Subaru Impreza WRX Full Boost Problem

9

99belle99

New member
Hi all first post on these forums so bear with me. I bought a 2001 Subaru Impreza WRX bugeye (Irish Car) a few months back and everything is fine when you drive the car normally(Like revving up to 4500 etc..) but if you drive the car hard revving up to the near the red line you will get a misfire fault in cylinder 3 and car is acting like it went into limp mode.

I have a bluetooth OBDII scanner which I hook up to my android phone with the app torque and read the misfire in cylinder 3 fault and clear it and then drive the car normally again and everything is fine no misfire faults or nothing.

Does anybody here know what the problem is?
 
Could be a whole heap of things
Maf, coil pac,plugs,knock.

Best get it looked at by a professional
 
Might Help :thumbsup:

*This is not a thread for posting your own misfire problem!*
Please start your own thread in the General Maintenance & Troubleshooting forum. Please do feel free to post your own resolution to misfire problems though in this thread.

Once or twice a week an individual posts about having a misfire issue. This is a very common problem and there are alot of threads addressing this very problem. So here are the possible issues (read this first,then post about an issue if you have no resolution after trying said solutions):


[FONT=&quot]MISFIRES[/FONT]​


1. Wrong, worn or incorrectly gapped spark plugs. Generally NGK work best gapped between .028"-.030".

2. Clogged/dirty/bad injectors or fuel filter. Try changing the fuel filter. On the 04+ WRX's/STI's double check the fuel pump"sock" in the tank. The maintenance schedule for the filter is every 30K miles. Have the injectors professional cleaned or at least run several bottles of a good injector cleaner through the gas tank. Also make sure you are using the correct octane gas! Either 91 or 93 unless you are specifically tuned for another octane!! (IE: race gas or E85) You can swap injectors from another cylinder and see if the misfire follows. If so this would indicate an injector issue if it does move..

3. Check valve clearances & compression. Perform a leak down/compression test first.The FSM has the valve clearance specs. This is a complete PITA with the motor in car.

4. Dirty MAF sensor. This causes an incorrect airflow readings. Misfires can result. Clean with CRC MAF cleaner or NON chlorinated brake cleaner. Make sure you are actually cleaning the MAF sensor and not just the IAT sensor. Common mistake.

5. Vacuum leaks or preturbo leak. Check where the FPR hose connects (generally you could get a P0457 or P0171 with this as well). Check the turbo inlet pipe where it connects to the turbo. This pipe is famous for ripping and causing a huge preturbo leak (P0171 as well).

6.Poor grounds/grounding. Clean the battery ground cable and ones that run to the intake manifold. Make sure all are connected. These are sensor grounds and must be kept clean.

7. Cam timing. Check cam timing per the service manual. Clean the cam sensor and crank sensor face.

8. Excessive PCV blow by. PVC gases will effectively lower the octane content of gasoline/petrol and can cause misfires along with knock. Get a catch can or air/oil separator.

9. Carbon build up in heads/cylinders. You can use Seafoam or top end cleaner as well as other type of carbon remover.

10. Lightweight flywheels or crank pulleys. (phantom misfires) Can cause false misfires. Opensource tuning can disable.

11. Bad/loose coil pack or coil pack connector. Test coil pack and move to other cylinder to see if DTC changes. If so this would indicate a coil pack issue. Also check the tower boot for corrosion. Use dielectric grease on all connections.

12. Faulty fuel pressure regulator or fuel pump. Check fuel pressure. It should be between 35-38 psi idle @ sea level. Removing the vac line at idle should give you 43 psi. The FPR is a 1:1 rising rate. For every 1 psi manifold positive pressure the fuel pressure should rise 1 psi. You will need a mechanics fuel pressure gauge and have to install a schrader valve in the fuel system before the FPR. Best place is right after the fuel filter on the bug eyes or right before the hard lines under the manifold.

