GolfGTIforum.co.uk
Model specific boards => Golf mk2 => Topic started by: Classic16v on 23 February 2013, 21:23
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Hi everyone,
I'm looking for some help with my Mk2 ABF converted engine. The conversion was done a couple of years ago, and I had absolutely no problems with it until a couple of months ago. It's running the standard management system, straight out of the P-reg Mk3 it came from, and has a pretty standard cone air filter on it.
This winter it started to run a little rough at low revs/idle, and every now and then on a really cold day would be very lumpy and lacking in power up until about 2000 revs, until it had warmed up a bit. As this was intermittent, I didn't think much of it. It doesn't get used a lot in my current job - maybe a couple of times a week - and after coming back from a week away at the beginning of February (having sat in an airport car park in the snow) it started fine, ran very roughly, then died as soon as my foot was off the accelerator. Again, started fine, revved ok, but died once my foot was off. I managed to get it home (died a couple of times coming up to junctions where I had to stop!), and then all of a sudden it miraculously started idling again, albeit in a very lumpy manner, like it was mis-firing. At home I removed the ISV, soaked it in white spirit for a couple of hours and then flushed it through and dried it out. Once it was back on, the car would no longer start! It was still humming/vibrating with the ignition on.
The garage round the corner from me came and towed it - the mechanic there worked at a main VW dealership for 8 years and used to have Mk2's, as did a mate of his. He's now had the car for 2 weeks (as I've been away, and not needed it) and has tried lots of different tests (luckily without charging me too much!) but has not got very far. Below is a list of the things he's tried:
- new HT leads, ignition amplifier, ignition coil, distributor
- worn vacuum hose plugs replaced on air intake system
- tested spark plugs (said they have been flooding, so when it doesn't start from cold he's removed them, lit them to dry them, replaced, and then it starts)
- checked engine timing and ignition timing
- wet and dry compression tests (dry test all within tolerance limits, wet test suggestive of slightly decreased compression in cylinder 2)
- tried running diagnostics (not Vagcom - another system) on 16 pin connector but it only showed very basic info, and no live data. Didn't show any faults
- also tried adjusting injector pressure (floods itself sometimes on a cold start, and he's had to remove the spark plugs, and dry/heat them before putting them back in to start it)
So we've got to the point where it starts (sometimes...), and while it's running it's still lumpy at idle. Whilst idling (700-800 revs) it intermittently drops revs sharply, but the engine management seems to catch it around 500 revs and kick it back up to 800. It's misfiring up until about 2000 revs (especially under load), and struggles to rev up through that range, but above 2000 it goes ok (still feels down on power though). Every now and then it pops, like it's backfiring. If the revs are held around 3000 they'll sometimes drop down to about 2500 sharply, and sometimes when engine braking just under 2500 revs it becomes very jerky. The mechanics final comments are "engine is breathing heavily and suspect worn or mechanical failure."
So any thoughts would be appreciated! ISV? Crank sensor? My knowledge is limited, so any ideas would be gratefully received. I appreciate I may need to spend a bit more changing various bits, but I want to do it in a logical fashion, and I'm currently saving for a wedding so I'm a bit limited!
Thanks in advance,
Alex
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*Update 30/04/2014 - page 5 - found crank pulley keyway was stripped, fixed that but still not running right*
Couple of additional points (I fitted this engine) it's running mk2 coil set up and has had, since the conversion just over two years ago, new lambda and ecu temp sensor (non genuine). Engine was on 89k when fitted, prob around 110k now so not a high miler.
Loom was checked and wrapped before fitting, particularly the wiring to the throttle body. Alex has checked the idle switch is operating correctly.
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They replaced all those bits without changing th ecu temperature sensor. Cold start problems and wet plugs are the clue. Hence the reason I wouldn't go to a vw specialist.
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Presumably it wasn't changed as it's relatively new, easy to rack up a large bill if you start swapping out everything. Worth a try though, thanks for the suggestion :)
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I can see how the temp sensor affects the startup, but can that still explain the lack of power and misfiring when revving up to 2000 revs with a warm engine?
