GolfGTIforum.co.uk
Model specific boards => Golf mk3 => Topic started by: JW590 on 29 October 2011, 13:47
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I am trying to fix my son's car - like dads do! I know this has been covered several times, and I have read loads of them. Unfortunately my story is the same as the others.... change loads of parts to no avail. It initially cut out after a 20 mile drive, but now it cuts out after about 7 miles. I wait and start it, then it only lasts half a mile a time. If I change something and go for a test drive starting with a 'cold' engine it will last between 3 and 8 miles. Then it's limp home a half mile at a time.... at least I've done it enough times to work out to go round in circles so I'm never too far away from home!
So far I have changed -
Crank angle sensor
Coil
Distributor cap
Rotor arm
Plugs
Leads
ECU relay
Fuel pump relay
Fuel filter
Fuel pump
After all this it still has the fault.
Any help or tips greatly appreciated.
Thank you
John.
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Which engine is it?
Other things probably not the problem but
1. clean the throttle body
2.check all vacum hoses
3.if its abf check small hose to ecu
4.Check all earth points on engine and under battery tray
5. check battery it self
6. Try another coil if it was second hand or even new as some new ones are faulty :sad:
7. a good service plugs,leads check distributor cap and rotor arm.
8. get a vag com test done
9. check your lambda sensor
10.check maf sensor
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All parts except the fuel pump are new - but the fuel pump is fine. How do I tell which engine it is?
I am currently working on it and have worked out the following. If I unplug the fuel pump and put an external permanent feed on direct from the battery it seems to work fine - although driving around like that the other day it eventually did cut out (could have been the old relay). I have now replaced the permanent feed from the battery with a permanent feed from fuse 18 (fuel pump fuse), taking earth from the door hinge.
The 12v normally goes from the battery to the relay to the fuse and down the red+yellow wire to the pump.
It is now going from the battery to the relay to the fuse and down the external wire to the pump.
With the plug disconnected I have had 12v showing on the red/yellow wire - which is correct. However this is intermittent in that it is now showing 5v..... therefore the 12v is dropping somewhere along the red/yellow wire between the fuse and the plug.
I have also noticed on a wiring diagram on this forum that fuse 18 also feeds the Heated Oxygen Sensor Control Module - whatever that is. If I knew what and where it was I could disconnect it and see if the 12v comes back to the fuel pump plug.
Any ideas please?
Thank you
John.
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1.4/1.6/1.8/2.0 8v/2.0 16v??
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2.0 8v - I've just put it in the title. I'm wondering if it's the Heated Oxygen Sensor.
Where is it so that I can temporarily disconnect it?
Thank you.
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Oxygen Sensor being the lambda sensor, located in the middle section of the exhaust, but not heard of this causing cutting out issues before. Other than what you've replaced, definately check your breather pipes as these are very common failures. At Idle, get someone to rev the car, whilst you watch the pipes. They get old and very soft, and collapse under load. Also clean the throttle body out, and maybe replace the MAF. You can disconnect the MAF to check it, but it will probably cut out as usual. Usual signs though are hesitation at 3k rpm, and diminished performance. Disconnect it and take it for a spin to see if you have noticable gains. They are quite fragile, but I have cleaned mine using electrical contact cleaner, and a cotton bud and it made the world of difference.
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Thanks Sean, I'll do that tomorrow in the daylight.
I'm absolutely sure that I am on the right track now in that it's a 'spark' problem. Here is what I know....
Fuel pump unplugged with direct to battery 12v power on and it runs - however still cuts out after 7-8 miles.
Then cuts out at the same intervals of (say) half a mile. Same waiting time, same running time, therefore something is cooling down just enough for the engine to start again and as soon as it reaches temperature it cuts out.
Because the fuel pump has external power and is always running it cannot be a fuel problem but a spark problem, also think this because it just instantly cuts out rather than drops revs and cuts out.
Voltage across pump plug is 5v whether plugged in or not - which is strange because the red/yellow wire comes from fuse 18, and I have now linked into fuse 18 to get the permanent 12v supply (fuse is after the fuel pump relay) .... so somewhere along the red/yellow wire the voltage is dropping. i.e. the red/yellow wire and my external wire are coming from the same point, but the external wire has 12v on it, the red/yellow has 5v on it.
Fuse 18 also feeds the Lambda sensor control unit. Is the sensor control unit built into the ECU?
The plug earth wire is shorted to earth as it should be.
Stupidly I haven't yet checked the red/yellow wire against earth. Should be open circuit but may not be.
