It wasn't the air flow meters?

[StuartHP]

Hi All,

further to an earlier post regarding cleaning air flow meters I'm pleased to say that I 'won' some on ebay!

Arrived today, fitted this afternoon...still no better...

If anyone has any suggesttions as to what could be causing it to over fuel and run badly on low rev's please help to put me out of my misery, the summer is here and am itching to get back on the road!

Thanks in advance

Stuart

[Barkychoc]

What does it run like when its cold?
Just thinking along the lines of a duff sensor so the ECU always thinks the engine is cold and enriches the mixture.

[StuartHP]

Hi, thanks for the quick reply!

Its very lumpy and doesn't want to tick over by itself, smells of petrol and will only start with a boot full. I have had the temperature sensor changed also but that didn't change anything.

You seem to have the same thought as the auto electrician who suggested the air flow meters but not familiar enough with the car yet to know what to try next?

Thanks

Stuart

[Barkychoc]

I presume the air filter is reasonably clean?
You could always try it with the air cleaner removed to test it.

What state are the tubes in from the air flow meters to the plenum (big metal bit in the middle).
If there's an air leak anywhere it will run like a pig - the engine is getting air to run but the airflow meter won't be measuring it if there is a leak so it gets the fuelling all wrong.

I've read that squirting lighter gas around the various joints is one test for an air leak - if there is one it will suck in the gas instead of air and run quicker. Sounds like a recipe for an explosion to me!

I'm assuming that its running on all 6 cylinders and you haven't got a simple misfire (which will throw petrol into the exhaust).

Edited by Barkychoc on Wednesday 7th May 20:06

[Jed-S]

Before you get too bogged down with the over fuelling idea, how do you know that it is over fuelling?

Also how long have you had the car and has it always been like that? The reason for asking is that there was a car for sale recently and the previous owner had posted a while ago about over fuelling and I wondered if it was the same car.

Jed

[clarenceboddiger]

I hate to say it as it gets suggested so often but I would opt for a faulty throttle pot, my reasoning is that as this tells the ECU the position of the throttle, if it is telling it(incorrectly) that the throttle is open more than it is, then the ecu will fuel it accordingly ie "overfuel" it. This may also explain why it needs the boot full to start, it needs between around 12:1 and 17:1 fuel/air ratio to ignite, opening the throttle wide may be bringing the ratio within these limits.
Of course the above could be completely wrong but its worth a try, unplug the throttle pot and see what happens, you have nothing to lose.

[Barkychoc]

clarenceboddiger said:

I hate to say it as it gets suggested so often but I would opt for a faulty throttle pot.

Sounds entirely feasible to me.

[entwistlea]

I've had much the same frustration since i bought mine, i put £30 in yesterday and got 90 miles out of it - so pretty sure i have a bit of a problem.

So far i have
changed the throttle pot
cleaned air flow meters
replaced idel control valve ) with a recon)
full service - plugs, cap, etc etc
new air filter.

I then got it idling well, running ok, this last weekend i thought i'd solved teh problem - woohoo, off to work in her ( its tempramental - must be female), anyway, ran like a pig, wouldn;t idle, was popping like a curry fan, misfiring, felt like it was on 5 cylinders, then would run ok.

Nursed her home, got my tools out to sort it... and she ran perfectly....

So, next on the list, check the timing, new temp sender and then get it on a computer...

Like you, still looking for the darned answer...

[StuartHP]

Blimey sounds like a nightmare!

I am going to run through all the basics this weekend following all the advise and if no joy will take it to a tvr garage.

Thanks to all for the thoughts, i'll let you know how i get on

Stuart

[Adrian@]

Throttle pot wired the wrong way round is the norm...reading full throttle at idle. Q. IS this not standard practice to have to to rewire them.
Adrian@

[JT]

I had similar problems. After much fiddling and getting nowwhere it was traced to a poor earth on the ECU.

jake

[StuartHP]

Hi All,

After the weekend fiddle it looks like it could be the throttle pot. I had been told it was okay by the garage but when i disconnected it it ran much better, even pops and crackles on the over run!

Has anyone else bought one recently, I read all the threads on the subject which are all quite old now but am getting silly quotes at the moment?

Stuart

[Adrian@]

I thought that someone else would of popped up with a reply by now...TP,s with gold contacts on were sold by Ford with advice that you bought a new connector and this required that the wires were swapped (it must be 10 years since I have fitted one BUT I must of fitted 50 in my time) so that the TP was closed at idle, it is the first thing that should be checked (if I were to fit one now, I would check up stream of the connector to see what sort of wiring repair has been done when the new unit was fitted, and correct poor joints with soldered and heat shrink). In the past I have had contact failures with these where the sweeping arm has been put in the unit incorrectly and sent these back to Ford. Adrian@

Edited by Adrian@ on Monday 12th May 17:58

[jimed]

The throttle pot on my car was causing a problem some years ago, different symptoms though, and the local diagnostics specialist had it in a few times and found nothing wrong so had it into TVR (you can tell how long ago it was from that) and they diagnosed it straight away so no probs since. Apparently the TP can appear to work fine in static tests in terms of sweeping and resistance but can also apparently get what TVR service described as spikes which upset the system and aren't easy to find without an oscilloscope or something. Hope the new TP cures it OK particularly in this good weather.
Jim

[Adrian@]

"Apparently the TP can appear to work fine in static tests in terms of sweeping and resistance but can also apparently get what TVR service described as spikes which upset the system"......
This is what was showing on the TP's that went back to Ford, a chatter spike as it was opened, because the unit had been built incorrectly. Adrian@

Edited by Adrian@ on Monday 12th May 18:02

[clarenceboddiger]

Well? have you sorted it?

[Colin RedGriff]

It's been a while but I seem to recall they were pretty pricey a few years back, £50 sort of rings a bell.

[Yellabelly]

Try this guy on ebay, I've had a TP from him, they are identical to the Ford TP but only £19.99 ea.
Seem to work OK, at this price it's worth a try.

Item ref:180243301350

[StuartHP]

Hi All,

Good news at last! It was the throttle pot, perhaps with some help from the air flow meters?

All sorted now and went thru the MOT today for good measure so hopefully can now enjoy the summer. Eventually got the throttle pot from tvrparts, just over a £100 with vat and delivery which was painful for something so small but didn't have time to look around anymore and unfortunately didn't see that last post until now.

Thanks again to everyone for your posts

Stuart

[clarenceboddiger]

StuartHP said:

Eventually got the throttle pot from tvrparts, just over a £100 with vat Stuart

Great to see its all sorted.
For future ref the "Usefull Links" thread has the following
"Alternative Parts List"
this has the motorcraft part numbers I know its too late on this occasion but would be usefull to refer to in future for other items.

Edited by clarenceboddiger on Wednesday 21st May 08:37