2.0 8V Turbo Misfire

[peter 20]

My car feels like its hitting a slow cut rev-limiter, but only when under heavy load or above about 7psi (but this isnt always the case) somtimes it will do it on low load low revs.

 

So far i have changed;

 

The entire engine wiring loom, (as it had been wired up by a retard)

Spark plugs

spark plug leads

coil pack

Iginition amplifier

Injectors

fuel pressure regulator and rail

ECU

ecu temp sensor

throttle body and all sensors on it

ICV (This seems to make the problem worse when un pluged)

Fuel pump (wired to ignition live so it cant be cut by ecu)

Changed and imprved the earths.

 

the only things i havent change are;

 

fuel filter

crank sensor

 

as i dont have these to hand.

 

 

 

Any ideas? the car did work fine before this

[mang 3]

Does it fight thought the miss fire???

 

[peter 20]

yes!!

 

sometimes it dies if you give it full throttle though, then when i let off it just about comes back to life.

 

pops and bangs while thats happening

[Daviewonder 533 3 Cars]

Sounds a bit like it's over boosting. Do you have one of those spring and ball type boost controllers fitted?

[peter 20]

no bleed valve, it isnt the normal fuel cut that you get when over boost ocurs, ive even tried it with no pipe to the map sensor.

 

ive also wired the fuel pump to ignition live so it cant get fuel cut.

 

it also does it when its not boosting, it was fine running up to 1bar boost or even 1.5 bar then fuel cut kicks in

[Daviewonder 533 3 Cars]

Have you checked the Knock sensor?

[peter 20]

ive tried un-plugging it, ill try a different one though!!

[peter 20]

tried swapping the crank sensor, then not bolting it to the block so it cant detect anything, and it does exactly the same!

 

So i disconnected the ecu temp sensor this made the problem 10 times worse, even though i have tried using a different coolant sensor it makes no difference.

 

BUT, when i plug in the ecu temp sensor and leave it hanging in the engine bay so it will read a much lower temperature the car runs almost fine!

 

:s

[jonnyturbo 3]

story of my life this does it do it when its cold and gets worse when it warms up? im sure i heard about someone leaving there temp sensor plugged in but left on the side at the car ran fine.

[dave205 19]

story of my life this

 

Same here unfortunatly

[peter 20]

YES!! when its stone cold it seems fine, boot it for 30 seconds (past the point of caring to warm the oil up) and it starts farting along the road.

 

It did work fine though!?! with the sensor plugged in. then one day starts misfiring!

 

i tried running it with the sensor plugged in but to the side of the engine, this seems to work ok until the engine gets hot then it misfires on idle and on low amounts of load.

 

it also spat a load of oil out of the breather.

[jonnyturbo 3]

mine starts up idles fine when im guessing choke is on, rev it a few times and starts back firing worse etc as it warms up, mine sounds like this on tickover though

http://www.youtube.com/watch?v=lyUDrlrNlvo

 

seems i have alot of crank pressure in mine as its smoke out of the oil filler but not spitting oil out though.

[peter 20]

never heard a tick over like that. have you tried running it with the sensor plugged in but not in the engine? this does seem to sort mine out.

 

As for oil out the breather i was running 1.5 bar of boost so probably down to that.

[jonnyturbo 3]

runs a little worse with it plugged in to a sensor outside.

[peter 20]

Mine runs quite well :s

[peter 20]

MELTED PISTONS AND LOOSE SPARK PLUGS

[M@tt 77]

i take it its buggered then?

[peter 20]

well mine is

 

 

 

 

but it was an experiment to see what would happen with as much boost as that little turbo would produce.

The reason mine was breathing so hard was melted pistons though.

 

My low rpm misfire i think was loose spark plugs but thats just a guess as i only found that after i took the engine out.

[Tom Fenton 1,541]

So what max boost did it produce then??

[peter 20]

only 1.5 bar 22psi.

 

unfortunatly my wideband afr turned up a bit late so i have no idea what afrs it was

[jonnyturbo 3]

wish mine was loose spark plugs

[peter 20]

have you changed everything?

[jonnyturbo 3]

Yeah everything new apart from crank sensor and knock sensor which iv changed for known working ones

[peter 20]

ECU?

[jonnyturbo 3]

Yep for 3different ones