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Oct 13, 2011 18:31:23 GMT
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Hi guys, I think I've got another thread about this, but I'll start a fresh one. A few months ago while collecting a car for my mate, my '88 VW LT40 recovery truck (2.4td 6cyl engine) jolted and wouldn't accelerate while travelling at approx. 60mph. Got it to the services, checked it over, but there was nothing wrong that we could see, so carried on. Speed wouldn't go over 50mph and it was dropping down to 45mph and struggling to go up hills, both loaded and unloaded. If you accelerate up into 5th gear it gets to about 47mph and suddenly jolts and there is no power what to ever. The engine still runs, but the accelerator does nothing. If you let it slow down to 40mph the engine will start to work again until you get to 47mph again. Downhill, you can get to 50mph before it does it and up hill your limited to 40mph. Because I've been a bit busy, I hadn't had the chance to sort it out, so just drove carefully around. The other day though, I got onto the M6 to head down to W-S-M and the top speed on the flat was 35mph. Limped off the motorway and back to my storage unit. The air filter is dead (full of black dirt and oil), so removed it and took it for a spin. Sounded a little better, but still had the problems as above. Looked over the engine and the 3rd injector was leaking. Took it off and found somewhere that could recondition it for me. Refitted it today and the running problem is still there  It has recently had a new fuel filter (one on the engine as the bottom one under the passanger footwell has been bypassed) and I drained a little off today to make sure there was no water there, which there wasn't. I've taken the airpipe to the turbo off and the back of the alternator and surrounding parts have a lot of oil on them, but I can't see any oil leak near it. All the pipes to the turbo look to be OK. I've lost a few jobs due to this and because I'm self employed, I need it running. I was getting so frustrated and disheartend with it all today I was seriourly considering driving it over the weighbridge and walking home. If anybody could shed any light on what it could be or give me an idea what to look for, I'd be ever so greatful  |
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Last Edit: Oct 13, 2011 18:33:31 GMT by MiniDan
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Oct 13, 2011 20:31:56 GMT
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Without knowing anything about it, I'd be guessing pump seals based on the TD vehicles I've had. Ask for more power, insufficient pressure, maybe sucking in air... My Delica was an absolute nightmare when the pump went.
For all I know the LT's engine is totally different. So just a stab in the dark as to where I'd be looking first.
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THE_Liam
Yorkshire and The Humber
If at first you don't succeed... HAMMERS.
Posts: 1,363
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Oct 13, 2011 21:09:17 GMT
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Sounds like pump timing to me, had the same issue with a 306 DT when it slipped a tooth. Get it timed up  |
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Oct 13, 2011 21:17:20 GMT
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Without knowing anything about it, I'd be guessing pump seals based on the TD vehicles I've had. Ask for more power, insufficient pressure, maybe sucking in air... My Delica was an absolute nightmare when the pump went. I've read on another forum that if the pump is knackered, your best off just buying another vehicle for the cost of one. Even getting the original reconditioned is a joke of a price Sounds like pump timing to me, had the same issue with a 306 DT when it slipped a tooth. Get it timed up Could be timing. I did look at the marks on the pump but couldn't remember what was ment to be where. I forgot to say as well, there was a stedy stream of smoke coming from the breather pipe on top of the rocker cover. |
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Last Edit: Oct 13, 2011 21:20:25 GMT by MiniDan
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Oct 13, 2011 22:17:20 GMT
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Could be a dead turdbo (not enough air = not enough power), or perhaps knackered rings/bores (no compression = no power).
Turbo:
Do you have a boost gauge you can whack on to check that the turbo is doing something?
Rings/bores:
How thick was the stream of smoke from the breather? If it is steady at idle but clears up a bit when revved with no load then the rings are probably fine. If the smoke gets thicker when revved with no load they're probably tired/knackered.
Pump:
Can't help with pump symptoms I'm afraid. However, I will say that lack of air tends to result in thick black smoke from the tailpipe due to (effective) over-fuelling. Under fuelling results in no power (like having the accelerator only part way down) but no smoke (due to under-fuelling).
Throttle linkage reaching full power position?
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stealthstylz
Club Retro Rides Member
Posts: 14,960
Club RR Member Number: 174
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Oct 13, 2011 23:31:14 GMT
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It sounds like it's sucking air into the fuel system somewhere due to a leak - KFW truck had the same symtoms with the old engine, hence drenching many service station car parks with diesel as he bled it off by cracking the union on the injector. There was a discernible difference in engine note however.
