>>You seem to >> know what you are talking about. >>
Please excuse my ignorance! Thanks for the compliment!
Cheers,
Number_Cruncher
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I've now had an auto electrician out to trace the fault. Informed me it was the hall sender and couldn't be anything else (slagged off the garage etc. etc) I duly paid his callout fee and got another distributor form a breakers. The car I got it off was an accident write off so presumably it was running OK when it hit whatever it hit. Fitted the distibutor today and? The pink fluffy dice thing is still dead!!!!!!!!!!!!!!!!
The car has now been seen by several so called experts for - what I am sure will turn out to be a simple electrical fault. The saddest thing is that they are all very quick to blame each other as useless which leads me to the conclusion that they all are. In the meantime I am now £200 down and still have a car which won't start.
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Have you considered taking it to VW dealer to be fixed?
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When cranking is the fuel injector clicking and spraying shots of fuel into the throttle body. If so then the Hall effect sensor is not the problem as it also uses the information to fire the injector.
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Firstly check you have 12v at the coil +ve, measure it with a meter and also hang a 21w bulb on it to check you have sufficient current available.If not its most likely a failed relay. Check also you have 12v at one of the outside terminals of the three pin plug connected to the distributor.The opposite pin should be a good earth.If not check the wiring back to the coil for a break If ok, get a paper clip, open it out and push it into the centre terminal of the plug, then with the ignition on, stroke the paper clip to earth on the block. You should be rewarded with a crackling HT spark inside the dist. and the furious clicking of the injector(s), the fuel pump will also run. If the power supply side is ok and the system still doesnt work suspect the ignition amp.. We have had a few with the wiring broken in the dist plugs (roll back the boot for a gander) and many many amp failures, particularly the siamesed coil/amp arrangement.Check the earth strap between battery,chassis and engine.
Good luck
Andrew
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Simplicate and add lightness!!
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as andrew says and i seem to remember they have a silly little earth wire connected to the distributor as well these can go green with age and possibly cause a high resistance?(im not a vw expert)
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I doesn't fire the injectors or activate the fuel pump when I crank the engine but if I earth the middle contact on the hall effect connector I get a nice juicy spark from the coil lead, the fuel pump and injectors also activate.
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So the coil, amplifier, and power supply are OK.
Does the distributor actually turn when you crank the engine? For that matter, is the camshaft turning during cranking?
If you remove the distributor, and turn the shaft manually, do you get the spark from the coil and the fuel pump activity?
Number_Cruncher
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No problem with the camshaft, it's turning fine and I had a new cambelt fitted about three weeks ago. Done about 600 miles on the new one. I took the dist off, kept it earthed to the block and spun it by hand and I didn't get any spark or activity elswhere like I did when I earthed the middle terminal on the hall connector. It's doing my head in. This is with the old dist and the one I got from the scrappy. I don't want to fork out £100 on a new distributor in case it's not broken. Do you know if there is any way of checking the hall sender *off* the car?
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There is another possibility.
In my original reply, I described a method for checking the ignition which was different (in a very subtle way) to that described by Andrew. I suggested briefly connecting the central wire of the distibutor connector to the earth wire in that connector, while Andrew suggested briefly connecting the central wire to earth on the engine block. Both methods should give you a spark, fuel pump activiet, etc. So, try the test as I originally wrote, and see if you get a spark.
But, if there is a problem with the earth wire in the distributor connector, Andrew's test will not find it.
So, you may have an earth wire fault.
If, however, the earth wire is OK, then you have bought a duff distibutor from the scrappy.
Number_Cruncher
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Thinking a bit more about it, none of the tests so far have tested for a live at the hall sender connection to the distributor.
The three terminals should have a live.
The middle one is usually the signal from the hall sender
Then there is an earth.
Your checks so far have made sure about the signal wire, and everything upstream of that. But you could still have the lack of either a live or an earth at the distributor connector.
Number_Cruncher
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The tests would indicate that the distributor I got from the scrappy was also a DoDo. I have now ordered a new unit from GSF and will fit it in the next few days. Watch this space 'cos I'm still not convinced it's going to cure it - but then maybe I'm just a pessimist.
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HI, I checked the terminals last night - I can measure a current at the two outer terminals but it is only reading 6-8 volts on the multimeter. Is this normal or might it point to another problem?
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Hi Robbo,
Yes, it looks like you are onto something.