13. Faulty front O2 sensor. Replace with new. That easy. The OBDII system will probably let you know.

14. Damaged crank timing gear. The one behind the crank pulley.

15. Misfires all cylinders: Coil pack connectors mixed up (correct way:black to back,white to front),light weight flywheel,bad/unplugged crank or cam sensor,incorrect gaped plugs,cam timing off or wrong spark plugs.
Flashing CEL = Gross misfire. A DTC is not always stored. The resolution is generally one of the ones listed above.
FYI-The bugeyes were plagued with misfires. Updating the ROM in the ECU to the latest revision from Subaru helps alleviate most false misfire issues. This can be done through the stealership or opensource software.

source - http://www.clubwrx.net/forums/gener...553-if-you-have-misfire-code-please-read.html
 
Thanks for that wall of text Colm but tbh I do not have a clue where to begin finding out each of them faults(I'm not very technical)

I see that post above I suppose I could clean the MAF if I find a good guide online with plenty of pictures and text to explain what to do.

If that fails I will have to go to a specialist. Any good ones around? I don't mind travelling to someone who knows their stuff.
 
exactly, I could go first two gears all the way to the red line no problems, third gear, if I went from lows, like lets say 2k rpm to 6k rpm, then in high rpm's I got CEL.

Fourth gear, as soon as I got around 4500-5000rpm it appeared. It usually didnt appear right away, but with like 5-10 seconds delays.

Fifth gear, I never managed to get above 4500rpm, so never experienced it there.

Only difference from your explanation to my case is, that I didnt feel any difference in how the car was behaving, it drove just fine as if nothing was happening - truth be told, as soon as the CEL started flashing, I released the gas not to damage the car in case something more serious.

Also, sometimes CEL just came on and stayed on, sometimes it was flashing for a while then disappeared, and sometimes it was flashing and then stayed on.

Errors were varying from cyl 1-4, but cyl3 was always there and mostly if only one appeared, it was 3rd cyl.

Edit: Even if our symptoms are exactly the same, I would still recommend you getting it on diagnostics and getting this confirmed by professionals. The Neutral switch costed me about 50-60yoyos, so not that dear. Diagnostics in Authorised Subaru was about 80 yoyos, so all in all total was about 150yoyos including the labor in Caroll and Roche
 
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Zheiko said:
exactly, I could go first two gears all the way to the red line no problems, third gear, if I went from lows, like lets say 2k rpm to 6k rpm, then in high rpm's I got CEL.

Fourth gear, as soon as I got around 4500-5000rpm it appeared. It usually didnt appear right away, but with like 5-10 seconds delays.

Fifth gear, I never managed to get above 4500rpm, so never experienced it there.

Only difference from your explanation to my case is, that I didnt feel any difference in how the car was behaving, it drove just fine as if nothing was happening - truth be told, as soon as the CEL started flashing, I released the gas not to damage the car in case something more serious.

Also, sometimes CEL just came on and stayed on, sometimes it was flashing for a while then disappeared, and sometimes it was flashing and then stayed on.

Errors were varying from cyl 1-4, but cyl3 was always there and mostly if only one appeared, it was 3rd cyl.

Edit: Even if our symptoms are exactly the same, I would still recommend you getting it on diagnostics and getting this confirmed by professionals. The Neutral switch costed me about 50-60yoyos, so not that dear. Diagnostics in Authorised Subaru was about 80 yoyos, so all in all total was about 150yoyos including the labor in Caroll and Roche
Click to expand...

Thanks that is a very helpful post.
 
Looking up on coil packs for my car. And I noticed my 2001 bugeye should have FK0140 but the ones fitted to my car are FK0186 which are off a the newer 2.5 engine. Does it make any difference?
 
Have you put a fresh set of plugs into it? That would be my first port of call, especially if car is new to you..

Also there is a difference in high revs and full boost....

Load up the car in high gear, this will bring on full boost earlier in the rev range, chances are you will get the problem now lower in the Rev range.

But if your not mechanically minded, just cut to the chase and get someone to fix it for you
 
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