Its been a while since i posted as after the Cinq failed the MOT the second time on emissions again i changed a few more bits and somehow managed to make it far worse than it was!
After swapping a few more sensors and injection body gaskets i had an issue that for no reason the car would constantly rev up and down when it was idling (it seemed fine when driving, apart from a little lacking in power) and if you had been going along and stopped at a junction, the revs would jump straight up to about 3’000!
After a little more fiddling and not being able to sort it out i gave up in frustration and left the car! It was late autumn and not the right sort of weather for messing about with it.
After a long, wet winter with the little Cinq sitting there and not getting much love apart from a wash now and then. It was finally March and the weather was looking a little better so i had renewed energy to get the little Cinq running again and to try and solve the issue.
So the plan! After doing lots of reading over the winter it seemed to come down to possible 3 issues.
- It could be the crank sensor
- The MAP sensor
- or an air leak around the injection body.
So i ordered a crank sensor from Ricambo (which turned out to be crap and did not work) and then one from ebay that was a genuine fiat one. I also ordered a new MAP which was a bosch one. and after a bit of searching for the spacer under the injection unit and not being able to find one i got some gasket paper.
Now with a bit of testing the car ran fine with the MAP sensor tube disconnected (which it seems goes into some sort of limp mode and should run fine) no revving up and down, but also if i sprayed some Easy Start around the injection area, the revs picked up, so could it be an air leak?
My plan of action. Fit the working crank sensor, put the new map sensor.
And when i was looking for a new injection body spacer so i could make sure this was all fitting correctly, I noticed that the gasket on a new one covered the whole face and the one i had fitted from the injection refurb kit was different, so could this be the issue?
As you can see from the images of the old one with the original gasket and some pics i found of a new one (which i was unable to order as they don’t ship to the UK) So it got me thinking, could the gasket i used be letting in air somewhere as the car never had any running problem when i first got it going, it ran super sweet! and i didnt change the gasket until after the second MOT failure, so could it be the gasket?
I cut a new gasket for each side and as you can see from the image below, its a lot different to the service kit one??
After fitting all the new bits and double-checking everything, with fingers and toes crossed i turned the key! and it fired up and ran perfectly, after a couple of minutes the idle was about 800, and it was running nicely. It let ti get up to temp, revved it a bit and all seemed fine. After a few more starts over the next couple of days, and it was running fine it was time for a test run.
And the little Cinq was driving just like it used to, as sweet as anything. Now until i got for an MOT i wont knwo if any of this will have cured the emission issues, but its now got every new engine part and a new cat, the only bit i have not changed is the throttle body itself! and i dont know which one of the 3 items actually solved it!
So if you have a Fiat Cinquecento that revs up and down when started and ideling, it could be the MAP sensor, but also check the injection body space gaskets as well!