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Model specific boards => Golf mk2 => Topic started by: weazgti on 22 December 2009, 16:50
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Just pulled the ecu out to check the connecter were ok and all seemed fine. so i put it all back in and now it wont start. The fuel pump primes and stops as normal but as soon as i go to start it the relay goes nuts.
Any suggestions to whats gone wrong?
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broken it :grin:
have a search, but i am sure if you dont do things in a correct way you can fudge the ECU :huh: :shocked:
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Just pulled the ecu out to check the connecter were ok and all seemed fine. Any suggestions to whats gone wrong?
Hi
Was it the 16 pin connector ?
Was the ignition ON when you unplugged/plugged it ?
Are you sure it is seated tight ?
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yes the huge one. ignition was off at the time and all i did was unplug everythin,check for corrosion and plugged it all back in.
Fuel pump primes and goes off but the relay for it clicks like mad.
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.......and all i did was unplug everythin,
Hi
What else did you unplug. ?
Relay clicking like mad can also be a low battery. Charge the battery.
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was the battery disconnected when you unplugged the ECU? Please say yes.
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No...it was connected.Thought it only mattered trying to start with no earth which i didnt do. why would that matter then?
mattkh.... i unplugged the tci plug and whatever the other plug on the front is aswell as the huge connecter.
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As far as I'm aware the ECU has a permanent live, I may be wrong though. The ECU is very sensitive (female) so any voltage too high and it will fry it.
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Did you connect the ignition moduel back up? it sits ontop of the ecu.
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I believe Khare is spot on and you have fried the ecu.
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I did a search and could nt find anything that says disconnect battery before removing ecu.
I will be venturing outside in a mo and hopefully its something really silly like i ve damaged a pin or something
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I believe Khare is spot on and you have fried the ecu.
or fudged it as posted earlier :wink:
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Just been out and it fires once every now and again but then the relay goes crazy and stops it. Took plugs out and spun it over,no fuel come out and then my battery died trying to start it so looks like ill be getting a bus to go get my wifes car to jump start.
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started with jump leads relay stopped clicking after a while then it started. soon as i tried without the leads on it started clicking for a bit then starter gave up and just spins not turning over engine.can it get any worse.
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started with jump leads relay stopped clicking after a while then it started. soon as i tried without the leads on it started clicking for a bit then starter gave up and just spins not turning over engine.can it get any worse.
You may have filled the bores with petrol.
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no checked that and just got it running by hitting the starter. It starts and runs on its own now just every now and again the relay clicks once and the engine surges
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sWAP OUT THE RELAY-THEY ARE A COMMON FAILURE, AFTER ALL!
Caps, sorry!
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am off to get starter and relay. thanks for that didnt know they were common fault.
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got relay off a mate but does same thing.water in fusebox maybe? just gonna leave it till after christmas now and get new relay aswell as pulling the fusebox down.
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new ECU :lipsrsealed:
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Not too sure because its not filling engine with fuel and i can start it but the relay goes nuts and cuts the fuel supply.
Thinking maybe when i took ecu out i might of somehow got water on the fusebox but then i cant really be 100 % till ive got a known working relay in there and taken the fusebox down. Im finding this disconnecting battery before removing ecu plug a bit weird because i have searched but found no answer to this and i ve asked mates that have taken ecu out without disconnecting battery and they ve had no problems.
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Maybe you've just been really unlucky then? It seems the biggest variable in this is your ECU.
Engine works fine
ECU is tampered with but nothing else
Engine no longer works.
There is a pattern, but there's also the possibility that it's a coincidence and it is something else! Have you checked all the plugs are firmly connected to the fusebox?
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......Thinking maybe when i took ecu out i might of somehow got water on the fusebox
Hi
Impossible beacuse the fusebox is on the drivers side and the ECU is on the passengers side.
When you unplugged the ECU, was it raining or is the car under a cover ?
Disconnect the battery and put it on charge.
Then unplug the ECU again and :
1. take a picture of the pins for us
2. use a hairdryer and blow dry on a very low heat to drive any moisture away
3. clean the pins with a maplins switch cleaner
4. allow to dry before pushing the plug back on
5. clean and redo the earth points
and away you go hopefully.
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Maybe you've just been really unlucky then? It seems the biggest variable in this is your ECU.
Engine works fine
ECU is tampered with but nothing else
Engine no longer works.
There is a pattern, but there's also the possibility that it's a coincidence and it is something else! Have you checked all the plugs are firmly connected to the fusebox?
......Thinking maybe when i took ecu out i might of somehow got water on the fusebox
Hi
Impossible beacuse the fusebox is on the drivers side and the ECU is on the passengers side.
When you unplugged the ECU, was it raining or is the car under a cover ?
Disconnect the battery and put it on charge.
Then unplug the ECU again and :
1. take a picture of the pins for us
2. use a hairdryer and blow dry on a very low heat to drive any moisture away
Yes you re right,probably just been unlucky and damaged ecu and hopefully try a mates one on there.
Ecu is drivers side same side as fusebox. I did it on a dry day outside but the area underneath the ecu was damp so will be giving the hairdryer treatment like you say. Also i havent had a chance to check back of fusebox ill try have a look today and get some pics of the pins on the ecu.
3. clean the pins with a maplins switch cleaner
4. allow to dry before pushing the plug back on
5. clean and redo the earth points
and away you go hopefully.