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Yes, It affects fuelling.
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I can see how the temp sensor affects the startup, but can that still explain the lack of power and misfiring when revving up to 2000 revs with a warm engine?
If the ecu thinks the coolant is cold then it will I over fuel, as cold engines need more fuel to run. It will be very rich all the time and overly rich mixtures don't produce much power.
Seems a large bill of parts has been racked up already, may as well add a little bit more. :wink:
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If the ecu thinks the coolant is cold then it will I over fuel, as cold engines need more fuel to run. It will be very rich all the time and overly rich mixtures don't produce much power.
But conversely, it shouldn't have any trouble starting when it's cold...
Either way, Alex will no doubt report back on whether it fixes it :)
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If the ecu thinks the coolant is cold then it will I over fuel, as cold engines need more fuel to run. It will be very rich all the time and overly rich mixtures don't produce much power.
But conversely, it shouldn't have any trouble starting when it's cold...
Either way, Alex will no doubt report back on whether it fixes it :)
Depends what resistance it is when it fails.
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Check crank sensor, too. Might be in the process of failing.
Always handy to have a second engine to swap these things out from.
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As above was going to say check crank sensor.. if its failed be careful as i bought one from euro's and it had the wrong plug fitted..
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jesus that seems as bad as me! Problem- fuel rail, resolved- new engine!
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Have you check the vacuum hose that goes into the ECU?, there a common problem on the MK3 ABF setup. Like you have said, engine was taken from a MK3. Check that
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Yeah that damn thing. I found out the cutout wasn't quite big enough for the vac hose so the bonnet crushed it making it run bad. Weirdly it didn't do it all the time.
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Obviously all vac lines were replaced when engine was fitted; I think they have all been looked at, but will check. Thanks for all the suggestions, not sure if the new ecu temp sensor has arrived yet.
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Thanks for the input so far guys. A new coolant temp sensor arrived today, but unfortunately hasn't fixed it. I had my fingers crossed and everything, and for a short time (minute or so) it seemed to run smoother, but I took it out on a test run and it showed the same symptoms again. It seems like it becomes more unstable when it's warmed up a bit too. i had a couple of runs of normal acceleration, but for the most part it was the same, lacking power in the lower rev ranges when my foot was to the floor, and only picking up later on. One new thing today, which I hadn't noticed before, was that when I held it at 1250 revs (in neutral) it was fluctuating up and down about 100 revs either side. I didn't test this last time, but at this point it wasn't misfiring (during the minute or so of it running smooth today).
The crank sensor is another thing we had thought about, and were hoping it would have showed up on the diagnostics, but nothing did. The mechanic didn't use Vagcom though, so I don't know how reliably the system he has performs on older engines. I'll have a look at the vac lines, but I'm pretty sure they were checked.
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Get a spare known working ECU, ISV even a hall sender swap each out for testing then come back :wink:
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Wires down the back of the inlet manifold?
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Get a spare known working ECU, ISV even a hall sender swap each out for testing then come back :wink:
Dizzy has already been swapped out for another, no change.
Wires down the back of the inlet manifold?
These were repaired and re-wrapped when engine fitted, but being checked tomorrow.
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Ecu relay? Checked resistance of plug leads?
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I think the over fueling is a good indicator, look from start to finish the fuel delivery system.
I have known old fuel rail looms to get brittle from heat and sometimes intermittenly leave injectors to jam open or the Ecu is not sending the right signal to the injectors?
Where the injector test done flooding on all chambers?
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Another thing to check is fpr. I had a dodgy one and have heard people squirting wd40 in them. Beware though mine stuck in a using grips to get it out f@&ked it.
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Wires down the back of the inlet manifold?
