MR2 Roadster Owners Club

The Workshop => Maintenance, Problems & Troubleshooting => Topic started by: M.Dub on February 7, 2024, 16:07

Title: All cylinders misfire
Post by: M.Dub on February 7, 2024, 16:07
Hi all,

Took the roadster out for a quick drive today after it not getting much use over the past few month and it gave me fault codes for misfires on all 4 cylinders.

I have had random misfires before and changed coils, plugs injectors and checked for vac leaks but it always pops up now and then. Just wondering if there's anything else that could lead to all 4 misfiring randomly?

Any help appreciated

Thanks

Title: Re: All cylinders misfire
Post by: J88TEO on February 7, 2024, 17:09
Have you cleaned the MAF?
Is the fuel contaminated?
Title: Re: All cylinders misfire
Post by: M.Dub on February 7, 2024, 19:22
No haven't cleaned the MAF for a while actually so I'll do that tomorrow.

Fuel is about 5 months old thinking about it, you think that could be the issue?

I'll stick some new fuel in it tomorrow see if it helps.

Thanks
Title: Re: All cylinders misfire
Post by: Gaz mr-s on February 7, 2024, 21:35
Do the MAF only first.
Title: Re: All cylinders misfire
Post by: Joesson on February 7, 2024, 22:14
@M.Dub
Each year since  2011 I have started my 2 after SORN for 6 months with 6 month old fuel that has been in the tank since last use. I typically use Tesco or Gulf Regular
Each time the car has started first time of trying. I suggest your problem is likely elsewhere other than the fuel.
Title: Re: All cylinders misfire
Post by: shiny on February 8, 2024, 06:00
crank sensor?
Title: Re: All cylinders misfire
Post by: M.Dub on February 8, 2024, 10:18
Quote from: Joesson on February  7, 2024, 22:14@M.Dub
Each year since  2011 I have started my 2 after SORN for 6 months with 6 month old fuel that has been in the tank since last use. I typically use Tesco or Gulf Regular
Each time the car has started first time of trying. I suggest your problem is likely elsewhere other than the fuel.

Yes same here, I use V power in mine and it never fails to start first time even after months of none use.

Fuel trims are good etc might check the plugs also clean the MAF although the plugs are not very old.

Title: Re: All cylinders misfire
Post by: M.Dub on February 8, 2024, 10:19
Quote from: shiny on February  8, 2024, 06:00crank sensor?

Is there a way to check? Or just replace and see what happens?

Easy Job?

Thanks

Title: Re: All cylinders misfire
Post by: Carolyn on February 8, 2024, 10:22
Quote from: M.Dub on February  8, 2024, 10:19Is there a way to check? Or just replace and see what happens?

Easy Job?

Thanks



Very often, if it's a crank sensor problem, it's the earth for the sensor that gets corroded.  Unfastening the earth, cleaning it all up and putting it back together will do the trick.
Title: Re: All cylinders misfire
Post by: M.Dub on February 10, 2024, 11:02
Would this always affect all 4 cylinders or could it sometimes affect individuals? I ask this as v had misfire records on random cylinders now not always all 4.

Thanks
Title: Re: All cylinders misfire
Post by: Gaz mr-s on February 10, 2024, 14:41
Do the MAF first.  Easier & quicker.  (the maf sensor is up inside, not the blob at the bottom.)

The earth connection for the crank sensor is at the bottom front corner of the timing case. Bolt & ring terminal.    Jack the car up high, it's ergonomically awkward. If it is the issue, the weak connection makes it random misfire-wise.
Title: Re: All cylinders misfire
Post by: Joesson on February 10, 2024, 19:09
Quote from: Gaz mr-s on February 10, 2024, 14:41Do the MAF first.  Easier & quicker.  (the maf sensor is up inside, not the blob at the bottom.)

The earth connection for the crank sensor is at the bottom front corner of the timing case. Bolt & ring terminal.    Jack the car up high, it's ergonomically awkward. If it is the issue, the weak connection makes it random misfire-wise.
y


I'm sure we all know that jacking the car up is just to enable axle stands to be placed before getting down and under.
But, I would rather mention that which is, hopefully, standard practice to everybody.
NEVER EVER get under or work on a car that is supported by a jack!
Title: Re: All cylinders misfire
Post by: M.Dub on February 10, 2024, 22:23
Thanks for the advice guys, really appreciate it.