Alright folk.

I own a Widetrack Blob STI (PPP), with a Nur Spec R. I've only been driving it for about 2 weeks.

Car currently has what seems to be a misfire that happens after 4000rpm, and goes away by approx 6000rpm, it only happens on full throttle (to the floor) and you can hear the pops in the exhaust. It sounds similar to antilag.

Using my laptop and sh*tty free OBD2 software I found the following codes:

P0125
P0196
P0234
P0299
P0357
P0443
P0455
P0736
P1143
U0101 (and another UXXX one).

Now the majority of these codes seemed like nonsense, not related to anything really, except one that said "Turbo/Supercharge Over/Underboost condition". Which sounded a bit vague.

I did notice that the Throttle Position Sensor read 11.8% and 78.8% at foot-on-the-floor. Arent these supposed to read from ~15%-100%?

In order to try and sort out the TPS, I did an ECU reset today. The codes strangely stayed on (then the laptop battery died), but after reset, the car took slightly longer to start as I expected it would, and seemed to have slightly dulled the performance. Even though I drove it off boost until I could drive left-foot braking, in 3rd for about 10-15secs.

Since the reset, it seems to misfire slightly less violently, but more often. As in a wider spread across the rev range, and under less throttle (now 7/8 as opposed to WOT).

I will be taking it to my mechanic next week, but do we have any ideas? I'm inexperienced and certainly not a mechanic, but I'm thinking plugs? The TPS reading is puzzling me too. After that, possibly NPS, or crank angle sensor? I'm just guessing now really.

Just to add, the car is perfectly drive-able and quick in any conditions other than WOT 4500rpm-6000rpm (peak boost?) and has no CEL.

Apologies for the essay!

 

Anyone?

 

Not that I know much but I wonder if your car's had pops n bangs mapped in....but that wouldn't explain any fault code's.

 

It's not been mapped and the pops are on throttle not overrun.

 

P0125 Insufficient coolant temperature for closed loop fuel control
P0196 Engine Oil Temperature Sensor Range/Performance
P0234 Engine Overboost Condition
P0299 - ??
P0357 Ignition Coil G Primary/Secondary Circuit Malfunction
P0443 Evaporative Emission Control System Purge Control Valve Circuit Malfunction
P0455 Evaporative Emission Control System Leak Detected (gross leak)
P0736 Reverse incorrect gear ratio
P1143 Pressure sensor circuit range/performance (low)
U0101 - Lost Communication With Transmission Control Module

 

If I remember with regards to the P0125 if the sensor is knackered it will run like a bag of ****e.

Your correct on the TPS reading it should read 100% at full throttle.

What codes have remained on since your reset the ecu?

 

Sounds like the same problem I'm having with my RA fella i have changed MAF with no improvement suspect coil packs and plugs but also water temp censor as start up always takes two turns of the key? Which I think is down to not reading correctly not adding enough fuel when cold but i could be completely wrong lol

 

Cheers guys! It's drives fine apart that the above issue. It does seem to be running very rich since the ECU
reset though. Starts first time and is very well mannered.

All the codes have remained but the software was awful and may have been due to that. This weekend I'm back at home so will get Torque for my android tablet and see what that says and if that can clear it.

 

Right then. Cleared the codes fully and went for a drive. Misfire happens on fill throttle north of 3500rpm. Basically when boost kicks in. It's thrown the following codes and no more:

P0244 Turbocharger Wastegate Solenoid A Range/Performance
P0102 Mass Air Flow (MAF) Circuit Low Input
P0108 Manifold Absolute Pressure/Barometric Pressure Circuit High Input

That's the MAF then? I've just fought bloody plugs!!! This doesn't explain my dicky TPS readings though.

Would a MAF give my above symptoms?

 

Just remembered I unplugged the MAF and a couple of other sensors to make sure there was nothing wrong with the connectors. The engine was off but ignition on.
Does that explain my codes?

 

For your info when mine pops and bangs it also sounds like its coming from the middle of the exhaust - nur spec r . Mine are on over run though but deffo sound like there coming from the front to middle of the exhaust

 

Yeah I get that some times but this is defo under full throttle.

 

Plug Gaps...

 

That's what I was hoping. I bought some NGK PFR7Bs. Ill have a look through the history, if its had plugs recently ill just put these on the shelf and regap the existing ones.

 

it sounds like the car is overboosting, has it been decatted??

p0224 usually happens at overboost and cuts the power to avoid damage

 

It's got a PPP with a Blitz Nur Spec R. No other mods. Reached about 1.2 bar of boost according to the Torque app on my tablet.

 

Out for a run again today and cleared all the codes. It misfired, and no codes came back.

TPS still showing 11.8%-78.8%.

Suggestions?

 

So have you fitted the new plugs?

 

No not yet. I have limited tools and a 120mile drive tonight so didn't want to get stuck halfway through haha

 

Right I'm home now and I've been through the history. It had plugs in January. NGK PFR6Bs. Are these sufficient for a PPP? I've got PFR7Bs sat here on the table that will probably be for sale soon. Only other thing it might be would be the TPS. That's the only thing that seems out of place. Reading between 11.8% and 78.8%. Would that cause a misfire? NPS? I've no other codes.

 

Gearbox neutral switches are a complete **** on these, they were either the plastic tip off or fail to operate. can cause missfire codes & switches the avcs off.

have you decatted it on the ppp ??

 

That's the thing I've no codes. No CEL. it crossed my mind that it may be that but how can I be certain? The car was sold with the PPP on from new and it had a Nur Spec R fitted. So it'll still have the cat in the downpipe.

 

The misfire went away for a few hours last night. The car drove like a dream. Then when it came back it was a lot less noticable than before.
Any suggestions? It seems to be NPS but Ive also got that dicky TPS reading. Change both?

 

You dont often get a code for a neutral switch, they just fail... usually you may get a missfire code if your lucky

 

your TPS should real from 0 to 100%, Ive seen cars only hit 80% due to a thick car mat, and also less (92%) due to a under voltage battery(if your car is stood and then you check it)but have no reason besides being faulty for the 0 to 11.8% your missing.

 

Righto! Cheers lads, that's promising. And I don't think it's the floormat as I can feel a solid end to the pedal travel. From what I can see, the screws on the TPS seem impossible to get to without removing the recirculation valve from the intercooler. Am I right?
Also, I'm presuming due to wear and tear, it's best to replace the NPS with a new one, but is is a new TPS required? Or just one that is known to be working? Cos I can see this getting to being £150 of sensors and labour + VAT on top of that as well.

Hmm. I just want it sorted!

 

Would the faulty NPS cause a misfire?

 

*UPDATE*

Fixed by Brian at Cams. Turned out to be the NGK plugs that were fitted in January by a well known Subaru garage were actually Bosch, not gapped at all (2mm?) and only finger tight. I wont name the garage but will send by PM if interested. Car is now running like an absolute beast. My license wont last long!

I thought I'd post an update as I saw plenty of threads that looked to be never resolved when I was searching.