Engine: D5244: Throttle body cleaning

[ThomasG]

"Invalid link code"

[BlueRubber]

Originally Posted by ThomasG

"Invalid link code"

Fixed the link.
Just checked the vacuum lines and they all look ok.

[ThomasG]

Hmm..

Judging by graph, both potentiometers work(blue+green).
And show the same thing.
If one of them was worn, its reading would differ from the other.

(This comes from my knowledge of electrics and electronics, not the throttle- I'm a sparky by trade)

And yet the throttle doesn't seem to be closing all the way as it should.

So maybe mechanical, after all? Bit of crud left on, or maybe even pushed in during cleaning, the hinge?

At this stage I'd unplug the battery (so the ecu can reset whilst I work the cloth), remove that throttle and give it a proper one. A lil' bowl of petrol, paintbrush.. Wash it all out. That's what I'd do.

[BlueRubber]

Thanks Thomas, that sounds like a sensible diagnosis.
The issue only started after I cleaned the ETM so would be quite logical that I somehow push dirt into somewhere it shouldn’t go while cleaning.
So will clean it as suggested and report back.

[jgjones095]

Ok so yours being a N/A means there are very little vacumn lines and air pipes compared to the turbo models. So very little chance of air leaks.
Do check that the intake pipe has no cracks or leaks in.

Unplug the MAF sensor and try running it.

[BlueRubber]

Originally Posted by jgjones095

Do check that the intake pipe has no cracks or leaks in.

Unplug the MAF sensor and try running it.

I assume by the intake pipe you mean the pipe between the ETM and the MAF?
If so that seemed to be in good condition with no cracks.

What am I testing by unplugging the MAF?

[Dippydog]

Not sure of differences between the P1[mine] and your car are,but when the throttle position sensor needed changing[mine is also on Magnetti Morelli] to contactless the idle reves would constantly "surge" would not rev past 4,000 and when easing off the throttle the whole car would "hunt" so different symptoms to what you're experiencing.I've always used carburettor cleaner for cleaning throttle bodies along with an old toothbrush and a soft lint free cloth.The reason for removing starter motor when removing throttle body is that the wiring for it runs between starter and engine block to a plug near bottom of radiator and there's not enough clearance between starter and engine to get the plug past.On mine there are two[from memory] bolts holding starter to bellhousing and a support bracket holding other end of starter to engine block.

[Bearintheair]

Old thread I know, but I came across this while searching for the solution to the exact same problem and I've managed to solve it, at least for me and hoping I can at least guide someone. Symptoms were the same including a magneti marelli throttle that seemed to be healthy.

Started by cleaning the throttle body, as it was filthy and sticking open occasionally, so that helped a little but didn't solve it. What solved it for me was replacing the thermostat (and rad hoses but I doubt those did it).

Noticed in the summer it would run slightly cool sometimes, but didn't think anything of it. As temperatures dropped in to winter the engine temp was getting lower and the heater was getting poorer so I decided it was time to replace the thermostat. This seemed to solve it, and even after a battery swap (which makes the throttle relearn its mappings), I had a few moments of funky idle as it learned its self, and it's been perfect since.

Hope this helps someone.