A bit of terminology - you aren't measuring a current. You are measuring a voltage.
I have just re-read Andrew's original post, and he does mention checking the voltage at the outer pins. He also suggests using a lamp which will draw much more current than a voltmeter. Using a lamp will highlight if there is a poor connection, or high resistance elsewhere in the circuit - I suspect that the lamp won't light!
If the lamp doesn't light, you need to find whether you have a poor live feed, or a poor earth.
Put your lamp between the live pin and the engine block. If it lights now, then you have a bad earth.
Put your lamp between battery positive and the earth pin. If it lights now you have a bad live supply.
Whichever you find, trace the wiring back, and you should find the problem.
I think that the problem you, and everyone else who has worked on your car has had is that a complete set of tests hasn't been done - until now!
Number_Cruncher
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OK - I've done the 21w bulb test to see if I have a bad earth side or live side on the outer terminals. The bulb won't light up on either. The bulb is fine by the way, check on battery. What is this telling me?
I've contacted the electrician who traced the problem to the hall sender and he seems as confused by this as I am.
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Hi Robbo,
I don't know off the top of my head where these wires will track back to. The ignition amplifier would be my first guess though. If you can find the same coloured wires there, repeat your test lamp test.
However, if that gets you nowhere, in your shoes, I would follow the wiring harness from the distributor back into the loom, and see where it ends up. You may need to unpick some tape.
I would check at the ignition amplifer, and at any connector blocks for a poor connection. It seems odd that you have lost both live and earth at once - perhaps wires in the same dodgy connector block?
Number_Cruncher
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>>kept it earthed to the block and spun it by hand
Sorry, did you mean direct touching to earth or slightly away?.Sorry to ask
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Steve
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Have you considered taking it to VW dealer to be fixed?
This site and many others are full of people who have had this problem and similar electrical faults which their VW dealer has been unable to fix. My own local dealer didn't exactly fill me with confidence when I asked them what they would do and they told me to buy new relays and replace them one by one till I find the right one because thats what they do!!
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It sounds like 15 quid on a haynes manual and a fiver on a cheap digital multimeter (Maplin, etc) would be well spent at this stage!
There are two relays which can cause problems on the mk3, the fuel pump relay (bottom RH corner relay) and the x contact relief relay, one has been upgraded by vw. The ignition switches have also been known to give problems.
The above generally fail in a manner which gives intermittent faults after an amount of driving though.
It may be worth checking be the copper coloured earth wire between the coil and rocker cover, they can break. Also it may be worth switching the ignition 'on' and confirming that the fuel pump buzes for around 1 second.
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Thanks for the advice but:
I've got a haynes manual which doesn't even cover the hall sender.
I've changed all the relays but the haynes manual doesn't list them all anyway.
The electrician checked the fuel pump
The injectors, coil etc all appear to be working.
In short, the obvious things have been checked and, as stated earlier in the thread, several so-called experts have so far failed to fix it.
Thanks anyway
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Now let me see, how can I rephrase this
take it to the VW dealer and pay them to fix it.
unless you want to carry on complaining about everyone else not being able to fix it for you.
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RF - currently 1 Renault short of a family
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Now let me see, how can I rephrase this take it to the VW dealer and pay them to fix it. unless you want to carry on complaining about everyone else not being able to fix it for you. -- RF - currently 1 Renault short of a family
Thanks for the advice. It hadn't crossed my mind to take it to a VW dealer. I'll book a few days off and push it the 30 miles to my nearest one without delay.
Have you considered a career as a comedy scriptwriter? I had just stopped laughing at your subtle use of sardonicism in your first post when BANG, you hit me with another one thus adding hyperbole to the mix - brilliant!
Not only are you helpful but a credit to the human race.
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Ok, enough with the petty squabbles. Teddy bears back in the box please.
DD. BR Moderator.
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.>> Ok, enough with the petty squabbles. Teddy bears back in thebox please. DD. BR Moderator.
Apologies, surely the point of a forum like this is to ask for/get advice. 'Take it to the dealer' would be the obvious answer to almost any question posted. Pick my dummy up
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Apologies, surely the point of a forum like this is to ask for/get advice.
I *think* your comment "so-called experts" was misinterpreted as a dig at the advice you got here.
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I *think* your comment "so-called experts" was misinterpreted as a digat the advice you got here.
