misfire problem??

[Peculiarfish0]

the CAT on my BRM has crumbled away, (rattles pretty loud now)
Took it for an emissions to see if the engine was running properly
& it came out like C02 17 times what it should be, etc.

Everything was waaaaay off!

Also been told its got a misfire!
I hadnt noticed this, it sounds ok to me, & ran fine apart from the obvious noise from the cat.

Tryin to find somewhere to get a diagnostics test on the ECU, see if it can shed some light Before i strip down the head & have a look...

Any ideas? or similar problems happen to you?

Getting worse & atouch smokey, temps fine etc coolant n all that.
Petrol consumptions terrible! lol & can smell it out the exhaust.

Worried this is gonna turn into a costly procedure!
Cheers guys for any help.

[Adam]

The cat has a dramatic effect on emissions, so hopefully that'll be your only problem.

I've got a sports cat on mine and passing MOT's is a nightmare as you have to get the engine really really hot! How are they diagnosing the misfire? If the exhaust is popping from cold then this isn't a misfire, its simply unburnt hydrocarbons hitting the dodgy cat.

[Frekkel]

I have a decat, much better for the sound, a lot worse for mot

[spankyban]

Hmm, you have a cat.. then you have a decat.. what is actually on the car? how are they dtecting a midfire.. if you have the cat on and it is misfire/stuttering i woudl guess it's the innards that are chocking causing the car to run leaner and therefore incorrect fueling, continued use of the car liek this will cause piston ring issues and potentially bore scoring.

Have you ran the car the opposite way round to how it was tested. Unplug the batt and leave for 15mins - so that ecu can learn new base setting then measure agin?

[spankyban]

EDIT.. just read on a bigger screen.. you do not have a decat

[Peculiarfish0]

um.. that all just confused me abit.. lol
I've been told the following..
without a cat - the engine should be running at certain CO2 emissions etc
(as a rough guide, say 1000) & it runs at like 8000 odd.. fast idle?
sumin sumin tis way off, the lamda reading drops when you rev, which it aparently shouldnt do (down to like 5-600, & it shouldnt drop below 7-800?)
& from listning to the engine & exhaust i was told by two differant mechanics that it was misfireing.
Possibly a bent crankarm/shaft? or sumin.. & told to get the ECU scanned first. (like £60 or sumin!) as it might diagnose the problem for us.

[Peculiarfish0]

btw what the hell is this smiley suppose to represent?? :deadhorse:

[The Youngsta]

Sounds like the missfiring could be a head gasket
they often on go on these engines, take it into a rover dealer, and ask them to do a test, which defines whether or not that is your problem.
Have a look see if it is guzzling water? if so almost definatly, you can put 2 and 2 together!

[The Youngsta]

btw what the hell is this smiley suppose to represent?? :deadhorse:

well, if you are talking about cows getting eaten alive qhilst being whipped, then this is the perfect smily for this occasion! :mml:



or maybe not :sad::chop:

[Adam]

um.. that all just confused me abit.. lol
I've been told the following..
without a cat - the engine should be running at certain CO2 emissions etc
(as a rough guide, say 1000) & it runs at like 8000 odd.. fast idle?
sumin sumin tis way off, the lamda reading drops when you rev, which it aparently shouldnt do (down to like 5-600, & it shouldnt drop below 7-800?)
& from listning to the engine & exhaust i was told by two differant mechanics that it was misfireing.
Possibly a bent crankarm/shaft? or sumin.. & told to get the ECU scanned first. (like £60 or sumin!) as it might diagnose the problem for us.

Best to get it sorted at a garage or dealer then I reckon. If somethings bent it could end up costing!

btw what the hell is this smiley suppose to represent?? :deadhorse:

Flogging the dead horse, was some old saying or somesuch.

[The Youngsta]

Flogging the dead horse, was some old saying or somesuch.


Oh Its A Horse :gathering:

[Dom]

check it's not something stupid like a dirty air filter first...

a spot of routine maintenance (clean the spark plugs) might help too... cheapest things first!

[spankyban]

check it's not something stupid like a dirty air filter first...

a spot of routine maintenance (clean the spark plugs) might help too... cheapest things first!


Second to that.. plus oil and filter change as well!

doubtful anything bent though

[marc_brm]

you'll struggle to bend anything in a k-series. i've had trouble with the map sensor before which can make it misfire.