Wires all look good as far as I can see. No areas of wear/melting on the black cloth tape surrounding the wire near the idle switch or TPS, I can't feel any breaks in this area, and the rest running along the manifold is encased in ridged plastic tubing. However, yesterday I tried depressing the idle switch with the throttle open and it didn't do anything. I also removed the plug on the throttle position sensor and the revs increased at idle, with a little bit of creeping up then dropping back down to around 1000. Things seemed a little more stable so I tried driving it like this (!) but still had the lack of power and jerkiness. Even if the idle switch is broken, would I still get the misfiring/lack of power and the engine flooding? My dad fired it up this morning just to move it on the drive (engine running for about 30s) and when I just went out to check the idle switch again it won't start (flooded?!).
I was going to check the fuel lift pump but it's raining at the moment - still, I would have thought if the lift pump was dodgy it wouldn't flood. It could explain a lack of power I guess, but not over-fueling, surely?
Another thing to check is fpr. I had a dodgy one and have heard people squirting wd40 in them. Beware though mine stuck in a using grips to get it out f@&ked it.
Forgive me, but what's 'fpr'?
Cheers
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Fuel Pressure Regulator.
I would suggest throwing a new lambda at it, or at least see whether disconnecting it makes any difference, but it says above it's got a recent one and TBH the symptoms sound more serious, although the cycling revs runs with the lambda suggestion. Disconnect it, see what the motor does.
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Lambda doesn't really affect power or how it drives. Will affect efficiency though. It's not a wideband so doesn't control fuelling that much. On high loads above 4k fuelling goes open loop and runs rich for component protection.
Misfires under load are ignition related. Check resistance of plug and king leads.
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Need to get it started again before I try anything else! The mechanic was saying that when it wouldn't start for him he had to remove the spark plugs, and heat them up to dry them out and get things going again. Does that seem reasonable? And is it literally as easy as sticking a flame on the end??
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Misfires under load are ignition related. Check resistance of plug and king leads.
Haven't checked the king lead, but the plug leads were all replaced with no effect. How do I check resistance of the king lead? I haven't really got much kit...my dad might have it's it's straight forward.
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Check the resistance of all leads with a multimeter. Should be less than 12kohms.
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Got the multimeter out, and it's dead! Tried a new battery, but no luck. The saga continues...
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As I have continuing issues with my Mk3 abf that sound quite similar to this, I will be keeping tabs on this thread!
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Update on my situation:
I took my car to another garage where I have received a lot of help previously, and asked them to look into it for me as I currently don't have the time/space/tools to be diagnosing it myself. I gave him the back story about what has already been tried and left it with him. Diagnostics this time showed up the crank sensor and temp sensor (having been cleared of fault codes at the first garage, therefore these are new codes). I'm sure the temp sensor fault is due to me having tried running it with this connected, but he mentioned hes seen some trouble with aftermarket sensors recently.
Anyway, he changed the crank sensor, which helped but didn't cure the problem. He then traced the problem back to corroded terminals on the ECU. He disconnected these and cleaned them as best he could, but after plugging them back in the engine isn't wanting to do much at all. Has anyone experienced this situation? My handy engine-swapper (Simeon) says the ECU plugs are in a water-tight holder (although this may have been leaking), and so the ECU could have just been damaged by removal and cleaning. Whatever the problem, it seems I now need an ECU, and I do trust this mechanic so I don't expect he would have just screwed it up.
Any thoughts/comments? And can anyone point me in the best direction for a new ECU? There are a couple on eBay (http://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2047675.m570.l2736&_nkw=abf+ecu) but do I just need that unit, or the immobiliser too? I understand they can be re-coded to my immobiliser, but how involved is that? And is it something he's likely to be able to do easily?
Cheers
*EDIT - there's quite a difference in price with those ECUs on eBay - do you reckon that's just the 'eBay shop' seller vs a private seller?
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Make sure you get the same code at the end of the ECU. If yours has immobiliser then you need the new ECU coded to the key, or get it de-coded by someone for £50-60ish.
IIRC AB code ECUs are non-immobiliser. They are worth more.
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just scanned your first post and it says that your running the mk2 coil set up and the ignition modules been changed. Is this definaty the case? No expert but when I had the 8v engine in mine it run exactly as you described. I took off the ecu plug, checked terminals and put it back on which resulted in a non runner.
