MR2 turbo wont boost over 10psi? misfires

[Revo]

Picked car up last week (rev 3), running at 15psi no problem

Left in garage for a week due to snow.

Got out this weekend and its got a misfire kicking in causing the car to shudder and drop power unless I wind the boost down to just under 10psi


The battery did go flat and we had to jump it. Would a poor battery cause this (its also got a fair bit of audio kit to power). Although I guess not if the car is running?

Any tips for some basic things I can check or likely causes?


Many thanks

[Marf]

Check all the HT leads are connected to the dizzy ok. My king lead kept coming loose a couple of weeks ago which was causing a misfire above 8psi.

[Revo]

OK cheers mate, will give that a try

[Quigonjay]

but its running fine at 10 psi?
if so you where probably just hitting fuel cut

[Marf]

Fuelcut on a Rev3 is 19psi though, I never see overboost of more than about 1.5psi in cold weather with my boost controller set to 15psi

[Quigonjay]

18 mate, with the cold weather it would only take a tiny spike to take it over

[Revo]

Well touch-wood I fixed it just by taking it out for a blast.

left it on 10psi and took it for a spin then gradually turned the boost up to 15psi and its been fine. not a single misfire.

fingers crossed it holds up!

[greeny]

What fuel you running?

What turbo?

Do you get any cel flashes or checked for codes?

[Revo]

No cel flashes, cant check for codes without faffing around with flashing LEDs apparently.

Running Vpower, unknown uprated tubby

Although sometimes the Traction control "TRC" warning light comes on and wont go until i restart the engine.. Don't think thats related to the misfire I had though?

[RobCrezz]

Might just be due to dizzy cap or leads being wet. higher boost always seem to show up any weakness in the ignition.

[greeny]

Well it cant be a rev3 turbo/actuator as the lowest boost you can run on a rev3 actuator is 13psi IIRC.

Maybe take a pic of the turbo?

It could be ignition probs as said above, id pull your plugs and take a look.

It could also be picking up some pinking/det.

1.2bar on one turbo is alot different to 1.2bar on a bigger turbo. If your running a bigger turbo then you might be trying to run too much boost!

Are you still on the OEM intercooler?

Id check for codes also, its pretty easy to do.

[Marf]

Well it cant be a rev3 turbo/actuator as the lowest boost you can run on a rev3 actuator is 13psi IIRC.

With my boost controller off I get 8psi until about 5000rpm, then the boost creeps to between 10-11.5psi depending on how cold it is outside.

[greeny]

Well it cant be a rev3 turbo/actuator as the lowest boost you can run on a rev3 actuator is 13psi IIRC.

With my boost controller off I get 8psi until about 5000rpm, then the boost creeps to between 10-11.5psi depending on how cold it is outside.

Really i thought the rev3 actuator was 13psi?

Maybe remembering wrong then!

[Marf]

Nah its around the 8psi mark, its the boost level you get when the ECU decides boost is too high for the gear you are in/outside temp too cold/knock is detected, that is assuming the ECU and TVSV are still in control of the boost.

[ci_newman]

No cel flashes, cant check for codes without faffing around with flashing LEDs apparently.

Running Vpower, unknown uprated tubby

Although sometimes the Traction control "TRC" warning light comes on and wont go until i restart the engine.. Don't think thats related to the misfire I had though?

Checking for error codes is ****-easy with the use of a paper clip Don't be a lazy bu88er!

[RobCrezz]

Well it cant be a rev3 turbo/actuator as the lowest boost you can run on a rev3 actuator is 13psi IIRC.

With my boost controller off I get 8psi until about 5000rpm, then the boost creeps to between 10-11.5psi depending on how cold it is outside.

Really i thought the rev3 actuator was 13psi?

Maybe remembering wrong then!

Mine goes as low as 0.6bar with boost controller off I think.

[Lee @ 3S Service Centre]

stock actuator pressure is 0.5bar and then teh vsv bleeds off about 0.3bar to give you around 13psi of boost.


it sound like your iginition components where wet, possibley a crack in your coil and now it has dried out its nto struggling with the increaed load on the engine.

definately ignition and wet related though

lee

[JJ]

All the above factors will contribute to misfiring... First protocol though,

Pull the plugs out.. and decrease the gaps to 0.6mm then see how it goes... The odd weak lead ( in the cold ) and combination of fuel enrichment and cold air can disrupt the spark.

By reducing the gap in your case, you're increasing the spark attributes.

Often enough too, people chuck in spark plugs without checking the gaps, in the summer, you can generally get away with it, however, if they're a cold grade plug, incorrect gap.. this all contributes to the plug breaking down.