Saltlick

Saltlick

Well-Known Member
Hopefully a really quick question, as I couldn't find anything on the search.

AS the title says - Disco 1, 300tdi, manual, 1996 non EDC: does it have a fuel filter or strainer in the diesel tank?
I've cleared out the sedimenter and replaced the engine bay filter and also replaced the 6 month old leaking lift pump with an electric one. I also replaced the air filter with the fuel ones a week ago.

This is a twin- tank veg oil burning beastie and I've been sorting through a few fuel related issues, but that also make help to eliminate things (hopefully), as it drives well on pump diesel (less poke than it had a year or two ago though) but hits a limit of about 3000 rpm on veg oil at the moment.

This feels a bit like a fuel starvation problem, like a blocked filter, but the tank is the only unknown here.

Just thought, I haven't yet tried reverse flushing the oil heat exchanger to dislodge any possible crud, but I don't think it's that.
Thanks
 
so no strainer even?
Balls :(
I suppose I'll have to see what sort of flow I get through the pipes, heat exchanger and veg oil filter now that I've got the leccy lift pump on, hopefully the problem is somewhere in that little lot, as the next bit in the system in the injection pump!
Maybe it's crud in the pipes?
 
I know you say you have a heater on the veg side ! But it as been a TAD cold !:eek: IF it were mine I would stick a gallon of petrol in the oil to thin it out !!
 
Also, there may be, not sure, a fine gauze filter in the inlet of the FIP?
Some pumps have them some don't, easy to check.
 
Has it only very recently been getting fuel starved, or did it start a while back?

Would check the FIP inlet banjo filter as Flossie suggested first.

There is a strainer in most decent quality plunger style electric pumps (60-120 micron), and many of the solid state pumps have no strainer at all, and will rapidly die on veg new or old. (Might be where the block is, leccy pump strainer or dying solid). Most of the old Bosch VE pumps in consumer format need at least 5ish - psi maintained of fuel supply pressure to not starve, if that helps. (thats at idle and it should stay above 2-3ish at full chat if memory serves)
 
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Thanks for the replies - my veg viscosity is fine, it's already slightly thinned with some misfuel, but is lidquid down to about -6c and it's nowhere near that here in the sw. A few years ago I had some clouding issues, but sorted those with a bit of planning.

My comment about crud in the pipes stems from some intermittent varnish type build up that I found in a few veg components in the systems last year. But the IP Inlet mesh is a good shout - I'll have a look at that.

Goc3k - the leccy pump is brand new and seems to be almost superfluous as the ip seems to cope well without it switched on (wired into an existing switch on the dash temporarily) but the it is a 5-6.5 psi pump. It's been on about 3 days so far and has only slightly improved the fuel starvation feel - presumably because the old knackered lift pump was allowing air to leak into the fuel lines and this one doesn't.
I'll report back later..
 
Ok so at lunch today I took the FIP inlet and outlet banjos off but couldn't see a gauze filter anywhere, though I don't know what they look like - how big, how visible, exact location etc.

I also checked the boost pin - I had to file & polish it the other day as the pin that rides it in the fip was digging in and gouging the ramp badly. The pin that rides on the face of the boost pin seems to not be moving up/down the ramp very much - half or a third maybe? I'll see if I can add a photo.

As above it has an aftermarket boost pin but isn't really acting like it at the moment!

I also reversed the oil flow through the heat exchanger to see if there were any blockages but that made no difference on my way home.

Other stuff done aside from both fuel & air filters and sedimenter and levy lift pump, was to remove all four injectors and clean the nozzles - I stripped them down and decoked then ultrasonic cleaned them, but couldn't get the pins out of them at all. Not really any more power, but a lot less smoke!

I've also been suspicious of a boost leak on the air inlet side, having replaced the exhaust gasket and drilled/tapped the inlet manifold studs to M10 after stripping them out. It just doesn't seem quite right, but I can't tell if that is a real problem as there are others that might be masking.
Could the actuator not be 100% so causing both boost and fuelling issues as it's linked to the FIP?


Any other ideas chaps?

The disco has very dull performance compared to a year or two back and I'm kinda stumped as to what might be causing it.
 
Just to add, switching the leccy lift pump on or off doesn't make a lot of difference at all that I can tell (slightly helps on veg) so could that possibly point to a boost issue, as there may already be enough fuel present, but not enough actuation of the boost pin in the FIP?

Level, straight road performance means revs on veg top out at 3100rpm, diesel about 3600rpm both without any real go - there is a slight "shove" in the back around 2500rpm which has all but gone by 3k rpm. Both of the above are foot floored.

Cheers
 
my brain is out to get me with remembering stuff just after hitting the reply button!
I forgot I also cleaned out the inlet manifold, intercooler and somewhat decoked the inlet ports on the head a couple of weeks ago after sorting the inlet bolts and gasket.
 
Stick a boost gauge on it, should see circa 15psi ?
Compression check 400psi +
I've got the stuff here to check that but you're miles away from me:(
 
Saltlick said:
I also checked the boost pin - I had to file & polish it the other day as the pin that rides it in the fip was digging in and gouging the ramp badly. The pin that rides on the face of the boost pin seems to not be moving up/down the ramp very much - half or a third maybe? I'll see if I can add a photo.

As above it has an aftermarket boost pin but isn't really acting like it at the moment!
Click to expand...

Sounds like the crux of the problem to me, more so if as you suggest she starts up and idles easily / nicely and potters about well under 1500rpm at light throttle.