Next day it would fire once but not run until I started wiggling the ecu bracket. Took the 2 screws out of ignition amp and bingo. Run spot on, no huge flat spot. Changed it for a working one, drove it for 2 years and then threw it all away when I abf d it. I figured I'd rather just keep a spare coil for the mk3 set up in the car than bodge mk2 electrics on a mk3 engine.
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So we've managed to get hold of another ECU, but the mechanic struggled to code the immobiliser using Vagcom. He used to be able to do it with his old Bosch system, but has never done it with Vagcom - does anyone have any pointers to a guide on how to do it?
Or, better yet, does anyone fancy giving him a call and explaining it.....? :wink:
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I had the same symptoms on my Cordy (6K2/C2) 2.0i ABF. A crank sensor sender, set of HT leads and a new ICV swap out cured it instantly.
All the best!
/ Crit
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So we've managed to get hold of another ECU, but the mechanic struggled to code the immobiliser using Vagcom. He used to be able to do it with his old Bosch system, but has never done it with Vagcom - does anyone have any pointers to a guide on how to do it?
Or, better yet, does anyone fancy giving him a call and explaining it.....? :wink:
Very easy. Do this (http://www.ross-tech.com/vag-com/cars/immobilizer2.html)
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So have you actually checked the ECU and Fuel Relays?
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Very easy. Do this (http://www.ross-tech.com/vag-com/cars/immobilizer2.html)
Thanks tshirt2k. I've let them know and they're going to give it a try.
So have you actually checked the ECU and Fuel Relays?
Not sure Len, as it's been out of my hands for a while, and I'm finding it hard to keep up with my limited knowledge and the long list of things that have been tried! I can certainly try and find out though. Simeon has spoken to them as he has supplied the second ECU, so maybe he knows...
I had the same symptoms on my Cordy (6K2/C2) 2.0i ABF. A crank sensor sender, set of HT leads and a new ICV swap out cured it instantly.
All the best!
/ Crit
I wondered if the ICV might have something to do with it, but it seems like we're now in a situation where the 1st ECU is not working, so we'll see what happens once the new one is in. Supposedly it fired up ok with the new ECU fitted, but the immobiliser cuts it off as it hasn't been re-coded yet.
Cheers for all the comments
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So have you actually checked the ECU and Fuel Relays?
The garage has checked power to the ecu and pump apparently, both fine.
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I had similar issues with running in an old mk3 ABF of mine a couple years ago. Tried all the obvious and it ended up being the ECU relay. £11 or so from VW and all solved. These relays along with the fuel one were not particularly well made hence the high number of them failing. The difference in weight and quality from the replacement one I bought was like night and day compared to the faulty one it replaced.
Either way, best of luck!
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It's more to do with a voltage regulator inside the relay failing, that doesn't give the correct voltage to the ecu. IIRC.
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In case anyone is reading this with a similar problem, I eventually took a trailer down to Bristol to pick it up so I could have a look.
A cursory check of the static timing revealed it was 4 teeth out on the cam .... removing the crank pulley revealed it had stripped the keyway on the pulley. This is why I hate it when garages just plug things into laptops and expect all the answers, they could have figured this out in an hour if they had actually checked the timing..!
Anyway, I have replaced the pulley, dowel pinned it onto the crank, replaced the fuel filter and tidied up the wiring (which the garage didn't leave in a particularly good state) replaced the ISV and although it runs, it doesn't run well :(
I have compression tested it and cylinders 1,2 & 3 are about 12 bar, cylinder 4 is about 10psi down on the other three. Doesn't suggest bent valves to me, so that's a start.
Once it is up to temp the idle will slowly drop to about 500rpm, before the car blips itself back to about 1500rpm before dropping to 900rpm and then starting the whole process again a short time later.
Another issue is that the pulleys on the crank end seem to have a relatively significant amount of wobble in them, it's definitely either the mounting face of the crank nose to the crank pulley or a twisted crank has been suggested?