Something somewhere is dragging the fuel pump 12v feed down, and whatever it is is cutting out when it gets hot. It must be cutting the spark.
I disconnected the Lambda plug near the downpipe. The 12v did not re-appear at the pump. However all I have done is to isolate the sensor and not the wiring circuit / control unit.
I dropped the fuse/relay box down and the O2 sensor control module relay cannot be taken out, therefore I cannot isolate the wiring for it unless I can find the unit and unplug it.
The breather pipes on the top of the engine are split.
I've thought that tomorrow I will put battery 12v straight to fuse 18, ignition off, and check for 12v at the end of my new permanent wire and see what it is on the red/yellow wire. I'll then turn the ignition to first position and check again, then start the engine and check again. That should help to isolate where the problem is. If only I had a circuit diagram.... I'm good with circuit diagrams.
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Pretty sure the Lambda control is built in to the ECU although not 100%. Obviously controlling timing/ignition/fuelling so it would make sense. Split breather pipes will cause cutting out issues though, but you should have a rough idle as well, although you suspect spark/ignition to be the culprit go with what you think mate. You obviously know what your doing with regard to electrics/electronics etc, so I think you may be on the right track, just dont overlook the simple things is the only advise I can give. Good luck with finding the problem, and keep us updated with how your getting on. :smiley:
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What engine code is the car? Also have you have any possible fault codes read?
I would not rule out an ECU problem too but that is very unlikely as they are usually pretty reliable.
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Thanks for all the help so far.
Sean - the idle / tick over is fine despite the breather pipes being split.
Mart - no codes were showing up. I don't know where to find the engine code.
I will update as I go along tomorrow - it always annoys me when people don't put an end to their threads once they've repaired the car.
Thanks again.
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Today's update.
I did all my wiring checks and found that the 12v on the red/yellow wire to the pump is intermittent, with no regular pattern and doesn't seem to be linked to anything - i.e. revs etc. Really strange how it's at the fuse and at the end of the 'permanent' feed I've taken from the fuse, yet intermittent on the red/yellow that comes from the fuse. I have determined that there's nothing wrong with the fuel pump earth lead that is in the same loom. The plug is on the pump now with the red/yellow disconnected and replaced with the 'permanent' feed.
I checked and cleaned some of the earths - no change.
I bought some 10K Boost, followed the instructions and cleaned the Throttle Body - no change.
I disconnected the MAF and the car wouldn't tick over but I ran the car (at standstill) by keeping the revs up - but it also eventually just cut out. I took the MAF off and looked at it but it was clean (doesn't mean it's working).
Whatever it is, it is kicking in and cutting out when the engine is around about the temperature when it is hot enough to start the electric fan - it runs for a while and then the engine cuts out - probably coincidence because sometimes it cuts out beforehand. Disconnecting the fan switch and the fan doesn't make a difference.
Tomorrow I am going to buy a new breather pipe - the one that links to the valve on top of the camshaft cover is badly split. I would say that it was almost torn in two.
I've put it away for the day now, another six hours spent on it.
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dont rule out a cheap crank sensor i had this cut out when temp got up to 82 ish let cool down would go again got a gen part of vw a day later prob solved
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Today's update.
I did all my wiring checks and found that the 12v on the red/yellow wire to the pump is intermittent, with no regular pattern and doesn't seem to be linked to anything - i.e. revs etc. Really strange how it's at the fuse and at the end of the 'permanent' feed I've taken from the fuse, yet intermittent on the red/yellow that comes from the fuse. I have determined that there's nothing wrong with the fuel pump earth lead that is in the same loom. The plug is on the pump now with the red/yellow disconnected and replaced with the 'permanent' feed.
I checked and cleaned some of the earths - no change.
I bought some 10K Boost, followed the instructions and cleaned the Throttle Body - no change.
I disconnected the MAF and the car wouldn't tick over but I ran the car (at standstill) by keeping the revs up - but it also eventually just cut out. I took the MAF off and looked at it but it was clean (doesn't mean it's working).
Whatever it is, it is kicking in and cutting out when the engine is around about the temperature when it is hot enough to start the electric fan - it runs for a while and then the engine cuts out - probably coincidence because sometimes it cuts out beforehand. Disconnecting the fan switch and the fan doesn't make a difference.
Tomorrow I am going to buy a new breather pipe - the one that links to the valve on top of the camshaft cover is badly split. I would say that it was almost torn in two.
I've put it away for the day now, another six hours spent on it.
Split breather will not make is cut out.
