My 1989 240 wouldn't start. I pulled the cover off the fuel pump relay and found that one side of the relay engages with the key on but the other side never engages while cranking or otherwise. I manualy engaged the second side of the relay with my finger and the car starts and runs well. I searched the forums but can't come up with what triggers the second side of the relay. I also installed a new relay and that doesn't work either. Any suggestions?
Thanks,
Malcolm

My "89 240 wagon is suffering from exactly the same dying symptoms you describe, but they started as a hesitation under load and are now intermittent "dead car" (ignition comes on and starter turns, but it's like there's no fuel). I checked the fuel pumps and replaced the in-tank pump (probably unnessesarily) before thinking to check the relay. I didn't see any cracked or broken solder that might suggest a bad joint. When I put it all back together, the car ran fine--for about 200 yards.

My "Check Engine" dashboard light is not on. After one of the intermittent starting and dying events, I checked the little black diagnositc box under the hood and got nothing (!). The Benley's manual indicates the fuel pump relay requires a signal from the RPM sensor. (Bentley's indicates a 1-3-1 code means no RPM sensor signal, and it would also not have the Check Engine light on. But I didn't get any diagnosic code, so I'm still stumped).

I don't know if any of this is helpful to you, but I could use any ideas too!

Sorry for the delay Dave,

I believe Bentley over-simplified the Fuel Pump Relay "signal". I'm not sure of all the pin #s, but according to Bentley's diagram (p390-46) the "RPM" (Impulse) sender #197 feeds the Ignition ECU"211, which sends an "OK" to the Fuel Injection ECU" 214, who (delighted beyond measure) puts a ground on its Pin 20, and thus via the Blue/Green wire to Fuel relay #217, terminal 86-2. Or should.
--
Bruce Young,
940-NA (current)
'80 GLE V8 (Now gone)
'83 Turbo 245
'73 142 (98K)
'71 144 (track modified--and going to be crushed unless...)
New 144 from '67 to '78
Used '62 122 from '63 to '67

The "second side" Coil has +12v applied to terminal 85 from the first relay. But it doesn't get picked till the ECU gets a signal from the Ignition CU and grounds the coil via pin 86-2 (Blue/Green wire).

The crimped connections in the relay connector plug have been known to fail, which might account for the 2nd relay not working. You might try pushing a jumper in with the Blue/Green wire, then grounding it to see if the relay picks when cranking.
--
Bruce Young,
940-NA (current)
'80 GLE V8 (Now gone)
'83 Turbo 245
'73 142 (98K)
'71 144 (track modified--and going to be crushed unless...)
New 144 from '67 to '78
Used '62 122 from '63 to '67

As you discovered their are 2 independent relays in one. The one that picks with the key supplies power to the AMM and injectors. The other which is the fuel pump relay only picks when the fuel ECU detects that there is spark signal going to the coil. You have spark because you are able to start when you finger the relay (that was good diagnostic step).
I seem to remember discussions here about certain Fuel ECU's failing with exactly that symptom, some Bricksters have wired around the problem by applying 12V to the coil directly, which is what I would do. Others may have more info on the part number of failing units and suggested replacement.
--
David Hunter