Mis-firing m20b25

[325_driver 422]

Grrr, hey guys, now that im 99% finished ofcourse some thing else has to go wrong

my engine is missfiring, so heres my guess, wondering if any one else could agree that it could cause mis firing

Before i ripped the engine out it was fine, plenty of grunt, no misfiring, or shaking of engine,

engine is in a different shell, and ironically runs like a pig.

So all parts below are new

- Leads are fine, firing on every one

- Replaced All spark plugs

- Replaced Rotor

- Replaced Dizzy cap

My guess, in removing the engine, some unnamed idiot (brother) rigged a chain onto the front mount above dizzy

and when removing engine stripped a bolt, mounting the dizzy to the head. so the dizzy isnt propperly secure im assuming, and is on a slightest angle.

CAN this cause a car to run like a pig ?

Yes, that most definately could be a problem ?

Or no the car should run fine all be it its bolted on half decent ?

Edited November 4, 2008 by 325_driver

[323e30 0]

Have you tried the following..

crank angle sensor?

airflow meter?

ecu?

if the dizzy and cap are new ,a micro millimeter difference from the torn nut wont effect it enough to have it misfire i doubt.

[325_driver 422]

Have you tried the following..

crank angle sensor?

airflow meter?

ecu?

if the dizzy and cap are new ,a micro millimeter difference from the torn nut wont effect it enough to have it misfire i doubt.

what is the correct position of the crank angle sensor ?, that may have been moved during the transplant, ecu im unsure of, will have to get it tested, and afm, im pretty sure is working fine, if its going to be a hassle ill just have to hang tight till the turbo build

[325_driver 422]

Right, so after a bit of fiddling, have narrowed it down to the crank angle sensor,

how do i know if it

1- needs adjusting e.g. correct position

2- is farked and needs replacing ?

because now ive fiddled with it, i have NO throttle response what so ever

atleast i know what the problem is,

any help on solving this ?

[323e30 0]

Prob just need to get a new one,

i dont think i have any but ray is bound to have a few

seems to be a pretty common fault during an engine swap for some reason

[325_driver 422]

This is the one on the front were talking about ?

not the ones bolted onto the side of the gearbox bell housing ?

installing a new one shouldnt be that hard? im having trouble following where the wires go

thanks heaps for the heads up

[323e30 0]

yeah thats the one. hopefully that sorts your prob once you replace it, Theres a way to test them i just cant remember what the reading is ment to be tho. normally the just stop working tho, not likly to be an adjustment issue

[325_driver 422]

lol yeah in adjusting it, it managed to get fired off and shot into the alternator, never the less, hoping if ray pops onto this subject, is the top supposed to be shaved off ? or should there be a lip of metal coming out ? e.g. in this picture is it WORN to bugger

[BM WORLD 1270]

the prefacelift model front sensor is only for the diagnostic plug , has no effect on the engine .

is the fuel pump any good , some times they can split and not supply enough fuel .

the ones on the bellhousing do all the work for the ecu . if one of those leads is broken or not pluged in it will also cause issues .

[325_driver 422]

99% sure its a facelift engine, because of the front mounted distributor,

and ever since i touched the sensor on the front its caused a HUGE difference in throttle response, e.g. now i have none

[HELLBM 1531]

Brent is correct if yours is pre-facelift (motronic 1.1)

If its facelift (motronic 1.3) then the crank angle sensor on the front of the block can only be positioned in one place. The bracket takes care of that. The front pulley will be toothed not smooth like motronic 1.1

Check all of your plugs especially the one under the inlet manifold.

Take your pics a bit smaller and clearer. The blur dosn`t help identification.

[325_driver 422]

trying to help out with all the right information here, so some one could point out what is definately the problem,

another thing that ripped off during the transplant were these earths, near the diagnostic plug, if all of them arnt earthing correctly could it cause sufficient power loss ?

in taking the loom off the vehicle there are clips under the intake manifold, if any one knows which ones im talking about, (the injector plugs) i could have got a pair mixed round the wrong way, is there any way that could cause sufficient power loss ?

going to be attacking it tonight

but more so, if theres any thing you guys can rule out, that would be handy

Thanks heaps

Sorry if its a bit confusing, but wiring can some times drive me crazy, and it doesnt matter how well i seem to fN label things, i seem to mix things up. haha aw well, learning

[QuickSilver 0]

No one can point out the definite problem, as we are not there. We don't know what is exactly wrong. But well do out best!

To clarify, your motor is a pre-facelift 325, just seeing the diagnostics plug in the backround is enough, it is the old style. Plus the plug you hold up is not the engine speed sensor that people have mentioned.

That plug that you held up in the photo is not a crank angle sensor, and as again previously mentioned does nothing to affect the motor, its just used for the diagnostics plug.

This means you have the sensors attached the bellhousing of your gearbox - these are known to cause problems.

If your flywheel has lost a tooth or something along those lines this can cause crazy problems for these sensors as they count the teeth. Check it all out!

Another area you may want to check out as Ray has already mentioned is the plug underneath the inlet manifold, this is the plug that connects the injectors to the engine loom - they are SO common to corrode because of where they are and they can open up a can of whoop ass problems on your car with craaazy symptoms!

(its the circular plug directly underneath inlet manifold)

Its a good idea to connect those grounds/wires.

Edited November 4, 2008 by QuickSilver

[BM WORLD 1270]

"Its a good idea to connect those grounds/wires"

ah yes you better conect those wires up they need to be earthed !!!!!!!!

[QuickSilver 0]

"Its a good idea to connect those grounds/wires"

ah yes you better conect those wires up they need to be earthed !!!!!!!!

Hahah I was trying to put it nicely

[325_driver 422]

sorry guys, they were connected, i just un-earthed them to take a photo, and with out that front position sensor pluged in the car wont run, which just confused me, because if that sensor doesnt effect the running of the vehicle, its strange that it doesnt start now.

[323e30 0]

yeah that plug you showed doesnt connect to anything, its purly there for the diagnostic tool, only the facelift engine has the front crank sensor, all motronic engines have the distributor like yours but theres still prefacelift and facelift varients. If your earthing is not 100% all sorts will go wrong aswel so make sure it earthed well.

Are the brown wires under the diagnostic plug earthed?

also mite want to check your fuel regulator if its not starting at all now.

Edited November 5, 2008 by 323e30