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Mart - I understand that a split pipe won't make it cut out, but I may as well replace the breather pipe while I'm working on it - so I have bought a new one off Ebay for £14.94 including postage.
Dragon / Mart - I have found out this morning that the engine type is ADY.
Skater - The new crank sensor is Bosch, so not a cheap one.
The only thing I have not replaced on the ignition side is the actual distributor - and the Hall sensor is built in to it and may be failing when it gets hot. I suppose I will have to buy a new one as it is the only way to eliminate it.
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Deleted because of duplication.
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The latest update -
Ignition - all new parts
Crank sensor
Coil
Distributor
Dizzy cap
Rotor arm
Plugs
Leads
ECU relay
Fuel- all new except pump
Fuel filter
Fuel pump - used but works
Fuel pump relay
Breather hoses replaced with new ones because they were split.
Cleaned out Throttle Body
Changed off-side front sidelight bulb.
Last night it ran for 16 miles then cut out. Immediately started, ran for 1 mile and cut out, waited a while, started, ran for 3 miles and cut out... and so on until I got home. On one of the later cut outs I sat and waited and heard a relay click - I turned the key and the car started.
I think it ran for 16 miles because it took a while for it to get up to an indicated 90 on the temperature meter. It drove the last three miles home, with my fingers on the relays hoping it would cut out, running at about 70C on the temperature indicator, but it didn't cut out. Left it ticking on the driveway while I moved the other cars - it hit 90c and cut out. Therefore something somewhere is breaking down at temperature.
The (new) ECU relay was hot.
I assume I have changed all ignition parts except for the ignition switch, the ECU, and the Lambda sensor.
When it ticks over it is very steady, and when it cuts out it is an immediate stop, no spluttering or anything.
Anybody got any fresh ideas that I haven't tried?
Thanks
John.
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Have you replaced the temp sensor then?
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No, which one and where is it?
I can get one while I'm out today.
Thanks
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Good diagram in this thread: http://www.golfgtiforum.co.uk/index.php?topic=101400.0
:)
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Have replaced the temperature sensor with a new one.... no difference.
The next thing I have to change is the ignition switch.
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Get yourself one of these, can't go wrong for the money
http://www.ebay.co.uk/itm/VW-VAG-Diagnostic-Fault-Code-Reader-CAN-OBD2-/150667799048?pt=UK_Diagnostic_Tools_Equipment&hash=item2314802a08
Can read and clear fault codes, just had a play with mine and found some old and new codes!
You may have already fixed the issue but need to clear the codes.
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Changed the ignition switch, but the problem persists. So now all the following have been changed -
Crank sensor
Coil
Distributor
Dizzy cap
Rotor arm
Plugs
Leads
ECU relay
Temperature sender
Ignition switch
Fuel filter
Fuel pump
Fuel pump relay
Breather hoses replaced with new ones because they were split.
Cleaned out Throttle Body
Changed off-side front sidelight bulb.
What's left!!!
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knock sensors
faulty new part
ecu it self some do fail
timing
do as wherry saids scn for old codes perhaps the ecu is storing a code which is making this happen
idle control valve
vapour canister
injectors
Battery
Alternator
Bad earth
:undecided: sounds like a tricky one my guess is still on a faulty new crank sensor or coil pack or ecu!
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It may be fixed.
Last Monday night I drove the car 26 miles to my good friend Stewart's garage http://autotech-garage.co.uk/ because I had run out of time (holiday was the next day) and patience. I managed it because I kept at 40mph and 70C - easy as most of the trip is motorway. As soon as I parked up at his garage the temperature rose to 90C and it cut out.
He has found the problem!! The large multi-wire round plug behind the distributor was soaked in oil when the high oil pressure switch previously failed. When I changed the switch I then gunked the whole area down - but I didn't (couldn't) take off the plug and clean it out. He disconnected and cleaned the plug and socket and has had it running for hours with no problem. He has also been using the car without it cutting out. He's using it again tonight, and then if all's well tomorrow I'll take the Porsche up for some work to be done on it and bring the GTi back here at normal speed and temperature.
I cannot recommend http://autotech-garage.co.uk/ enough - he has looked after our family cars for 13 years and does a great job for a reasonable cost. He also doesn't take offence if I try to fix it myself and is always willing to give advice.
The problem is we've now got a spare GTi with all the new bits on it. We'll probably sell it because we don't need it anymore - we have a spare car so my son has now moved up to a Mini Cooper..... and I don't think he'll want to change back.
Thanks for all the tips I've received.
John.