Hi folks. Can I ask for some ideas as this one has me scratching my head? Car was recovered home yesterday after the engine cut out. There is no power to the fuel pump. (Car starts up when easy start is sprayed direct into the throttle intake) Working backwards.... On the pump relay there is no sign of a switched positive to activate the relay. My wiring diagram suggests this should be coming in from the start relay? Am I right in thinking the start relay is activated by the air flow switch on the metering head going to ground? My wiring diagram is not helpful here. It references a Coolant expansion tank temp sensor that my car does not have As a sanity check I jumper wired the fuel pump relay and sent power to both output terminals (87). The pump sees voltage and car tries to start but wont catch. Just because I know they are bad, I checked all the fuses, all seems ok. Any ideas?
Yep, that would help wouldn't it! sorry! Its an 82 Euro GTSi 2v. It was a US grey import although no obvious mods that might affect this issue.
A US version 308i-2V has a thermal switch sensor on the coolant tank to operate the "cold-running mode" (e.g, retards the ignition timing, runs the cold start air valve system, turns "on" the cold-running warning light in the dash). Yours being removed, or present, should have no impact on the engine starting and running. One thing that can cause your symptom (when you "jump" the fuel pump relay to directly put +12V on the fuel pump and you hear the fuel pump run) is that the pressure the pump is delivering may be low. The cold start injector will squirt fuel into the intake system during starter motor cranking at any fuel pressure (so would "cough" into starting), but the K-Jet system needs the fuel pressure to be the full ~5 bar to keep working. If you "hear" the fuel pump running with the jumper in place, but the engine only "coughs" when starting and then won't keep running, the next step IMO would be to measure the system fuel pressure from the fuel pump to confirm/deny if in spec.
HI Steve. OK, that makes sense. I don't have a suitable pressure gauge setup but I'd planned to get hold of one anyway. Are we saying that even with the start and pump relays not working, the engine should start if the pump sees voltage? (TBH, the pump has never made any noise)
It better make some noise. It should "hum" softly if it is actually running at all. If it is just silent when +12V and ground are directly applied to it = it's dead.
OK, I'll have a listen. Seems improbable a pump would die at the exact moment the wiring would pack up. Wonder if its drawn a load of current and caused further damage. Is there an easy way to tell which pump it has if I have to order one. I can't see anything in the pipe work between the pump/accumulator. I'm guessing that means its an internal non return valve?
I just replaced a pump on one of those. The early style pump is available. The only ones I found were very expensive and I really didn't want one anyway. The pumps with the screw in check valve require a different hard line to attach to the accumulator. NLA for some time but T Rutlands had some reproduced. Not a cheap part but allows use of a much less costly pump. I found a very inexpensive pump but had a large female thread at input. I bought a 5/8 hose nipple to cure that issue.
I can't really hear anything from the pump. It must be doing something as the engine coughs when the pump is fed 12v, nothing without power so perhaps its just weak. On closer inspection it is the external NR valve type so have ordered a new one. Now to figure out why the pump isn't getting 12v.
Just... stop. If there's no power to the pump, check the relay. If there's no power to the relay, check the fuse. I always start at the fuse box (I am, fundamentally, a very lazy man)
I can tell… you didn’t read post 1! Lol . Agreed. Fuse box is always step 1. I actually woke up last night to realise I’ve been an idiot. (I think). if the pump relay is activated by the start relay, and that is activated by the air flow switch on the metering head, nothing will activate until there is airflow to pull the metering pkate down? Ie the pump only sees power when the engine is cranking???
Turn on the ignition, pull the connector on the side of the air flow meter (air filter box removed) and press down on the flap - you'll hear the pump start and the injectors will squeak a little. Don't do it for too long!
New pump and it immediately fired straight up. As it happens I got the pump wrong and mine was on an internal check valve pump. Was easy to fit the wrong pump by removing the screw in valve. Rather than ordering the correct one, after reading a bit on here, my plan is to convert to use the external check valve version. Looks reasonably straight forward, just the usual messing around to get the right fittings to make up a new pump to accumulator pipe.
