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Model specific boards => Golf mk3 => Topic started by: admc6 on 07 May 2008, 19:32

Title: Need new ecu
Post by: admc6 on 07 May 2008, 19:32
I need to get a new yet old ecu for my 8v gti

Where is the best place to look and how much should i pay?
Title: Re: Need new ecu
Post by: Neaty on 07 May 2008, 19:38
best bet would be to try ebay or a scrap yard.

I don't know of any VW/Audi scrap yards in the Wirral area but if you can make it over to Altham near Burnley then there is one there which may be able to help you.
Title: Re: Need new ecu
Post by: admc6 on 07 May 2008, 19:42
I was thinking that. Have seen a couple on ebay. They range from 40 to 100 quid.

Do you know what you needto do to fit it?
Title: Re: Need new ecu
Post by: Neaty on 07 May 2008, 19:55
http://cgi.ebay.co.uk/vw-golf-gti-2L-8v-bosh-Ecu-mk3_W0QQitemZ140230543401QQihZ004QQcategoryZ9889QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

there's one ^^^

as far as I know its just un plugs and you plug in the new one. There is of course a bracket or two to hold it in place so is just a simple unbolting job
Title: Re: Need new ecu
Post by: admc6 on 07 May 2008, 20:02
thanks neaty.

i thought you had to do something with the codes?
Title: Re: Need new ecu
Post by: Neaty on 07 May 2008, 20:06
Ah, well I don't know about that mate. I have swapped ECU's on mk2's before and it has been fine so if you have an early mark 3 then you should be ok. However i am not entirely certain about later models.
Title: Re: Need new ecu
Post by: admc6 on 07 May 2008, 20:13
no worries. thanks for that.

Its just a shame no one would be open now, when your ready to do something
Title: Re: Need new ecu
Post by: Rmachines on 07 May 2008, 20:39
I have one for sale now,  trying to get rid of the damn thing to get it off my desk  :grin:

No one bid last time so u will probly get it for £15.00

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=170217228586&ssPageName=STRK:MESE:IT&ih=007
Title: Re: Need new ecu
Post by: admc6 on 07 May 2008, 21:02
Thanks i will pm you.

Does anyone know if any mk3 ecu will fit any of the others?

I have a late 1996 mk3 golf gti 8v anniversary
Title: Re: Need new ecu
Post by: Pete Taylor on 07 May 2008, 21:21
Why do you need a new ECU exactly?
Title: Re: Need new ecu
Post by: admc6 on 07 May 2008, 21:45
Its becasue it has a damaged earth to it, and the auto electrician it went to see today said that my new problem was related.
He couldnt find anything else wrong with it, and the fact it likes to cut out when it warms up was a good indication
Title: Re: Need new ecu
Post by: Pete Taylor on 07 May 2008, 21:58
sounds more like the ecu temp sensor to me. A diagnostic scan would be a lot easier than replacing the whole ECU!
Title: Re: Need new ecu
Post by: admc6 on 07 May 2008, 22:04
Its had a scan and it came back with no faults
Title: Re: Need new ecu
Post by: boneybradley on 07 May 2008, 23:16
Can i add......you need the ecu,ignition switch assembly/transponder and key from the car its removed from as the later post 95 models has a coded key which needs to match the ecu...... unless you fancy moding the ecu?
Title: Re: Need new ecu
Post by: Kenny_1.6 on 08 May 2008, 03:00
Why do you need a new ECU exactly?
exactly what i was about to ask  :laugh:
Title: Re: Need new ecu
Post by: admc6 on 08 May 2008, 07:25
when you say moding, what do you mean?
Title: Re: Need new ecu
Post by: Pete Taylor on 08 May 2008, 07:25
Its had a scan and it came back with no faults

And only cuts out when it warms up? Change the ECU coolant temp sensor then
Title: Re: Need new ecu
Post by: admc6 on 08 May 2008, 08:33
It seems to. Its doesnt take long, You will get about 2 miles and then when you let the revs drop it cuts out.

Where is that located?

