Technical Fiat Tipo 1.6 i.e Idle switch, RPM sensor, Air temperature, O2 sensor shorts ?

[Zlatandrajer]

Now what bothers me is this. The whole mechanism is "laggy" and i don't where the problem could be TPS sensor ? False air ? Or maybe the mechanism is set up wrongly? Have you ever met with an issue like this ?
View attachment 449956

O2 sensor doesn't seem to be the culprit, bcs i've unplugged it and the problem stays the same.

 

[jonti]

O2 sensor doesn't seem to be the culprit, bcs i've unplugged it and the problem stays the same. should have

From the video, it looks mechanical. Your throttle isn't returning to position. There is a maladjustment affecting the return action of the spring. That would be my opinion. I think I mentioned the possibility of the mechanism, from the action of the pedal right through to the throttle opening. If you've not checked that please proceed to, here it looks like the throttle is sticking.

 

[Zlatandrajer]

Is it safe to disasemble the whole throttle mechanism ? I read in a guide book i have that i shouldn't ti ker with the bolt that you can see on the video, but in my opinion, if someone built the mechanism, there should be a way to take it apart and build it back. If it's safe or if you've done it, i will have a look at it with my dad in two weeks probably, bcs i have state exams coming up . The "spring" looked fishy to me too, maybe there's some garbage that accumulated during the 29 years of the car

From the video, it looks mechanical. Your throttle isn't returning to position. There is a maladjustment affecting the return action of the spring. That would be my opinion. I think I mentioned the possibility of the mechanism, from the action of the pedal right through to the throttle opening. If you've not checked that please proceed to, here it looks like the throttle is sticking.

 

[jonti]

From the video, it looks mechanical. Your throttle isn't returning to position. There is a maladjustment affecting the return action of the spring. That would be my opinion. I think I mentioned the possibility of the mechanism, from the action of the pedal right through to the throttle opening. If you've not checked that please proceed to, here it looks like the throttle is sticking.

A disassembly and a clean of the pivot, if that is possible. It's a little while since I was dealing with my throttle body would need to open mine again to see how to tackle it.

 

[jonti]

Is it safe to disasemble the whole throttle mechanism ? I read in a guide book i have that i shouldn't ti ker with the bolt that you can see on the video, but in my opinion, if someone built the mechanism, there should be a way to take it apart and build it back. If it's safe or if you've done it, i will have a look at it with my dad in two weeks probably, bcs i have state exams coming up . The "spring" looked fishy to me too, maybe there's some garbage that accumulated during the 29 years of the car

I think same, except that sometimes with a tensioned spring, once un-tensioned, is not possible to re-tension without the tool they used in the factory to twist it round. You'd need to assess how much tension is on the spring.

 

[Zlatandrajer]

After finishing state exams (master's degree and succesfully) i finally had time to work on Tipo. I didn't have to disassemble the throttle, i just cleaned it with various sprays and changed the idle control valve with new one. The problem which was captured on video was suddenly gone, on idle the engine is around 850-900 and throttle comes back nicely.
Also i checked for the false air, found one spot under the engine cover which goes on the throttle body , but i fixed it with tightening the three screws on top of the cover.
However...
RPMs don't oscilate if the O2(lambda probe) is disconnected. When i connect it, the idle goes to 1500-2000 or more. So the lambda is indeed faulty, but i had two problems at once.
Now i just have to do try and error with O2 sensors and find out which one is the correct one to use.
I will keep the thread updated.

 

[jonti]

I will keep the thread updated.

Ok thanks for the update. Logic must prevail, there is a cause for everything, but it can be terribly frustrating at times. It makes me wonder if my very old O2 sensor is causing my slight idle wobble.

 

[Tipo19GR]

Great work and thanks for the update.

The Bosch number that I provided to you earlier in this thread works perfectly in my Tipo.