900cc '94

Just completed the replacement of cylinder head gasket and reset the tappets. Now runs well but has a hesitation when under acceleration. I had to replace part of the small pipe to the carburettor from the air filter box as it was collapsing under suction.

I don't suppose these complete hoses are available.

Any suggestions would be appreciated.

Ivan

PS Any Cinquecento owners in the Edinburgh area?

Hiya, I've moved this to the technical advice section as it's more of a question and not a guide. Should get more people viewing it here too

If it's just a vacuum hose, then you'll be able to buy generic vacuum hose either online of from a parts supplier and just cut to size. Normally the hose has the size written on it.

A temporary fix is cable ties tight around the hose to stop it compressing.

H

Thanks for that.
Does the vacuum hose work in the same way as as an old fashioned advance/retard system on a distributor? Unfortunately the hose is part of a multi connection system which comes from the filter box and also connects to the head.

Just thinking through here, 899 cinqs don't have carbs, they have injection...single point ecu controlled, so it'll be the throttle body/injector unit you mean?

Been a while since i worked on an spi system, and even then it'd have been a modified 1108cc or 1242 cc one but fundamentally they will be the same, i think from memory there's 3 or 4 vacuum take offs in total, there should be 2 off of the inlet manifold... one going to the brake servo and one going to the map sensor. On the throttle body, there's one to the airbox (i think) and one maybe to the carbon canister, but not sure on that one. Anyway, No, the vacuum doesn't work like an advance/retard, that's just all ecu controlled. However the vacuum issue might be altering the map sensor readings, which in turn will alter the fuelling and probably cause hesitations and the likes if there's leaking or a sudden pressure change under loads. The hoses are all standard sizes available as generics

Thanks for that.

The continuing saga ends.
Since fitting the cylinder head gasket the hesitation has disappeared presumably the ECU has learnt. I have had however a big problem with excessive idling speed 1200/1500. I replaced the Lambda sensor as the warning light was coming on while idling. I also replaced the Air Filter and lucky to get a new rubber breather pipe system from eBay £20.00. Still idling too fast. Lots of thought and research and purchased a idle control step controller no change. Then bought a throttle position potentiometer £8.00...sorted!

All the parts cost less that £20.00 each and the car is now going better that ever and the hydraulic tappets are quiet.

The story continues. Following all of the above car ran well for perhaps 2 weeks. Then I began to get hesitation on acceleration when load was applied. Under light throttle no problem. I thought it was electrical so changed plugs and leads, no difference. Colleague thought it might be fuel problem so changed fuel filter and checked fuel flow which was good.
Doing my head in. Any suggestions?

Maf/map sensor?

Been changed 3 months ago. Original Fiat part. No warning light.

Could it be the injector?

Run some injector cleaner through. Could be coils though.

could also be a tear in the map pipe etc or vacuum leakage.

Coolant temp sensor

Ah yes,

My favourite problem sensor or "the arsehole" as i like to call it

That thing throws up the most random side effects when it starts to die.

Map pipework checked and OK. All induction pipework has been replaced.

Where is the Coolant Sensor?