Flat spot from idle in traffic 98 300tdi auto.

Hi guys

yesterday the missus and i helped one of our daughters move onto her new flat so yesterday morning reversed the disco 98 300tdi auto out of the drive and reversed it into the drive to hook the trailer on then went to her mates to pick up her suite ( storage ) anyway once the disco and trailer was loaded went to set off to her flat but when i selected D ( h/brake off ) the car wouldn't accelorate for a few seconds but all af a suden would and was ok previded you didn't go under 1000 rpm over 1000 rpm the car was fine but if it went under 1000 rpm i seem to have a flat spot ie stopped in traffic then go to set off again, so spent the rest of the day trying to fix it.

this morning i tried to start it and it took a while to get it started kept on cutting out at first then would run rough and chuck out some white smoke that smelt of diesel but went after i could rev it and then let it idle again.

gives the impression its fuel related and yesterday i replaced.

(1) the fuel filter and checked fuel lines where clear in engine bay.

(2) took the lift pump off my mates disco as i had it in my garage and fitted it onto mine just to try.

(3) removed and checked fuel sender was clear.

the car also has E.D.C. so wonder if it could be that any ideas of where to look .

i have had the car for nearly 12 months and is the first time the car has let me down, the car was serviced and new timing belt fitted at same time when we bought it and has only covered about 1.500 miles since then.

the car is used nearly every day but just for short runs and has all together done 106000 miles from new any ideas.

I had lods of things fo wrong with my 300 auto with edc but nearly everything was a std mechanical problem.
Was the fuel filter full to the brim when you removed it ?
Have you checked all the sensor wiring especially around the engine.
I can vaguely remember corroded pins on the edc ecu up above the throttle pedal, due to a leaky windscreen.
Could it just be low gearbox oil?
Are the throttle and kick down cables set correctly.


;Lynall

lynall said:

I had lods of things fo wrong with my 300 auto with edc but nearly everything was a std mechanical problem.
Was the fuel filter full to the brim when you removed it ?
Have you checked all the sensor wiring especially around the engine.
I can vaguely remember corroded pins on the edc ecu up above the throttle pedal, due to a leaky windscreen.
Could it just be low gearbox oil?
Are the throttle and kick down cables set correctly.


;Lynall

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Hi Lynall

(1) the fuel filter was full when removed.

(2) i haven't looked at the sensors yet, want to rule out the fuel system first and move onto the electrical side if it isn't mechanical

(3) checked the trans oil level and is ok and is red in colour.

(4) wouldn't no if the cables are correctly set, but does still do this when the transmission is in park / nuteral ( sorry i forgot to mention that )

Sorry i cant offer much more advice than ive said above.
Have you checked the air flow meter flap opens and shuts smoothly, engine off and just poke it with your fingers.
Its the box bolted to the nearside inner wing between the turbo and the air filter.


Lynall

lynall said:

Sorry i cant offer much more advice than ive said above.
Have you checked the air flow meter flap opens and shuts smoothly, engine off and just poke it with your fingers.
Its the box bolted to the nearside inner wing between the turbo and the air filter.


Lynall

Click to expand...

Hi Lynall

yeah i will have a look tomorrow if i get chance, due to me removing and checking the sender unit the other day i decided to remove the sedimentor as the 12 months i have had the car it has never been looked at and looking at the state of it i don't think it has been off for a few years so for piece of mind i wanted to remove it and ended up removing the fuel pipes completly due to the pipe connections on the sedimentor being siezed

then had to go to work at 2.00 pm - 10.00 pm

think i may have got to the bottom of it, a few days ago when all this started and replaced the fuel filter and lift pump as you would expect all i could smell was diesel then the other day when i was removing the sedimentor there wasn't much of a smell then today i started to split the sedimentor and managed to spill some fuel on the floor and noticed after a few mins it had all dried up and thought that is odd as diesel doesn't soak up as quick as diesel on concrete so smelt the end of one of the piped the fuel had come from and i could smell petroly diesel

apparrently a few days previuse the fuel light came on in the drive as the missus was going to work so went to the petrol station on the way and put a tenner in and she must have put petrol in instead of diesel, so thinking as the tank doesn't have a drain plug i will just have to fill the tank with diesel and hope it sorts its self out once i have re fitted the sedimentor and replaced the fuel filter again and once it running right replace the fuel filter again.

when i split the sedimentor it was full of everything, water as i expected, some greasy black stuff, and mixed with petrol and diesel so once its cleaned out refitted, replace the fuel filter and re filled with diesel and the new fuel has gone through the system it should be ok.

Should be fine once you fill with diesel,I dilute my bio with 10% petrol in middle of winter,any higher though and I can run into vapour lock problems(petrol vapourising inside warm injector pump)-so brim her with derv and drive on bumpy road to mix

just hope it all clears through in time for its m.o.t.

i only managed to refit the sedimentor and the fuel pipe that goes to the lift pump today as the hevens opened and when it stopped was to late to go back out there as i am back in work at 1.00 pm but i am off tomorrow so come rain or shine i want to get it filled up and running.

AS said,10% petrol is used by many in SVO/WVO fuel mixes, so if you can get the percentage down enough that your pump is getting some lubrication....all good. Some of the veg oil forums suggest a small addition of PAS fluid for pump lube but I dont know the rights and wrongs of that one.


re MOT....Wynns do a good pre MOT diesel emissions treatment, Trago got it for under a fiver.Worked on one of mine,going from smoky to fast pass after adding the wynns and belting up and down the A30.

re One of your earlier posts,you said that you wanted to clear up the fueling problems before moving onto electrical......with EDC thats not really possible.You can do the obvious filter-sedimentor-top of fuel tank stuff but the fueling system itself is governed by the sensors that you (so rightly !) wanted to avoid. I wont try to explain further as I will make a mess of it.However,the workshop book and hence Rave download has a good clear diagram of the EDC system that makes it a lot easier to understand.Did for me at least.

Even so, I hope you have got it sorted and am glad its an easy answer.Let us know how you get on. I for one need all the EDC related anecdotal knowledge that is possible to get !

thanks guys for all your help, i managed to get everything done that i couldn't do yesterday as the rain just got worse and worse, anyway i fitted the pipe from the tank to the sedimentor clipped the pipes into the clips on the chassis then walked to the petrol station for a gallon of BP ultimate diesel then rememberd that i had a half gallon can of diesel i use for filling up fuel filters when servicing so that went in and a cup full of clean engine oil to lub the pump then got otgoing and drove to the petrol station and filled it up with BPs finest then once i had run it round the block a couple of times i set off for matlock and back 100 mile round trip with no probs.

just before i got to the buxton bypass the flat spot had vertualy gone and by the time i had reached matlock the flat spot had gone completly so i am well chuffed.