'87 240 Spark, No fuel

Denied72 · 2024-09-11T10:52:19+00:00

Heyo, i'm at my wits end and need a bit of help Just put my engine in with a new ignition harness and for the life of me I can't get it to get fuel to the e...

TL_V70

Shouldn't come apart easy sorry.

TL_V70

There just an auto resetting fuses. So you don't have to carry fuses with you.

ramrod

Is there any injector pulse?

Denied72

ramrod I don't believe so. Injectors fire on the bench when given 12v. Haven't been able to properly test it with the multi yet.

ramrod

This needs to be verified.

Pull out the rail again, leave the injectors attached. Ensure the ground wiring is still bolted down and crank engine to see if any fuel injecting.

That or use a noid lamp to test for pulse

Denied72

ramrod Ah yeah, I've had them out, grounded and cranked the engine while jumping the fuel pump and nothings come out of them. I can go back over after and get fuel out if I give them 12v from an external battery.

So currently, I have spark, timing is correct but fuel pump and injectors are not running when on/cranking.

ramrod

I did not realise the fuel pumps weren’t running.

Have you checked the fuel pump relay?

That’s the first thing you would check when diagnosing a no start.

Denied72

ramrod I would think that the injectors would be firing without the pump relay, but no I haven't gone and looked at it yet. Will when I get time next but I'm not sure how related it is to the injector problem as i've heard its possible to run the car with the fuses jumped if the relay is dead.

ramrod

Yes, so long as the ECU senses the engine is rotating, it will ground the injectors and they will open if fuel pressure is present.

The relay not working can prevent this.

You mentioned you replaced the ignition wiring harness. What about the rest of the injection harness? No injection could quite possibly be the result of shorted wiring. Very very very common on a 1987 240.

Have you examined the engine wiring?

Denied72

ramrod I've replaced the engine wiring harness with new, including the ignition harness. the fuel harness looks to be in good condition up behind the firewall too. I believe I have everything plugged in in the right places.

Didn't realise the fuel relay was played a part in the injection circuit. I thought it would've just had a sender.

ramrod

That’s great that you’ve replaced the harness.

I would double check all individual wires are seated completely.

Triple check the orange and black wires are connected underneath the inlet manifold. As well as the ground wires for the injectors.

You can hold the terminals closed inside the fuel pump relay, pumps will run full time.

I would then check injector pulse. And permanently connect the fuel injection fuse wiring by the battery.

If none found, and all wiring is verified connected, ECU could be faulty

Denied72

ramrod Where does the orange wire go to? From memory I have one female single blade connector on the harness poking out near the dizzy with an orange wire, doesn't seem to be for anything, I assumed it was for the coolant temp sender but it could be my problem

ramrod

It goes back into the main harness.

It’s a black rectangular connector.

Your new harness should have come with this fitted

Denied72

ramrod Yeah everything was labelled on the new harness so the main stuff should all be right. I'll have another look this arvo I guess.

Denied72

Ok so, currently I have no fuel pump and no injector pulse. I've tried

Testing continuity over breaker in place of the underhood fuse, its fine, continuity achieved when installed in the housing
Testing both in tank and main pump with fuse jumping, both work
moving grounds around on for the injector and hall sensor, nothing changed,
swapping ignition ecus, no change
swapping fuel ecus, no change
manually pushing the fuel relays together. Had it working for a bit but has now stopped.

Car still does not get fuel into the cylinder. not sure what to check next. Very stumped, would love help because the car is meant to be out of the driveway this weekend.

Denied72

I've also got this random brown cable coming out of the part of the harness that goes to the dizzy.

I've got no male blade connectors left to plug it into and it can't reach any other wires.

Not sure if it's important or not.

Image description

ramrod

That’s the knock sensor wire.

Or is there another wire already connected to the knock sensor?

Where abouts are you from? If local to Sydney I could supply a new fuel pump relay because it seems like you need a new one

Denied72

ramrod I'm in Wollongong, so not quite local to Syd. These relays are too old to be available off the shelf at your jaycars and etc right?

jamesinc

Knock sensor is a two pin plug. It could be a switched 12V for diagnostics, similar to the blue connector on the firewall harness that you use for triggering the starter. Probe it and see?

Denied72

jamesinc yeah it's not something that's on the old harness so not quite sure. I'll be tracing everything to the diagram over the weekend and hopefully I'll find something.

ramrod

jamesinc

Not on LH2.2

That system uses a single pin sensor unlike LH2.4 which has two pins thus two wires