Fuel Issues

[Brom]

I picked up a 1990 cabriolet this weekend and am now trying to get home. I was told it wasn't running due to a busted fuel pump. And at this stage it's definately a fuel supply issue. But I have a couple of questions to make you all laugh at me. (i've never owned an EFI car before)

My relay board has points 1 and 2 empty. I found out two is the fuel pump relay and so i bypassed it and am getting the main pump to work. But in tank is not, though i still need to check its getting power. Should 1 also have a relay to control the EFI?

Also what i think the fuel pump relay should have 4 terminals, bypassing it i'm only using two so it's always on. Can you tell me what the other two are. One i'm guessing is ignition and one ground mayeb? but which is which?

Also if you have a spare used or used intank pump please tell me as i only need it to get home.

Cheers all

[Brom]

Just put two other relays - wipers and something else into slots 1 and 2 and had the car running for about a minute until i tried to give it a little throttle and the main fuel pump started buzzing. Left it alone for 10 minutes then again it will run until i touch the throttle and the buzz starts again.

After removing and bench testing the in tank pump, its definately fine.

Next step is to remove the main pump i guess, beat it with a blunt stick, maybe try putting it in reverse for a second and see if anything happens.

Otherwise i suppose i need a new main pump and relays. (i still have no idea about the electonic injection)

Any tips or spare parts available?

[paulie71]

Have had same problem in my 93 cabrio.

Check the relays first as the pumps (so I am advised) are pretty sturdy units.

Also check your wiring to the main pump.

[Brom]

thanks mate,

Does anyone have a fuse/relay diagram for the cabrio. I'm sure its the same as many others. I did find one but i think it was american and completely wrong for me.

After hearing the buzz in the main pump i removed it and bench tested it with a spare 12v battery and can't really fault it now either. So i'm completely confused. Maybe it could be only under load, or a bent/blocked fuel line ao just the relays. I have no experience with this type of thing. But it was fairly painless to get the pumps out.

[paulie71]

I used the trusty Bentleys Manual for guidance. There was a Russian VW tech site (can't seem to open it) that had scans of these pages. PM me with an email address and I will send what I have.

Also don't forget to purchase new union rings/seals (alloy washers where the fuel line bolts into fuel pump outlet (cost $2.00 all up from VW no less) just to make sure the line is sealed.

Also remember that cleanliness is next to godliness with this project so make sure you clean everything and keep it clean when reinstalling. I used a hydrocarbon based brake clean (carby clean would also do it) to blast out crud as I reassembled.

Cheers

Paul

[Brom]

Thanks mate. your a hero. I havent got round to sourcing a manual for this one yet. And it's just a tad beyond the technology of the 1980 diesel manual I have.

I think i will replace the pump as it did have a nasty buzz/grind. Aswell as putting in new relays. Actually if your in your cabrio tomorrow would you mind have a look down at the relay numbers in positions 1 and 2 (top left). As i currently have nothing. I only have relays in positions 6,8,9,10 and 12 on the lower panel which i kinda worrying.

My emails hughbromley@optusnet.com.au

Thanks again,
Hugh

[Brom]

I am still having no success on this. The new fuel pump and relay seems to have gotten rid of the loud buzz and now seems to amke a normal noise. However the car will still only start and run for 3 or 4 seconds before stuttering and stalling.

I've pulled the injectors and they're in horrible condition. Seals are destroyed and one is missing its cap. So i stuck a wire into the injector hole to see iff its stuck. But i couldnt feel anything. I hope it hasnt fallen into the cylinder. I don't think it can.

Still people are telling me it can't be the injectors and is more likely still the fuel pump or perhaps air flow. Any help is appreciated.

[paulie71]

Have you changed fuels? If you are using Ethanol based or Premium fuel this could have committed some crimes against humanity in you fuel system.

Next best thing is to send it to a fuel specialist (a Bosch one preferably) to check it over. I paid $350 all because I put Premium in the tank which glugged up the whole system with old crud.

Also sorry about not shooting through photo. PC was having issues. Still need snapshot of fuse/relay locations?

[Brom]

I found a fuse and relay diagram. Thanks.

Normally i would send this off to a professional only my intention is to get it back to sydney and drop in a diesel to run on biofuels. So spending money on the fuel system is an enourmous waste. At the moment i've realised i should have just driven the diesel and done the swap here, regoed in canberra (less restrictions on mods) and drive home in the deisel cabriolet.

So this is my new plan for next week. In the meantime i'll start parting out the other golf to pay for it all and look forward to mechanical pumps and natural asperation

[roccodingo]

info,,

Go here and have a read, K jet is suprisingly simple, and definately reliable. My Scirocco has been running for well over 28 years with only minor attention to the fuel system.

http://www.diagnostic-assistance.co.uk/mech_inj.htm

Pay special attention to the relay section, think you may have the problem there bud ..(.uses a tacho signal )

HTH

[Peter Jones]

yep, sounds like the tachometric relay. try hardwiring the pump and see if it keeps running. I,d say the relay is priming the system at ignition on but isn't seeing the ignition pulse to keep it running. The auto-solve site above has the wiring details.

Pete

[Golf Loon]

Yeah hotwire is the answer mate.
I`m in Camden and will lend a Golfing brother a car trailer if all else fails

[Brom]

Thanks for the advice. It's certainly over my head.

I put a brand new fuel pump relay on so i didnt think this would be the problem. Still this morning i tried a hotwire - no success.

But then i pulled the injectors again and noticed only one is getting enough fuel pressure to give a good spray. The rest nothing. So i swapped over an injector. Same fuel cylinder sprays. I then took off the injectror lines at the unit end and sure enough only one had any residual pressure. Cylinder 4. So i'm thinking i have problems inside there. And that's beyond my ability by the sounds of it. I'll give it a couple of hours, then i'm going to start prepping for the diesel engine swap - unless i come to some revolation.

I'll list the parts i dont wan't / need off both cars over the next week.

Also thanks for the offer Matt. But i think i'll swap it over here as in the ACT i don't need an engineering certificate or even blue slip to swap over to an older engine.