Hey guys... I'm new to Golf ownership and this is my first... Sorry for the long winded essay I just wanted to include all the info... VW Golf Gti 8v 1988 (Digifant Early type Fusebox) Only had the car since Thursday. The car was running nice with no major issues that I could see. On Friday/Saturday I performed a decent service (oil, oil filter, plugs, dizzy cap, rotor arm, air filter The HTs were renewed in Dec 2010). I also removed the original alarm from the interior loom as It wasnt working and sorted out some loom on the ignition and behind the fuse box which were very messy (simply cut and wrapped together with no solder, crimps or even electrical tape Looks to me its been hot wired to bypass the broken alarm at some point and never sorted properly). Car started stuttering ever so slightly on Saturday on the first test drive for about the first 2 mins. We wriggled the dizzy cap etc which seemed to solve the issue. The car was ok from then on until Sunday night (I covered probably 200 miles since then). On Saturday after the service I went for a good blast to test out the car with no issues. On Sunday I did some motorway driving all day with no issues until night time. On Sunday night the car started stuttering again ever so slightly like it was trying to stall every couple of minutes then went back to normal. I stopped, played with the dizzy cap again and went on my way.. After another 2 mins the car suddenly then cut out without any prior stuttering. When I tried to re-start the car instantly loads (and I mean loads) of smoke came out of the exhaust. It was either white or black but it was too dark to tell, If I were to hazard a guess I would say black. I then got towed 10 miles down the road to some service station. When the car was off the flatbed, I instantly smelt petrol. The ignition was on and petrol was pouring like a tap from in front of the drivers side wheel. When I opened the bonnet petrol was all around the inlet and sat on top of the throttle body. After a poke around, I found out that the inlet was filling with petrol, it was leaking out of the TB/airpipe seal, going down/inside the air pipe through the AFM and out of the airbox onto the floor (hence the pouring from the front wheel). Now, I hadnt tried to start the car since it first stalled and I didnt dare for the rest of the evening. If I unplugged the injector rail the fuel stopped pouring out of the inlet, as it would stop If I turned off the ignition. If the ignition was turned on or the injectors plugged back in the fuel started pouring again. I unplugged the vacuum pipes from the pressure reg and it made no difference to the previous statements. Which would tell me an injector was stuck open or the fuel pump priming wasnt stopping after the standard 1 second or so prime. After the above tests I then removed the keys to find out the ignition stayed on and fuel kept on pumping. I inserted the keys and removed a couple of times and it stayed on still, I tapped the ignition and wriggled it, tapped and wriggled the fuse box to no difference. I then pulled out the No: 53 Relay which is to the top left of the fuse box and the ignition went off (fuel pump relay according to haynes). Now if I inserted the relay again the ignition was still off BUT if I turned on the ignition again and then turned it off/removed the keys the ignition stayed on until the relay was once again removed and reserted. I repeated this process a few times to confirm my findings. After the relay business the fuelling had stopped pouring with the ignition on and I repeated all of the above steps to confirm this. Now whether this is because the petrol had run out at this point or unplugging/plugging in the sensors had fixed something I dont know. By this point it was almost midnight and I gave up and waited until I got towed home. I have been on E38 where people have stated that this could potentially be a relay/fuel pump or ECU issue. Most people thought it to be the ECU as these are prone to pooing their panties due to bad earths. I have checked my earths on the engine block and as far as I can see there is one from the battery negative to the gearbox, and one on the inlet (passenger side) which is left fastened to nothing (I assume should go to the coil). There also looks like a earth strap should be on the rocker to the coil. Can anyone confirm the earth strap locations so I can renew/replace any straps as a precaution Also can any one confirm if I can replace the ECU with any 8v Digifant or does it have to match my ECU age/serial? And/or Give me any advice on what to test/look for regarding my issue. Any info would be greatly appreciated as Im new to golf ownership (but had loads of VWs so familiar with them and Im handy with a spanner).
Hello You got two problem more than likely related #1 the pump is keep running #2 the injectors are still open and widely open I haven't got wiring diagram in hand but will let you know if no one did earlier what it could be
Thanks for your reply.. I have been searching all over the internet and apparently if the main engine earth (battery Neg to gaerbox) is tired/old the main current will bypass the old earth and instead uses the injectors as an earth point, this is known to fry the ECU. If the ECU has died the symptoms are fully open injectors and a constant primed fuel pump. Which goes with your diagnosis and my problem. After I finish work I'm popping to a motor factors to get some engine earths. Now I just need to find where the main earths should be. Any recommendations?
