mk3 16 gti ecu question

[Si3]

Hi I have got a 1995 Golf GTI 16v. Has been missing, hesitating and generally drivers porrly for a couple of weeks, Its been on the fault reader and it says there is a MAP sensor fault, which I believe is part of the ECU. Checked all the pipes etc and they seem ok. If I need a new ECU, is it as simple as pickinmg up a new one and plugging it in, or will it need setting up for my immobilsor etc?

[dragongreengolfgti]

Iif the fault lies with the MAP sensor that is bolted to the side of the throttle body and needs changing they do break down same as a MAF sensor so i would start there. If you were to change the ecu you would need it de- immobilised or need the locks key and transponder plus ignition barrel from a different 16v with same part numbers (i think) .

Seems my information is useless  i thought it was the map sensor on the throttle housing side sorry 

[Dogbot]

Theres No map sensor bolted to the abf throttle body... The map sensor is in the ecu box, that's what reads the vacuum pipe from the manifold..

[thai-wronghorse]

When was the ecu vacumm hose last replaced?

[Ess_Three]

If you were to change the ecu you would need it de- immobilised or need the locks key and transponder plus ignition barrel from a different 16v with same part numbers (i think) .

Incorrect again I'm afraid..
You can adapt the ECU to Immobiliser using VCDS (VAG-Com).
It takes all of 30 seconds to do.
You need to do it before the car will start and run, after the replacement ECU is installed.

[Len]

To OP

Before you go to the expense of changing the ECU first try the ECU relay costs approx 12 quid and fits up in under the fuze box so dead easy to change!

[Si3]

Would the ECU Relay cause the MAP sensor fault code.

[Si3]

When was the ecu vacumm hose last replaced?

Unsure, as only bought the car a few weeks ago. The guy who read the codes and checked the pipes he said it was a bit crushed but sorted it out, drove it again and it was still driving like crap.

[technics100]

I would order some 3mm silicone tubing from ebay for £6 for 3M of it and redo the hose.  Mine was having problems cold starting and changing the vac line sorted it.  I also removed the ECU and replaced the length of vac line running inside the ECU.. easy to do and worth ruling it out.

There is a pic here of the map sensor inside the ECU.

http://www.golfgtiforum.co.uk/index.php?topic=240267.msg2224175#msg2224175

[Si3]

Bit of an update on the situation, and wondering if changes anyones thoughts.

Drove a 120 mile round trip a couple of days ago. For the 1st 6 or 7 miles drove like a pig, missing hesitating etc. Suddeningly it was off someone flipped a switch and the car started to drive absolutely brilliantly with no probs at all.

I drove the car or my normal communte to work (8 miles) and it was back to its old tricks!!!!

Any idea why it can do over 100 miles with no probs (60 mile drive, parked for 5 hours and 60 miles back) but struggles or a short journey?