TVR S2 2.9 losing revs

[King Fisher]

My son has just been out to the Malton Sportscar meet in his S2, and has had some problems.

The first problem he had was when he arrived at my house to meet up with another TVR (GrahamW48 ). When he went to start the car, it didn't idle right and then stalled (which he told me happened a couple of times throughout the day). It normally idles at around 900-1000rpm, but today it was dropping to around 750rpm, picking up, dropping off, and then stalling.

The second issue he's told me of is that when he is under gentle acceleration (between 2500-3000rpm), the car seems to cut out, then cut back in, then cut out. The car also did this once under hard acceleration during an overtake (less than ideal!).

His passenger managed to get some videos of it, so I've uploaded them to my Youtube for you to view.

Any help would be appreciated as he's a bit worried his wallet will take another hit!

Video 1:
http://www.youtube.com/watch?v=ujqL4_a1HHY

Video 2:
http://www.youtube.com/watch?v=QNEVW8AqMtg

P.S, it may sound like he's feathering the throttle, he's not, the car was doing this by itself....

[clarenceboddiger]

I would go for the throttle potentiometer as being the 1st suspect, unplugging it will put the ecu in "limp" mode and it should run smoother even though not perfect.The track inside the Pot wears and causes the erratic response.
Ed ited to say---Read these links further to chris's comments below
http://www.pistonheads.com/gassing/topic.asp?h=0&a... bl**dy pots!

http://www.pistonheads.com/gassing/topic.asp?h=0&a... I've got a hiccup.

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

Edited by clarenceboddiger on Sunday 4th April 14:52

Edited by clarenceboddiger on Sunday 4th April 15:00

[Barkychoc]

2 things spring to mind - idle speed control valve gunked up - though I'm not sure if that would give you issues on the move.

There's also a multiway electrical connector I think on the drivers side rocker cover that a few owners have reported problems with - some have cut it out and just hard wired the connections together.

It might be worth just seperating the 2 halves and having a look at the contacts initially.

Edited by Barkychoc on Sunday 4th April 14:52

[Harry1972M]

Had these symptoms on a mates S2 a while back and after changing all of the above plus the coil etc we eventually traced it to the infamous yellow connector in the steering column.

[King Fisher]

Ok cheers guys. I think my son and Graham will be taking a look at the car soon. Is there any diagnostics equipment that can be connected to help diagnose the problem, or is this car too old for that kind of stuff?

[Gerald-TVR]

Another possibility is an air leak somewhwere between thje air flow meters and the plenum chamber - worth checking.

I've got a Star tester designed to work with the 2.9 efi engine happy to lend it if you cover postage costs

[pacman1]

Is the petrol cap vent working properly?

[Jaye R]

Hi

My S3 did exactly the same before & on the way to S club last year - 'hunting' as she idled and at low revs.

It turned out to be the sensors in the air flow meters.

Take off the air filter and, carefully - I used a cotton bud - clean the sensor just inside the air flow meter (when I did it the cotton bud came out 'blackened').

When done all was fine again.

HTH

Cheers
Jaye

[King Fisher]

Brilliant, thanks for all the great advice guys! He's just been reading the Steve Heath book on the S, and thinks it may be the throttle pot. He'll also clean up the sensors as suggested. If this doesn't work, he'll start checking the other possibilities. I'll keep you updated on his progress...

[King Fisher]

Gerald-TVR said:

Another possibility is an air leak somewhwere between thje air flow meters and the plenum chamber - worth checking.

I've got a Star tester designed to work with the 2.9 efi engine happy to lend it if you cover postage costs

Also, is this some kind of diagnostics equipment? How much would it cost to post? Cheers.

[Gerald-TVR]

Hi

Its a tester designed top work with the EEC IV ECU as used on the 2.9 EFI engine.

The test is a three stage one. Plug in tester into ecu. Firstly run test with ignition on but engine off. The display shows codes. The second test is the "waggle test" ~ waggle wires and see if led on tester goes out. This is as far as I got as it was then I found a fault.
The third atage is to have engine running. Once again codes will show on display and there is a guide to show what each code means.

Running the tests seems pretty straightforward. Interpreting the results may be a little more complex but for me it was great. It told me there was a wire loose and it just took a bit of waggling to find which one.

Please note that "waggling" is an official technical term quoted in the manual. Not a term that I have made up!



Postage should only be £3/4 ish but needs to be special delivery as its not replacable

[grahamw48]

What a gentleman...to make the offer.

[King Fisher]

Gerald-TVR said:

Hi

Its a tester designed top work with the EEC IV ECU as used on the 2.9 EFI engine.

The test is a three stage one. Plug in tester into ecu. Firstly run test with ignition on but engine off. The display shows codes. The second test is the "waggle test" ~ waggle wires and see if led on tester goes out. This is as far as I got as it was then I found a fault.
The third atage is to have engine running. Once again codes will show on display and there is a guide to show what each code means.

Running the tests seems pretty straightforward. Interpreting the results may be a little more complex but for me it was great. It told me there was a wire loose and it just took a bit of waggling to find which one.

Please note that "waggling" is an official technical term quoted in the manual. Not a term that I have made up!



Postage should only be £3/4 ish but needs to be special delivery as its not replacable

Brilliant, this could cut down his fault finding time massively. If you can give him a call on 07906 00 4105 (ask for Nick). He'll be at work until 5 tonight, but free after that.

[Elfit]

I can confirm that the "waggle test" is the approved technical term!

It sorted me out ~ finding a loose connection at the fuel pump relay. I may not have found it without the tester.

I hope that it finds your problem as quickly

Cheers
Tim

[Gerald-TVR]

Been away will phone tomorrow

[Gerald-TVR]

Will be posted to Nick in York tomorrow

Posted special delivery £5.50 so if Nick could cover that and return (didnt include my address but if you PM me i'll let you have it) with a small donation that would be great

Edited by Gerald-TVR on Thursday 8th April 11:58

[King Fisher]

Gerald-TVR said:

Will be posted to Nick in York tomorrow

Posted special delivery £5.50 so if Nick could cover that and return (didnt include my address but if you PM me i'll let you have it) with a small donation that would be great

Edited by Gerald-TVR on Thursday 8th April 11:58

Arrived today! Will definitely cover the postage costs with a donation, no problem. Only problem he's had is he can't find the 3 point socket to plug it into.....

[Gerald-TVR]

How did you get on?? Did you find the socket??

[Elfit]

Gerald-TVR said:

How did you get on?? Did you find the socket??

as the actress said to the bishop.........

[grahamw48]

I think we're going to try to sort it this weekend.

Thanks for sending the fault reader...very generous.