If it was misinterpreted then I'm sorry. All of the advice I've got here has made sense and I'm frustrated that the thing is still dead. I also don't like to be beaten which is hacking me off just as much.
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look its a serious suggestion for sound reasons.
1/ Its dead. Its been dead for weeks.
2/ You have had a series of suggestions, ideas, ad hoc people on site to poke about with it, none of whom has a 100% familiarity with the actual bits involved.
3/ You asked the VW dealer on an ad hoc basis for advice who (naturally) told you nothing for nothing.
Therefore its logical that if you want it fixed, its got to be dragged to the dealer who would be given the job of fixing it.
Surely its got to the point where all this messing about is counter productive.
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RF - currently 1 Renault short of a family
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>>look its a serious suggestion for sound reasons.
I appreciate your suggestion but did not appreciate your tone.
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you havnt mentioned the earths though?
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Hi there, thanks for mentioning. I checked the earths on the metal distributor cap cover, the strap from the block to the bodywork and the battery earth and they are all OK. It's looking as if Number Cruncher may be right about a dodgy connection further along somewhere.
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You have proved the power supply to the coil and amp is ok and those units and the ECU are functioning ok. The dis (pin 1) is powered up from pin 8 on the ECU and should measure about 9-10 volts (only a few milliamps, wont light the bulb)assuming battery is ok. Pin 2 is the centre terminal and is the signal wire, Pin 3 is earth. If all this pans out its got to be the hall switch. On the secondhand one check the terminals are all visible and clean, they sometimes walk back into the body of the distributor. New Hall switches are available.
Andrew
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Simplicate and add lightness!!
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Hi Andrew. As you know from above I have checked all three pins out and, as you predict, I have a 6-8 volt reading on the power pin (pin1) I can get a spark by earthing the centre pin but the earth (pin 3) looks like it might be iffy. I have now fitted a brand new distributor and I'm no further forward. Is pin 3 a permanent earth? If so, presumably I can re-wire it quite simply. If not I assume I will need to re-run this cable back to the ecu connector.
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Wiring diagram shows pin 3 routing direct to earth. Suggest you add a new earth wire to the existing wire. Dont just cut the wire, bare some insulation and wrap the bared end of an additional earth around it. This will serve to prove the point after which if succesful make permanent by soldering and insulating to make a neat job. My only slight concern is that the supply voltage is a little low, I would like to see minimum 9v on supply. Try unplugging the ecu plug and reconnecting to wipe the pins clean in case theres a bit of corrosion causimg the volt drop.
Andrew
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Simplicate and add lightness!!
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hi just flicked through what you all said
if you want to try fixing this yourself be keep toys etc in pram
i only throw mine at last resort that is usually when i relise
i didnt check something obvious and feel a prat
1) as a rule of thumb vw group relays for injection/engine management middle of part number has 906 i.e 191906381a
it is usualy wort popping the cover off the relay and look at the solder joint around the pins
2)ignition switches do fail 3 different ways
not crank over / no warning lights or non start check for battery voltage on the black wire under the steering column whilst trying to start it
3)ground the middle wire of the distributor plug see if your coil lead emits a spark (good idea to have a spare spark plug and lead pluged into coil and ground spark plug on cylinder head
if the three main things are ok you need to sit down with the wiring diagram for the computer &check the supplies & earths to the computer with the computer pluged in
has any one tried a code reader???
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It was the earth after all. The earth lead on the hall sender connector was breaking down somewhere else in the loom. It was showing voltage instead of an earth. The solution was to cut the earth wire and put a 3 inch loop of wire back to the block. Thanks for everybodies help on this one.
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Glad 'you' fixed it. For what it's worth m8, it's worth having a quick poke about any forum to see who's who. Had you done so you'd have realised that Renault Family is a bit useful, to say the least. FYI VW don't seem to have a specific interval for changing spark plugs or leads on the Mk3. So suggest if you are unsure about yours I'd change them before they break you down in the middle of nowhere. Which, seeing as you clearly don't have AA or equivalent, would really annoy you.
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Well done, was it you or did call back the auto electrician?
With hindsight this quote from you on Nov 15th:
< >
Indicates where the problem was, except that you were measuring volts not current.
We've all learned a little bit more.
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"HI, I checked the terminals last night - I can measure a current at the two outer terminals but it is only reading 6-8 volts on the multimeter. Is this normal or might it point to another problem?"
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