Gurgling

[RRoller123]

So what is the basic issue when the car gurgles and burps (from exhaust tailpipe only) as it slows down under engine braking? No backfire, just not a smooth deceleration, lots of gurgling?

[bradartigue]

So what is the basic issue when the car gurgles and burps (from exhaust tailpipe only) as it slows down under engine braking? No backfire, just not a smooth deceleration, lots of gurgling?

The carburetor is delivering more fuel than the motor needs during deceleration. Either you have IDFs, which always sound like a poorly tuned motorcycle, or you may able to compensate by setting your timing, lean your mix slightly. See if that helps. If not then you may just want to live with it, I've rarely found Spiders that don't have this "note" on decel unless they are dead stock. Early cars sounded like this when new. The factory cars in the later years (70-on) didn't do it so much because they had stuff like the high throttle device working to keep the engine speed above 1600 RPM on decel, which you likely don't have.

[76was124]

Is it gurgling or light popping?

If it's a light popping, my 81 with FI does that due to what I think is a small exhaust leak. It's not what I call a full backfire (bang sound) just light popping.. It's on my repair list, but I have been working on the restoration from the front of the car back.....

[RRoller123]

Mine is FI too, I will check out the exhaust carefully, thanks for the tip. I wonder if the CSI is leaking? I noticed yesterday that the nozzle portion is very slightly loose in its metal housing, i.e. it can be rotated just the tiniest bit. The injector itself is fully sealed at the plenum, so I don't think this makes any difference, but will check it just to be sure.

[bradartigue]

Mine is FI too, I will check out the exhaust carefully, thanks for the tip. I wonder if the CSI is leaking? I noticed yesterday that the nozzle portion is very slightly loose in its metal housing, i.e. it can be rotated just the tiniest bit. The injector itself is fully sealed at the plenum, so I don't think this makes any difference, but will check it just to be sure.

Sorry I didn't read the bio and thought the picture was of an early car. On an FI car I'd check the ignition timing and the vacuum advance for a leak.

[ga.spyder]

I thought they all did that !! If you don't like gurgling on deceleration,dont drive one of the new Abarths! Tony Miracle let me thrash his at FFO.The exhaust note on accel and decell is fantastic.Lots of gurgling and popping,and it was a stock system.

[majicwrench]

Hmmmm, sounds to me like you are looking for a problem.. LOTS of cars/fiats gurgle on decell, do you feel it is excessive??
I really doubt if the CSI is leaking or causing this "problem,"

[Kevin1]

On the FI cars a poorly adjusted throttle position switch can cause it to do exactly what you describe. Set it using a test light or meter so it is tripped just before the throttle hits the full-closed position against the stop.

[RRoller123]

The thing is it didn't do it before, so this is a change. Logically it seems to me that this would be caused by too much fuel in the plenum, either due to leakage or AFM setting or whatever. TPS is properly set, timing set with a light, vacuum advance controlled by Mark's Computronix ignition. I know the PO fiddled with the AFM spring settings, so it may be a little too rich. Might fiddle with it myself and see if I can improve the running. At any rate, as reported in another post, at least the issue where the idle would drop to near zero and then slowly recover over a few seconds is solved. Appears to have been caused by the TPS holding the throttle plate a little bit artificially open.