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Discussion Starter · #1 ·
Hi all,

Over the last few weeks my 1995 F has had a gradually worsening misfire. It starts on the button, as it always has, but then quickly settles to an uneven idle/misfire.

As soon as you blip the throttle the miss is very evident and that will continue through the revs upto approx 2750 rpm.

I have already had a quick investigation and found the following:
  • rotor arm looks OK
  • dizzy cap looks OK
  • when I removed the cap and rotor I discovered a small oil 'weep' coming from the rear camshaft seal (new seal here and ready to fit).
  • pulling the leads off to remove the plugs, I found a small pool of engine oil down each bore. This presumably is caused by a leaking rocker cover gasket (new one here ready to fit). I assume that oil on the plug threads would affect the earthing of the plug(s) and cause a misfire?
  • with the engine running, I pulled each lead off in turn, trying to find a cylinder that was the culprit. Surprisingly, they all seemed the same upon removing the plug leads. This led me to think that it must be the common link between the cylinders i.e. the ignition coil (dizzy cap or rotor - both already visually checked).The coil was the one fitted on the car for the 11 years I have owned it, so figured a replacement wouldn't do any harm at all. New coil fitted - no difference...
  • I then wondered if I might have a leaking inlet manifold gasket - new one ordered, here ready to fit.

The I saw a thread about the new Rover MEMS diagnostic program/App, so decided to get myself the required cable and software etc and give it a go.
After a few niggly problems, I managed to connect to the ECU on my car (MEMS1.9) and gathered some data. I decided it might be helpful to get some data without the engine running, then start it to get it when it was running, albeit it badly.

I have two CSV files of information that I can share with you (somehow!) if required, but first I wanted to ask:
a) Any other suggestions to the cause of this misfire - things to check and/or replace please?
b) Which readings would you gurus be interested in from the data files that might suggest a cause of the problem?

Naturally I can provide a list of the column headings for the data to help you ask for what might be of interest - but there is probably about 20 of them.

Thanks in advance everyone.
 

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Hi all,

Over the last few weeks my 1995 F has had a gradually worsening misfire. It starts on the button, as it always has, but then quickly settles to an uneven idle/misfire.

As soon as you blip the throttle the miss is very evident and that will continue through the revs upto approx 2750 rpm.

I ha
Hi all,

Over the last few weeks my 1995 F has had a gradually worsening misfire. It starts on the button, as it always has, but then quickly settles to an uneven idle/misfire.

As soon as you blip the throttle the miss is very evident and that will continue through the revs upto approx 2750 rpm.

I have already had a quick investigation and found the following:
  • rotor arm looks OK
  • dizzy cap looks OK
  • when I removed the cap and rotor I discovered a small oil 'weep' coming from the rear camshaft seal (new seal here and ready to fit).
  • pulling the leads off to remove the plugs, I found a small pool of engine oil down each bore. This presumably is caused by a leaking rocker cover gasket (new one here ready to fit). I assume that oil on the plug threads would affect the earthing of the plug(s) and cause a misfire?
  • with the engine running, I pulled each lead off in turn, trying to find a cylinder that was the culprit. Surprisingly, they all seemed the same upon removing the plug leads. This led me to think that it must be the common link between the cylinders i.e. the ignition coil (dizzy cap or rotor - both already visually checked).The coil was the one fitted on the car for the 11 years I have owned it, so figured a replacement wouldn't do any harm at all. New coil fitted - no difference...
  • I then wondered if I might have a leaking inlet manifold gasket - new one ordered, here ready to fit.

The I saw a thread about the new Rover MEMS diagnostic program/App, so decided to get myself the required cable and software etc and give it a go.
After a few niggly problems, I managed to connect to the ECU on my car (MEMS1.9) and gathered some data. I decided it might be helpful to get some data without the engine running, then start it to get it when it was running, albeit it badly.

I have two CSV files of information that I can share with you (somehow!) if required, but first I wanted to ask:
a) Any other suggestions to the cause of this misfire - things to check and/or replace please?
b) Which readings would you gurus be interested in from the data files that might suggest a cause of the problem?

Naturally I can provide a list of the column headings for the data to help you ask for what might be of interest - but there is probably about 20 of them.

