Help please - Engine cuts out

[MickS2]

A couple of weeks ago my 2.9 developed an intermittent fault of the engine cutting out (as if the ignition had been turned off) for a few seconds and then bursting into life again. It only happened whilst accelerating, if I just trundled along at a constant throttle opening it was fine. Disconnecting the Throttle Pot "solved" the problem, but leaves the engine somewhat gutless in limp home mode
I replaced the TP with a spare I had kicking around - problem returned
Replaced throttle pot again (with my second and final spare) - same problem. So probably not the TP?

Are the symptoms I'm getting typical of a dodgy TP?
I didn't check the replacement TP's in terms of open/closed resistance - am I right in thinking that doing this would give optimum performance but failure to do it would not result in the cutting out at mid revs that I am getting?

My thoughts are turning to the wiring/connector that runs next to the rocker cover (I have had problems with this before) but on checking it all looks good.

Anyone got any ideas of what else I should check/change else?

Thanks in advance

Mick

[Barkychoc]

Have you checked / sorted the yellow connector in the steering column that melts and burns out?
Sounds like a classic symptom.

Cue Norman with a pic.....

[Gerald-TVR]

As requested

[/quote]

[MickS2]

Barkychoc said:

Have you checked / sorted the yellow connector in the steering column that melts and burns out?
Sounds like a classic symptom.

Cue Norman with a pic.....

Thanks for the suggestion, but that is all sorted (with hefty soldered connections)
Mick

[Barkychoc]

Could be worth asking nicely for a loan of the tester.....

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[MickS2]

Barkychoc said:

Could be worth asking nicely for a loan of the tester.....

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Yes, that looks easier to use than the Gunson one that I tried a couple of years ago. However as the ECU does not store a fault log am I right in thinking these testers are of limited use in tracking down an intermittent fault?

[Barkychoc]

From what I've read it does allow a 'wiggle' test of the wires - probably one of the most useful tests of all!

[MickS2]

Barkychoc said:

From what I've read it does allow a 'wiggle' test of the wires - probably one of the most useful tests of all!

That will be very useful - I'll dig out my Gunson tester and see if that supports a "wiggle" test, if not I'll be after loan of the Star tester.

Thanks

Mick

[Elfit]

Now come on.
If you're going to use technical terms please use them correctly.
It's not a wiggle test it's a waggle test

If you get your wiggle mixed up with your waggle who knows where you'll end up!

It was the waggle test that did it for me. Once the machine is plugged in you waggle every wire you can find. If there is an interuption in the connection the light goes out.
As I have said before the machine is very simple to use it only takes a couple of minutes and may be an easy way of highlighting a problem.
At presant it is ( still) on it's way to Steve (LastS4) The post office seem to be holding onto it at the moment. Most of the price of postage goes towards storage costs these days.....

Cheers
Tim

[MickS2]

Tim
I want to get the problem sorted before this Sunday's Prescott Hill Climb event so will try the Gunson tester - but have not had much joy with it previously.

If this does not fix it then, in slower time, I'll be looking to borrow the Star tester if I may. Will PM you if necessary.
Cheers
Mick

[Colin RedGriff]

Another thing worth checking is the injector wiring that sits by the coil. One wire from each injector all come together in a poorly executed joint. I remade the joint by splitting them out and soldering them together in 2 pairs of 3 and then using an insulated screw terminal to join the 2 joints together.

[Elfit]

Hi Mick
The tester does not belong to me. I borrowed it from Graham (Harry1972M) ages ago. He offered to lend it out to others in this thread http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Steve contacted him and asked to borrow it. Graham agreed and I sent it on.
I suggest that you contact Graham to ask him if you can borrow it once Steve has finished with it. It is highly unlikely that you will get it before Sunday as it hasn't even arrived at Steve's house yet, Graham is on holiday and you are at the other end of the UK.
Sorry!

Try the Gunson tester. Even if there is not a specific "waggle" test it's worth waggling the wires when its pluuged in. It may show an error.

Tim

[Gerald-TVR]

Hi Mick see you at Prescott

Norman

[MickS2]

Hi Norman
I'll be there, even if I have to continue to run the poor old girl in "get you home" mode
Mick

[clarenceboddiger]

I know its unlikely you have 3 Dodgy TPs but I would be looking at that part as I dont see why a poor connection would only cause problems when accelerating also it describes a TP fault perfectly.Is there no one near you who can let you try a known to be good TP?

[jimed]

If it sounds like a TP problem maybe its the wiring to the TP that is the problem? Would using a meter to check the connector and wiring (with suitable waggling of course) be any use there?
As another thought as you had a spare TP in the garage is it new or just an old one from somewhere? I did have trouble with my S several years ago that was intermittent and was eventually found to be a spike in the TP which normal testing in terms of resistance and TP wiper working, etc. didn't locate so maybe the spare TP was lying about for a reason - unless you know otherwise.
(Hope you get it fixed quickly - nothing more annoying than a simple problem that's hard to find though!!
Jim

[MickS2]

Jim
All three TP's are good AFAIK.
I thought I had a TP problem (intermittent misfire) about four years ago. The Local TVR dealer (they existed then!) said a Cerbera TP is a substitute for the S one and duly sold me one. Fitted it and it made no difference. Tried Austec and they said Cerbera one is not good for S so bought a Granada one from a Ford dealer. Fitted it, no difference. Hence three TP's kicking about.
I finally tracked the misfire problem down to the engine wiring loom. I replaced that but maybe, as you suggest, that is where the problem is now. Will investigate further.
Mick

[Barkychoc]

Something is nagging away at me that I read somewhere that the cerbera throttle pot fits but you have to swap 2 wires round or something? Sorry can't remember any more than that.

[Gerald-TVR]

Here it is

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

and this might help

http://www.pistonheads.com/gassing/topic.asp?t=816...

[MickS2]

I believe you need to swap the outer wires when replacing an original 'S' TP with brass (?) contacts to one with gold contacts. I guess all Cerb ones have gold.
(The mod had already been done on mine so I guess a previous owner had already changed the TP to the later one)