Fuel Pump?

[Mk2Tony]

Good morning Guys,

I had a small starting issue with the van yesterday. She started fine in the morning drove down to the beach didn't miss a beat all the way 60-65 on the motorway. parked up at the beach went for a wander when we came to leave she started fine again. after pulling up 2 mins down the road to run in the chippie, went to start, fired for a brief moment but sounded like it was running out of fuel then died. would not start after this so we disconnected the fuel feed pipe before the carbs and turned it over while the hose was in a coke can to see if we had fuel coming through but it was only a trickle. finally started it after getting some fuel from the tank, pouring it down the carbs and turning it over. After this it got us home and I stopped and started it a few time outside the house with no issues. Will try it again when I get home tonight.
I am wondering whether you knowledgeable peeps think this could be the mechanical fuel pump on its way out or just a blockage in the line or something of the sort?

Tony

[AlandAnn]

Just watching your post Tony...

In the last 3 weeks

I've replaced 2 Fuel Pumps, replaced the distributor cap, renewed all the fuel lines and empty and refilled the tank with fresh fuel!

The only thing I didn't do was replace the Fuel Pump Rod which, I've been informed could be a mm short.

I've ordered an electric fuel pump in the hope that this will fix the issue.

Hope you have better luck than me at finding the source of the problem.

Al

[Mk2Tony]

Its a bit of a strange one because its never done it before, and didn't miss a beat on the way down and fired straight up when leaving the beach. It was only when I stopped again at the chippie, and even then I restarted it once again with no probs to pull forward a bit. Then next time I turned the key I just died and wouldn't go. Then a cup of fuel in the carbs and away she went, got all the way home no probs

Tony

[bigherb]

It could also be a blocked fuel filter or fuel line.
Replace the filter just as a matter of course to eliminate that. Then check you can blow down the fuel line from the pump to the tank.
After that check as you did above the fuel pump rate it should be good pulses of fuel coming out if it is just short spurts then fit an electric pump, mechanical replacements are variable quality.

[Mk2Tony]

The fuel filter looked ok from what I could see, I will change it later when I get home anyway I'm sure I've got a spare one. It could have possibly been a blockage in the fuel line, But then when I got it started it ran fine all the way home (25 miles) and then started up straight away when I turned it off to try it!
I don't really want to go to an electric pump if I don't have too, I know VW Heritage sell new mechanical ones for 50.00 so will probably change that and see how we go from there. I think it has been going downhill for the last few weeks as if I leave it a week or more without starting it the fuel must run back to the tank and it can take a good few turns to get going, I'm guessing to pull the fuel up the line. This has only been recently, and as I don't usually leave it without use for more than a few days at a time, and once she is fired up she doesn't give any problems until she has been left to sit again.
Roll on moving house so I will have a garage and the engine will be coming out for a long awaited rebuild!

Tony

[Ian and Lins]

We had this problem. It was the fuel pump pushrod. Easy and cheap to replace and very obviously worn with 'flat' instead of rounded end. The trouble was the replacement then wore out within a few thousand miles with the same symptoms. 'Can't be the push rod.' we thought but it was. So cheap we keep a spare in the van now.

[CovKid]

I often wondered if tempering the steel would help but perhaps its somewhat sacrificial and hardening it would just wear something else. Sadly, the quality of fuel pump pushrods are not always good. I had similar probs with a worn clutch operating arm that developed flats on the fork. A touch with the mig welder solved it completely without having to replace arm but this may be a bad idea with a pushrod.

[silverbullet]

The pushrod is hardened for a good reason. It is raised by a flat ramp on the distributor drive gear, also hardened. The pump diaphragm centre also has a hard button in its centre.
If any one part were "soft" it would wear very quickly and put the resulting fines into the cam gear's oil sump.

Sent from my Gizmondo

[Mk2Tony]

new pushrod ordered, for £4.95 I'll give that a try before buying a new pump. I will be buying a new pump at some point when rebuilding the engine anyway so if the pushrod sorts the issue for now that would be great!
Cheers for the info guys hopefully pushrod should be here Thursday so that gives me something to do in the evening!

Tony

[AlandAnn]

In most machines where there is a high amount of stress, there are parts that are constructed as sacrificial so that they go before any major component goes. Surely the rod must be the sacrificial part? I've ordered mine as well, I'll be very happy if it is the worn component. But I'll be pissed with the garage who couldn't diagnose this and cost me upwards of £200 including fuel pipes

Please let us know how you get on.

[Mk2Tony]

To be honest I never take my van to any garages unless they are owned by someone I Know and trust, I find most mechanics can't be bothered looking at the old stuff and even when they do they haven't got a clue what they are doing really. I try to do everything myself if I can, you can always get plenty of information and help on here, plenty of extremely knowledgeable people with lots of experience of these vehicles. Hopefully my pushrod should be here Thursday so I'll get that done after work and see how we go. I'm not even sure where it is on the engine yet though lol, I'll have to get the Bentley manual out hopefully it will be in there. I will let you know how I get on and if it cures the problem, fingers crossed!!

Tony

[smashyvan]

Not been on here for ages but had same exp as you guys.. Think it was at least 2 new diaphram pumps I fitted and one pushrod. It was never a reliable system - when the van was left for a long period of time it took ages to crank over before got fuel at the carb. One breakdown was when the pivot pin fell out on the M4 (on the way to Switzerland..) and i bodged it with a bolt from the wifes bike. At this point i got fed up..

Even with in line filter also got blockages in the carb. 2 years ago fitted electrical pump as per old recommendation from Big Herb and changed the fuel tank for good measure. That was the root cause of all my carb blockage breakdowns - it was full of "pooh"...
And the electric pump has meant no other starvation issues since..

[AlandAnn]

My Chinese fuel pump has arrived in the post today Looking forward to getting her fitted and hitting the road again.

[Mk2Tony]

I've got my new pushrod so I'm going to strip the pump off tonight when I get home, Might grab a pump too just to be on the safe side incase the diaphragm is gone in the old one. I have had issues where it takes a good few cranks to get going but only usually if its left for a week or more, I was considering putting a non return valve in the line to stop the fuel running back. I need to change the little bush on the starter motor too and maybe get that reconditioned as it can be slow turning over which probably doesn't help as the fuel pump is mechanical so only pumps as fast as the engine turns over?
I have to be fair though I've done over 10000 miles in the last 2 years and Sunday was the only time I've broken down anywhere, and even then we got her going and didn't miss a beat all the way home so I can't really complain it is 36 years old after all!
I don't really want to fit an electric one if I can help it, if the original mechanical one has lasted this long then hopefully a repro should last at least a quarter of that!

Tony

[AlandAnn]

I've just replaced my rod and she still isn't firing up....oh well fit new electric pump tomorrow after I sabre up.

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