hesitation under acceleration

[mannik]

when I put my foot down on the accelerator the car does not pick up smoothly (almost jerks forward)...
any ideas?

[GreenV8S]

Throttle response problems are often cause by a faulty throttle pot.

[Loubaruch]

Either the TPS (throttle pot) or the multiway connectors linking the various sensors and injectors to the ECU.

Disconnect your TPS and although the ECU will revert to limp home mode if it is the TPS it should run a lot smoother.

See: http://bertram-hill.co.uk/tvrs3.aspx

[Roy C]

http://www.tvrsseries.com/throttlepot/throttlepot....

[ketvrin]

I also had to replace my TPS recently and found that the spare I had been carrying was incorrect (shaft dia too small) and so relied on the NE Communal S Spares team to come up with the goods... Thanks Graham/Tim.

So I started to look for replacements and could see the Ford/Motorcraft number on my failed TPS was 86TF-9B989-AD which cross referenced to Intermotor 19935. Using this link from our useful links wiki I can see that the 19935 is also used on MG's, Rovers and some Freelanders... I bought a Rover TPS for the princely sum of £9.20 and it appears to be the right fit... Time will tell...

http://partfinder.smpeurope.com/?p=154 <-- click on search ...

the old TPS was disected out of interest and I must admit the internals were a lot simpler than I had expected. heres a pic of the bits... (sorry but uncle dave pic upload appears to have changed since I last used it ...)

http://ketvrin.myphotoalbum.com/view_photo.php?set...

I hope that helps someone...

K

ps: only one TPS died in the making of this picture...

Edited by ketvrin on Friday 22 May 09:13

[Chris71]

Could also be your HT leads. The driveability improved no end on my car when I changed them - no more kangarooing in traffic and it actually smoothed out the transition to engine braking when you lift off.

[Spathodus77]

I had a power boost valve fitted recently and initially this was set too lean so my car exhibited the symptoms you describe. Making the mixture richer has remedied the situation.

Could it be that you have blocked fuel filter making the car run lean?

Ralph.

[Mr Clifford]

Loubaruch said:

Either the TPS (throttle pot) or the multiway connectors linking the various sensors and injectors to the ECU.

Disconnect your TPS and although the ECU will revert to limp home mode if it is the TPS it should run a lot smoother.

See: http://bertram-hill.co.uk/tvrs3.aspx

Agree with the multiway connectors. My car was rough for the first 6 months of ownership until i had these cleaned off.
Ever since perfect acceleration.

[Last S4]

I wondered about the connectors too - is it not better to just remove them and solder the cables? I know a solder joint is a slightly higher resistance but I think that would be much better than a duff plug/socket?

[Barkychoc]

I think for the connectors if you think they are past their best (at the end of the day how long was a sierra / granada engineered to last?!) I'd cut them off and replace them with new weatherproof connectors if it is feasible.

Fit the wires into the new connectors one at a time to avoid screwing it up.

Edited by Barkychoc on Saturday 23 May 10:49