I'm getting my hands on a code reader in the next week or so, so will plug it in to see if any of the sensors are throwing a fault code.
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Mine idled same before Christmas.
Brake pipe clamp on fuel pressure regulator vac hose made it run nicely when it was doing this
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Thanks for the thought, vac pipes are all new and tight.
Plugged it in, got two fault codes;
Air inlet temp sensor - not surprising as it wasn't connected.
Throttle Position Sensor.
Cleared the codes, plugged in the air inlet temp sensor, started it up, checked for codes again and none came back.
Anyone got any bright ideas about how I can check whether the crank nose is flat without removing the crank?
Anyone got any thoughts on the idle issues?
I'm grasping at straws now, engine might get pulled and replaced in a couple of weeks..
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Bit of a bump. Did you sort crank nose? Had a similar issue with an ABF. Used a hammer to peen of the high spots then draw filed the nose with a small file.
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Nope, spent a while trying to sort the crank nose, but the pulley is all over the place. Decided to pull the engine and start again, gonna do it in a few weeks when I have the time. Bit of a pain really.
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Just to update, purely for your entertainment...
We fitted a new engine over a weekend a couple of weeks back, bolted all together and it started and drive fine :)
However, we had a tapping from the top end, so I decided to swap the tappets over from the old engine, not a big job (he thinks..)
Whip out the cams, swap the tappets over, refit and find that 4 of the cam cap studs will not torque up. Great.
Remove those to find they have previously been helicoiled/bodged, who knows. New helicoil kit bought, studs repaired, bolted back together and think .. finally sorted!
Nope. Now it barely runs, back fires etc etc. Immediately thought I'd cocked up the static timing (been there, got the t-shirt) so double checked it and all seems fine :(
Bugger
The time of messing with old cars is slowly drawing to a close methinks, next year I'll have my professional qualification in hand and I can go join those old buggers on the mk7 board :grin:
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That's a whole bunch of bad luck there bud. Don't go to the dark side just yet, burn that bad luck to the ground or break it and start a fresh.
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did you compress all the old oil out of the tappets before fitting? if not then try that. I use an m8 bolt and vice for it. bet that will sort it :wink:
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infact do a compression test first to see what like.
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I didn't do anything with the tappets, just swapped them. Why do they need compressing and how could they cause the lack of running?
I compression tested it before I swapped them out: around 13bar except for cylinder one, which was a little lower at about 10.5. Not really a problem.
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old tappets can get so gunked up that there adjustability can get limited. when you swap from 1 engine to another you have no idea of wear rates in cam/tappets/valve seats between old and new engine so the valves might be sticking open slightly. do a comp test first and tell us how it reads. btw 3 pots at 13bar and 1 at 10.5 is not something I would be happy with(might be fine but im mega fussy)
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OK, so played around with it and it now starts, but it runs like a dog. Fine for about 30 secs then idles rough and revs die off if you apply any throttle.
I've scanned it and it's not throwing any codes. Stinks of fuel, but to be expected I guess as indoors and on choke. The fuel in it is pretty old, so I think I'll stick a bit of fresh in it tomorrow.
Sadly the tapping noise has not cleared, I reckon it might be something else, but definitely top end.
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old tappets can get so gunked up that there adjustability can get limited. when you swap from 1 engine to another you have no idea of wear rates in cam/tappets/valve seats between old and new engine so the valves might be sticking open slightly. do a comp test first and tell us how it reads. btw 3 pots at 13bar and 1 at 10.5 is not something I would be happy with(might be fine but im mega fussy)
Fair enough, might delve under the rocker cover again tomorrow. I'm not stripping the head off if I can avoid it, six cars in my garage and only one currently works :tongue:
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God how big is your garage.
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It's big... but when you have a big garage you just fill it with crap, so there's not much room in it :tongue:
Ok it's running now, a combination of messing around with connections and some of Shell's finest (the fuel in the tank was pretty old) got it going.
