Idle surge and no acceleration in boost

[555*]

03 WRX
COBB AP 93 Stage 2 tune
Catless TBE
AEM short intake (out of the box tune)
STI TMIC

Problem:
Car sat for a week and went to start it and it fired up and idled pretty normal and after about a minute or 2 it started surging from about 500 rpm-1000. Car drives fine if its under boost. If I give it gas and get it into mid boost it just feels like I'm pulling a dump truck behind me.

Attempted problem solving:
Did the ol carb cleaner test to see if there were any vacuum leaks around couplings, ends of hoses, etc. Probably even over did it but no changes in idle. Cleaned MAF which was not dirty at all. Unpluged MAF, car died. Not showing any codes either. Cleaned the IACV and replaced the gasket which looked fine anyways. No dice. Tried swapping out the IACV for a known working one. Again no worky. Unplugged IACV, idle increased to about 1500 and stayed steady. Fresh tank of 93 oct gas. Installed a Hallman Boost controller last night, since my pro tuner prefers tuning with that and it didn't help either (didn't expect it to). Any other suggestions?

[zax]

Does the car consume/burn oil? Do you have a lot of oil blow-by?

[555*]

Oil level appears to be about the same level it was. It ran great. Sat for a week. And started it up and it does this. If I drive under boost, car runs great till I start going up a hill, etc that puts strain on the motor. Then it starts stalling and sounds like it wants to backfire. And of course the idle surges from 500-900ish. It does have a kill switch that I turn off whenever I shut the motor off. Could that reset the ecu? I tried swapping a different untuned ECU over and it ran the same. tried scanning with the COBB for codes but it just says none found. I'm about to rip my hair out.

[zax]

Oil level appears to be about the same level it was. It ran great. Sat for a week. And started it up and it does this. If I drive under boost, car runs great till I start going up a hill, etc that puts strain on the motor. Then it starts stalling and sounds like it wants to backfire. It does have a kill switch that I turn off whenever I shut the motor off. Could that reset the ecu? I tried swapping a different untuned ECU over and it ran the same. tried scanning with the COBB for codes but it just says none found. I'm about to rip my hair out.

Re-flash the Stage 2 tune and log the following parameters on the AP:

Boost
Throttle Position
Dynamic Advance Multiplier
Feedback Knock
Fine Learning Knock
RPM
Calculated Load


Take the system out on the road and drive it hard. Post up the log file and link here.

[555*]

When I got the car, it only came with a OBD connector and the V1 accessport. I reflashed Stage 2 and said "done". But have no way to log it.

[zax]

When I got the car, it only came with a OBD connector and the V1 accessport. I reflashed Stage 2 and said "done". But have no way to log it.

Yeah IIRC you can't log with the V1 AP.

HOWEVER, you may still be able to log. If you contact Cobb, they may be able to get you up and running with AccessTuner Race, which can datalog.

[555*]

Yeah it only logs boost. Which is 8-9 psi idleing, depending on the surging RPM.

[zax]

Yeah it only logs boost. Which is 8-9 psi idleing, depending on the surging RPM.

Do you mean -8 PSI?

[555*]

Yes, lol. Sorry.

[zax]

What does your maximum boost read in a 2nd gear pull?

[555*]

It won't even get into boost. It like slows down and then starts jerking if I try to give it more gas so I have to down shift to a lower gear so it stays out of boost and slowly take the hill by my house. If I try to keep giving it gas, it will go up to about 8-9psi. I havent adjusted the MBC, either....

[zax]

It won't even get into boost. It like slows down and then starts jerking if I try to give it more gas so I have to down shift to a lower gear so it stays out of boost and slowly take the hill by my house. If I try to keep giving it gas, it will go up to about 8-9psi. I havent adjusted the MBC, either....

OK, I would seriously suggest putting the OEM EBCS back on the car. Without a datalog, it's virtually impossible to diagnose anything. Follow my post below and contact Cobb.

[555*]

Will do so. I'm hopeing it is something small. I believe the cable can be used to datalog straight to my laptop with Enginuity?

[mycologist]

Yeah IIRC you can't log with the V1 AP.

HOWEVER, you may still be able to log. If you contact Cobb, they may be able to get you up and running with AccessTuner Race, which can datalog.

My V1 AP cable worked perfectly with Romraider's logger - I think it didn't work for some other people, but mine was fine.

[mycologist]

Kind of sounds like a bad fuel filter. I'd look at A/F learning and fuel pressure (with a gauge in the line temporarily).



Check for leaks in the intake track, make sure the filter box is closed, torn turbo inlet coupling etc.


(this in addition to what Zax is saying, not disagreeing with him at all).

No codes? That part seems bizarre.