Montego overfuling

[hairyone]

Can anybody help just got back from Brooklands but car is overfueling badly.I have already changed the vac pipes on the carb valve checked all the other vac pipes and all is o.k.It will idle but it is rough is it possible the stepper motor o rings have died it ran perfect on the way, but i had to keep it to at least 75 mph on the way back to stop it missing and when coming to a stop i had to keep blipping the engine to keep it going.I will check the o rings when it cools down a bit.Just in case has anybody got a carb valve for sale and a set of o rings for a 1989 1.6l montego so i can rule them out.A part from that it was yet again a great day out hope next time to be in the turbo Thanks Mick

[G Force]

hi

Is it pre face lift or is it the 89 1/2 MY with the silver ERIC ECU under the bonnet?

[hairyone]

Old type with the black box ecu

[G Force]

Old type with the black box ecu

Hi in that case have you tried checking the vacuum switch. That's the device that attaches to the carb by two black tubes, and has a vacuum pipe connected to it.


Remove vacuum switch and test diaphragm for any air leaks. (If you suck on the small vacuum connection you should NOT be able to suck air through) PART No. LZX2292

Check to see if any fuel is dripping from the carb vent tube down the back of the engine near the heater drain tube.

[hairyone]

Cheers thats the first thing i thought off but it seems o.k when i suck it you can feel its o.k.The one thing i did was unplug the temp sensor on the head and it did not change and i thought the temp gauge should go to the top when unplugged.When i plug it in it does work normally if not a little low because i changed the themostat not long ago because i thought it was running a bit cool,i have unplugged the fuel ecu a few times and no change and it all looks o.k.I am at a loss becuase it just started as i left brooklands it was fine on the way down

[G Force]

The one thing i did was unplug the temp sensor on the head and it did not change and i thought the temp gauge should go to the top when unplugged.When i plug it in it does work normally if not a little low

Hi ok.

The temp gauge should default to reading around 1/4 on the gauge when you pull off the temp sensor plug.

You would need to bridge the wires of the temp sensor plug to make the gauge read full and flash the high temp warning light.

If the gauge reads cold when you first start the car on a morning and rises gradually to the "NORMAL" position that it has always read. It could be one of the many cars that read on the low side? as the norm.

what gives you cause to feel it is running rich rather than say a bad miss fire? Black smoke? smell of petrol? leaving a pool of petrol at front of car when parked & running? Very sooty plugs etc.

I would do a compression test to assist in your diagnosis, to rule out a valve sealing miss-fire.

[hairyone]

well i have put it all back together tonight and it ran a lot better,after playing with the mixture screw it ran rougher all most cutting out then it smoothed out and it is now running like a dream again so i am happy but just wish i found out the cause.It still puzzles me why it just played up and now its fine because that is the first time i have touched the mixture since the mot in november,i would also like to say thanks for the help