as above several issues here. the top left slot #1 is the ECU relay which is a #53, i suspect this is the one you pulled out not the fuel pump. the fuel pump relay is slot 2, if there was a 53 in this spot this would result in the pump being live with the ignition, this means the fuel pump wont cut out in a crash so is a safety issue. fuel pump relay should be 67, 80 or 167. as well as the blown ecu, you also have an ignition fault, either down to the ign switch or the wiring. i suspect you need to go back behind your fusebox and look again, follow the black wire from the switch to make sure its not shorted anywhere. to rule out the ign ition switch itself, simply pull the electric plug off it. if the above problems continue its a wiring fault, if not its the switch. to prevent your replacement ecu blowing upgrade to the later type battery -> gearbox earth, these run direct to a stud on the end of the rear engine -> gearbox mounting bolt. MK3 Golf a good place to pillage these bits from, MK3 cables are also much better then MK2 so i would get the whole lot including the +ve and alternator wiring. only issue is you'll need to make a short length of chunky wire from the batteery tray stud to the MK3 -ve ring terminal, as it wont quite reach. secure to the mk3 cable with a nut & bolt then earth to the tray point as per standard.
Your correct about the fuses just checked.. It's an up-side-down '53' in slot #1 and slot #2 is a '80' I'll have a look at the wiring tonight. But I'm fairly sure that there are x2 black wires out of the ignition. Both were cut into (until I fixed them). Also, I remember a black wire behind the fuse box (top right when looking at the front of the fusebox) which was cut into for the alarm.. It just seems bizarre both the ignition and ECU happening at the same time? I'll upgrade all the earth's tonight.. I have a gold terminal made for audio along with some hefty earth cables I've just picked up, would that suffice until I can get hold of a MK3 section? Also, when you say tray point, what do you mean? I don't think Mine has that!?
hmm have a closer look, should be just the 1 black wire for the ignition switch. your hefty cabless should be fine, just mk3s easy to nick from scrappy. The MK3 battery terminals are much better than the crappy mk2 ones though, you'll see what I mean main thing is you get a better earth point to the gearbox, the early style which is earthed to the top of the gearbox mount arm is just a really rubbish earth point. from 89 on ish they moved it to the rear bolt on the engien itself,and again mk3 golf an easy place to find one.
Ahh, ok.. I'll make sure it goes to the back of the gearbox then. What do you recommend for the earth's on the rocker cover to coil and inlet to coil? just renew the wires?
yeah, nick from a mk3 as well. wont cause the issues you're seeing though but worth making sure they're good either way
Nice one! I have an ECU on order, got all the braided earth straps, have a few spare #53 relays to try and I'll check all the wiring. I'll update this thread once all the work is done and see if it remedy's the issue. Thanks for all your information!
Also, juts thinking, will I have to re-new the engine oil? As I'm fairly sure petrol will have made it's way down the breather pipe... On that note, will be engine be ok??
To volt drop a line in your case your earth You need a voltmeter Connect one probe to your earth battery terminal And the other probe to one earth of your engine ie cylinder head or gearbox Crank your engine if the reading is above 0.5V you got a poor earth The thing is if the earth lead was the problem read it the lead between battery and gearbox you will have a lazy starter motor because of the resistance or poor contact the starter will get only 10V unstead of 12.6v figures are only example So if it is an earth problem I m thinking more of the actual ecu earth which will still give a good cranking from starter motor but do dodgy thing to the ecu Still can't tell you yet were the ecu is getting it s earth from but I m pretty sure it more this than the main earth Regarding the oil I am affraid It would be better to replace it just check if the oil level didn't go up What you might need is also to squirt tiny bit of engine oil through the plug hole To counteract bore wash I hope I made sense
Yep, That made perfect sense... The starter wasn't slow cranking as far as I'm aware, although sometimes it would take a few turns to start if you could class that as the same? I'll research into the ECU earth as I agree this could do with looking into. Good shout on the bore wash..
Yep... I understood the principle.. It's raining bad here so Can't do it tonight.. Hopefully tomorrow!
ecu earth is to the side of the head, if the ecu had a bad earth then the car would just not start at all, you wouldn't see the injectors stuck open or anything. the symptoms here are of a blown ecu, not a poor ecu earth. i wouldn't bother with the volt drop test, just go ahead and upgrade the earths. it can only help the situation and is recommended for anyone with a mk2 as the std cabling just isn't that good once it gets over 10 years old
Agreed with the earth not powering the ecu and injector open It was just to sort out what caused the ecu to blow And not blow the new ecu for the exact same reason
Which side of the head? Also, I've had the ECU apart and there are no obvious signs, should I be searching for something? I am curious to why it blew? I know earths can cause this. But what else? I don't want it happening again!
Don't know that s why the volt drop is a good tool to verify the poor earth theory No weird smell in the ecu? I think you better get yourself the wiring diagram and work step by step If it s ecu fault make sure all the earth and live are good
