Throttle Plate/Linkage

[Odoyle]

Started the car up this morning and it was idling at 800-900rpms, went out for a drive and at the first light I noticed the idle had jumped to 2500rpm while the car was stopped. Sensing that something was wrong, I decided to take her back home. It looks like the throttle switch isn't fully returning. Also, I just replaced the engine coolant and haven't fully burped the system, would that have contributed to my problem?

[adrians]

Check third last post in this thread, the bolt that retains the return spring/s had worked itself loose.

http://www.fiatspider.com/f08/viewtopic ... 55#p229314

Bolt is the bottom right hand corner of your photo. I also see that the idle bolt/screw has a large gap - that looks excessive.

[131]

I also see that the idle bolt/screw has a large gap - that looks excessive.

Because the throttleshaft is not returning and it's idling at 2500. Solve the first issue and there'll be no gap.

[Odoyle]

Check third last post in this thread, the bolt that retains the return spring/s had worked itself loose.

http://www.fiatspider.com/f08/viewtopic ... 55#p229314

Bolt is the bottom right hand corner of your photo. I also see that the idle bolt/screw has a large gap - that looks excessive

Which part are you referring to as the bolt that holds the return spring?

[narfire]

If I'm not mistaken, I believe there should be a "lock" nut on the threaded part the cable is going through. Perhaps that has fallen off and the threaded bit has backed out pulling the cable?

Just checked my car and yes there is a 17mm nut on the end of the threaded shaft.

[adrians]

Next to your position number 3

The return spring is held in place and in tension by the bracket running along the side of the chamber, the bolt to the right of the spring that holds the upper and lower parts of the chamber together also retains the bracket. The bolt screws in the intake manifold.

Yes I also noticed that the accelator cable was missing the retaining nut.

[RRoller123]

I can't see the whole pic, but the locknut is supposed to be on the same side as the adjusting nut, i.e they don't clamp across the housing, they lock each other.

[adrians]

Interesting I have a lock nut on both sides to retain the accelator cable in situ, perhaps it's because it's right hand drive and the cable is longer and crosses in front of the cam cover, a big loop.

[RRoller123]

A lot of our cars have it done that way, but I think it is in error. The casting as far as I can tell doesn't have fully parallel sidewalls where the cable passes through, so the locking needs to be done nut/nut versus across the casting. But this is counterintuitive, which is probably why so many are done this way. I did so myself at first but it seemed to cock the cable at a slight angle, and my bet is that it would have worn somewhat faster that way. (?)

Pete

[76was124]

If you remove the throttle cable from the mounting boss to give it full slack, does the throttle plate return all the way? A frayed throttle cable inside the outer sleeve can cause the problem you are seeing.

Another thing to check is if the TPS (throttle position switch) somehow was moved, it can prevent full return of the throttle plate. The TPS is the black plastic housing with a connector on it, located opposite the throttle plate return spring.

[So Cal Mark]

the two nuts on the cable should be locked together, not on opposing sides of the mount

[Odoyle]

If you remove the throttle cable from the mounting boss to give it full slack, does the throttle plate return all the way? A frayed throttle cable inside the outer sleeve can cause the problem you are seeing.

Another thing to check is if the TPS (throttle position switch) somehow was moved, it can prevent full return of the throttle plate. The TPS is the black plastic housing with a connector on it, located opposite the throttle plate return spring.

I did try to move the cable outside of the mounting boss and it doesn't seems like that is the problem. Next thing to check is the TPS on the other side, anything in particular I should be looking for there?

[bradartigue]

I would reset the entire idle - but first you have to see if your throttle is closed - remove the big air hose and inspect it. Then (because it looks open), loosen the TPS and see if it closes. If not clean it up, get rid of whatever obstruction is there. Once it can close set the idle:

Get your stop screw correctly installed as noted
Close the bypass screw
Set the stop screw so the car idles around 800 RPM
Open the bypass screw so the car idles around 850 RPM
Set the TPS position