So I've had some intermittent issues on my wagon relating to fuel. Occasionally on cold (ok so I live in California so 40F isn't REALLY cold) mornings the car won't start. When I turn the key I can tell if it's going to start or not because I either can or can't hear the hum of the fuel pump before clicking it over to crank the engine. If it won't start then, it will usually start later in the day when it warms up.

Things I've done recently:
Fuel filter, new copper/brass ceramic fuses (cleaned all terminals before), new KAI (german) fuel relay, replaced underhood 25a fuse and holder with waterproof marine grade unit, new crank sensor.

My question is where to go next with this? Does it sound like a fuel pump? What should I test?

Thanks in advance, this is really bugging me.

 

My 1990 240 wagon also had fuel pump issues. The car would run fine when the tank was at least 1/4 full, any less and the car would not start or die when running. The problem was the in-tank fuel pump was bad and the main pump was not keeping up properly. This may not be your problem but something to consider.

 

Check your connections on the main pump, they are exposed and intermittent starting would make since. If you sometimes hear it come on and sometimes you dont its either the pump or the connection if ur relay is new like you say.

 

This morning it wouldn't start either, so I jumped the #4 fuse to the #6 fuse and could hear both pumps run, so it seems that the pumps are functioning and their connections are ok (?), just not getting switched on at startup. I could REALLy use some leads here please. It did this with the old relay, and now it does it with the new relay.

 

Search this forum for "pink label ECU". Those have a known failure where they stop grounding the blue-green wire on the fuel pump relay.

 

Also look at the radio suppresion relay on the passenger side, little black box. My wires came out of mine on the connector as well as I had one that worked intemittantly. In the described condition it will crank and crank but never get fuel due to no injector pulse due to no connection to the relay. You can get a handful of the relays at a pick your part for under $10.

 

Looked at the ECU. It's a 933 white label. Started fine in the afternoon, just won't start in the morning. I guess it's going to be a radio suppression relay next. Thanks for the help guys.

 

Please forgive me if I'm missing something, but it doesn't look like the 90 240 had a radio suppression relay. If it does and I'm missing something please redirect me.

 

No radio suppresion relays on 240s.

From the symptoms you describe, I would suspect the relay but since you replaced that already, you need to check elsewhere. If when you turn the key that you don't hear the fuel pump run, jumper the right side of fuse 4 to fuse 6. If you still don't hear the pump, I would suspect a failed pump or bad connections at the pump.

 

Thanks, I already tried that yesterday (posted further up), and the pump sounded pretty happy when I jumped the fuses. Checked both sides of fuse 4 and heard both pumps individually.

 

The fuel ecu will not ground the blue/green wire, turning on the pumps, until it sees spark pulses from the ignition control unit. I would check for trouble codes from both sockets 2 and 6. Also, see if you have spark at a plug wire during the no start condition.

 

NO RSR?? Well check the connections on the main pump then, mine were cracked and not holding on, when it was in a cetain direction it would not kick on.