I know that peter as already discussed this in my other thread. But thought I would start a new thread so other members maybe could also possibly help with my correct thread title.

Heres the issue.

When the cars been sat all night it fires up fine, i always leave a minute or two for the revs to idle around 800rpm when i go to move away, it jerks extremly bad, like its going to stall, after a minute or two on the road it runs perfect.

The car will run perfect all day, can even leave 8 hours outside work and will start and drive perfect on the way home from work.

Park the car up and leave overnight and then next morning same problem.

Peter said possibly throttle body, any body else think this is the case before i pay the £80 qouted by the garage.

Chris

when mine is cold, it stays at higher revs than 800 for quite a bit longer than a few minutes if just idling.
My throttle body is having some issues. When I turn on the ignition and leave it, the throttle body motor whines but the throttle plate doesn't do its initialisation (travels through 90 degrees to fully open and back again) which I believe it should do.
When warm, if I give it 10% throttle the revs rise to say 2k, but then oscillates to say 500 rpm and back again. If I engage the clutch as it drops to 500 rpm the car will stall.
If I give it more throttle I don't have the issue.

Recording the throttle plate with my phone, it seems stuck closed (tiny gap) for a while and then opens quite wide when I blip the throttle to high revs (4-5k).

I wonder if you have a similar issue, where you give it say 10% throttle (which feels natural for pulling away slowly) and it oscillates, making the car jerk or stall?

Yeah when i start from flat cold it idles around 1500 rpm for a minute or two then drops to 800rpm, i then try to pull away like you say giving little thottle and it jerks really bad, the whole car shakes. Get to top of the street same again, getting a little better, next street perfect. So it only lasts a couple of minutes then sorts it self out and runs perfect all day. What you thinking the issue maybe?

if you give it a little throttle but don't release the clutch, what happens? In other words, is the jerkiness just with clutch engaged?

it almost sounds like it thinks it is warmer than it is. Which might lead me to water temperature sensor? I think the gauge in the car uses a different sensor to the ECU, but i'm not certain, so don't go by the gauge when wondering if the ECU temp sensor is giving a bad reading. I'm not sure if OBD2 gives the same reading as the ECU is using, but on mine the gauge hits 90c and stays there, whereas my OBD2 reading can fluctuate to 94/95 (and the dial stays dead centre at 90c).
Whether OBD2 temperature is a good test is hard to say, as I only notice the difference in mine at over 90c.

So you dont think its the throttle body? And no clutch pedal mate its semi automatic the flappy padel version.

ahh, Selespeed. Didn't consider that.
Do the revs drop to say under 500 when it starts jerking, or do the jerks start when the revs are higher? Just trying to figure if the jerks are a symptom of low revs or not.

I'm going out in the car to collect my son about 6pm, it's been stood since yesterday. So I guarantee the jerk will happen, I'll watch the rev counter and report back once I've collected him. I'm hoping it's going to be something simple, as once running it's flawless, plenty of power, flys through the gears. Just this issue when it's been stood cold.

As said before, clean the inside of the throttlebody with carburetor cleaning spray, to get rid ofd the accumulated gunk, sooth, carbon and other dirt that's 100% sure present, preventing the throttle valve to close completely, causing jerking as described.

not wishing to totally hijack the thread BUT.......;-)

my throttle valve doesn't close completely. With it off the car and dismantled, the springs hold it a fraction open. I can close it fully (one more tooth on the big gear) but I do this against sprung resistance, and it springs back one tooth. I'm not certain the 1.6 has an idle bypass valve though (as I've not seen it, or controls/power to it....and I did have them on my Seicentos), which would leave a requirement for it to be a crack open on idle.
What do you think?

Peter Pick-Up said:

As said before, clean the inside of the throttlebody with carburetor cleaning spray, to get rid ofd the accumulated gunk, sooth, carbon and other dirt that's 100% sure present, preventing the throttle valve to close completely, causing jerking as described.

Click to expand...

Cheers mate, ive been qouted £80 to have it cleaned.

The car was stood cold for about 27 hours, started it up and idled about 1500 rpm, i waited about 4 minutes for it to slowly come down to around 800rpm, and moved away, jerking was lots better only one hard jerk and then was fine. The revs didnt drop or increase when it jerked stayed same.

So you deffiantly think clean throttle body?

wac84 said:

Cheers mate, ive been qouted £80 to have it cleaned.

Click to expand...

Come on.. you can do it yourself in 15-30 minutes, and the cost of a spraycan carburetor spray...

I'm going to have a look at the weekend, your no where near Leeds are you lol?

Peter Pick-Up said:

Come on.. you can do it yourself in 15-30 minutes, and the cost of a spraycan carburetor spray...

Click to expand...

There is some water between us, I'm afraid...

Peter Pick-Up said:

There is some water between us, I'm afraid...

Click to expand...

Haha, is it easy to clean on the 2.4? I heard you need to remove some negative cable or something, maybe under some electrical wire?

if you're not gonna try this job yourself, owning a Fiat is not gonna be financially feasible ;-)

Mytheroo said:

if you're not gonna try this job yourself, owning a Fiat is not gonna be financially feasible ;-)

Click to expand...

:yeahthat: