pgrbff Posted January 22, 2021 Share Posted January 22, 2021 I live 3km from the main road and the road to my home can't be cleared of snow. We have over 2 feet of snow. We leave my wife's car on the main road and use the 300tdi to ferry us back and forth with a full set of chains. A couple of days ago she started lacking power, even at full throttle it would only crawl. It's pretty cold at the moment, I haven't been able to get to a petrol station for ages. The tank probably has little more than 10l of diesel in it at any time. I'd had a leaky return pipe at one time so I prodded the return pipes and when I started her up power was back to normal. I checked the pipes, one came off in my hand, very perished and luckily I had a spare, so I replaced it. Next morning wouldn't start. Took a while to prime but eventually started and I noticed another return pipe was damp with diesel and there were very small air bubbles. The only pipe I had was silicon fuel pipe for model nitro engines so I used that. Drove about 1/2 mile and power was gone again. I now get approximately one second of acceleration with foot fully down, then 4 or 5 seconds of juddering and no power. This repeats over and over again. I can drive one cars length then power goes, wait 5 seconds and she'll move again, about one car length. HELP! Quote Link to comment Share on other sites More sharing options...
Ed Poore Posted January 22, 2021 Share Posted January 22, 2021 How old is the fuel in the tank? Doesn't sound like it's particularly fresh. I had similar issues in the 6x6 which was because it had had diesel sat in it for ages and algae had started to grow in it causing issues pulling enough fuel through. If you're confident you've sorted all the leaks then I'd be changing the fuel filter out if you can - it might also be worth giving the lines a quick blast with an air hose back towards the tank incase something's got jammed in there. Quote Link to comment Share on other sites More sharing options...
monkie Posted January 22, 2021 Share Posted January 22, 2021 Check the fuel lift pump is working also Quote Link to comment Share on other sites More sharing options...
pgrbff Posted January 22, 2021 Author Share Posted January 22, 2021 22 minutes ago, Ed Poore said: How old is the fuel in the tank? Doesn't sound like it's particularly fresh. I had similar issues in the 6x6 which was because it had had diesel sat in it for ages and algae had started to grow in it causing issues pulling enough fuel through. If you're confident you've sorted all the leaks then I'd be changing the fuel filter out if you can - it might also be worth giving the lines a quick blast with an air hose back towards the tank incase something's got jammed in there. The fuel is fresh but not very much of it in the tank at any one time. For the last 3 weeks the snow has been so deep we have to bring it home, 3km on foot, in a 10l can Quote Link to comment Share on other sites More sharing options...
pgrbff Posted January 22, 2021 Author Share Posted January 22, 2021 16 minutes ago, monkie said: Check the fuel lift pump is working also Intermittant fuel lift pump problem? Quote Link to comment Share on other sites More sharing options...
monkie Posted January 22, 2021 Share Posted January 22, 2021 No, just not feeding enough fuel to the injection pump. They do go. Easy to check to rule it out. Quote Link to comment Share on other sites More sharing options...
Ed Poore Posted January 22, 2021 Share Posted January 22, 2021 When you say that it judders - do you ease off the accelerator in order for it to recover or does it do so on it's own? With only 10l in the fuel I'd still be cautious of it just picking up carp from the bottom of the tank - any chance of putting more than that in there just to see if it helps improve things? Quote Link to comment Share on other sites More sharing options...
pgrbff Posted January 22, 2021 Author Share Posted January 22, 2021 22 minutes ago, monkie said: No, just not feeding enough fuel to the injection pump. They do go. Easy to check to rule it out. She ran perfectly yesterday having changed one of the return pipes. Changed the other pipe today, 1/2 mile perfect then started playing up. Quote Link to comment Share on other sites More sharing options...
pgrbff Posted January 22, 2021 Author Share Posted January 22, 2021 (edited) 2 minutes ago, Ed Poore said: When you say that it judders - do you ease off the accelerator in order for it to recover or does it do so on it's own? With only 10l in the fuel I'd still be cautious of it just picking up carp from the bottom of the tank - any chance of putting more than that in there just to see if it helps improve things? It's a perfect cycle. Press the accelerator yo get approx 1 sec of normal acceleration, power drops off so instinctively you release the accelerator a bit, after 4 or 5 seconds the power returns for a second, then drops off for 4 or 5 secs, and so on. It's quite hard carrying 10l of diesel through 5km of snow, with school books, shopping etc, so it's 6-10l at a time depending on who is carrying it. I noticed the juddering when I opened the bonnet and accelerated with the cable, one second of power then power drops off, air filter box starts shaking because engine judders. Engine never dies. Edited January 22, 2021 by pgrbff Quote Link to comment Share on other sites More sharing options...
monkie Posted January 22, 2021 Share Posted January 22, 2021 2 minutes ago, pgrbff said: She ran perfectly yesterday having changed one of the return pipes. Changed the other pipe today, 1/2 mile perfect then started playing up. Worth a check. Who can say it's just one thing that's failed? Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 22, 2021 Share Posted January 22, 2021 Maybe a blocked fuel filter? Quote Link to comment Share on other sites More sharing options...
Stellaghost Posted January 22, 2021 Share Posted January 22, 2021 (edited) This sounds similar to what I've just had with my 200tdi in my lightweight and that was perished hoses I would check full length of fuel lines to make sure there has been no past additions that could be past there sell by date also the water traps on the fuel lines quite often get removed due to corrosion and replaced with fuel hose to join them up check this area as well regards Stephen Forget the water traps had disco 1 in my head Edited January 22, 2021 by Stellaghost Quote Link to comment Share on other sites More sharing options...
steve b Posted January 22, 2021 Share Posted January 22, 2021 With a constantly low tank any condensation inside the tank will be a higher proportion of fluid content and then get into the fuel filter and in your current climate freeze reducing flow to the point you are at now . If you don't have a new one to hand , drain it off the vehicle and warm the case with warm water to clear any frozen muck. When you refit you can check the lift pump delivery as you bleed the filter head . It should be strong and regular every lever cycle or if cranking a constant strong flow . There may be a sediment/water trap unit under the rear wheel arch too , drain this too if possible . hope this helps Steve Quote Link to comment Share on other sites More sharing options...
pete3000 Posted January 22, 2021 Share Posted January 22, 2021 i was going to say a blocked, waxed up fuel filter. depending on how cold it is with the snow it could be the fuel waxing up and blocking the filter/sedimenter. Pete Quote Link to comment Share on other sites More sharing options...
Troll Hunter Posted January 24, 2021 Share Posted January 24, 2021 Years ago I had something similar with my wife's 300Tdi CSW. Out of gear the engine would rev quite happily, but as soon as I put load on the engine the cycle of high revs, almost stalling and back to high revs would persist. It turned out to be the air line between the air filter and the turbo was delaminating. When the engine ran at normal speed the turbo would cause a low pressure in the inlet line, and the inner lining would delaminate and block the air flow. At the then reduced engine speed, and reduced air flow, the inner lining would return to its correct shape and the engine speed would pick-up again. I was told that this is not an uncommon failure. Mike Quote Link to comment Share on other sites More sharing options...
pgrbff Posted January 24, 2021 Author Share Posted January 24, 2021 On 1/22/2021 at 8:44 PM, pete3000 said: i was going to say a blocked, waxed up fuel filter. depending on how cold it is with the snow it could be the fuel waxing up and blocking the filter/sedimenter. Pete It's was happening at around 0C, even a bit higher so I thought it unlikely. I had added diesel antifreeze as well when the problem started. I changed the diesel filter any way and so far she has done around 5km without problems. It has been an intermittent fault over the last week to 10 days so I'll have to wait and see. I have also managed to get 30l of diesel in the tank. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 24, 2021 Share Posted January 24, 2021 I mentioned fuel filter as I had the exact same symptoms. It was a different era, different vehicle and petrol. I had dragged-up muck from the bottom of the tank. Had a horrible journey down the A1 from Durham in the dark and cold. A surge of power then slow almost to a stop, then repeat for 140 miles. The next day when I cleaned the bowl filter, it was full. Fingers crossed for you. Quote Link to comment Share on other sites More sharing options...
Snagger Posted January 26, 2021 Share Posted January 26, 2021 On 1/22/2021 at 9:10 PM, Ed Poore said: When you say that it judders - do you ease off the accelerator in order for it to recover or does it do so on it's own? With only 10l in the fuel I'd still be cautious of it just picking up carp from the bottom of the tank - any chance of putting more than that in there just to see if it helps improve things? The level of water or sediment in the bottom of the tank won’t change with fuel level, but if agitated by rough conditions, a low level of fuel would suffer a greater percentage of contamination than a high level for the same amount of rubbish in the tank. I think your problems are likely to be the low level of fuel causing the pickup pipe to suck in air periodically and the fuel pumps to cavitate. It could also be condensation in the tank getting into the fuel filter and freezing. Low tank levels allow a lot of air, and in humid conditions, that increases condensation a Dan water contamination of the fuel, with secondary effects of tank and pump rusting and fungal growth. Fuel tanks are best kept either full or completely empty with the cap open (filler protected from rain and FOD entry) for that reason. Quote Link to comment Share on other sites More sharing options...
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