Misfiring??

[Sweeny]

Recently had my engine rebuilt, and its done over 1k miles now, and all has seemed well up until now.

I did my last oil and filter change, let her warm up, then started to put the boot in a bit.

Got upto about 5-6k revs hitting about 1 bar or maybe just over and it sort of cut out like it had a fuel/boost cut, then started missing straight away.

It seems to read fine on the commander of my power fc, no knocking or anything unusual. And i even plugged the standard ecu back in but still the same problem.

I've changed everything i.e. plugs, leads, dizzy, rotar arm, and the compression seems fine.

Any ideas .

 

[Fast Guy]

Any boost leaks? split air lines etc? Fuel pump?
Is it a full time misfire now or only when you get to about 1bar?

Do you have another gauge to confirm it is 1bar?

 

[Sweeny]

Any boost leaks? split air lines etc? Fuel pump?
Is it a full time misfire now or only when you get to about 1bar?

Do you have another gauge to confirm it is 1bar?

Yep, its a full time misfire, even on tick over, cant hear any boost leaks etc and the fuel pump appears to be fine as its noisey as f00k when i turn the key, and i have the standard gauge and an aftermarket one too

 

[Fast Guy]

compression seems fine

Did you do the test? If not do one
I'd be tempted to pull the plug leads and injector leads off one at a time to see which (if not all) cylinders it's missing on.
Other lines of attack are :- Ignition amp, Cas, afm, injectors, fuel filter, ignition timing, valve timing, broken rocker arm?
I don't know much (well anything) about the power fc but maybe that could be playing up. :?

 

[Sweeny]

compression seems fine

Did you do the test? If not do one
I'd be tempted to pull the plug leads and injector leads off one at a time to see which (if not all) cylinders it's missing on.
Other lines of attack are :- Ignition amp, Cas, afm, injectors, fuel filter, ignition timing, valve timing, broken rocker arm?
I don't know much (well anything) about the power fc but maybe that could be playing up. :?

Not done a compression test as yet, need to get a tester, but the compression wouldn't just drop like that would it :? .

I pulled the plug leads off one at a time and seemed to be the same on all.

It just happened all of a sudden so i'm swaying towards a broken rocker arm, but would i not hear this rattle, coz the engine is still quiet.

 

[geetee]

yes it would lose compression like that if it chucked a ring or 2 :?

 

[Sweeny]

yes it would lose compression like that if it chucked a ring or 2 :?

Please no :x .

 

[geetee]

Halford's do a pretty cheap compression tester.... screw in type, think it was about £15 - 18 IIRC.

It's a half hour job and is good for putting your mind at rest (or otherwise).

Cheers
GeeTee 8)

 

[Fast Guy]

If it's on all 4 it's unlikely to be compression (not impossible tho)
It might be worth checking the dizzy hasn't moved and your timing's OK.
After that I think it's be worth looking at the ignition amp/cas or afm.

 

[Sweeny]

Halford's do a pretty cheap compression tester.... screw in type, think it was about £15 - 18 IIRC.

It's a half hour job and is good for putting your mind at rest (or otherwise).

Cheers dude, i'll be getting me one of these .

If it's on all 4 it's unlikely to be compression (not impossible tho)
It might be worth checking the dizzy hasn't moved and your timing's OK.
After that I think it's be worth looking at the ignition amp/cas or afm.

I checked the dizzy timing etc and its fine, will try an afm off a mates R just to check its not that .

And the ignition amp/cas what are these and how do i check them :? :lol: .

 

[Olly]

Hard to check Ignition amplifiers but if you can borrow one thats a good thing to try. Normally they miss at a constant engine speed.
8)

 

[Anonymous]

Try checking your plug gaps.
Relatively quick and easy to do. Also free

Sounds simular to a problem i had, which turned out to be the plug gaps were to large. I set mine at 0.8 for 1 bar boost

 

[Sweeny]

Hard to check Ignition amplifiers but if you can borrow one thats a good thing to try. Normally they miss at a constant engine speed.
8)

I'll borrow one off a mate then .

Try checking your plug gaps.
Relatively quick and easy to do. Also free

Sounds simular to a problem i had, which turned out to be the plug gaps were to large. I set mine at 0.8 for 1 bar boost

I will mate, but would the gaps suddenly change as it was fine one second and poo the next.

 

[Mr GTiR]

has Si been near your engine ? :shock: :lol:

 

[Sweeny]

has Si been near your engine ? :shock: :lol:

:roll: I knew that woz coming :lol: :lol: .

At least mines managed to get over 1000 miles .

 

[Mr GTiR]

At least mines managed to get over 1000 miles .

LMFAO, hell it would be rude not to fella :lol:

Well the new one will be mint! Have you got this fixed yet? I've got plenty of spare if you need anything electrical

Hope you get it fixed before the next owner gets it

 

[Sweeny]

At least mines managed to get over 1000 miles .

LMFAO, hell it would be rude not to fella :lol:

Well the new one will be mint! Have you got this fixed yet? I've got plenty of spare if you need anything electrical

Hope you get it fixed before the next owner gets it

Not fixed yet, but got a few things to try tonight. New owner, what you on about :? .

 

[Sweeny]

Just done a compression test and its fine, narrowed it down to number 4 by takin the injector plugs off. So hopefully its the injector thats gone down, and i have one on its way tomorow from the good old uncle winnet.

Are injectors known to go down like this??

But if its not that then the rocker cover will have to come off to check the rocker arm's not f00ked. So fingers crossed.

 

[zia]

what injectors are you using and at what duty cycle? is it mapped with the fc? is it constant missfire right from start up to peak rev range?

zia

 

[Fast Guy]

Some one had a problem with a broken injector wire a while back.
Also the resistor block thingy wotsit could be worth looking at.
It may be worth getting them cleaned (properly) this should involve a flow check and let you know if they're ok or not.