Pinto idle servo acting up

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Posts: 15
Joined: Fri Jul 03, 2015 1:46 pm
Car(s): Custom Ford Sierra (1987)
No Capri yet..

Pinto idle servo acting up

Postby elmars » Wed Jan 03, 2018 11:25 am

Ford Sierra with 2.0 pinto with weber carb, problem is, that now at winter car starts and runs fine, if I press the gas strongly then the idle servo moves all the way out and car idle rpms are really high, like 3 to 4k. Choke is working fine. When I re-start the car, servo moves back in on its own and no problems, till I step on the gas hard again. This problem is only seen when I let the engine be over 4k rpm, like passing etc. If I drive like an old lady changing gears at 2k then servo works ok.

Right now I have disconected the idle servo and manually adjusted its position. Car runs a bit rough, but no problem right now.

Wanted to know: any ideas what could cause such a problem? Bad servo?

Are there any issues with eunning without this servo?

Thank you all in advance!

Paul G
Posts: 1236
Joined: Fri Jul 03, 2015 5:21 pm
Car(s): MK 3 3.0S needing restoration, 2.0S, 1.6 Laser (nearly ready), Fiesta mK2 pop plus, Skoda Octavia VRS, Rover SD1 Vitesse.
Location: High Wycombe

Re: Pinto idle servo acting up

Postby Paul G » Wed Jan 03, 2018 1:34 pm

Your Sierra at 1987 will be fitted with the later type Weber which uses an electronic, ECU controlled, stepper motor to control the idle and fast idle on the carb. Other than making sure that the pushrod on the second choke vacuum unit is moving freely and that the engine is running at the right temperature there's not a lot that can be done to them - there's no adjustment as such. It may be an electrical problem to the ecu but in most cases back in the day it was straightforward stepper motor failure.

While you're at it make sure all the other vacuum hoses around the manifold have no splits in them letting in air.

If you can afford it and the car is worth it the best long term solution is to change to the older type 32/36 DGAV carb.