Help - Search - Members - Calendar
Full Version: Engine Idling Eratic
Alfa Romeo 145 - 146 Forum > Technical > FAQ
doubleplugs
ive just bought a 2000 145 1.6ts its done 95k, i just about got her home when it cut out, ive had a mobile tuner diagnose the rpm sensor,and phase sensor as a fault, he cleared the ecu memory ran it for 10 minutes until it cut out again checked the ecu and just the rpm sensor fault came back he said the phase sensor could be various things and that the rpm sensor is the problem so after clearing the ecu memory again he put a new one in and no more faults, 25 miles later the idle revs will jump from 600 up 1000, ive not got any serv/hist with the car and does sound like a bit like a diesel so in the long run or probably sooner new belts would be best, but short term what checks can i do as a novice with engines. ive read some threads about cleaning the butterfly thingy, i dont think its the lambda sensor cos this didnt come up as faulty, the exhausts back box has a hole a the bottom dripping out black s**t

how do i clean the butterfly thingy?

what is the average £price for a belt change so i know i wont get ripped off?

will most garages be able to fit a new exhaust and for ho much £?
GialloEvo94
First just try unplugging the MAF and seeing if running the car with it unplugged resolves the problem. If it does then you have a faulty MAF and need to replace it. A faulty MAF won't necessarily show up on a diagnostics check. You will find the MAF between the air box and the throttle body housing on the right hand side of the engine bay at the back. The electrical connection plug you need to remove is on the top of it...

[attachment=3873:MAF.jpg]

To clean the throttle body housing, remove the pipe with the MAF in it (2 jubilee clips, one either end) then either try and clean the housing with it still attached to the car or unbolt it (4 ribe-headed bolts) and clean it off the car. You will also need to unclip the throttle cable and unplug the stepper motor (the black thing on the side)...

[attachment=3874:ThrottleBody1.jpg]

[attachment=3875:ThrottleBody2.jpg]

[attachment=3876:ThrottleBody3.jpg]

[attachment=3877:ThrottleBody4.jpg]

[attachment=3878:ThrottleBody5.jpg]

If neither of these things work then you might have a faulty throttle stepper motor. Replacing this is a specialist job as it needs to be correctly calibrated after fitting. Other people on this forum have quoted prices between £100-200 for the part, fitting and calibration.

For a cam belt change you are looking at around £200-£300. The diesel sound on startup is a knackered variator (it's on the end of the inlet camshaft). It's better to get one of these fitted at the same time as the belts are changed to avoid paying additional labour charges for having the belts removed and refitted again at a later time. Add around £100 on top of the belt change for a new variator.

Exhausts can be fitted by any garage.

Look here for cheaper exhausts. They're not genuine Alfa ones but are pattern ones which look identical to the genuine ones (or as close as can be).
Dodger
If you do take off the throttle body I assume it doesn't b**ger up the idle settings?

Can you clean the stepper motor gigger at the same time??
GialloEvo94
You won't screw up the stepper motor settings by simply removing the throttle body housing. However, I wouldn't advise you to unbolt the motor itself and actually take it off the housing without proper reason in case by doing so you do somehow upset the calibration. As you can see by the pics, the stepper motor is a sealed unit and is just connected to one end of the central rod of the butterfly so there is nothing to clean as far as the actual stepper motor goes. Just clean up everything else you can see smile.gif
doubleplugs
thanks guys, i'll wait for the sun to come out first before attempting anything
adzipalmer
What would you suggest to clean the Throttle body with??
Dodger
Carb cleaner from a motor factors.
Proteo Red
My 145 recently developed this erratic idle & sometimes revving up & down by itself.
I also noticed driving at constant speed on the motorway, the engine would occassionally get these very subtle 'power-kicks'.

I had it checked out last week as part of it's MOT & service. No fault codes came up, but they suspected intermittant fault with the TPS. I've not heard of this TPS before, but after digging around on here, the TPS is another name for the Stepper Motor?

I've had this replaced now...but SO EXPENSIVE! The motor itself was £143, & what with fitting, cleaning the throttle body, & re-setting the parameters etc, the final cost came in at around £250.

Anyway, importantly the good news is the idle is steady as a rock now so if anyone else out there has similar problems looks like unfortunately it's time to dig deep in the wallet...again.
Even better news, is that I gave it a good blow-out on the dual carriageway between Hitchin & Stevenage to see if there was any improvement in performance.
I put my foot down, & OMG it was like the car suddenly had a rocket shoved up it's AR*e !
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.
Invision Power Board © 2001-2021 Invision Power Services, Inc.