this nearly has me beaten its been 3 weeks and still can't get my mk2 gti 8v 1988 digifant going. basically i have no spark. If you bear with me I will give you a full run down. Going home from work in very wet heavy rain got about 5 miles done and car started to fart and miss, eventually got into a car park just about and assumed water in plug leads distributer etc. bought a tin of wd eventually had to hold a rev to get her cleared and it got me home, missing slightly. A day later i bought and fitted new plug leads as i had never changed them and car kept turning over and over reluctant to start, put old leads back on and eventually got car going. I left her to run went into house, out 5 mins later and car had quit (ign lights still on) Put timing light on main plug lead and there was a very weak, intermittant spark. Everytime i was turning vehicle over and over the car just seemed less reluctant to start. Over time this got less and less and now there is no spark at all. Got haynes manual out and tested ign module and coil, getting batt voltage across 2 and 4 on module. but the test across lt terminals on coil going to 2v with ign on then dropping to 0 for a few seconds was not happinging. At this haynes says to replace ign module and coil. Fitted ign module (new from ebay TOPRAN) and beru coil from Eurocarparts) and still no improvement and still failing test. P.S when centre wire on hall sender is earthed I am getting the rise in voltage to about 5v. I then replaced starter switch - no difference Then starter (had new one from last year) - no difference Checked timing marks - all aligned - set rotor arm to mark I had studied wiring diagrams, online guides etc and have checked and cleaned all earth connections. I have checked continuity with all the wires from the coil, ign module, starter, to and from fusebox and all ok. The battery although showing 11.5 - 12.5v gets too low when cranking, its now goosed but I have been jumping off my other car. I am showing battery voltage across LT terminals and about 10v across outer terminals of hall sender which I think is how it should be. I removed and inspected fusebox and on the drivers side of it there is a little bit of rusty residue and I'm wondering it this would cause this problem. I'm left in a bit of a pickle, fed up at maybe spending money on parts i didn't need. This is what i'm now thinking 1) would the fuse box cause this problem if water had got to it during the heavy rain (there is no sign of any dampness) 2)Fauly relay cause no spark? 3) Have I bought a faulty ign module and or coil? or is there something else distroying these? p.s tried changing back to originals one at a time with no difference 4)Would ecu cause this problem? I have experienced a blown ecu before because of the gearbox earth with fuel flooding cylinders. I can hear fuel pump prime for a few seconds every time, but can they go faulty in other ways. 5) Hall sender fault? I'm reluctant to think its this as I got a brand new distributer from VW in December. If anyone is still reading and can suggest anything or had this experience, any help is greatly appreciated, this is the time of year i want to be out and about! Thanks Stephen
check your earths, there are 2 main earths 1 to head and 2 to the battery -ve. make sure the hall sender wires are all ok, pop the rubber boot off to check where you cant see and look for insulation tape on any parts of the loom as underneath you'll probably find bodges. look at the pins on the ecu, tci and hall sender (may as well check everything!) look for bent or dirty pins, and make sure they're pushed all the way out and not pushed back into the plug. check the leads match the coil & dizzy, the later type have a pin inside the coil and cap holes, the leads have a thin end with a circlip that clips onto them firmly. mix old leads with new cap/coil and this wont help. finally what is the quality like on these parts? you want bosch/beru oem stuff. buy from here: http://www.vwspares.co.uk
I have just recieved another ign module (motaquib) I'm hoping that will sort it. Have checked and cleaned and tested all earths and plugs. Also tested hall sender with the voltage fluxuating when car cranking over. Is the ecu cage meant to be earthed to the body (i noticed that this was very rusty, i now have it all cleaned with new washer and nut). Also during my investigation I found a wire cut near to the ecu plug, on investigation this is for a hall sender. My car does not have one.... should it have???? was running idleing well without it. thanks for all replies Stephen
no the cage shouldnt be erthed. the wire is it red/white? if so thats for lambda probe heater, which uk spec digis didnt get
there are two wires wrapped in outer wire sheath, it has continuity with knock sensor pins on ecu plug (can't remember colours). Why would someone have maybe removed it? I now have spark!! replacing ign module again worked, still not starting though fews things to note spark plugs very damp had them in and out and cleaned a few times (fuel smell) Dipstick level about 10mm above max level (fuel) Again as before fuel pump primes for a second, would the repeated turning over and over during the last few weeks have pumped in this amount of fuel? do you think that oil change and new plugs required? (only changed these in march) Thanks rubjonny p.s your fusebox guide has been very helpful
that isnt good, it'll never run well without the knock sensor connected so best to splice one back in. cut out a long section of knock sensor wire as it needs to be properly shielded an oil change is deffo worth doing, but plugs should clean themselves up once its on the road
do you mean oil? or do you mean that the fuel is washing down the bores, past the piston rings and into the crankcase and you can see a fuel line on your dipstick? if you did indeed mean oil, is the car on level ground?
yea there is about 10mm of fuel reading on dipstick, will do an oil change tomorrow hopefully Would anyone have any pics showing the plug on loom side of knock sensor, or of where exactly the knock sensor goes? or even better any spare looms or sensors
knock sensor is fitted to the block near the alternator, the plug runs round near the distributor. 2.0 8v vw/audi will have the knock sensor you need, mk3 era. mk3 16v long knock sensor will do as well
my car is alive again! needs a good drive now. knock sensor is bugging me now, what would be the best way to join in the knock sensor wire? i could join the white and brown wire with solder or sleve connectors, could the wire sheath just be wrapped around itself then insulated over? don't wan't want to get it wrong. thanks again stephen
when i had to repair one of these what i did was splice the 2 inner wires together, bare the metal sheilding either side of the joint. then i wrapped tinfoil over the joint over the 2 sections of bared sheilding. then taped over the lot. was tol this would be a suitable repair, but it was a right pain in the ass to get right! but the next time I had to do this on a butchered ecu loom instead of the above i just removed all of the shielded wire right back to the ecu plug and replace the whole section with fresh wire cut out from a donor loom. much easier! the handy thing is the mk2 digi loom can be removed from the car by disconnecting it at the coil and the plug in the scuttle, it splits from the main loom back to the fusebox. so dead easy to remove for repair or replacement. what i would do is get another loom, unwrap it end to end, check it over very carefully then rewrap and swap in into the car, bin the old one
I have searched through my spare wires and looms and I have managed to find the plug, broken at the connectors and the lenght of wire. The plug had a good number on it so main dealer is able to get me plug, wiring repair pins and soldered heat shrink connectors. With all that, and tinfoil I should hopefully be able to join the lot together. Eurocarparts getting me a decent knock sensor and main dealer getting me the bolt. Will let you know how i get on. Thanks again for all your help EDIT mean't to say i must have cut the wire away as there was nothing to connect it to and assumed it wasn't required.
