HELP!
My beloved 1987 740 GLE is not running. It died during a stop at a stop sign. [insert curse words] It started to accelerate, then immediately died as if I just turned it off.
I checked the Fuel relay and it clicks when I turn the key. I tested the plugs and I'm getting spark. The battery is practically new and fully charged. No dead cells. I wired 87/2 and 30 together the fuse board and heard both pumps. The pre-pump was whirring, and the main pump sounded like it was straining. But, they were both pumping gas. Both are original, and the fuel filter is new.

I investigated the RSR (radio suppression relay) and I tried to do a diagnostic test on it. The relay wires almost came apart when I went to disconnect it. I jumpered the (red and green) two larger wires together and nothing happened. My next suspect would have to be the ICU (ignition control unit) but I'd rather not mess with it. Any ideas people?

I don't have a multi-meter or a voltmeter, but I do have a 12v test light. It seems like I'm not getting juice to the injectors? Is that the RSR or the ICU? The RSR sends pulses to the injectors, but isn't the ICU responsible for making sure I'm getting spark and fuel? I am planning on taking the pre-pump out and checking the fuel strainer "sock". However, that is a pain in the tucus on a whole new level.

I KNOW that since I have an 87', that my wiring is crap. Most wires literally disintegrate in my hands. I feel like I'm chasing electronic gremlins constantly. Is the only solution to change out ALL the wires?

Thanks people,

Mike

 

Look at the Hall Sensor and wiring. This is the pick up from the distributor whose wiring is often bad internally and it will cause what you describe... It's a "coaxial" cable but you can just splice another piece in, the coaxial coating is just for radio interference.

 

Before you go much further, have a helper crank the car while you look down the oil fill hole on the valve cover. If you don't see the cam turning, you've broken the timing belt.

There are improved main engine harnesses available, although they are scarce. If you go to davebarton.com you can find the original harness number as well as the new, improved version's number. A j/y search is your best bet as new ones have all but disappeared. As Volvo never admitted to faulty insulation, there are no smaller, tower harnesses available that are improved versions. On my 84, after replacing the main harness, I ended up building the smaller ancillary harnesses. It's not difficult...just challenges my patience.

 

I'm pretty sure my Hall Sensor is working well. The car has new bosch wires, rotor, cap and spark plugs. The tach also jumps just before I crank the car, so I'm pretty sure it's good. It's worth an inspection though, thanks Levi.

@swiftjustice - I'll look into it. And I'll make sure my timing belt is working properly. I'm going to check out some Volvos in a junkyard tomorrow. Obviously, get an older harness so the wires aren't falling apart, right?

Also, I wanted to get another RSR from a junker, just to see if anything would happen. I'll post later and let you know what's going on. thanks again guys.