Alfa Romeo 1.8 TS - weird idle Options

[IecramZk]

Hey guys! First of all I would like to apologise for my grammar mistakes that I'll make!:D
So my problem is:
When the car is cold, it doesn't want to rev. I mean it is okey from idle to 2000, but after that it stopped about 2500. If I push the pedal a little bit more, it "wakes up" and everything is fine. (I know, and I never rev high the engine when it is cold.)

When the car is hot, it acts weird. After shifts, it revs up a little bit. Or not up, just stays there (and it doesn't go down - just when you accidentally stay on the throttle when you press the clutch:D)
And the idle is rough. It really likes to go up and down, up and down for no reason. It always go down first (about 500-600 RPM) and up to ~1000 and again down... But what is more interesting for me is when I played a little with the throttle: I tried to hold the rpm and 1500, and didn't move my foot, but the idle was still "wavy" .
Another interesting thing: when I pull all the way in the throttle and shift , it behaves normally. (It doesn't matter if I rev to 4-5k or just 2.5-3k).

It feels, the car reacts slowly for the idle changes. (For example, when the fan turn on.)


I hope that you can understand what I wanted to write, and have a nice day!

And I almost forget the datas:
'99 1.8TS 144hp

This post has been edited by IecramZk: 24th June 2018 21:27

[shpuncik]

have you tried connect diagnostic to check for any DTC?
faulty throttle body?

[IecramZk]

I don't really know what DTC means, but there are no trouble code.
Except this the car works fine, consumption ~8.5~9 /100km

If it would be a faulty throttle body, it would show trouble codes, wouldn't it?

[alfizta]

1st I would try to find any air/vacuum leaks between MAF and engine, then check MAF. unplug MAF to see if there is any improvement. if there is any, clean MAF, replace if necessary.

[IecramZk]

If I will unplug the MAF and it will be okey, then it can still be vacuum leak, right? I mean I don't know if I'm right, but in that case (unplugged MAF) there wouldn't be anything what can meter the air, so the engine would get a normal/usual values of air. (Because if the MAF is okey, but there is a vacuum leak , the engine get the metered air + unmetered from the leak)
Sorry if I'm a bit complicated, it's late:D
And another question: if I go for a ride (a 10 km) with unplugged MAF, can it cause damage to the engine?

[alfizta]

If I will unplug the MAF and it will be okey, then it can still be vacuum leak, right?

I believe yes, it can still be a vacuum leak.

Sorry if I'm a bit complicated, it's late:D

you're welcome

And another question: if I go for a ride (a 10 km) with unplugged MAF, can it cause damage to the engine?

no, wont damage the engine, knock sensor would prevent that.

from my experience, with MAF disconnected, low rpm idle will be very weak with the engine sounding like it will stall at any second. will run OK in normal driving, I mean with foot on throttle pedal.

I would also check if hitting the brakes with car stopped does any change on idle.

[IecramZk]

Oh, I'm glad that you mention the "brake part".
Yes, sometimes when I'm at a red traffic lamp, and I'm hitting the brake pedal, the rpm goes down and the pedal become softer. (It "fall" in a little bit.)
My dad told me that he changed the MAF. I totally forgot it, sorry.

[alfizta]

check this hose, then
http://forum.alfa145.com/index.php?act=att...ost&id=4547

and the thread
http://forum.alfa145.com/index.php?showtop...amp;#entry86654

the fit has to be really tight

[IecramZk]

Okey, I will check those things asap and I will write back my experiences.

Thank you for your, and everyone's help! Have a nice day/night guys!

[IecramZk]

Woohoo, I think we found the problem, it was the Idle Stepper Motor.
We get it from a 145 '98 1.6 TS, did an ISM reset with Multiecuscan, 20km ride, and it is normal now. (It was normal, I hope it will be normal! )
Thank you guys again!

[alfizta]

sometimes things are just as easy!