Cheap carbon steel boost pins never last very well, and if there is little to no boost compensation you'll be getting bugger all fuel in which would explain it, id put the old pin back in if you have it first and foremost and see if the trouble improves. Worth checking the boost line to the pump isn't leaking also, air leaks at the manifold / intercooler / hosework will manifest as black smoke out the back & no guts (as long as the pump is getting the pressure)

Pics of the gouging?
 
Flossie said:
Stick a boost gauge on it, should see circa 15psi ? Compression check 400psi +
Click to expand...

+1 - 'specially as it's so easy to do - there's a tapped hole in the rear of the plenum which isn't used on the manuals - M12 fine thread - same as the larger fuel banjos.... I've got a boost gauge fitted to mine all the time now ( and EGT and trans oil temp )

Goc3k said:
Sounds like the crux of the problem to me, more so if as you suggest she starts up and idles easily / nicely and potters about well under 1500rpm at light throttle.
Click to expand...

+1 - boost pin is meant to be clean and shiny - worth having a nosy down the hole :eek: and seeing how much carp is kicking about :(...

My other thought is:- How many miles have your injectors done? Mine had 175K on them, and were knackered - fitted new ones, and it made a noticeable difference - MUCH quieter, more fuel efficient, and more "urge" !!
 
I'm pretty sure the disco 1 had a strainer in the tank. I had one in Zimbabwe and suddenly started getting fuel starvation symptoms when low on fuel. We were getting fuel out of drums then an turned out the holes at the bottom of the strainer were blocked.

So if the problem is worse with low fuel I would pull out the strainer/fuel gauge sender and check it. If the problem happens with a full tank the other solutions may be more likely.
Cheers
Graham
 
Flossie said:
Stick a boost gauge on it, should see circa 15psi ?
Compression check 400psi +
I've got the stuff here to check that but you're miles away from me:(
Click to expand...
Thanks Flossie, I don't have either of those which is a bummer, er, well I have a gunsons compression tester, but I think it's for petrol engines?

Goc3k said:
Sounds like the crux of the problem to me, more so if as you suggest she starts up and idles easily / nicely and potters about well under 1500rpm at light throttle.

Cheap carbon steel boost pins never last very well, and if there is little to no boost compensation you'll be getting bugger all fuel in which would explain it, id put the old pin back in if you have it first and foremost and see if the trouble improves. Worth checking the boost line to the pump isn't leaking also, air leaks at the manifold / intercooler / hosework will manifest as black smoke out the back & no guts (as long as the pump is getting the pressure)

Pics of the gouging?
Click to expand...
It's stainless boost pin, and it did have some deep ruts in the face, but I've filed them all out and gave it a fine polish with some 1000 grit and buffing gear. There is a little mark back again already and I have a pic on my phone, will see if I can post it.

Disco1BFG said:
+1 - 'specially as it's so easy to do - there's a tapped hole in the rear of the plenum which isn't used on the manuals - M12 fine thread - same as the larger fuel banjos.... I've got a boost gauge fitted to mine all the time now ( and EGT and trans oil temp )


+1 - boost pin is meant to be clean and shiny - worth having a nosy down the hole :eek: and seeing how much carp is kicking about :(...

My other thought is:- How many miles have your injectors done? Mine had 175K on them, and were knackered - fitted new ones, and it made a noticeable difference - MUCH quieter, more fuel efficient, and more "urge" !!
Click to expand...
Yep, I keep meaning to get the boost, egt and oil gauges done, and have all those saved in my eBay watch list, but getting around to it seems to be an issue!!

My injectors are I suspect the originals, and she's getting on for 230k now, so is definitely due some more, but with funds being tight I thought I would see what difference could be made with cleaning the nozzles, as that was a free option!
I've got another set on an engine sat with 140k on it that I could try too..

Graham Carter said:
I'm pretty sure the disco 1 had a strainer in the tank. I had one in Zimbabwe and suddenly started getting fuel starvation symptoms when low on fuel. We were getting fuel out of drums then an turned out the holes at the bottom of the strainer were blocked.

So if the problem is worse with low fuel I would pull out the strainer/fuel gauge sender and check it. If the problem happens with a full tank the other solutions may be more likely.
Cheers
Graham
Click to expand...
Thanks Graham, I know the V8's had them, but thought the diesel models were sans tank filteryness, but wanted to check with the collective on here. Especially as I'm sure that I'll probably need to renew almost everything when I remove the tank inspection cover, as it's probably never been opened.

Ok, so the kids are in bed, and it's cold enough to freeze my tits clean off out there, but I'll venture out and change over the boost pins for an original.

Oh and see about that photo...

Thanks chaps - really appreciate the help for an obscure problem :)
 
Alright, I've got to admit it was late and I was tired when polishing the boost pin, so it's actually a bit rougher around the edges, but was mirror finished in the wear area as far as my memory of the other night went!!

You can make out a new gouge forming less than a week after filing the old marks out of it. You can also see a very light full length witness mark.

For some reason I can't get it right in my minds eye which bit of the ramp is the full boost/full fuel delivery end - is it the thin end of the wedge or the full width end?
 
upload_2018-1-17_21-16-54.png

Thats a picture of what is in the Discovery Tdi tank. I don't think there is a strainer as such. But the car definitely ran into problems when the tank was under 1/4 full. Definitely cused by gunge somewhere in this lot.
Good luck!
Graham
 
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