No start: Fuel problem

[Schniddy]

Well, I think It's safe to say I jumped the gun on the timing belt issue. I was in such a rush to call it on the timing, I looked at the improper mark on the crank flywheel ( yes, it is possible, and it made it appear as if the camshaft was off by over a tooth). The lines are infact lined up!!

It's all back together now and I'm trying to figure out what the real problem is. The car won't run, it wasn't running before eaither when I thought it was a timing issue.

Right now its all fuel related. Hopfully


1. The injectors themselves are not viberating when the car is in the on position. They are freshly rebuilt M50 injectors so I'll take a wild guess and say the resistances are fine. This means I need to check the voltage at the connector aparently.

"on models with 6 cylinder engine, there should be battery voltage between the red/white wire and ground when the ignition is on."
Red/white wire? What? Where??


2. On my first start up I had the two fuel lines to the FPR and the fuel rail mixed up. This in turn could have fucked up the FPR, but this still dosn't explain the injector issue. As of now only fuel is comming out of the top hose to the FPR. Shouldn't fuel also be comming out of the bottom hose to the fuel rail?

[jlevie]

If the fuel pump is producing sufficient pressure and the FPR is good, fuel will flow from the bottom (return side of the FPR) when the pump is running. If that's not happening either the pump of the FPR is bad. You can tell which by checking the pressure at the inlet of the fuel rail (should be at least 44psi)

[Schniddy]

should it still flow from the bottom hose with the car just cranking, not actually running?

Also,


1. The injectors themselves are not viberating when the car is in the on position. They are freshly rebuilt M50 injectors so I'll take a wild guess and say the resistances are fine. This means I need to check the voltage at the connector aparently.

"on models with 6 cylinder engine, there should be battery voltage between the red/white wire and ground when the ignition is on."
Red/white wire? What? Where?? Basically, how can I test the harness out?

[jlevie]

If the DME is running and sees timing data from a rotating engine, it will run the fuel pump. Thus the pump runs when cranking over the engine and there should be fuel flowing through the return line from the FPR. For testing purposes, you can enable the fuel pump by jumpering pins 30 & 87 in the fuel pump relay socket. I strongly suggest checking the fuel pressure at the inlet of the fuel rail to know whether the pump & FPR are operating as they should.

The injectors are organized as two banks of three injectors. Each injector has two connections. One pin of each connector is spliced to a common that is tied to 12v when the key is switched to start or run. The other pin is tied to the bank 1 or bank 2 common, as appropriate, that goes to the DME. The DME grounds each of the injector banks in turn to fire the injectors and that only happens when the DME sees timing data from a rotating engine.

The injectors won't vibrate just because the key is in the on position. The engine has to be rotating and timing data must be present at the DME for them to fire.

Pull an injector connector, switch the the key to pos 2 (ignition on) and check for 12v at the pins. On pin should have 12v on it and the other will have some random voltage.

[Schniddy]

If the DME is running and sees timing data from a rotating engine, it will run the fuel pump. Thus the pump runs when cranking over the engine and there should be fuel flowing through the return line from the FPR. For testing purposes, you can enable the fuel pump by jumpering pins 30 & 87 in the fuel pump relay socket. I strongly suggest checking the fuel pressure at the inlet of the fuel rail to know whether the pump & FPR are operating as they should.

The injectors are organized as two banks of three injectors. Each injector has two connections. One pin of each connector is spliced to a common that is tied to 12v when the key is switched to start or run. The other pin is tied to the bank 1 or bank 2 common, as appropriate, that goes to the DME. The DME grounds each of the injector banks in turn to fire the injectors and that only happens when the DME sees timing data from a rotating engine.

The injectors won't vibrate just because the key is in the on position. The engine has to be rotating and timing data must be present at the DME for them to fire.

Pull an injector connector, switch the the key to pos 2 (ignition on) and check for 12v at the pins. On pin should have 12v on it and the other will have some random voltage.

"I strongly suggest checking the fuel pressure at the inlet of the fuel rail to know whether the pump & FPR are operating as they should."