Thanks in advance everyone.
ve already had a quick investigation and found the following:
  • rotor arm looks OK
  • dizzy cap looks OK
  • when I removed the cap and rotor I discovered a small oil 'weep' coming from the rear camshaft seal (new seal here and ready to fit).
  • pulling the leads off to remove the plugs, I found a small pool of engine oil down each bore. This presumably is caused by a leaking rocker cover gasket (new one here ready to fit). I assume that oil on the plug threads would affect the earthing of the plug(s) and cause a misfire?
  • with the engine running, I pulled each lead off in turn, trying to find a cylinder that was the culprit. Surprisingly, they all seemed the same upon removing the plug leads. This led me to think that it must be the common link between the cylinders i.e. the ignition coil (dizzy cap or rotor - both already visually checked).The coil was the one fitted on the car for the 11 years I have owned it, so figured a replacement wouldn't do any harm at all. New coil fitted - no difference...
  • I then wondered if I might have a leaking inlet manifold gasket - new one ordered, here ready to fit.

The I saw a thread about the new Rover MEMS diagnostic program/App, so decided to get myself the required cable and software etc and give it a go.
After a few niggly problems, I managed to connect to the ECU on my car (MEMS1.9) and gathered some data. I decided it might be helpful to get some data without the engine running, then start it to get it when it was running, albeit it badly.

I have two CSV files of information that I can share with you (somehow!) if required, but first I wanted to ask:
a) Any other suggestions to the cause of this misfire - things to check and/or replace please?
b) Which readings would you gurus be interested in from the data files that might suggest a cause of the problem?

Naturally I can provide a list of the column headings for the data to help you ask for what might be of interest - but there is probably about 20 of them.

Thanks in advance everyone.
That's a tricky one. Have you swapped the plugs, that would be my first try with a compression test at the same time. I wouldn't have thought a manifold air leak would give these problems, usually that presents as a higher tick over and a flat spot when the throttle is snapped open. ( on cars with carbs).

Best of luck.
 

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Check dizzy cap and rotor arm again...I had a Citroen Bx 16v some years back had fitted new rotor arm, plugs, dizzy cap, etc. would cut out when warm...changed sensors, fuel rail, ecu, etc. (mate had the same model) but could not fathom the problem, also another mate who worked for Citroen at the time put it on their diagnostics but had no joy....then my older brother (who was a motorcycle mech) said he would look at it for me...within a few hours he had found the problem which had eluded me and others, turned out the new rotor arm had an hairline fracture in it which when becoming warm would widen. The dizzy caps I've noticed also sometimes have an habit of the spring loaded carbon brush either becoming loose or the spring weaken meaning the contact onto the rotor arm is lessened.
 

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hi Ian

is the idle air control valve working properly ,

or have you thought about low fuel pressure ? I've had it a few times in customers cars where everything tests ok ,

can you read the knock and misfire counts on the rover meme app? it should show up as cylinder 1 having the most and cylinder 2 having a little , 3 and 4 should be unaffected unless the injectors are weeping.

Ive had it caused buy poor electrics that improve with revs eg alternator, poor pump connections, pump starting to fail , weepy injectors etc etc .
 

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Discussion Starter · #6 ·
Thanks for all your suggestions, much appreciated. However, I have been thinking about this again and it goes back further than I initially remembered.

It actually goes back to the time in May when I brought it out of hibernation in an attempt to get an MOT on it after 3 years... Basically, the fuel in the tank was low (just above he red) and I kept running it around checking things, oving it on the driveway etc - without putting any more fuel in it (as it wasn't road legal).

Then on the day of the MOT I set off and it started spluttering - it was then that I realised that the fuel gauge was hard up to the empty stop - oops! I managed to get to a garage and put about half a tank in it, but it still occasionally spluttered/hesitated. As the emissions were out on the MOT I added some Cat cleaner, a bottle of injector cleaner and a new fuel filter in an attempt to get an emissions pass and to solve the possible dirty tank/fuel issue.

It flew through the MOT retest and it was mostly fine for a couple of weeks - apart from the occasional hesitation/hiccup.

So what could I have done by running it so low on fuel? Screwed the pump up?, dragged up some muck from the tank into the fuel lines and/or injectors?

Thanks again everyone.
 

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Pumps usually stop working when run nearly empty...happened to one of my TF's which went for an MOT...brother took it for me, mot tester was delayed, went to pull onto the bay and cut out. Fuel pump stopped working :(

Could be some crud causing flow to the pump being reduced due to the filter around the fuel pump being partially blocked..everyone tends to forget the filter in the tank! Funnily, one of my other brothers who as a passat diesel has recently had a similar issue...new fuel filters but still no flow..turned out to be the filter in the tank was blocked.

Fuel filter would stop crud getting to injectors so you shouldn't have a worry there.

