Running Rough once warm

[MADNESS]

I've made some good progress with my Tasmin FHC last few week ( considering lack of time ), I've got the engine running and charge coming from the alternator.
Problem which I do have, once the car warms up after say 3-5 mins running, the engine develops a misfire, if I up the revs it'll keep running otherwise it just dies .

Any idea what could be causing this?

(1980 Tasmin 280i S1 FHC)

Cheers

[mrzigazaga]

Hi mate


Sounds like lack of fuel....Has anyone touched the mixture adjustment on the metering head?

[MADNESS]

I was thinking maybe lack of fuel, when I first got it running it was ticking over nicely.
I put 5l of fuel in it but still the same problem, have not adjusted anything on the fuel injection side .

I do have lots of other bits to do on the car, just looking for ideas for when I next work on it.

[jon haines]

Could be so many things, out of tune, lack of fuel something more sinister or lack of use! These cars need to be used, most of the running probs I have had over the years have been when I havent being doing many miles in it.

[mrzigazaga]

When it is warming up is the rpm high?

[RCK974X]

Or a faulty electrical connection/no power to the warm up regulator...... Can you smell petrol at the exhaust pipe when it runs rough ? 'cos it will go rich if this is so. Try contact cleaner (or even WD40) on those engine front plugs....

[MADNESS]

It hasn't been used for 20 odd years, when I first got it going it run and ticked over nicely, it now starts and ticks over nice when cold, the revs seem to sit at around 1100rpm, once warm it struggles to keep running.
Can't be a lot wrong with it!

Another thing that don't work to well is the rev counter, it kind of works but don't go back to 0 when the engine is turned off.

[mrzigazaga]

Has the fuel filter in the bulkhead been changed?.....Also it could well be valve clearances...At high idle there is enough compression but when the idle drops then air is escaping through slight valve recession ...

Edited by mrzigazaga on Monday 8th May 10:38

[MADNESS]

I changed the fuel filter which sits next to the fuel pump at the rear of the car, that is the only one?

Ill check the valves then, as when I rev it up it clears and runs on all 6 again

[TA14]

When I stopped using mine everyday and laid it up for winter I had this kind of trouble. A 45 minute drive through the Pennines cleared it up nicely every time. I figured that water must condense/capillary action into unwanted areas and the heat would eventually get rid of it.

[mrzigazaga]

MADNESS said:

I changed the fuel filter which sits next to the fuel pump at the rear of the car, that is the only one?

Ill check the valves then, as when I rev it up it clears and runs on all 6 again

No...there is a large one up near the metering head...This system is very sensitive to cruddy fuel....Ideally a good run out to blow the cobwebs away but I would make sure that everything else is okay first...

Be careful changing the bulkhead filter as using the alloy nut on the unit can lead to catastrophic circumstances!!!...
I can give you a good tip for that....

[MADNESS]

Would love to give it a good run, it's a little way off that right now though!
I'll take a look for the other fuel filter by the metering head, hadn't noticed one there and could well be the problem.

[mrzigazaga]

Check valve clearances....Valve recession is a real problem....

[MADNESS]

Had another look over the car tonight, found the hose going from the air box to the engine has split, I put some tape over it and now it's running well again!
It's not 100% as has the odd occasional miss on tick over, responds well to the throttle etc.

Thanks for all the advise guys 👍

Got some more questions coming up, I'll start a new topic though :-)

[MADNESS]

[mrzigazaga]

Thats good news....You could always do away with the concertina hoses and fit something like I did on my dear Delilah....

[MADNESS]

I'm having a look about now for a replacement hose, love the look of your engine bay!

Seen I can get the stock ford part for £38, it don't look half as good as the red one there though!
How dose fitting a hose like that affect the engine? The ford one seems to decrease in size on the connection points, thinking with air passing through this it'll cool the air? On the red one there it looks the same id all the way.

[TA14]

The red one will be higher flow and less time for the engine to heat the air. Tim at ACT usually has a good stock/able to get a bespoke one made.

[mrzigazaga]

I used these...
http://www.autosiliconehoses.com/silicone-hose-sho...
Have a measure of the throttle body OD and the rubber cap, they should be the same....I think it was 80mm but might be wrong...

[marcus1875]

Nah the ODs are different. The airbox end is bigger. Well it is on mine.
Marcus