Hopefully one of you guys can shed some light on what I think is an electrical problem on my 328. As soon as I start the car I can hear a continuous clicking sound coming from the Fuel Pump Starter relay and then after say, 7 or 8 seconds the engine dies as if its starved of fuel. You can immediately restart the engine and it does exactly the same again.....every time. At first I though that maybe the aftermarket immobiliser that's fitted to the car (by the previous owner) is faulty......but now I'm not so sure ? This particular immobiliser functions by cutting the fuel pump off. When you turn the ignition key to the Pos II you can hear the relay make a single click to the On or "Closed" position which I assume completes the circuit to feed positive current to the fuel pump, but as soon as you start the engine the relay starts clicking ON-Off-On-Off ..... and the engine dies. I tried swapping the relay over with another of the same type but it made no difference. Since the relay is effectively just an electromagnetic switch that's activated by a low tension circuit I was thinking for test purposes that I could remove the relay and bridge the In and Out terminals of the high tension circuit on the fuesboard with a bit of wire to close the circuit. If the engine does then run ok this would tell me that the fault lies with the low tension feed to the fuseboard .... maybe the positive feed from the ignition switch is shorting out , or a bad earth connection to the relay ? Has anyone else experienced this problem and do any of you auto electrical gurus agree that my testing suggestion is the right way to go. I'm slightly worried that I might fry the fuel pump or melt the wiring ! Appreciate any good advice on offer. Cheers Franco
(Just to be clear) -- are you saying that the Bosch ...101 relay "s" --the "Fuel injection delivery pump starting relay" is the relay that's clicking irratically? If so, try unplugging the safety switch at the fuel distributor. (Again, if this is the right relay) during normal engine running (i.e., safety switch open), relay "s" would be unenergized and terminal 30 would be connected to terminal 87a (which supplies +12V to close the fuel pump relay "r"). The "click" you hear when you turn the key to Pos II with the engine not yet running (i.e., safety switch closed) is this relay "s" energizing which connects terminal 30 to terminal 87 (and supplies +12V to close the fuel pump relay "r" only when the starter motor is actually cranking -- i.e., Pos III). You could "bridge" this relay "s" by connecting terminal 30 to terminal 87a in the female relay socket, but unplugging the safety switch does the same thing when relay "s" is in place (if relay "s" is OK). What version 328 -- standard, CH, or US? Image Unavailable, Please Login
Hi Steve Thanks for such comprehensive information .... you obviously have a wealth of knowledge about this issue and your detailed explanation is excellent. Your are correct when you say that I'm refering to Bosch 101 relay "S" .... the fuel pump starter relay. I have already tried unplugging the safety switch from the metering unit and it made no difference to the situation. What I do get when I unplug the safety switch is the sound of the fuel pump running with the ignition switch at Pos II, engine not running. I believe that this is how it should be ? I'll try bridging terminals 30 and 87a and see what result we get but if that doesn't work I would much appreciate any other suggestions as this one's got me puzzled and frustrated. My car is standard UK spec, non cat, non ABS. best regards Franco
These two results would be a little contradictory for an unmodified standard 328. With the safety switch unplugged and the key in Pos II (so the fuel pump is running as you noted), you should just be able to go to Pos III and start the engine (and it should stay running). Since this doesn't work for you, I, too, would suspect that the problem is something to do with your Immobiliser set-up. Do you know if your Immobiliser is wired somewhere into the relay "s" connections, the relay "r" connections, or directly into the fuel pump wires?
Hi Steve When you said that the two results were a little contradictory I decided to backtrack and go through the motions again. This time when I unplugged the safety switch the engine ran perfectly. What a relief ! So if it'll only run with the safety switch disconnected then we're obviously compensating for some other fault in the system. Any suggestions .... ? Thanks & regards Franco
I'd suspect the safety switch itself first. Measure the resistance between the two terminals on the unplugged safety switch -- should be: 1. engine off and airflow plate not deflected = 0 Ohms (or a few Ohms maximum) 2. engine running at idle or above (i.e. airflow plate deflected to a running position) = infinite Ohms Your symptom would say that you'll fail test #2, but also look at the wiring to make sure a wire isn't pinched/grounded somewhere.
