Performance at Acceleration

[Fiatbrit]

Hello,

This is a great site. Thanks for all the help. The Fiat is now running without quiting. I took it for a brief drive. I noticed it hesitates a bit on acceleration and then will suddenly grab almost like it is not advancing fast enough? Also when I rev it in neutral and then let off I have to persuade it to continue to run for a few seconds before it returns to a smooth idle. Is this likely the advance? I also hear on neutral rev some clicks in the relay area?

Thanks again,

[Daniel]

what year is your spider? if your referring to "advanced" meaning timing advance? that wouldn't cause the idle
to fall off like that. Sounds more like intake manifold pressure issue, causes could be but not limited too, brake
booster going bad,vacum lines leaking, gaskets. If you have a fuel injected car you might want to check your
rubber inlet tube from the air cleaner to the throttle body one of mine had a crack on the underside that i didnt
see while looking from above the engine.

[vandor]

On accel likely it is too rich, is it carbureted? It may be getting too big a shot from the acellerator pump.
It could also be too lean, but then they usually backfire into the intake.

[Fiatbrit]

Sorry, it is fuel injected. It is a 1981. Thanks.

[babu2001]

When was your last tune-up? I presume the gas filter is OK? As for the spark plugs, wires and distributor cap. The simplest things are always overlooked.

[RRoller123]

Check the AFM door flap for smooth action through its entire range of motion, and also there is a thread here on the forum about refurbishing the AFM wiper arm. Doing so made a big difference on my 80 FI.

Pete

[narfire]

Check the AFM door flap for smooth action through its entire range of motion

Did that with my car in the winter things to do. made a difference with smoother acceleration. I also changed out a leaking brake booster, so that likely helped as well.
Bought insurance the past Tues. and the weather promptly changed to rain and shmoo this past week

[RRoller123]

Agreed Yeah! That AFM door flap sticking will cause all sorts of havoc. Completely confuses the computer! You can sand down the chamber walls very carefully, very slowly, a little at a time, using 220 or higher grit, then cleaning thoroughly, until it "flaps" smoothly across its entire range. There is a thread somewhere here on the forum about drilling out and disassembling the AFM chamber, but I wasn't going to get into that, I personally would have bought a new one first. Try the sanding approach first. Mine was binding up a surprising amount! It caused hesistation, an occassional bucking, generally unsmooth running. After freeing it up, my car runs much better.

[Fiatbrit]

Thanks Everyone. I will give that a try.

[Fiatbrit]

Hello,

Pardon my ignorance is the AFM chamber right after the air cleaner on the fuel injected cars. Please advise.

thanks,

[4uall]

http://www.fiatspider.com/f08/viewtopic.php?f=9&t=20792

[Fiatbrit]

Thank you for the great info