Wouldnt it come up with a fault?
Title: Re: Need new ecu
Post by: Pete Taylor on 08 May 2008, 09:20
The ECU uses resistance as a measure of detecting broken sensors and faults. If you get an ABS fault it will be because it's detecting low signal (low resistance resistance). The problem with the ECU coolant temp sensor is the fact is works on resistance. If it completely and utterly breaks or it's unplugged it will throw up a fault. However, they tend to break down within certain resistance (or temperature) ranges and not show faults. They are extremely difficult to test, so just worth replacing.

The heat from the coolant changes the resistance in the sensor and relays it to the ECU which equates a fuelling level from the given resistance. Basically if it detects a low resistance (i.e detecting the engine is cold) it will up the fuelling mix to compensate. If it detects a high resistance (i.e engine upto temp) then it will lower the fuelling for maximum fuelling efficiency. Hence why the engine needs to be hot to control emissions when MOT testing
Title: Re: Need new ecu
Post by: admc6 on 08 May 2008, 09:25
How does that make it cut out when the revs drop to an idleing speed?

Where is the sensor located and how easy would it be to change?
Title: Re: Need new ecu
Post by: Pete Taylor on 08 May 2008, 09:48
Overfuelling the engine. It helps control the ignition advance curve and warmup using negative temperature coefficient. Yours being an 8v should, I believe, have a 4 pin plug. If yours is a 4 pin it will be sending the same signal to your temp guage on the dash so you will be able to see the engine coming upto temp correctly. If it is a 2 pin then the temp guage will take a reading from elsewhere and put you completely in the dark. If it is a 4 pin, check to see if it cuts out at around the same temp rather than a given time span
Title: Re: Need new ecu
Post by: admc6 on 08 May 2008, 09:53
I will have a look at that. thank pete

If i was to change it. I have read they are £25ish, but where is it located?
Title: Re: Need new ecu
Post by: Pete Taylor on 08 May 2008, 10:18
I couldn't tell you on the 8v engine mate, on the 16v it's on the right hand side of the head. Should be about that price for a genuine one from VW, not the kind of part to go getting cheap.

Title: Re: Need new ecu
Post by: admc6 on 08 May 2008, 10:45
ok cheers pete, i will look into that.

If i did have to get an ecu after, if its one for an 8v mk3 2L gti would it be ok, if the garage sorts the two out?
Title: Re: Need new ecu
Post by: Pete Taylor on 08 May 2008, 11:30
Why does a garage have to do it?

They're both really simple jobs, ECU is just unplug and plug in another. Whatever year your car is, get hold of a pre 1996 one for your car. OBDII have the ECU and the key coded. If you got a post 96 ECU you will need new clocks, keys, ignition barrel and all the locks. Pre 1996 weren't coded so it's a straight swap
Title: Re: Need new ecu
Post by: admc6 on 08 May 2008, 11:40
Oh excellent. The bloke in the garage forgot to mention that  :rolleyes:

Title: Re: Need new ecu
Post by: Pete Taylor on 08 May 2008, 11:47
He would of got you a brand new ECU from VW coded to the car. It would probably of cost more than the car is worth
Title: Re: Need new ecu
Post by: Pete Taylor on 08 May 2008, 11:50
http://cgi.ebay.co.uk/VW-MK3-GOLF-8V-GTI-EARLY-ECU_W0QQitemZ190220098427QQihZ009QQcategoryZ9889QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Title: Re: Need new ecu
Post by: admc6 on 08 May 2008, 11:52
Thanks pete. That one is new on.

Rmachines has one on ebay £15 off a 93 2L gti
Title: Re: Need new ecu
Post by: Pete Taylor on 08 May 2008, 11:59
Can't argue with £15
Title: Re: Need new ecu
Post by: remapped on 08 May 2008, 12:17
how do you know if you have a codded ecu ? was there a change point in 96 as mines a 96 car   i was looking in to getting a second ecu and modding ( prob bricking it ) 


admc6 !! £15 for an ecu is worth having as a spare if that would not be the problem.. 
Title: Re: Need new ecu
Post by: admc6 on 08 May 2008, 12:50
Thats what i was thinking. I already knew i had a problem on it. Not sure that my new problem is related, but neither is the mechanic so 15 is worth finding out and it will solve my previous problem to.