This is my first time posting so bear with me. So to the nitty gritty. Car sat for 4 years. Owner said it was fuel related. So I did it all. Removed all old fuel. In tank pump is new and wired rite. In line pump is functional. Filter is new. Relay is new, I replaced it. 25 amp fuse under hood is good. All fuses cleaned. Key on no power to #4 fuse. Jumpered #4 to #6 both pumps verified working and verified pressure at rail. Checked new relay and its plug. With key on relay dose not fire. Is it the ecm? Thank you for any reply.

 

The ECU will not turn on fuel pumps until it detects a signal that the engine is turning. On the LH2.2 fuel injection system (which is what you have), the signal comes from the hall sensor on your distributer. That same signal fires the ignition as well. Have you verified that you have spark? Also, have you tried to start the car when fuses 4 & 6 are jumpered (both pumps running)? If it doesn't start when both pumps are running would also indicate you have an ignition issue.

 

Yes I tested for spark and cam rotation. The ecm thats in it says Bosch on it. Is that an OEM box?

 

Yes it has spark but the mafs is not connected its missing the tube that connects it to the throttle body. I'm waiting on that part to get here monday. And yes I tried starting when jumpered.

 

Every plug cleaned and checked on exhaust manifold while turning over.

 

I don't know how well it will run (if at all) without the plumbing from the AMM to the throttle body. I would think that it should at least start with the AMM unplugged but I have never tried. Have you tried starting it using a spray of starting fluid? If it fires with starter fluid that would confirm a fuel problem

 

Has spark to plugs but no run when sprayed

 

And it has the correct fireing order.

 

the ECU (Fuel Injection Control Unit) is mounted on the right side of the right footwell, just forward of the right (passenger) door lower hinge, behind the plastic kick panel. They are Bosch, yes.

if you're referring to some other sort of ECM, you'll need to be more specific.

 

So I know where the ecm is I was just wondering if by looking at the markings if it had been replaced. Anyway I got it to fire with starting fluid. And can now here the fuel pump relay buzzing and clicking but no pump noise with out jumpering. I read somewhere that the ground to the ecm might be at fault here?

 

the markings would only indicate it had been changed if the person swapping it marked it as such.

a 1987 240 is LH2.2 and probably has a -511 or -544 ECU

 

So I cleaned the 25 amp fuse again and now it runs but only with the pumps rigged (#4 and #6 jummpered). And after all the crap flushed out of the injecters. Why? So tomorrow I'm buying a brass fuse kit and am going to clean every contact I can get to. Which wire to the ecu is the ground that needs to be reestablished?

 

the ECU grounds (there's a couple) should all be brown/black or black wires, and are grounded at the fuel rail, the frontmost of those two ground screws is used for signal/control stuff, and the rear one is used by power stuff (injectors, etc). at the ECU, the main grounds are pin 25 (injector ground), pin 5 (ground for the shield on the O2 sensor signal) and pin 11 (main ECU signal ground)

 

Excellent. Thank you all for your replies. I'll keep you posted.

 

Still the same. Runs and drives only with #4 and #6 jumpered. Any idea where to go from here?

 

your fuel pump relay is either not being told to turn on by the ECU, or its broken. or the wiring from the ECU -> relay -> fuse panel is broken, which IMHO is less likely unless someone has been in there hacking on wires at random...

87 /is/ a suspect year for bad wiring, they had a run of bad insulation from circa 82 to 87, so called biodegradable ecojunk. early RoHS stuff. the insulation will flake away in places where the wiring is exposed to heat under the hood. this happens inside the black plastic guard tubes.

 

ECU pin 17 is a blue-green wire to fuel pump relay pin 86/2 ... this is driven to ground to enable the fuel pump relay. so if you can get a volt meter onto pin 86/2 or ECU pin 17, while everything is connected, it should read +12V when you switch the power on, and it should read close to 0V when you crank the car over. if you never see the 0V on there, your ECU is bad. if you see the 0V but no power on fuse 4, then the relay is bad.

the fuel pump relay output is pin 87/2, a yellow-red wire that goes to the fuse panel fuse 4. the main pump comes off it before the fuse, and the tank pump is on a yellow-red wire off the other side of that fuse.

 

If the ecu was bad how come I feel the relay fire and the fuel injection works?

 

But no pumps. I have installed a switch between 4 and 6 and have been driving it.

 

And the relay is nockoff new