Plugged the code reader in and I'm getting 'no signal from o2 sensor' .. damn. Will investigate that further tomorrow.
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Let me tuck a car in the corner aha, you will never know I'm there :grin:
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Let me tuck a car in the corner aha, you will never know I'm there :grin:
Me too.
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(http://i7.photobucket.com/albums/y285/howardlinn/Faultcode_zps1bad4fd0.jpg) (http://s7.photobucket.com/user/howardlinn/media/Faultcode_zps1bad4fd0.jpg.html)
Presume this code (which is recurrent) is just lambda sensor (which is annoying as it's not that old), but does anyone know any testing I can do before replacing it?
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try running car with it disconnected. you could also check all the wiring to it for breaks.
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try running car with it disconnected. you could also check all the wiring to it for breaks.
On this idea you could also do a continuity test in the wiring also. Make sure it hadn't been melted somewhere by the exhaust.
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Soooooo, just to keep this updated for your continued entertainment...
Changed lambda sensor, which sadly didn't resolve the issue. Checked continuity of the wires and all good.
Then I started it again and got the following additional fault;
(http://i7.photobucket.com/albums/y285/howardlinn/IMG_20141008_193949_zpsxmnuedp3.jpg) (http://s7.photobucket.com/user/howardlinn/media/IMG_20141008_193949_zpsxmnuedp3.jpg.html)
So, I've pulled the wiring from behind the manifold and although there are no breaks, there's a couple of suspect bits. Going to replace those wires and try again.
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The saga continues!!
So, this weekend we swapped out the loom (the 'vw mechanics' had messed around with the old one quite a lot). This time we used the mk3 coil and did away with the TCI set-up as all the wiring is 25 years old and thought we may have more luck using the newer set-up.
It's up and running, but it intermittently dips idle a little and hunts, then misfires at higher revs :( Also seems to run quite rich as smells of fuel. No codes being shown on VCDS unfortunately.
Going to stick some fresh fuel in it and see if that helps, then take it for a run and give it some beans to clear the cobwebs. Not holding out too much hope of that fixing it though.
Rev counter is playing silly buggers though, which may point towards a problem: when you turn the ignition on, the rev counter sweeps up to about 5k then back down to zero. Behaves itself when you start the engine. Anyone have any ideas what would be causing this? We have added a spade terminal to the Mk3 coil, then connected this to G1/12.
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Pulled the plugs, it's running very rich! Probably get some fresh fuel in it on Wednesday.
Any ideas what causes an ABF to run rich, other than the ECU temp sensor (white one on side of head), which I replaced last year.
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Lambda, but you say thats new and working?
Unplug the temp sender and bridge the connections so that the ecu thinks the cars warm.
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Cheers for the reply. Yeah was having a read last night on various forums about ABFs running rich and the recommendation is to try running it with the lambda disconnected, so I think that's my next step. Good idea re the temp sensor, next time I get it warmed up I'll try it.
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Doesnt even have to be warm. I did it with a 20vt converted mk2. Bridge the plug and it ran peoperly.
But that was using mk4 plug and wouldnt read. So swapped for mk3 temp sensor. Rewired and sweet as a nut.
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Interesting, I'll give it a go, cheers.
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Shockingly this now has an mot :shocked: Engine is running ok, still a bit lumpy at idle and rev counter sweeps when you switch ignition on (but not every time), but drives ok, so happy days.
Moral of the story ... lease a brand new car and get on with your life :laugh:
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Moral of the story ... lease a brand new car and get on with your life :laugh:
Lol'd at that. I have a mk2 ABF that is being a dick having been sat outside in cold but now with similar symptoms. Good info pointers on where to start so cheers
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Moral of the story ... lease a brand new car and get on with your life :laugh:
Lol'd at that. I have a mk2 ABF that is being a dick having been sat outside in cold but now with similar symptoms. Good info pointers on where to start so cheers
Someones back from the dead :grin:
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Someones back from the dead :grin:
Large as life and twice as ugly :smiley: