Club 80-90 Forums

Hello,

Wondered if anyone can help with a problem we've got with our 1980 2.0l petrol Aircooled which broke down on the M5 yesterday on the way back from a great week in Devon / Dorset

Had a problem on Friday when going up a really steep hill - lost power through each gear in turn until couldn't actual move; engine died and couldn't restart. Let van cool down for about 45 mins then started okay and carried on up hill fine, drove to our next campsite then didn't fire up again until leaving for home yesterday morning. Drove for about 1 - 1.5 hours no problems (over various terrain) then got on M5 by Bridgewater on a long upward slope and same loss of power again (35 mph on motorway not good!).

Then seemed to right itself again on flat or downhill but as soon as going up any sort of hill - power loss again until it eventually died right on the roadworks at Bristol! Had to be towed off via free recovery / police escort then got RAC out. I suspected the fuel pump possibly(?) but RAC man didn't have a clue. He did take some fuel out of the filter and said it had a bit of a funny smell not really like petrol. He got us going again but same thing happened after about 2 miles on an upward slope again - so ended up being towed home...

Anyone got any suggestions? Is this likely to be fuel pump as still seems to work okay intermittently or on flat / downhill? The only other thing I can think off is dodgy fuel but I went through a whole tank and replaced whilst we were away so surely both batches wouldn't be dodgy. I did put some fuel additive in whilst we were away (Redex) which may be quite an old bottle - could this still be sitting in bottom of fuel tank and be getting sucked in when going uphill or could there be general crap in bottom of fuel tank that only gets sucked through when going uphill?

We got tickets for Octoberfest this weekend and really want to get the van going for then as don't want to miss it. If it is the fuel pump - can you get repair kits for the old mechanical type and is so where? I know they've stopped making the pumps now so chances of me getting another one (electrical) and fitting before Friday are looking slim....

Thanks in anticipation of your help.

Chris

heat build up or fuel probs

the pumps are mech so work or dont they wont be intermittent.

is all and i mean all your tinware in place??

engine bay seal good???

carbs in good order?? any air leaks???

to me it sounds like a mixture / heat prob causing your motor to overheat and die.

carefull cos next stage is seizure!!!!

Hi, when it starts to loose power does it missfire? My 2 litre Aircooled lost power and missfired a few times, turned out to be shyte in the tank. I replaced the fuel filter, cleaned the carbs out and drained the tank. Its fine now..
IAN

Hi Ian,

No didn't seem to misfire at all. Fuel filter is almost brand new as I only changed this recently... How do you clean the carbs and drain the tank? Is it a big job?

Cheers,

Chris

Hi well I strip the carbs apart at work where I have the use of compressed air to blow all the muck out of them. I took the mixture screws out too, counting the number of turns when I unscrewed them. As for the tank I just drained it from the fuel outlet to the engine, but guess best way is to removed tank and clean it out properly..then you could end up finding the top of it rotten
IAN

Thanks Ian.

I'm worried now as I thought it was fuel pump and now don't actually know what is wrong and need to get it back on road for Friday so only got 4 evenings...

Could be fuel pump, they can go weak and not supply enough fuel for full throttle.... but you would expect it to keep running on a small throttle.. So more worrying is it sounds like it was over heating and seizing... but you would normally expect it to smoke very badly and upon restarting be quite noisey..
As said.. ALL of the tin ware and the engine bay seal MUST be in place and the fan free of debris for the cooling system to work.. So you need to go look and check.. if you dont know what you are looking at take some pictures of the engine bay and post on here (or mail me them)..

With any engine, if its feels like its losing power, slow down and pull up in a safe place (difficult on the motorway I know, but stopping near a bridge where passengers can shelter behind the barriers and under the bridge is best.. )
DONT keep pushing the poor thing on until it finally gives up, how sensible is that??? have a bit of mechanical sympathy..

Also if an air cooled poss is over heating, then DO NOT just switch off, run the engine at a fast idle to allow the heat to be "blown away" by the fan.. then perhaps try and carry on your journey at a slower speed less throttle..

Without seeing/checking it over we can only advise what it might be... there are many items that it could be from poor maintenance, worn out carbs, air leaks, fuel pump failing, incorrect ignition timing, blocked oil cooler, etc etc etc... or even a failing electronic component..

If it has overheated and nearly siezed, once you have been lucky, twice I would be surprised you have been lucky... and its a near certainty its suffered some damage...
what does the oil look like?? very black and not very nice smelling?

Electric fuel pumps are easily available from Demon tweeks or even GSF do one..)

I had a similar problem...it was fuel leaking past the cut off valve in the carb. When the engine cuts out pull the air filter clear of the carbs, check if there alot of white smoke/vapour coming out of the carb.

i bet your tank breather is blocked, thus not allowing air into the tank to replace the fuel you're using, thus slowing down the flow of fuel til it doesn't have enough to run on(will allways fail on hills as thats when you're trying to pull fuel at the fastest rate with your foot to the floor).. try driving it till you get the problem then immediately take the fuel cap off and listen to see if it sucks air in. if so then just stuff a rag in to complete your journey and then clear the breather. the reason it gets going again after a rest is that air slowly bleeds back into the tank at a slow rate which then allows fuel out of the bottom again. the fuel pump is just a sprung diaphragm so once a certain level of vacuum or negative pressure is reached in the tank the diaphragm simple stops working.
i have known this problem suck tanks flat where a strong fuel pump was in the circuit but thankfully the volky one is pi$$ weak at best.

Brill thanks Rozzo! Sounds like a good place to start. Now the silly questions How do you go about unblocking the breather pipe? What is this likely to be blocked with?

Thanks again for all the answers and responses.

Chris

Hi Chris
Rozzo's reply seems highly likely. The best way to clear a fuel pipe breather is by blowing air through it, I haved a foot pump or bicycle pump effectively. Probably blocked due to internal breakdown caused by 20++ of being attacked by fuel vapour.
It could be the fuel line itself internally collapsing due to the same problem.
However as the repair chap, I think his name is Simon? said unless we are there it is conjecture as to what the prob may be although I feel these are good places to start.
I would be wary of stuffing a rag in a petrol tank filler spout, but it can be a necessary evil.
If you can it would be a good idea to try running the van on a jury rigged feed from a can, if it runs OK then the problem is the fuel delivery/storage system and BEFORE where you take the (sucessful feed to).
Finally this may sound silly but has your van got a locking fuel cap? We had a lorry years ago that would cut out after losing power. Give it ten minutes bleed it and off it would go. When using a fuel tank inspection torch I saw a shimmer that turned out to be a piece of cling film floating in the tank, it was being sucked up and blocking the fuel outlet pipe.
Hope these suggestions are of some help.

Hi - yeah have got a locking fuel cap. Will try clearing the breather pipe first as you suggest and see if that rectifies the problem. Fingers crossed...

toomanytoys wrote:Could be fuel pump, they can go weak and not supply enough fuel for full throttle.... but you would expect it to keep running on a small throttle..

As Si says but elaborated to address "small throttle"

Fuel pump push-rods on the 2.0 l a/c can wear down causing fuel starvation.

When great demand for fuel is required the restricted action of the push-rod against the actuator in the pump means the fuel chambers inside the carbs get depleted.

When the rod is well worn and power loss has occurred its hard for the engine to recharge the carbs of enough fuel to continue the journey.

After the engine has cooled and hopefully with enough charge in the battery, turning the engine over for a while would allow just enough petrol to get it going again but not at any great speed or on a straight run.

I had a similar sort of problem for many months before deciding to check out the pump and duly found the push-rod to have a very sharp burr around the engine end where it had worn down by approximately 5mm
It could be worth a try ,taking the pump off and checking

I hope your problem is solved soon and its nothing really serious
Andy

i'm not exactly sure where the fuel tank breather exits but on most cars its piped low down for safety reasons so will probably be blocked with mud/road crap.
clear that first and i'll bet your problem goes away.
just as a point to note, always start with the most simple solutions as they usually effect a cure. i really think from how you describe the problem its running out of fuel so for me it would be breather first, then fuel pump and lines.
sick engines don't get better after a rest but they do get going if they run out of fuel then you give them some more.
good luck with it.

Cheers Andy & Rozzo.

'Gut feel' is it is something causing fuel starvation not an overheating / mixture problem. Breather pipe is where I will start as, like you say, start with the simple / easy things and rule out one at a time. I agree, if the engine was 'sick' it wouldn't repairing itself and would just get progressly worse so think fuel issue - i.e. dodgy fuel / fuel additive in tank; fuel pump diaphragm possibly warping when hot so not pumping fuel through to carbs. If it isn't breather, might remove fuel tank and flush just to put my mind at rest that it isn't the fuel additive that I put in. I am also going to recheck oil level now got van on level drive at home and if still overfilled will drain back to required level. (Don't know whether this may be the issue? Clogging oil cooler if over full?). After that I would suspect the fuel pump and will take that off and see if there is anything obviously wrong with components. Is it possible to get a refurb kit for these as don't really want to go down the electric pump unless really have to - would rather get a replacement mechanical pump for a scrapper...

Chris