Nexus7

Lots of crank/no start postings over the years, but I'm seeing something different than described in those. Trying to start an '86 ('87 engine) that sat for around a year, but was running well until then.

The fuel pump won't come on. Initially, the main relay (behind driver's side strut tower in engine bay) wouldn't click on, but does now (clicks when key is turned to ON). However, pulling and replacing the EGI fuse causes no clicking, whereas back in the days it was running, I remember clicks when this was done.

Jumpered the fuel pump test connector (behind AFM, white in my case), and pump ran when key turned to ON and we finally got some fuel into the engine bay. However this didn't happen again, that is, after this occasion, the jumper + key ON did not result in pump coming on again.

AFM door moves OK with the spring action. The fuel pump relay (in interior, mounted to steering column) has resistances in spec with FSM. The relay connector is not showing any 12 V. It shows 0.1 V or so on the Fp and 3-4 V on the terminals in the middle (forgot the name). At the fuel pump connector (behind rear driver strut tower), no terminal shows 12 V either.

The battery however is strong, it is 12 V on its terminals, and cranks the engine strongly. The dash lights seem to come on OK.

So what could've happened to a car just sitting there (no rat/mouse/pest problems in garage)?

Thanks!

Nexus7

Checked voltages at circuit opening relay (on steering column).
Per FSM, this is supposed to be as follows.
Fp -> to fuel pump
Fc -> To fuel pump switch (where is this?)
B -> To ign switch

<pre>
Fp Fc B
IGN ON 0 12 12
AFM Open 12 0 12
</pre>

What I get is B is 12 with AFM open, but 0 with just IGN ON. Fp is 0.1 when AFM Open, 0 with IGN ON.

Could this be a main relay problem?

HAILERS

The MAIN RELAY and nothing to do with the circuit opening relay and the fuel pump.

The ENGINE fuse has everything to do with the pump running. Replace same and try again.

Fuel pump runs if key is ON and the vane in the afm is pushed aft.

Fuel pump works if the key is HELD to start.

Fuel pump runs if the yellow two socket fuel pump check connector is jumpered.

Fuel pump works if the engine starts and pulls the vane in the afm aft approx 1/8 inch or more.

Fuel pump does not run if the ENGINE fuse is blown.


The FP in your dwg means power to the fuel pump. Remove the plug from the fuel pump itself on the aft side of the rear left strut tower. See if the large BLUE wire on the harness side of the connector has power when the vane is pushed aft,......with key ON. Should be there.

That large blue wire mates with a black/white wire in the pumps pigtail harness. The only other wire in that harness that means squat as far as the pump working, is the BLACK ground wire.

HAILERS

/The measurements have to be made with all connector on the circuit opening relay. You backprove the wires going into the plug.

HAILERS

N

Nexus7

OK, will do and report back. EGI fuse in engine bay looks OK, but maybe flaky inside. Engine fuse in interior foot-well looks OK too.

Thanks.

Nexus7

Both fuses are OK. Checked resistance, and also swapped them with other fuses.

At the fuel pump connector (behind rear drv strut tower), the voltage is 0.1 V (not 12 V) when the fuel pump check connector is jumpered (my check connector is white... weathered down from yellow?).

Also, as mentioned earlier, when I reinsert the EGI fuse, nothing happens. Can someone confirm something should be clicking when I do this?

Thanks.

HAILERS

Right off hand I can think of nothing the EGI fuse(s) would do to cause anything to click OTHER than the Blue in color Relief solenoid on the vacuum rack.

ENGINE fuse causes the Main Relay to click and also causes the Circuit Opening Relay to click IF the fuel pump check connector near the right front strut tower is jumpered. Never seen anything other than a yellow two socket fuel pump check connector..........but then I only own three clunkers one of which is a 86.

One wire on that yellow connector should be brown/black and the other BROWN. IF you can determine there is a pure brown wire there, then try just jumpering that single brown wire to a nearby ground point.......like the bracket that holds the boost/;pressure sensor on to the chassis. It's possibel the brown black gnd wire is not attached to the ECU ground point 24 is why I say that.

As you've seen from looking at the wiring diagrams, the Circuit Opening Relay has two coils that can pull the relay in and feed the fuel pump. One coil is pulled in when the key is HELD to START. So pull the small trigger wire off the starter.........put the key to START.........and listen for the Circuit Opening Relay to click and the fuel pump to run......or look at the large BLUE wire on the fuel pump connector (Rear harness half of the connector) and see if it now shows batt voltage.

Still no fuel pump power? Then just make a jumper wire. REmove the Circuit Opening Relay.............Jumper the Black/white wire to the Blue/red wire. Pump now runs or at least the Blue wire now has power at the fuel pump connector.

That would be the B/W wire in the upper left hand corner.

Aw hell, don't pull the trigger wire off. Pull the relay out and just jumper the MIDDLE B/W wire to the Blue/red wire and the pump runs with key to ON. Power on the middle B/W comes from the ENGINE fuse. Blue wire runs to the fuel pump connector. Pump now runs. 'That shouldn't take more than a half hour on the outside.

HAILERS

I stole the attached jpg off this site. It shows the yellow two socket connector on the left of the picture. Circled it.

Nexus7

Yeah, that's about where it is on mine. However it isn't a turbo; the car (and harness) is '86 NA, although the engine is a Japanese import, '87, IIRC. It has a rubber boot. The only other open connector around there is a green 3-socket one.

HAILERS

Your at the right plug then. Turbo or non turbo it's in the same area.

I'd just go to the Circuit Opening relay then and jumper the black/white on the top left to the Blue/red and turn the key on and the pump should run. Or at least have power at the blue wire at the fuel pump connector.

Nexus7

I disconnected the starter trigger wire. Also got fresh batteries in the multimeter, and got a new (used) fuel pump relay (on steering column). Now I have 12 V (approx 11.7 V actually) at the blue wire at the fuel pump connector (on rear drv strut tower) when key in on START. Nothing when key is ON. Not sure if this is a malfunction or not. In any event, since the pump isn't running when the blue wire has power, I think I should get a new fuel pump.

Hailers: Thanks for the very detailed help!