DaveW

DaveW

Member
Please help!

I have a RRC 3.9 efi (1991) which has been stood for about 18 months. I'm struggling to get it started and any tips or advice would be gratefully received.

So far i have discovered that the fuel rail isn't getting fuel. When I turn on the ignition, the fuel pump does it's 2 second run and then stops. I assume that the fuel pump should carry on pumping as there is no fuel at the rail? As it's been stood for a while the lines have no fuel so I can't get to the point where I can discover if the injector/ spark plugs are working.

I've tried starting it on quick start and it will fire but doesn't run (no fuel!!).

I have replaced the fuel pump and its does continuosly run when tested, the relays near the EFI box are working, the fuel inertia switch is working, earths all have been checked and re-checked, I've replaced the ht leads but I'm stumped as to whats stopping the fuel getting to the engine!

Any help would be really great

Dave
 
Start from the back and go forward. Check the fuel pick up pipe, the filter could be choked and all you are doing is pumping air or creating a vacuum. Work forward and check the lines for blockages or holes (it's a pressurised system and if there is a hole there is no pressure). Is the fuel bye-passing the engine and pumping back into the tank? Then the stepper motor - is it jammed? Injectors could also be clogged although all eight at once is quite rare - you would expect maybe two or three would still dribble and give an attempt at starting. I had similar probs years ago on a 3.9 - turned out it was the stepper motor gasket had disintegrated but not before I had changed the coil, cap, leads, plugs etc. It was running but misfiring and cutting out. Go over all the connections again and check the things I've listed. Naturally others will be along later probably with something I've missed - give them time
 
DaveW said:
I have replaced the fuel pump and its does continuosly run when tested, the relays near the EFI box are working, the fuel inertia switch is working, earths all have been checked and re-checked, I've replaced the ht leads but I'm stumped as to whats stopping the fuel getting to the engine!

Any help would be really great

Dave
Click to expand...

Don't laugh but the fuel pump is wired the right way round isn't it? I have seen a fuel pump with the polarity reversed so the pump was actually trying to suck the fuel back in to the tank. Might be worth a check.
 
Thanks for the advice, I've removed the fuel pipe after the filter and it was dry, I then checked it where it comes out of the pump and the pipe was a little wet with petrol but that was it, the pipe wasn't any where near full! All the fuel lines appear sealed so I'll check the stepper motor see if the gasket as well.

I'll double check the fuel pump for reverse polarity and see if that works! It sounds like it's sucking fuel then dropping it?

I was wondering if as the fuel lines are completely dry I would need to manaully bleed the system a bit like a diesel run vehicle but wasn't too sure if that was required?

Oh and I've put approx 2.5 gallons of fuel in it so enough to run on!

Thanks once again

Dave
 
Quick update, the pump is wired the correct way around, the fuel lines are initially really difficult to pull apart which I would guess means a vacuum so I'll get a new filter as the next step.

On a slightly different track, once the pump has primed is there another set of electronics that tell it when it needs to carry on? All I'm thinking is; could their potentially be an electronic fault with the pump that way?
 
Two and a half gallons, 12 litres or so isn't much really. You've probably just wet the bottom of the tank. It might take another couple to properly submerge the pick up if it hasn't been run for a while. Remember too that fuel tends to lie in the lines when a car isn't running but is in frequent use and yours will have evaporated after 18 months so it will be pumping air through as well. You may have answered your own problem anyway in saying the lines are dry after the filter. That will be paste inside for want of a better term.
 
Thanks,

I've disconnected the line after the fuel pump and turned the ignition and get a decent flow when the pump primes but then it stops and doesn't pump anymore once it does the priming sequence. I would have thought that there would be a sensor or something that should tell the pump to carry on after priming as there is no fuel at the engine and that might be a problem?

Also, once I re-connected the fuel line it was again priming to a point then dumping the fuel back into the tank as if it was getting too much pressure in the system so couldn't get the fuel very far. This would suggest to me one of the following;

Injectors not working or
Blocked fuel line (triple checked and I think are clear)

I'm thinking that the injectors aren't working because they're not getting the electrical signal to start so moaybe a relay not working or something?

Once again, I really appreciate your help with this, I'm determined to get it going!!
 
It's not something silly like the pump primes with the ignition on but then needs the engine to be cranking to keep going?
 
I think not, I've tried keeping the engine cranking as well as getting it to fire briefly on quick start to see if that solves it!

Oh I forgot to put on my last post the stopper moter gasket was fine, the little rubber tube was cracked to I've replaced that but still the same problem. Could the valve that the stepper motor is connected to be the problem if it's seized?
 
Has anyone mentioned spark plugs yet? They could be glazed over if not used for 18 months. There is a similar live thread ongoing at the mo where someone has had starting problems. Have you had the plugs out to check they are wet, white or sooty? Remember that easy start stuff is more volatile than petrol and will burn with a weak spark.
 
Thanks, yeah I'm going to replace the spark plugs this weekend and check them as I remove them. I've also done a diagnostic check on the EFI stuff and there appears to be no faults on that front so i think its a mechanical not EFI fault. Fingers crossed ill bottom it this weekend!
 
Hi all,

Quick update, the fuel will get as far as the regulator but seemingly no further. Could the regulator be ceased or is it more likely to be the stepper motor (I've removed it and cleaned it, it's getting power from the efi box as well).

The vacuum pipes all appear to be in good condition, I've replaced a perished one between the regulator and stepper motor. The other thing I thought is a weak fuel pump but its brand new.

The fuel pipes are clear and I can't find any leaks in them.

Is there anything obvious that I should try first?

Thanks
 
Hi. Did you find a solution to this. I have a similar problem. The fuel relay isn't switching to power the fuel pump and I can't find out why.
 
DaveW said:
Hi all,

Quick update, the fuel will get as far as the regulator but seemingly no further. Could the regulator be ceased or is it more likely to be the stepper motor (I've removed it and cleaned it, it's getting power from the efi box as well).

The vacuum pipes all appear to be in good condition, I've replaced a perished one between the regulator and stepper motor. The other thing I thought is a weak fuel pump but its brand new.

The fuel pipes are clear and I can't find any leaks in them.

Is there anything obvious that I should try first?

Thanks
Click to expand...

you've not fit a low pressure fuel pump by any chance? there's two types of pump,one for diesel and one for petrol injection. they're identical to look at but very different pressure output.
 
I've changed nothing. It started no problem a couple of weeks ago. Now turns over OK and has a spark but no fuel. I put a couple of gallons in the tank just in case but the problem is no power getting to the pump as the relay isn't switching with the ignition on.:(
 
Bonesy said:
I've changed nothing. It started no problem a couple of weeks ago. Now turns over OK and has a spark but no fuel. I put a couple of gallons in the tank just in case but the problem is no power getting to the pump as the relay isn't switching with the ignition on.:(
Click to expand...

1 - Check inertia switch.
2 - Test/replace pump relay
3 - Test/replace main EFI relay as both relays need to work for the engine to run.
 
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