injectors. I have a 90 AWD, 14b with Stage 1 mods, a walbro 255, and a 5 knob afc currently zeroed out.
Under boost it sounds like I'm hitting a rev limiter in 3rd or 4th. Yet my TPS isn't showing that I'm flooring the car when I am.
What all should I look for and check into? It looks like boost spike in 1st, but then in 3rd it goes to 16psi and holds. Fuel trims say I'm running lean, o2's and injector pulse look o.k. I'm confused.
