A4 1.8T Won't Run

[K555]

:aargh4: Hi everyone! Sorry my first post has to be a problem but my A4 has decided to take early retirement:(

The car is a 1998 1.8T Sport, just gone over 100k miles.

Basics of fault are that it won't start at all unless i have throttle open slightly, if it does start and i take foot of throttle it dies, if i hold my foot steady on throttle it will run at approx 1k revs but will rev itself up to 2k back to 1k revs over and over. If i press throttle down further it more often than not dies though occasionally it will take revs to 4 or 5k and rev itself up and down at that position:confused::confused::confused:

I've replaced the air flow meter but no change.

If anyone could point me in right direction i'd really appreciate it.

Thanks, Keith.

[audimad]

I would say you have an intercooler or similar hose split or off

[K555]

Thanks Audimad, i'll check that out and let you know if i find anything.

[K555]

:confused: I've checked all the hose's and as far as i can see they are ok, the temp sensor, throttle body and air mass meter have all been tested and the readings taken are as specified by manufacturer. I can't source an ecu locally to try on the car and blowing £££'s on a part which might well be ok doesn't appeal:1zhelp:

Can anyone offer any other theories?

Car is an AEB engine code with a 8DO 907 558 E ECU, any ideas where i could get one for sensible cash?

[audimad]

I have a spare 557 T ECU , that works fine on my AEB engined A4. I know they are compatable as i have a 558E in my car now, and to test the spare i swapped the 557 in and recoded the dash and job done.
Where are you based?

[docurley]

I would also swap out the coolant sensor as they can cause similar symptoms I would also check the plug just incase.

[K555]

Audimad, i'm in the south of Scotland. I'm heading to a breakers yard tommorow morning for another look. I was given an ECU from a '96 A4 1.8T but its code ended 557 and the wiring connections were completely different to the loom on the car:confused:

What other cars have a compatible ecu with the A4 1.8T? Enquired about ecu from a Passat 1.8T but it was a 8DO 907 557 as well:(


docurley, can the sensor still be cause if its giving the voltage readings which the tech manual states? Willing to try anything to get it back on the road but at same time the car is at an age and mileage where i need to watch whether its worth throwing lots of cash at it or not.

Thanks for the suggestions!!

[audimad]

As long as the 557 has the same connectors and is from the same engine, you are fine. A passat ECU will be fine, as thats what i run in mine. The 96 had a different type of ECU you need at least a 97 one

[K555]

Audimad, you mention in your post about 'recodeing the dash', is that something i need to do? How would i go about it and is it possible that my current ecu has 'forgot' its basic settings? Could that be the cause of my troubles?

Sorry for all the questions:o

[audimad]

You would need VAG-com to do it, and you would need to do it or the immo will stop the car starting and the little key emblem will flash at you.

Its unlilely that the dash has forgettoen your immo codes as the light would be flashing if that were so

[K555]

Fingers crossed;) picked up a 557S ECU this morning along with another air flow meter, throttle body, air temp sensor, coolant sensor and some other bits and piece's from breakers yard, i really hope something i've got makes it run again:dunno:

I'll let you know!