Other option is to give it a good thrashing to show it whose boss and see if it accepts your authority!
 

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Discussion Starter · #8 ·
Pumps usually stop working when run nearly empty...happened to one of my TF's which went for an MOT...brother took it for me, mot tester was delayed, went to pull onto the bay and cut out. Fuel pump stopped working :(

Could be some crud causing flow to the pump being reduced due to the filter around the fuel pump being partially blocked..everyone tends to forget the filter in the tank! Funnily, one of my other brothers who as a passat diesel has recently had a similar issue...new fuel filters but still no flow..turned out to be the filter in the tank was blocked.

Fuel filter would stop crud getting to injectors so you shouldn't have a worry there.

Other option is to give it a good thrashing to show it whose boss and see if it accepts your authority!
Thanks Dert, much appreciated. Is the pump filter available separately?
 

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shouldn't be too much crud in there as I think its a plastic tank (unless you're a fan of Tesco fuel) and should have a plastic gauze on the end to stop you dragging any big muck though it if it was a blockage it would run worse at higher revs not better , more likely just worn pump as petrol does have a cooling effect and at higher revs the control unit should tell the pump to spin at full whack , or maybe fuzzy connectors inside the actual pump cartridge
 

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I should know this, but I don't. Is there a take off on the fuel rail to enable the fuel pressure to be read?
 

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Thanks Dert, much appreciated. Is the pump filter available separately?
No idea, if I could remember where I put the one I took off I'd take a pic of what it looks like, but not sure where I put it...obviously safe just in case I need it for something :unsure:
 

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Discussion Starter · #12 ·
No idea, if I could remember where I put the one I took off I'd take a pic of what it looks like, but not sure where I put it...obviously safe just in case I need it for something :unsure:
Lol, yes indeed - I have plenty of those places too.
 

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Discussion Starter · #13 ·
I should know this, but I don't. Is there a take off on the fuel rail to enable the fuel pressure to be read?
No idea mate - anyone else know?
 

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Discussion Starter · #14 ·
A little update on this. I haven’t had any improvement, as I haven’t really done much except think about it quite a bit.

Today I fitted the new rocker coved gasket to keep oil away from the plugs and cleaned the IACV. After that I performed a TPS reset. The result = exactly the same 😂

Thinking it’s now probably fuel related in some way, I am going to try the following:
  • remove the fuel filled cap in case there is some kind our air lock.
  • stick some injector cleaner in the tank.
  • give it an Italian tube up as Dert has already suggested.

None of those can do any harm and you never know I might just get lucky... 🤷‍♂️

Will keep you posted. Have a nice weekend everyone.
 

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Discussion Starter · #15 ·
Well.... removed and refitted the fuel filler cap - absolutely no difference (as I expected).

Took it out for an Italian tune up and now it’s actually worse, it’s missing right up the range - bum!

Now I don’t see the point in putting the injector cleaner through it.

Every now and again it seems to clear its throat when it’s on a steady throttle, but maybe I am just imagining that?

How would it run if the timing was out?
 

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You do not have a Pscan tool or anyone nearby who has it, do you? I have it, but I am thousends of miles away.
Asking this in order to see if there are any errors stored in the engine ECU possibly narrowing our search and guessing game.
 

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Discussion Starter · #17 ·
You do not have a Pscan tool or anyone nearby who has it, do you? I have it, but I am thousends of miles away.
Asking this in order to see if there are any errors stored in the engine ECU possibly narrowing our search and guessing game.
Hi RL, I hope that you are keeping safe and well?

I did download and connect the RoverMems software last week and I have two files (one without the engine running and one with it started and running from cold).

Shall I try to upload them?
 

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Discussion Starter · #18 ·
I still keep wondering if I have damaged the fuel pump in some way by running the tank almost completely empty.

Perhaps I should order a pump repair kit?
 

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Hi RL, I hope that you are keeping safe and well?

I did download and connect the RoverMems software last week and I have two files (one without the engine running and one with it started and running from cold).

Shall I try to upload them?
I am well, thanks. Hope the same for you?

I do not know if RoverMems can read error codes? Two files are actually parameters of the engine, but I never tried to diagnose things that way since I do not have baseline parameters to compare with.

If you want you can send them to me by e-mail on [email protected]

Pump can be damaged if run without fuel, but until know I did not hear of damaged fuel pump in the way it would cause this kind of problems (but always can be first time). Pump is either working or is dead.
 

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Have you checked condition of plug leads? on my 1996 F they became brittle and were falling apart when I went to remove plugs...
 
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