Fuel Not Getting Through

[peteinnit]

Hi all and Merry Christmas to all.

Nice Boxing Day pressie for me, van wouldn't start. I'd been on a long run day before but following morning it was just turning over. Assuming it's the fuel pump but just wanted to check quickly if there are any other simpler things it might be!? Have checked the fuse on the pump and the connections and all seem good. Put some easy start in and it catches, so definitely fuel issue. Last time the pump went there was no fuel in the filter, but this time it's 3/4 full still, so that's why I'm wondering if there might be something else. I've got a Pierburg 7.21440.51.0 pump, which was on the van when I bought it in 2006. I replaced it less than 3 years ago, so a bit disappointing if it's failed so soon. I have a spare which I will probably fit this afternoon, unless anyone can suggest any other possibilities.

Trust all had a good Christmas and thankyou for all the advice received over the year.

Cheers,
Peter

[peteinnit]

So I've changed the pump and still not getting any fuel! I removed the feed before it reaches the filter as well and there's nothing coming out there either, shouldn't it flow out? Or does it need the pump to bring it from the tank? And yes, I have checked there's petrol! I've also rechecked all the fuses. Is there something I'm missing? Any help greatly appreciated, if I can't get it fixed, it'll be staying on the road until April, as I'm going to be out the country!

Thanks again.

[porthyt]

Hi,

I’m by no means an expert but perhaps you have a fuel lock somewhere. I have managed to start by removing the fuel cap and starting it. Or a good check is to remove the fuel hose from the carb (in engine bay), put it into a clear bottle or pot and have someone turn the van over. It should spurt out of the hose, if it doesn’t then the pump could be at fault. I don’t have an electric fuel pump so unsure on the fuses. Often pouring a few capfuls of petrol into the carb bowl (may take a few times)is enough to get it to suck through again. Fuel shouldn’t come out the line when you removed from the tank (apart from a dribble)as it needs the pump to pull it through.

Otherwise, if it’s def fuel then could be a blocked filter or jet? Are you at the bottom of your tank or anything?

Good luck.
Josh

[peteinnit]

A block is the only other thing I can think off, it must be before the pump as I disconnected the pipe from the exit end and turned over engine, and nothing came out. Would be very bad luck if the new pump was faulty, will take the old one to a garage tomorrow to see if they can connect it up and test it. Will try and blow up the pipes tomorrow see if I can feel any blockage. Stupid question alert.... if I take the petrol cap off is it OK to try and blow back up into the tank from the filter to try and clear any block in the tank?

[maxstu]

Fuel filter before pump?
Stuart

[937carrera]

Take the air inlets off the top of the carbs and pour an eggcup of neat petrol into the top of the carbs. It'll start and run for a few seconds before running out of fuel.

Be prepared to repeat a few times until the pump pulls fuel through from the tank........ speaking of which I don;t understand the reference for a fuse for the fuel, they're mechanical unless you have modded the system, in which case simply wire a temporary 12v feed supply to the pump to make sure it is operating and that fuel is coming out of the feed to the carbs.

I have to do this with my CU project regularly due to fuel evaporation.......... and tip 5 litres fresh fuel into the tank, unless you are certain that fuel is in there. Fuel does evaporate off on these vehicles

[peteinnit]

I've only got one filter on mine, before the pump and it's clear. When the rain stops I'm going to see if I can blow through the pipe into the tank. There was fuel in the filter when the problem started and it was getting pulled through, so maybe it is still the pump and I got sent a new dud one.

I read on another forum that air was being sucked in through cracked pipes, hoping it's not that as I think that would be a tank out job, which is on the list, but not at this time of year on the street!

[peteinnit]

I've got a Pierburg electrical pump on mine, hence the fuse check. I left the fuel line off the carb end of the pump and nothing is coming out. I've also put some easy start in, but it dies once it's burned off, same it would if I poured petrol in. It's not been standing, so fuel shouldn't have evaporated over night (I used it the previous day), but I did also think about filling up a petrol can and topping up, just to be sure. That's what I'm off to do in a mo when I've had a cup of tea. Cheers

[porthyt]

Fresh fuel is a good idea. I would give the fuel in the carb thing a few goes. I have an Aircooled and with mine it takes a few tries, splutters, backfires and eventually pulls through.

[937carrera]

Ok, so put some fresh fuel in and put a 12v feed to the fuel pump you should see fuel coming out of the fuel line to the carb. No fuel then either there's no fuel to the pump, the pump is not working or there is a blockage in the line from the pump to the carbs.

The advantage of a separate 12v feed is you can check the fuel delivery without needing to have the rest of the vehicle live - and you'll feel / hear the fuel pump working.

[peteinnit]

Just popped in for a cuppa as it started raining again!

So, I hooked up the old pump to 12V and it was purring nicely, so think it's safe to say the new pump is working (but I will check it), but still not drawing fuel from the tank and filter still empty. Also topped up with new fuel even though I filled up a coupla days earlier so all is fresh and I poured some into the carbs too. It wanted to start but still not drawing anything into the filter from the tank.

Next I removed the feed into the filter and blew back up into the tank and sucked some out and got a mouthful, so no block there. Also removed feed from filter to pump and no block or leaks there. Will go back out in a mo and make sure there is no block from pump to carbs, but since it's clear from the tank to the pump it should be drawing petrol up to any blockage beyond the pump shouldn't it?

[937carrera]

Take the inlet hose off the pump - you should have flow due to gravity.

Assuming that's the case, put the inlet back on and remove the outlet hose. If you can put some spare hose on and allow the fuel to run into a container, then operate the pump again.

It is possible that the pump motor is spinning, but it is not creating fuel pressure due to internal failure.

[peteinnit]

I don't get any flow from gravity, even if I disconnect the hose to the tank!

But I think I have figured out the problem, the pump doesn't seem to be getting power when connected up on the van. Not sure why, but I will replace all the wiring tomorrow. Seems strange though, I tested on separate 12V using the existing earth cable and used a separate wire to connect the power and it worked, but when I put back on the van and earth it using same piece and connect power to separate 12V again it doesn't work! So it may just be a dodgy earth, but it seems strange that the earth would fail suddenly overnight, so I'm still not sure. Using the separate 12V though it has pulled some fuel into the filter.

The power cable goes to a switch box and then into the coil and another earth, so I guess the problem could be in there or the coil as well. If I can't sort it tomorrow, think I'll have to get someone out to check it out as I'm not sure how to check if those bits are working.

[bigherb]

Where is the pump mounted? They are not a suction pump and need to be mounted below the fuel tank level and near the tank.

[937carrera]

If there's no flow from the tank outlet to the pump then either there's no/very little fuel in the tank or a blockage. Is the van on non level ground meaning there is no fuel at the tank exit ?

It sounds like you bench tested the pump, rather than testing in situ - is that correct ?

On the fuel pump, it sounds like it is working when current is there, so that's good. Do you know how the aftermarket fuel pump was wired?

Normally they only receive current when cranking or when there is a signal/voltage to the fuel pump relay indicating the engine is running. This is so that if the car is in an accident and the engine stalls, fuel does not continue being pumped even if the ignition is on.

I would focus on the physical delivery of the fuel to the pump first, then see if it starts before messing around with the wiring.