General motor hesitation bravo 1.6 '97

[bravo1616]

Hi,

When cold in 1st and 2nd gear the car starts to accelerate smoothly but soon it does not respond for a while and then resumes slowly to accelerate. Noticed that when moving the crank-sensor to advanced, the situation improves a little. When warm, there is a quite normal acceleration in 1st and 2nd gear, but it could be felt a little lack on acceleration. Have changed the fuel-filter and used an injector cleaner (Wuerth), but no improvement. Measured also the resistance of injectors, all ok...

There was a thread of Johntra some 2 or 3 years ago, very similar problem... it would be very helpful if he could report how did he fix the problem.

Best regards,
Bravo1616

 

[ShaunCo]

is it only in 1st and second?

i had hessitation problems with mine, it lead to fuel sufication but could be many things, like the MAP sonsor of throttle potentiometer or ICV

maybe test ur fuel pump see if thats pumping right

 

[Peter Pick-Up]

Our 1,6-16V (Palio) acted the same, turned out to be the O2 sensor, in the exhaust.
It should be replaced every 100.000km's ( 60.000mls) according to the original Fiat workshop manual (in practice, nobody does.....!)
Our car runs fine after the swap!

 

[bravo1616]

is it only in 1st and second?

i had hessitation problems with mine, it lead to fuel sufication but could be many things, like the MAP sonsor of throttle potentiometer or ICV

maybe test ur fuel pump see if thats pumping right

Yes, it happens only in 1st and 2nd, probably because these are the shortest (strongest) gears. Did you fix the problem with the fuel sufication?

I think the O2 sensor could be excluded, because it is out of function during the cold-mode.

 

[Peter Pick-Up]

With a non or barely working O2 sensor, the ECU goes into some special "limp home" mode, and that affects running of the car during all conditions, even cold.