[Peculiarfish0]

ok yeah i'll give the sparkies a clean n check out the air filter etc..

hopefully not working tomorrow so should get a chance to get diagnostics done on the ECU! will keep updating if i find anything out

Cheers guys

[Peculiarfish0]

Havent had a chance to get it to the Diagnostics place,
So ECU hasnt been scanned yet.

Going to do a compression test tomorrow. as it may be running on only 3 cylinders...

With the ECU scan/diagnostics thing, Do any of you know if the RAC or AA can do it? like from their vans, as i was thinkin of waving one down & asking, but havent seen any, dont wanna waste a call out if they cant! lol

Cheers guys will update tomorrow!

[Dom]

should be able to?

[Peculiarfish0]

okies.. done compression test.
Cylinder 1,2 & 4 are ok at 190, cylinder 3 is only at 175ish

So we are gonna pump some compressed air through see if we can hear a leak or sumin.. hopefully anyway if its quiet enough this evening! too much damn traffic all the time!!

[Luti]

The car should pass with a dodgy broken CAT. I've recently had a VVC MGF pass with a rattling CAT

[Luti]

The coils on the back of the engine can deteriorate with water running past them. If the car has never had these replaced then I would suggest changing them. I'm changing mine soon just to prevent a missfire in the future.

[spankyban]

Any news on the cylinder that was down?

[Peculiarfish0]

..cars wont pass an MOT with a broken cat... would fail on the emissions..

Stuffed some compressed air down, no signs of a leak anywhere..
So onto checking other problems, gonna swap over the coil things, as if that is causing the loss of pressure, it would then be on a differant cylinder.

Will keep updating..

[Dom]

a coil wouldn't cause a change in pressure... have you checked your coolant for exhaust contamination?

[Peculiarfish0]

nah it wont, but the cylinders only down by about 10-15
not enough to cause the emissions to be down so badly & the cylinder still runs ok, anyway swapped them over - all the same so it isnt that lol

Next thing (which is pretty much last on my list to check)
Dodgy injector. so tomorrow its onto the annoying, but cost-free task of removing the thing that says VVC on it etc & swapping two of the injectors over see if it changes, hopefully it does cause i really just wanna get it sorted now! lol

[Peculiarfish0]

spent like 5hours messing about with the car yesterday.

It isnt the injectors, took it apart twice & swapped over differant ones, no change.

However, it now seems, that the two right hand cylinders are doing all the work, & the left hand two arent doing much at all!?

Very confusing, gonna av to start taking off the camshaft covers etc & checking them, probs wont bother till monday tho as im bit busy over the weekend..

Anyone had this specific problem before?
will keep updated

[brmatty]

have you ever thought that the cam-belt may have slipped a tooth....my mate had this happen to his vi ...it would still run but had all the signs of a mis-fire....we carried out a timming belt alignment check and found that it was a tooth out after much head scratchin!!!...check that the timming marks align....... new belt properly re-timmed cured it!! he was very lucky no valve damage occurred.......

[Peculiarfish0]

aye thats what i need, little things to check, that arent obvious! lol & dont cost anythin to check either helps =P

Cheers for your input mate i'll have a look on monday, gonna be takin off the cam covers anyway checking they arent worn down or anything etc etc

Will let you know if i discover anything! Cheers again

[Peculiarfish0]

im back! lol didnt get round to checkin them cams yet etc..
Took it for a diagnostics, & it had a whole list, deleted them (except ambient air temp wouldnt delete) Took it for a spin, 2-3miles, & scanned it again.

Only thing there was the ambient air temp sensor again..
Checked it & its working correctly so it says..
Lamda sensor is telling the ECU that its running rich. But ECU isnt changing anything.. so still no idea what the problem is..
My MOT runs out on monday, so tomorrow is the day to find out!!!
otherwise im f**ked, as i cant get to work lol
Any new ideas? We were gonna have a look at the Map-sensor tomorrow morning.. not 100% sure what it all does tho etc or how to check will see what me mate does with it lol :shoot2:

[Peculiarfish0]

okies map sensor is now a possible suspect... as we think it runs better without it connected.. need to find one that works to swap over see if it helps before going out & buying a new one! lol just incase, MOT is runs out tomorrow, so getting abit desperate now to fix it by wednesday!
anyone know roughly how much they cost?