Misfiring - Doh!

[Flyboy]

Hi Folks.

First of all - have a great Christmas

Now, down to the pain. I've been misfiring for a little while now.

Going back a few years (to points and low tension circuits), this 'miss' inclines me to think that I have an electrical issue. As such I replaced the plugs, cap, leads and rotor.

Every time I replace something (or just clean up) the problem goes away, albeit temporarily.

Initially, this problem occurred when I was stuck in traffic and my stop/start journey took 2-3 hours. She misfired dreadfully and I did wonder whether I would make it home.

She always starts and runs but I feel that power is not what it should be and pulling away in a higher gear than is sensible causes 'kangarooing'.

I have noticed that although the heater works, the gauge takes a while reaching the 3 O'clock position. Also, whenever I take out the plugs (which is quite often) they are always a little sooty - but they are firing because they're not completely black and coked up.

I know from experience that replacing stuff piece by piece can be time-consuming and expensive, so any ideas would be great. I don't have a Haynes but I'm not an idiot and can find my way around most engines.

C'mon Santa - bring me a fix, please......

Phil.

[JamesV70R]

Does the gauge sit at the 3 o'clock mark (or therabouts) while driving, or does it start dropping?

I'd be inclined to check the thermostat - they're only about £10 ish (iirc) so it could be a cheap easy fix.

[Flyboy]

Actually, on reflection, the gauge hardly ever reaches the correct position.

Great minds think alike they say - I've just returned from the shop having ordered the new Thermostat

Another fact that may be of interest - the idle also appears higher now than ever before. Just the round trip to the motor factor plus the odd deviation and she's idling at 1200. Normally this car is spot-on 875-900.

I get the impression that I have a good fuel system but suspect somewhere in the electrics. The real question is whether extraneous factors like the temperature is having some effect on the whole setup.

Why are cars nowadays some damned complicated!!!!!

Thanks for the idea - we're on the same page my friend.

Phil.

[JamesV70R]

Fingers crossed thats done the trick!!

Forgot to ask - is the managment light on? What year is the car?

If the car isn't getting to temp it will run richer (i think?) to generate more heat, to warm itself up quicker - self defence in a way. You'll probably notice a small change in your MPG too!

Throw the new thermostat in, take the car for a drive and make sure it gets fully up to temp - quick blat up the A41 should do it!

[Flyboy]

Yep - everything crossed

1998 2.5 10 Valve (Non-Turbo) Manual.

No management lights. Yep - MPG does seem a little low.......

Will change Thermostat tomorrow and update.

Good logic regarding the compensation for thermals - that probably means that this won't work - after all, when are car's logical?

A blat up the A41?? Local knowledge huh? Couldn't do that on the M25 could we?????

Thanks.

[JamesV70R]

Yeh, I'm only 10 mins round the M25 - Local knowlege indeed!

Naturally this blat staying within the legal limits, you never know who's sat in one of the laybys waiting ... !

[dgunthor]

when you changed the leads, did it include 6 leads - one to the distributor and 5 for the plugs?

[Jules_V70R]

'Every time I replace something (or just clean up) the problem goes away, albeit temporarily.
'

I'd be checking earthing points if this was happening.

Just a thought. I had an X1/9 years ago that did this and it was fixed by putting a new earth strap on the battery.

[Flyboy]

Hi Guys.

Well, I have read some very interesting posts searching for this particular problem and the opinions / advice ranges pretty widely.

On the battery front, someone posted that one of the 'supplemental' red wires that attaches to the +ve terminal came adrift on his car - that wasn't the case with mine (too darned easy). Grounding is another interesting theory and I'll cross that bridge another day if I need to.

I was about to experiment with cleaning the throttle body etc, but I guess I got lucky!

The advice from Villian, which I was looking into anyway for my heating issue, turned out to be the culprit. One replaced Thermostat and Hey Presto!

I now have no misfire and as the engine is warming up quicker it is also more comfortable in this chilly time of year.

Thanks for the input fellas - As usual, a problem shared....................

Phil.

[JamesV70R]

Awesome, thats what we like to hear, a problem solved! You'll be surprised at the number of people who disappear after getting help!