[Mk2] [Turbo] Misfire - REV2 Turbo

[Charged]

Hi all,

sorry, not much information to go on here.

I have a misfire at roughly 4500 RPM in all gears.. in low gears it will pass through this REV range very quickly but the misfire is there.. it is much more noticeable in 4th and 5th gears.

Plugs have been checked and gap closed down a bit..
Leads have been swapped
Dizzy seems ok, fairly new, rotar arm is fairly new as well.

I just want to pin this misfire down as it stopped me going to the Pod at the weekend.

What else can I be checking?

Thanks

Ollie

[ben_mr2]

silly qusetion but hav u checked all clips are really tight on the pipes. i had this a few months ago. i changed everything on it. then went round and really tightened everything up. also try resettin ur ecu. i didnt hav any codes stored but it made a world of difference!!!!!

[Charged]

It cant be a boost leak surely as it will boost through the problem and it only misfires at a certain rev range (between 4500 and 5000RPM)

I haven't reset the ecu yet.

[BenF]

If you can adjust the boost does it also misfire at lower boost pressures?

Misfires are 9 times out of 10 HT related so you're looking in the right area already IMO.

Only other thing I'd add is that if you're running non Toyota dizzy cap and arm I'd replace them as they've been known to cause flatspots even when new in the past. Also - do your HT leads have a year of manufacture on them (Toyota ones do)? Anything older than 5-7 years is well past its best IMO.

You tried the old trick of running the engine in the dark to see if there is any HT leaking away?

Hmm ...given it is passing 4,500 rpm it isn't likely to be an igniter issue that folks have had in the past.

[Charged]

Ollie,

If you can adjust the boost does it also misfire at lower boost pressures?

Misfires are 9 times out of 10 HT related so you're looking in the right area already IMO.

Given it is passing 4,500 rpm it isn't likely to be an igniter issue that folks have had in the past.

This is the strange thing Ben..

Boost was set at 13psi.. and has been for months. The misfire developed so the plugs were tightened but also the boost was adjusted to 15psi. At 15psi it was fine.. no misfire so it looked like tightening the plugs had done the trick. The same evening I put my footdown and it boosted just past 16psi because it was very cold weather. The ECU didn't like it and it went in to safe mode (no boost at all..). The next day the boost was turned down to 13psi but the misfire reappeared straight away.

So at 15psi there is no misfire
at 13 psi there is a misfire

[RobCrezz]

Ollie,

If you can adjust the boost does it also misfire at lower boost pressures?

Misfires are 9 times out of 10 HT related so you're looking in the right area already IMO.

Given it is passing 4,500 rpm it isn't likely to be an igniter issue that folks have had in the past.

This is the strange thing Ben..

Boost was set at 13psi.. and has been for months. The misfire developed so the plugs were tightened but also the boost was adjusted to 15psi. At 15psi it was fine.. no misfire so it looked like tightening the plugs had done the trick. The same evening I put my footdown and it boosted just past 16psi because it was very cold weather. The ECU didn't like it and it went in to safe mode (no boost at all..). The next day the boost was turned down to 13psi but the misfire reappeared straight away.

So at 15psi there is no misfire
at 13 psi there is a misfire

Did you ever resolve this mate? as im having the same problem.

[Charged]

yes mate, it was dodgy wiring. We rid did the earths and it has been fine since!