Technical Technical: Engine management warning light and rough running

[badawn]

L reg Cinq seems to run fine but only seems to be running on 2 of the 4 cylinders.

Red Spark plug light on constantly.

wont do above 55 mph

would it be worth geting a new set of coils ?

plugs and leads are going to be changed too along with oil and filters

any ideas thoughts or just plain help would be fine

i have never come across this problem before rest of the car seems to be running and doing what it should

awaiting your replies

thanks in advance

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[rallycinq]

Re: Engine management warning light and rough running

L reg Cinq seems to run fine but only seems to be running on 2 of the 4 cylinders.

Red Spark plug light on constantly.

wont do above 55 mph

would it be worth geting a new set of coils ?

plugs and leads are going to be changed too along with oil and filters

any ideas thoughts or just plain help would be fine

i have never come across this problem before rest of the car seems to be running and doing what it should

awaiting your replies

thanks in advance

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This would be bnetter asked in the cento section, but, while we're here, with engine running remove and replace one plug lead at a time to find which coil is causing trouble.

Cheers

SPD

 

[badawn]

cheers for that do you think it could be the ecu by any chance i will take leads off tonight and see which coil is giving me trouble ?

thanks

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[rallycinq]

I can almost guarantee its not the ECU. They are incredibly reliable.

The light is on because it is seeing unburnt fuel at the O2 sensor and can't do anything about it, no matter what it tries.

Cheers

SPD

 

[badawn]

ok new coils fitted and seems to be firing on all four cyclinders now but wont rev fully seems to struggle at high revs like its being starved of something ??

red spark plug light still on too would disconnecting the battery for 24 hours clear this fault ?

cheers

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[fingers99]

Did you do as rallycinq suggested or just change the coils? Have you changed the leads and plugs? It's important to diagnose a fault before throwing money at it (unless you are very rich).

Disconnecting the battery -ive for 10 minutes or so will clear the fault, but the chances are -- if it's running rough -- that it'll come back.

 

[badawn]

i have as yet just changed the coils.

the plugs i will change today when i pop to the motor factors

the leads seem to be ok no arking as i can see seems to run fine until you hit the acceleratror then it will rev up fine then gets to a point where it seems to be struggling to get any higher ?

i personally dont think its the leads but i am no expert

thanks for all the help so far

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[fingers99]

Let us know how it goes. At least you looked for arcing!

 

[rallycinq]

the leads seem to be ok no arking as i can see seems to run fine until you hit the acceleratror then it will rev up fine then gets to a point where it seems to be struggling to get any higher ?

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Reduced ability to rev, car is in limp home mode.

There is a sensor playing up, I'd probably start with the O2. don't change it, check it.

Could be TPS, so, again check before replacement.

Nominlas are in the FAQs I think.

Cheers

SPD

 

[badawn]

can any one tell me the firing order on the coils as i think they mabee wrong

starting at the top of coil 1 and working down to coil 2

i have the order of

(3) top
(2) coil

(4) bottom
(1) coil


I think someone has fitted the leads incorrectly before i had the car ?

thanks

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:devil:

 

[fingers99]

What you have is right. Really doesn't matter as long as 1 and 4 are on the same pack, 2 and 3 on same pack. (If you look carefully it's usually on the side of the coil pack bracket thingy).

Check that lambda/O2 sensor out.

 

[badawn]

All sorted seems like it was one coil and a HT lead was Damaged along with the spark plugs on 2 and 4 burnt out totally so all replaced new leads plugs and coils.

after scraping away the crap and build up of muck i found the Ht order as said on the back plate

No more lights no more revs right through the range with out holding back now.

so touch wood all sorted

Thanks for all the advice

much appreciated

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:devil::devil:

 

[fingers99]

Good job!