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cleaned pins and dried out and car starts fine. only thing is whilst testing i had the ecu cage laid against the bodywork of the car and it was sparking.
I put it all in and if i move it it sparks around the plastic nut and either stalls the engine or makes it surge. I tried putting another of the white plastic clips on the round locating pins in the scuttle because it looked like one should be there but that made it refuse to start.
Is the cage round the ecu act as an earth or something? Have cleaned all the crap out from underneath it and it starts and runs the same as before now so it was definatly that.
Perhaps someone could tell me if it supposed to have an earth or post a pic of there ecu in the car.
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no that definitly should not happen, sounds like the ign amp is earthing itself thru the cage? check the earths around the battery -ve, there should be a chunky black wire with a ring terminal on the end, that runs from ign amp all the way to the battery.
also, have you tried replacing the ecu relay?
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Would that be one of the wires in the plug or is it just supposed to have an earth attached to the ignition amp somehow?
Hopefully this is the reason i cant time the car properly and why it runs worse with something switched on like the headlights.
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ign amp should earth via that chunky black wire i mention above, if its earthing thru the casing to the ecu bracket something isn't right. might be the ecu thats damaged internally and earthing via the big metal heatsink on the back? either way, shouldnt happen!
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(http://i973.photobucket.com/albums/ae214/weazgti/008.jpg)
This is all i have.The only chunky black wire off the battery is the one going to gearbox and next to battery.
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the brown/white wire in that pic is the TCI unit earth, that one should run all the way to the battery -ve. its pin 2 on the plug, so you could check it for continuity to ground with a multimeter. you could pop the tci-h unit off the ecu bracket, then see if if the bracket still sparks to earth.
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Right. Have checked for continuity on the tci plug and all but one of the pi.ns buzz my multimeter when touching the battery earth.
Im not getting sparking recently and have been able to drive the car but it still has the huge flatspot its had for ages which is worse when something is turned on in the car. Yesterday morning i went to pull away and it stalled then wouldnt start so i wiggled the ecu and it run spot on for one trip really pulling well then it went back to normal again, gutless with a huge flatspot.
I dug out an old tci but its a 16v one.Would this work on this or is the ecu looking suspect still?
edit: just been out driving and while i was waiting for somebody i thought id have a look at the ecu relay. Pulled it out,wiped the contacts and put it back in and after a while all was well again on the drive home. Either pure coincedence or water in the fusebox connections maybe?
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Unplugging the battery is a no brainer when fookin about with electrics only a div would leave it connected 'no offence' :evil:
unplugging the battery for half hour should reset the ecu.
What you've done is leave it live hangin over the arch its then contacted mental and you've burnt something out.
ALWAYS ALWAYS ALWAYS disconnect the battery when playing with electrics regaurdless if it says to or not i mean if your electric cooker wasnt working right would you start mucking around with it poking a screw driver in there while it was still plugged in
Bonkers!!! i reckon a new ecu will shortly be on the way.
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The ecu shouldnt be live anyway.What you say doesnt make sense because what would it matter if it touched the arch? its sitting in the scuttle which is metal.
The reason i was playing about with electrics in the first place was to try and find out what was wrong before i even touched it.
If its back to running the same as before then i cant see how i have burnt anything out.
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The ecu shouldnt be live anyway.What you say doesnt make sense because what would it matter if it touched the arch? its sitting in the scuttle which is metal.
The reason i was playing about with electrics in the first place was to try and find out what was wrong before i even touched it.
If its back to running the same as before then i cant see how i have burnt anything out.
Ecu shouldnt be live anway 'what' its friggin electric with wires coming out of it even unplugged its still earthed to the car.
if the car is back to normal then no you havent burnt anything out but pulling out plugs or what ever you done obviously upset the ecu for 1 reason and 1 reason only. coz you didnt disconnect the battery
its the mother of all f**k ups i know this coz ive made the mistake myself and coursed magor headaches
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you shouldnt need to pull the battery for this kind of thing, but you never know what faults are in the wiring which will cause things liek this to happen! also pulling the ecu or battery for any length of time wont reset the digifant ecu as they have no memory.
the fact all but of the TCI piuns buzz continuity to earth is a problem, you defiitly have some wiring gremlins in your car! check over the loom in the engine bay very carefully, you're looking for any damaged areas or bits that have electrical tape on. I always home in on electrical tape, 9 times out of 10 when you unwrap it you'll uncover something horrible :grin:
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ok i need to investigate then. It has the remains of an alarm in there possibly immobiliser, aswell no box just wires. I disconnected the live for the alarm and lost all electrics so had to stick it back on for the time being,it just has a bag over the wires coming out the bulkhead.
Dont know if this is related but i will follow the wires and see whats tapped in where.
Not too clued up on alarm/immobilisers, would it be tapped into tci wiring at all?
oh and thanks for advice, i was considering shotgun diagnostics and just replacing ecu for the sake of it. :grin:
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could well be, on my gti the TCI ign live feed had been tapped into by a previous alarm install.
removing alarm is pretty straight forward, find the brain then follow all the nwiring from it. if you find any wires that have been chopped and spliced into, find the other end of the wire and rejoin.
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Have had a nose about and although there are no wires chopped/spliced in the engine bay there are a lot of snap on connecters under the steering cowling and little plugs near the fusebox.