Engine Miss fire and hesitation
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Not many rules really, this board being aimed at technical issues, it shouldn't fall foul (hopefully) of some of the more personal issues that can affect forums.
Rule 1 - Is that you need to think very carefully before posting anything technical or asking anything technical relating to the security system of the car - See 'Security Issues' sticky for more info.
Rule 2 - We (MGF Register) do not support copyright infringement and therefore references to CD ROM, PDF versions or paper copies of the workshop manual (for instance) should not be posted on the forum. We don't want to get into trouble and we'd rather sell you a genuine hard copy through our Regalia shop anyway!
Because advice is honestly and freely given in this technical section, much of it will be amateur experienced based, so any information is given in good faith and is not guaranteed as correct.
Engine Miss fire and hesitation
I wonder if anyone can help.
I have a low mileage (52k) MGF 2001 which I had sitting around all winter sorned. I got it back on the road but it has developed a mis fire and hesitation both when warm or cold. It’s ok for the first minute then problems from then on.
I have changed the fuel filter and taken tank pump out of the tank to clean which it didn’t need.
I bought a cheap scanner and it showed cam sensor and lambda. My assumption was these may show anyway with a bad mis fire as a symptom not a cause. Even so I changed cam sensor and coolant temp sensor. I also replaced coil packs, spark plugs and leads. All have made no difference.
I could go on replacing sensors - lambda, crank, idle control etc but suspect there is a more systematic approach.
Any advice appreciated.
I have a low mileage (52k) MGF 2001 which I had sitting around all winter sorned. I got it back on the road but it has developed a mis fire and hesitation both when warm or cold. It’s ok for the first minute then problems from then on.
I have changed the fuel filter and taken tank pump out of the tank to clean which it didn’t need.
I bought a cheap scanner and it showed cam sensor and lambda. My assumption was these may show anyway with a bad mis fire as a symptom not a cause. Even so I changed cam sensor and coolant temp sensor. I also replaced coil packs, spark plugs and leads. All have made no difference.
I could go on replacing sensors - lambda, crank, idle control etc but suspect there is a more systematic approach.
Any advice appreciated.
- Chris Tideswell
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Re: Engine Miss fire and hesitation
Is this the MPI or VVC engine?
- Barbour
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Re: Engine Miss fire and hesitation
Perhaps a reset of the throttle position sensor will help:
- Turn the key to position II.
- Give it full throttle 5x
- Then wait 15 seconds
- then start the engine.
Also, a bottle of injector cleaner before a refill helped a lot on my F and TF, old petrol tends to gum up injectors etc, worth a try I guess. Are you running on 98?
- Turn the key to position II.
- Give it full throttle 5x
- Then wait 15 seconds
- then start the engine.
Also, a bottle of injector cleaner before a refill helped a lot on my F and TF, old petrol tends to gum up injectors etc, worth a try I guess. Are you running on 98?
Cheers!
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Re: Engine Miss fire and hesitation
Thanks will try that. Premium petrol make a difference ?
Tx
Tx
- nigelandjo
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Re: Engine Miss fire and hesitation
New leads needed possibly. Coil packs starting to fail?
Nigel May
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- Barbour
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Re: Engine Miss fire and hesitation
Yes.
Don't use 95/E10 anyway, they don't like it..
Cheers!
Safety fast, S3XY, Born from jets...
Xpower grey 2002 MG-TF 135 SP CP
Steel grey 2003 Ford Mondeo Estate Centennial
Blue 2019 Tesla Model 3 SR+
Anthracite 1998 MG-F 1.8 Mpi (sold)
Silver 2002 Saab 9-5 Aero Estate (sold)
Safety fast, S3XY, Born from jets...
Xpower grey 2002 MG-TF 135 SP CP
Steel grey 2003 Ford Mondeo Estate Centennial
Re: Engine Miss fire and hesitation
I have unplugged the lambda sensor and the misfire stops so I think I should conclude I need a new sensor. My question is should I bother if the engine seems to work without this sensor plugged in ?
Thanks
Thanks
- Barbour
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Re: Engine Miss fire and hesitation
Yes, it's there for good reason.
Cheers!
Safety fast, S3XY, Born from jets...
Xpower grey 2002 MG-TF 135 SP CP
Steel grey 2003 Ford Mondeo Estate Centennial
Blue 2019 Tesla Model 3 SR+
Anthracite 1998 MG-F 1.8 Mpi (sold)
Silver 2002 Saab 9-5 Aero Estate (sold)
Safety fast, S3XY, Born from jets...
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Steel grey 2003 Ford Mondeo Estate Centennial
- talkingcars
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Re: Engine Miss fire and hesitation
It is actually "firmly and fully depress the gas peddle fully 5 times in 30 seconds" and "wait 30seconds".
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- talkingcars
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Re: Engine Miss fire and hesitation
All MGR cars since '96 are designed to run on E10.
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- Barbour
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Re: Engine Miss fire and hesitation
talkingcars wrote: ↑Sun Aug 08, 2021 1:20 amIt is actually "firmly and fully depress the gas peddle fully 5 times in 30 seconds" and "wait 30seconds".
I stand corrected...
Last edited by Barbour on Mon Aug 09, 2021 2:27 pm, edited 1 time in total.
Cheers!
Safety fast, S3XY, Born from jets...
Xpower grey 2002 MG-TF 135 SP CP
Steel grey 2003 Ford Mondeo Estate Centennial
Blue 2019 Tesla Model 3 SR+
Anthracite 1998 MG-F 1.8 Mpi (sold)
Silver 2002 Saab 9-5 Aero Estate (sold)
Safety fast, S3XY, Born from jets...
Xpower grey 2002 MG-TF 135 SP CP
Steel grey 2003 Ford Mondeo Estate Centennial
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Re: Engine Miss fire and hesitation
I had the same problem on my 01 MPI it was the first Lambda sensor before the cat , I bought a replacement and went to a local exhaust center who managed to remove the old one .it needs to be on a lift for access . The car runs better now , Running with it disconnected may cause it to over fuel which is not good.
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