Weird Relay None start issue

[petemcr 10]

Hi all,

 

Sorry if this is under the wrong section, it's a no start issue but I suspect it's a relay but I figure it would be under this section, feel free to move it over if needed.

I'll save rambling on too much but, I have decided to bring my Corrado out of storage after a year and a half, it went in running, but had a weird issue one day that went, but would idle, the second I let the clutch out it would bog right down and make a terrible noise, but then if you let the clutch in, it would idle fine again.

Fast forward a year later, I managed to drive it out of the unit I store it at, let it idle for a while so it would come up to temp, all okay, I switched it off and then came to move it again and it wouldn't start. I decided, because the 167 relay I had was old and tired looking I would short the 30/87 pins, and boom, she started up fine, ran fine. I've ordered a new relay (albeit cheap) from eBay to test, but with the relay in I still get no start, I jumper the pins and it starts no issue, weird part is I put the relay back in, it started for a bit and idled but if I try to move it, it cuts out and stalls, and then refused to start again, back to the shorted pins... drives perfectly fine.

Other than it being a faulty relay I'm at a loss as to what is causing it, I checked for voltage on 85 I think it is to make sure the ECU is shorting it correctly and I get 0 volts, I only see constant 12v on pin 30 I think it was and can hear the fuel pump when I short the pins. I did scan it with VagCom and the only code I get is for G28 crank position sensor, which from what I understand is expected when the engine is off because it's not getting any signal.

Sorry for the long post

tl;dr - VR6 wont' start after being stood, starts fine with the pins on the 167 relay shorted out but won't with a relay, bar one time where it started then stalled again

[Philly-R6 1]

Hey Pete,

Sounds like your fuel relay is your problem. The contacts inside the relay do get a bit cruddy over time - making the switching intermittent.

You can prise the lid off the relay and briefly sandpaper the contacts if you fancy meddling (you have another on the way anyway).

[petemcr 10]

  On 4/15/2025 at 6:44 PM, Philly-R6 said:

Hey Pete,

Sounds like your fuel relay is your problem. The contacts inside the relay do get a bit cruddy over time - making the switching intermittent.

You can prise the lid off the relay and briefly sandpaper the contacts if you fancy meddling (you have another on the way anyway).

Hey Phil, cheers for the reply.

 

I thought it was the relay, my old one already had the cover off it so I could see the internals, I actually taped down the contact so it was perm bridged and it started and ran, but even with a brand new relay it doesn't run, it has only run once with the new relay.

 

I just taped the old one again so I could drive it and it's not starting again, nor can I hear the pump. In term of relays it all looks like that side works, there's 12v, it clicks on, if clicks as I turn it over but it's just like it won't power the pump.

 

Think my next stop now is going to be probe the fuel pump plug and make sure it gets 12v when the relay is engaged, I'm out of ideas past that.

[fendervg 33]

The fuel pump relay needs to see a signal from the ECU relay with ignition on to let it know that the engine is running - maybe it is not seeing this? It is there as a safety feature  to cut off the pump.  When you bridge the fuel pump contacts you are bypassing this. The VR6 engines don't prime for a couple of seconds the way the Golf 1.8 etc do, the pummp will only run when the engine is cranking or turning over.

I would check ignition switch, ECU relay and fuel pump relay.