I would really appreciate some suggestions

[R1johns2]

Hi, i have a 1994 S2 avant ABY angine. Its my first Audi as i was into cossies before. Everything was going well as i started doing a few mods to the car, Full Miltek exhaust with high flow cat, K&N filter, Adjustable boost valve, In car boost Gauge. Then i had the Cambelt changed and bought some new wheels, Very nice! But the car has developed a PROBLEM! which is very frustrating.When the car boosts to about 1.2 bar it cuts very suddenly and then will cut at 0.5 bar. If you switch the ignition off and on the car wll boost as before and if you back off and don't boost over 1.0 bar the car is fine. Pleeeese some one tell me what this is or what it could be, i am a desperate man! I have tried removing the boost valve and it made no difference. I don't know anything about S2's apart from i really like the car and want to get the problem sorted as soon as so i can carry on with the mods. thanks in advance, John.

[jade]

Sounds like a boost leak the over boost protection kicking in , but there are other things which will cause this, but try there first then move to others
Jade

[Jon441cc]

Hi, i have a 1994 S2 avant ABY angine. Its my first Audi as i was into cossies before. Everything was going well as i started doing a few mods to the car, Full Miltek exhaust with high flow cat, K&N filter, Adjustable boost valve, In car boost Gauge. Then i had the Cambelt changed and bought some new wheels, Very nice! But the car has developed a PROBLEM! which is very frustrating.When the car boosts to about 1.2 bar it cuts very suddenly and then will cut at 0.5 bar. If you switch the ignition off and on the car wll boost as before and if you back off and don't boost over 1.0 bar the car is fine. Pleeeese some one tell me what this is or what it could be, i am a desperate man! I have tried removing the boost valve and it made no difference. I don't know anything about S2's apart from i really like the car and want to get the problem sorted as soon as so i can carry on with the mods. thanks in advance, John.

Adjustable boost valve NO NO NO! , i would not put it back in once the problem is fixed.
Sounds like overboost protection seeing that you have had a adjustable boost valve fitted
Reset your ecu and see if it solves the problem also check for boost leaks

[Jamo]

Welcome to the forum!

Sounds like overboost protection, i would say you have a boost leak.

Please Please take out the adjustable bleed valve, your ECU must hate you!

[newsh]

You can't do that adjustable boost valve thing with Motronic, its totally crap, get it properly remapped if you want to up the boost. You prolly have a boost leak somewhere but also would be worth cleaning the MAF connector.

[R1johns2]

Hi, i have changed a lot of the vacum/boost pipe for silicon as the old piping looked tatty. I will check all the pipes today and clean the MAF sensor...oh and remove the boost valve . One question... How do i reset the ECU?? i have removed it from the car as my friend who works for Audi said he would get me a test unit to try on the car. But then found he did not have one...Typical!! Thanks again, John

[s2dude]

To reset the ECU disconnect the battery and leave it all disconnected for Say 1 hour.
(may be wrong on the time here but 1 hour is a safe bet iirc)

[Jon441cc]

Hi, i have changed a lot of the vacum/boost pipe for silicon as the old piping looked tatty. I will check all the pipes today and clean the MAF sensor...oh and remove the boost valve . One question... How do i reset the ECU?? i have removed it from the car as my friend who works for Audi said he would get me a test unit to try on the car. But then found he did not have one...Typical!! Thanks again, John

Main fuse board under the bonnet, you will see a orange clip with the word MOTOUR on it, pull the two fuses, wait 5 mins then put them back in and give it a try, But if you have removed the ecu you have probably reset it anyway

[R1johns2]

I have re fitted the ECU and cleaned the MAF connector...if thats the plug on the black module fitted to the air pipe near the air box, it looked clean anyway. I have also checked the vacum/boost pipes, they all seemed ok. When it stops raining i will remove the boost valve and take the car out for a test drive. Thanks again for the info, i will let you know the outcome. John

[HPmuirt]

I have re fitted the ECU and cleaned the MAF connector...if thats the plug on the black module fitted to the air pipe near the air box, it looked clean anyway. I have also checked the vacum/boost pipes, they all seemed ok. When it stops raining i will remove the boost valve and take the car out for a test drive. Thanks again for the info, i will let you know the outcome. John

Well it has finished raining north of London, have you been out yet?

I think quite a few on here are waiting to hear that it was the variable boost valve POS that was causing your ECU to drop in to overboost protection mode and therefore run at only 0.5 Bar.

Hope it gets sorted.

Cheers n

Si

[R1johns2]

Great News!!

Hi all, What can i say. You guys know your Audi's and im very grateful. Car is running sweeeet, boosting to 1.2 bar and NOT cutting out. Im very happy again and want to say a big thanks to those who helped me out. please let me know of any S2 or audi meets as i would like to meet a few of you and see more S2's. All the best, John

[Jon441cc]

please let me know of any S2 or audi meets as i would like to meet a few of you and see more S2's. :

http://www.s2forum.com/forum/showthr...&highlight=gti