Hi all,
seems like I have a problem now.
Yesterday it felt like I sometimes had a lack of power, then on my way to work this morning my engine started to run a bit lumpy, then stalled on me. After much cranking, it just about caught and ran. After this I noticed that if I kept the revs below 3,000 all would be well. If it went above 3,000 revs it would start to loose power until it reached stalling point, but if I backed off the accelerator it would recover.

For all the world it feels like its running out of fuel, but there is half a tank left and the gauge is definitely working. 3 weeks ago I replaced the fuel filter and last week I cut some Bio Diesel in a 60-40 Dino-Bio diesel mix. I can’t see any signs of a big diesel leak, but I suspect that air is being sucked in to the fuel line somewhere. I have checked the filter and is done up tight by hand. Is this enough, or do I need to be a bit more vicious with it? Any other ideas?

- (#12640) dave Bright (Bournemouth), 11 Aug 04 06:46

Hmm. I'd wonder whether you've clogged the filter again/ got some water/ killed the feed pump inside the pump?...

- (#12640) David Miller, 11 Aug 04 07:15

Thanks Dave,
I have a couple of spare filters so that's going to be my first job when I get home. I don't have any knolwedge of the feed pump inside the pump. Can you elaborate for me?

- (#12640) dave Bright, 11 Aug 04 07:18

Dave. When you fitted the new fuel filter, presumably you charged the fuel line by pumping the priming pump mounted on top of the filter assembly. I had a similar problem to yours and I found that air was getting into the fuel lines from this pump assembly, ie, the sealed chamber, with it's reed valves, was allowing fuel to drain back into the tank. I stand to be corrected but, I don't think that there is a non return valve in the suction line at the bottom of a Townace tank so the condition of the check (reed) valve, on the suction side of the priming pump, is important. Also, the priming pump diaphragm needs to be sound. It's worth also, checking the suction and discharge hoses on this assembly. They are "push on" with those 10/12 year old spring clips. I had to fit another priming pump (s/h at around £25)with "Jubilee" type hose connectors and this cured the trouble. Unfortunately, the priming chamber, with it's valves, is a sealed unit and the valves cannot be cleaned of any debris but, in your case, hopefully, if the problem is air being drawn in under load, it might just be a faulty piece of hose.

- (#12640) John Davis (Leics), 11 Aug 04 07:21

Check the filter first. Sounds like fuel starvation, the pump is only sucking in enough to reach 3000 rpm.
Filter should be tight enough, otherwise it will leak.
Are all the fuel lines on nice and tight?
- (#12640) Clive (Bristol), 11 Aug 04 07:30

John,
yes I primed the fuel line because it was a bit reluctant to start and I didn't want to flatten the battery to much. You have confused me a bit with your description, but I think I understand that any leak in the pipes will allow air to be drawn in. That seems to fit the symptoms quite well. Its fine in park, I can rev it right up to the limit, but when in drive it struggles after 3,000 rpm. That doesn't fit the clogged filter symptoms because the power loss is more down the lower end of the revs. As I have a spare filter though, that will be my first prong of attack. sadly I can't do this before I leave work, because I don't have the right tools or the time now, so I will have to do it later at home. If it gets there that is! then I won't be able to test it because Tracey is working tonight and I'm baby sitting.

We do seem to be having a few problems today don't we.

- (#12640) dave Bright, 11 Aug 04 09:44

Clogged filters and the transfer pump inside the pump (a rotary vane pump...), by reducing fuel flow not just reduce injected quantity but also timing advance. The pressure produced by the vane pump acts on a spring-loaded plunger to advance the timing as the revs increase. But that additional advance is needed more under load than on free-acceleration.

Either could produce the symptoms described. Check the filter first ( and for airleaks in the pipes...), after that it's a visit to your local diesel place to get the pump's internal pressure checked. Although I'd wonder whether it's something else- debris in the tank getting pulled into the inlet at high levels of draw, perhaps?

- (#12640) David Miller, 11 Aug 04 15:34

Thanks for that Dave,
I changed the filter earlier this evening and have just got back from a test drive. So far it looks good. Power is back to normal, but the old filter doesn't look at all clogged.

I checked the pipes that connect to the filter, and whilst the inlet pipe at the front was as tight as tight can be, the outlet pipe to the pump, more to the side, is not as tight, and I can easily turn it on its spigot. I resisted the temptation to fiddle with it because I wanted to check the result of changing the filter first. As this seems to have improved thus far, I am going to wait a bit to see what develops.

