Engine Sensors

[mikee boy]

As my S2 is running like a tractor I decided to clean some of the usual suspects. Initial symptons were running poorly below 2500 RPM and the engine not wanting to idle below 1800 RPM.

First up were the Air Flow Meters. I cleaned the 2 this wires with carb cleaner and cotton buds. The job took 15 minutes and the result was a smoother tickover (1500 RPM) and the engine pulling better from lower down the rev range.

Next was the idle control valve. I took it off, separated the 2 parts and cleaned the central shaft, waited for it to dry and then refitted it. Total job took 15 minutes, and the result was the engine ticking over at 1100 RPM.

Unfortunately the engine still has a noticable 'step-down' from 2000 to 1100 RPM. What else do I need to clean/check/change?

Cheers

Mike

[clarenceboddiger]

You could check there is no play in the throttle linkages or on the butterfly's, smooth returning etc.

[tvrgit]

I would suggest wto things:

1. There is a large connector in the engine wiring loom as it runs along beside the right hand rocker cover, beside cylinder No 2. Take it apart and make sure the contacts are clean and dry - it carries the signals from most of the engine sensors and collects a lot of crap, and any resistance here can affect the ECU's interpretation of what's going on (and the signals it sends back to the ISCV etc)

2. Start it and leave it idling until it heats up and the fan cuts in, and then until the fan goes off again.

I don't know why, but mine needs this fully cold to fully hot cycle just once, every time I disconnect the battery or certain sensors. It seems to reset the ECU range and prevent the cold start keeping the idle speed up for a few seconds.

[mikee boy]

Cheers Clarence and tvrgit.

Took it out for a blast today and it feels like a different car. It now pulls in 5th from 1100 rpm.

[kenpage]

hi mike how about your sister we are in brugge at the moment moving tomorrow

[mikee boy]

Runs in the family!!

All's well here, hope you're having fun.