I jumped socket 30 and 87b ( they are not marked, so I tried both 87's. one produced a clicking sound in the engine and the other did not) there was no fuel released from the FPR.

Next step then is to check the transfer pump. I removed the cover under the back seat and jumped the relay again. There is no sound coming from the fuel pump.

After that the next step is to check for voltage at the transfer pump harness connector. There was a reading of 0 volts, which is what you want.

It then says to check for breaks/shorts to ground. Where would the ground be?

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The two fuel lines have been mixed up constantly throughout this troubleshooting process. I was told it should be one way, but I'm pretty sure it ended up the opposite way of what i was told. Fuel is supposed to come up the one hose into the fuel rail and then exit out the FPR. Thats how its been set up for the previouse (sp) tests.

I've been told having the two lines switched could ruin the FPR. could it also mess any thing else up in the system?

I'm getting fuel out of the FPR while cranking the car ( stuck a hose on the end into a small can), so what does it mean when this happends and yet it dosn't happen when I try and jump the relay for the fuel Delivery rate test?

I'll check for voltage at injectors now. After that, whats next?

Thank you jlevie for the detailed help, r3v needs more members like you!

[Schniddy]

"pull an injector connector, switch the the key to pos 2 (ignition on) and check for 12v at the pins. On pin should have 12v on it and the other will have some random voltage."

This is on the harness itself, or one the injector itself. Also, can't you only get one reading due to only having two pins (one wire to each pin)? I tested both and got 0 volts. Faulty harness?

[Schniddy]

scratch that, I'm getting 11.6 volts at the harness from the first two connection (the only two with easy acess). I'm also getting 16ohms from the first two injectors. These both seem good to me.

Can anyone help me out?

[Schniddy]

?

[jlevie]

Next step then is to check the transfer pump. I removed the cover under the back seat and jumped the relay again. There is no sound coming from the fuel pump.

Your 89 should only have one pump and it is mounted in the tank on the passenger (right) side. While should should be able to hear the pump start if it is good condition it should be pretty much inaudible. But what really matters is the pressure at the inlet to the fuel rail. Until you've measured the pressure there you are fishing in the dark.

[Schniddy]

So I need to get a guauge/t-fitting and test the pressure comming out of the FPR and also to rail, correct?

Would I be able to get an accurate reading from just cranking the car?
Again, I can't get the pump to turn on from jumping the relay, it didn't do anything. What would it indicate if I can' get fuel to come out during cranking, but when jumping the relay nothing happends?

[archemedes]

then the pump is bad, or you have a bad wire to it. Check that you have power at the pump when you jump the relay

[Schniddy]

You know what, I have a feeling I jumped the wrong relay. The bentley has a way of making simple things confusing.

Are you supposed to jump the "main relay" or the "fuel pump relay". It would make sense to jump the "fuel relay", but in the bentley they call for the "main relay"..possibly the "main fuel pump relay".

I'll check it out when I'm back home.

If the DME is running and sees timing data from a rotating engine, it will run the fuel pump. Thus the pump runs when cranking over the engine and there should be fuel flowing through the return line from the FPR.

So for the DME to see timing data from the roatating engine, the CPS must be working, right? So for me to get any fuel to come out during cranking, that is an indicator that my CPS is working?

[Schniddy]

Another note off the top of my head, the main relay had burn marks on each prong near the top. Does that mean its automatically faulty?

[jlevie]

Are you supposed to jump the "main relay" or the "fuel pump relay". It would make sense to jump the "fuel relay", but in the bentley they call for the "main relay"..possibly the "main fuel pump relay".

To tun the pump on you need to jumper the fuel pump relay.. Jumpering the main relay only powers up the DME and I've already covered when the DME will close the fuel pump relay.

So for the DME to see timing data from the roatating engine, the CPS must be working, right? So for me to get any fuel to come out during cranking, that is an indicator that my CPS is working?

That's pretty much true. Another indicator that the CPS and DME are good is that you'll have spark when cranking over the engine.

[another1bitesthedust]

if you had the fuel line swap,, you might,-could-of, possibly ,,, ruptured the rubber conector on the fuelpump to sending unit mount, from over pressure. just a thought