I think its possible that the problem was that air was getting into the fuel system through this loose pipe connection, as the symptoms are spot on with air in the fuel line. It maybe that this only started to happen once the new filter had some mileage on it and was slightly clogged. Then it could have been easier to suck air through the poor seal on the pipe, than sucking the fuel through the used filter under high demand.

Thanks to everyone for their advise, and I will let you know if things turn bad again.

- (#12640) dave Bright (Bournemouth), 11 Aug 04 16:29

Hi everyone,
I too have recently changed the fuel filter after having this wonderful vehicle for a year. I have been suffering from 'excessive smoke' since I've had it - not clouds and clouds, just noticable on medium to hard acceleration, especially noticable at night with car headlights behind!

It seems to have cured that problem....But I had a problem when I changed it. I did not have any spare diesel about when I fitted the new filter, so put it on dry and tried pumping up diesel with the plunger on top of the filter head. It would not pump owt. I removed the filter again and sucked up some diesel from the fuel tank and filled the filter up to the top and refitted it. I pumped again with the filter head pump (I cracked open the feed pipe union at the injector pump) but it did not seem to be 'pumping' it out, it was as if it was trying to pump but then sucking back. I tightened up the injector feed pipe and tried to start it. For the first time ever, since I've had it, I put the throttle about half way down in the hope that if it started It would get a good quick flush through before an air lock could stop it.

To my surprise it started and seems to run perfect. As I have said it seems to have cured the smoke problem and also appears to run smoother (is it just my imagination?)

The only thing is, that every now and again, when I start in the morning and sometimes when it's already warm, it faulters. It seems to 'chug/misfire' a little with a bit of black smoke for a few seconds and then it's ok.

It's only ever done this since I have changed the filter. I never touch the throttle on start-up and, up until now, it has always started lovely on tickover.

Do you think that there could still be a bit of air stuck in the system? After reading the other comments in this thread, could it be 'draining back' a bit?

Thanks in advance for any advice

- (#12640) Stewart, 11 Aug 04 18:58

I can back what Stewart says. Despite all the advice in our archives I have several times hastily started up like this when I know the fuel has drained back into the tank from the hose and the filter is empty, after changing a fuel filter. Under these conditions, or if there is the tiniest air leak allowing fuel to drain back, you will get the odd cough, even stop, but it has always recovered for me.
I much prefer the nut-and-bolt type hose clamps (12-14mm size) rather than Jubilee clips.
- (#12640) Dave Mason (Sussex), 12 Aug 04 04:23

Well it all seems to be back to normal this morning, and I've just popped out to my local accessory shop to get a pre diesel filter as suggested by Clive in an email. The parts man recommended a larger filter type than Clive had suggested because of the flow rate. He said the smallest type was good for a 1.6 diesel, but not really big enough for a 2 litre diesel. Might be ok to begin with, but after time it will reduce the flow. So that was £2.40 rather than 99p, but if it catches some of the nasties before they clog the main filter, then I guess it might lengthen the life of the main filter.

I was contemplating leaving the loose pipe to see if the problem returns, but I suppose its asking for trouble not to fit it, so I will do this as soon as.

- (#12640) dave Bright, 12 Aug 04 04:48

My trusty D-reg SpaceCruiser keeps dying on me - sometimes jsut after a few miles othertimes after 20-30.

Leave it 5-10 minutes and bingo! it starts again.

Suspicions centre around the fuel pump any ideas?

It might be useful to know that previously it was playing up starting when warm but that seemed to go away.

- (#12640) Dave Warriner, 20 Aug 04 03:07

Coil/ igniter?

- (#12640) David Miller, 20 Aug 04 08:00

Unlikely to be fuel pump that would be a gradual loss of power. There is a glass window in the carb for float level for an instant view on fuel supply, on the front side 10p size round bolt on frame with an hour glass shape glass inspection window.
As the great Mr Miller says likely to be dizzy related electrical connection that breaks when hot and connects on cooling.

- (#12640) Clive (Bristol), 20 Aug 04 11:25

first some questions, have you had to change or replace the fuel filler cap lately?
have you changed or/and renewed the inline fuel filter?
i had this sort of problem on a car quite some years ago, it turned out to be a lump of rag in the tank that would get sucked over the pick up pipe.
not a lot of help i know but just some different ideas.
good luck !!

- (#12640) Devon Dave, 20 Aug 04 12:11