Just bought another 8v Digifant (88). Locking wheels needed removing as it didn't come with right nut i welded a bit spot weld onto a new nut and removed them. I disconnected battery first, when i started it it ran lumpy then cut out and now won't start at all. Any advice or help please. Need it tomorrow for work.
Copied from here.....http://www.golfgtiforum.co.uk/index.php?topic=49436.80 check for spark 1) remove fuel pump relay. 2) remove king lead - place near head and check for regular spark. if the king lead sparks evenly, go to 3, if not, go to 4. 3) re-connect the lead and remove a lead from cyl 1 and check for interval spark, if even, go to 5, if not, go to 6. 4) turn the ignition on, then off, there should be a single solitary spark, if there is, go to 7, if not, go to 8. 5) repeat step 3 with the next cylinder. 6) this is either a ht lead, rotor or distributor cap fault. 7) this is either a hall sender or wiring to coil fault. 8 ) this is either a coil pack, hall sender or wiring to coil fault. coil pack, hall sender or wiring to coil fault testing the hall sender requires pulling back the rubber boot on the wiring (ensuring it stays connected), connecting a voltmeter to the middle pin and the other end to ground. put the car in 5th gear and rock the car back and forth (around 1-2m) and watch for fluctuation on the voltmeter. if it doesn't change, then replace the hall sender/distributor. testing the wiring/coil pack is using your voltmeter and common sense (wiggle wires, check for continuity etc.) ht lead, rotor or distributor cap fault to test the leads, swap the faulty lead with a known working lead and test again. to check the distributor cap/rotor, remove and inspect for signs of arc'ing, ensure contacts are clean with plenty of material. sometimes just replacing parts is the easiest way to test unknown parts (but not necessarily the cheapest). checking for fuel 1) after testing the spark first, refit the fuel pump relay, crank the engine very briefly (or just flick the ign on/off) and release, you should hear the fuel pump(s) prime. this relies on all wires being connected to the coil pack - without the wiring connected, the fuel pump will not prime (on a k-jet). if it primes, go to 1a), if it doesn't prime, go to 3. 1a) Disconnect plug from main pump under car and repeat #1, you should hear the in-tank pump prime, if it does, go to 2, if not go to 6. 2) fuel flow needs to be tested. 3) remove the fuel relay and bridge the large pins with a suitably crimped piece of fused wire (rated 20a). if you hear the fuel pump running, go to 4, if not, go to 5. 4) your fuel relay is faulty. 5) replace the fuse for the fuel pump, then repeat step 1. if you have got here a second time, go to 6. 6) fuel pump(s) or wiring fault. fuel flow needs to be tested i can't be bothered writing fuel flow tests, check your haynes. fuel pump(s) or wiring fault you need to use a battery back and suitable wiring to connectors on the fuel pumps themselves to ensure they run. be extremely careful - any spark could start a fire. use your brain, be careful and figure this one out for yourself.
Another thing, check your earth! If the battery was the only thing you disconnected, it might just be a bad termination.
Had a mechanic friend at it tonight. It's getting fuel and spark. With voltmeter checked hall sender, airflow meter, fuel throttle sender, timing, distributor, fuel pumps, relays, fuses all as per Haynes manual readings. It still won't start..... Any thoughts please.
How do the dash lights behave? When you turn the key to the first position, you have the battery (charge) & oil pressure light coming on, yes? What happens to the lights while in the cranking position? Does the oil pressure light go off after a few cranks and the battery light stay on, or do all the lights go off?
Battery and oil pressure lights on in first position. Oil pressure and battery lights stay on while cranking.
I don't like to say it and it maybe pure speculation, but it might be the ECU. Presumably the welding has sent a current up through the gearbox and bad gearbox earths are known to damage the ECU. How did you disconnect the battery both leads or one?
That was going to be my next question. Earth lead off, Positive lead off, Or both leads off? Also, which lead was replaced to the battery last when re-connecting. The method is simple. On disconnection, Earth first. On re-connection, Earth last. The order in which it takes place might not seem important, however when working on cars with an ECU it should be carefully considered!
I think that might be your problem then if you're going to take one off it should be the negative according to this, but it's possibly safer to do both. http://outbackjoe.com/macho-divertissement/macho-articles/car-welding-circuit/
I would get a working ECU, maybe take Mk1mania's offer up to rule it out! Some ECU's are serious money! I've seen cowboys fry ECU's jump-start machines without the faintest idea of how to hook up jumper leads correctly. Always remove the Earth/Negative cable first when disconnecting a battery and last when re-connecting. When hooking up jumper/booster cables, Earth/Negative last and on removal, first. A simple procedure that could have serious consequences if not carried out correctly!
No, you can hear it prime but it doesn't run continuously. I'll try an ecu the car did start and run for a few minutes when i took the nuts off, the revs hunted then it cut out I honestly thought fuel starvation but its getting plenty of fuel and all four leads and plugs with strong sparks. Is there a procedure to follow fitting it, disconnect battery (neg first) or just unplug old one. Do I need a new blue temp sensor to go with ecu?
If you are replacing an ECU and the fact that it is an electrically sensitive unit by nature, I would take the safe route and play cautious. Dis-connect both leads to the battery. Remove wiring harness at the ECU. Remove ECU. Refit ECU. Examine condition of pins/contacts on both ECU and Connecter and treat for any oxidation, Refit wiring harness then reconnect battery (Negative- last). Mushy16v online Haynes Manual http://members.home.nl/alien01/auto/ Click on last PDF file. Read Chapter 4 Part F under General Information and Precautions point e. Chapter 5 Part B, Chapter 5 Part D.