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To make it easier, I've put my replys in green Could be a dead turdbo (not enough air = not enough power), or perhaps knackered rings/bores (no compression = no power). Turbo: Do you have a boost gauge you can whack on to check that the turbo is doing something? Unfortunatly, no. I was looking at getting one fitted though in the future. I took the pipe going from the air filter box (behind driver seat) down to the side of the turbo off to see if it was spinning. Couldn't see inside it though from where I was standing (had my Jack Russell in the cab and he is stupid enough to stick his head into the timing belt).Rings/bores: How thick was the stream of smoke from the breather? If it is steady at idle but clears up a bit when revved with no load then the rings are probably fine. If the smoke gets thicker when revved with no load they're probably tired/knackered. Wasn't very think. About the cosistancy of steam, but it was definatly white/grey smoke. While revving it, it didn't get thicker, just a little bit more of it.Pump: Can't help with pump symptoms I'm afraid. However, I will say that lack of air tends to result in thick black smoke from the tailpipe due to (effective) over-fuelling. Under fuelling results in no power (like having the accelerator only part way down) but no smoke (due to under-fuelling). Apart from a small blast of black smoke on the very first start-up of the day, there is zero smoke from the exhaust.Throttle linkage reaching full power position? Nope. Did think this when it first did it as the accelerator was a bit loose. Moved it up so it was idling a lot higher. I did move it back down the other day and it made no diferance.It sounds like it's sucking air into the fuel system somewhere due to a leak - KFW truck had the same symtoms with the old engine, hence drenching many service station car parks with diesel as he bled it off by cracking the union on the injector. There was a discernible difference in engine note however. I've traced the fuel pipework from the tank to the pump and to the injectors and from what I can see, there arn't any leaks. Only thing that was leaking was the one injector that I had refurb'd. and thanks for the replys guys |
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with air leaks into the fuel lines, you wont loose any diesel, best way to rule this out is fit some clear fuel pipe to the pump back tot he filter, can see whats happenings then.
how ever if it was leaking air it would normally be a curse word to get started first thing or even after been off for a few mins if really bad.
my td was breating heavy out of the rocker, turned out 2 of the bores where scored, that drove fine speed wise, compression test would be the only way to tell.
defo need to check if that turbo is working
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Oct 14, 2011 18:38:19 GMT
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Me and my mate went and had another nose at this today.
My mate took it out for a run and it was doing as before. It was getting to exactly 50mph and then dropping exactly 5mph to 45mph. But the way it does it is if there is a limiter on there.
I know there is a governor on there, so does anybody know how do you go about raising it a bit?
You can feel the truck wanting to go, definatly has the power there, but it is being held back.
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Brian Damaged
West Midlands
Club Retro Rides Member
Posts: 9,555 
Club RR Member Number: 33
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Oct 14, 2011 18:47:39 GMT
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Check the advance/retard on the diesel pump, on these engines they sometimes stick in the 'advanced' position and if left will FUBAR the engine.
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Oct 14, 2011 19:17:36 GMT
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Cheers Brian. Will have a look at that tomorrow.
Found out what pump is on the truck (Bosch VE) and found a very good website explaining everything.
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Oct 15, 2011 15:54:39 GMT
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If this was a more modern diesel I'd say collapsed catalytic converter. Don't suppose there could be an exhaust system blockage holding it back?
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Oct 15, 2011 16:14:18 GMT
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 Good point about the exhaust - mine seemed to be slow one day, and then suddenly blew the seam apart on the silencer! It had come apart inside and the baffle was closing the exit off. |
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To get a standard A40 this low, you'd have to dig a hole to put it in |
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Oct 15, 2011 18:08:25 GMT
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Exhaust is tip-tip.
Checked out the advance/retard and that's also fine.
I had two mates out with me today. After sticking a broom handle on each of the injectors, there is a really nasty sound coming from one of them (No. 6 behind the pump). Going to whip that off and get it recon'd. Both of them were stumped by the problem though. Both are truck engineers.
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Oct 15, 2011 19:35:39 GMT
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Air filter inlet pipe collapsing under vacuum?
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Oct 15, 2011 19:48:07 GMT
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Air filter inlet pipe collapsing under vacuum? Nope. It's ridgid plastic. |
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rodney
Posted a lot
https://www.facebook.com/RD-vehicle-transport-and-recovery-services-525622614268010/
Posts: 1,677
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Oct 15, 2011 20:31:57 GMT
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this old truck still going?? i was on a job in a one night when it lost power and lost speed , the vacum pipe for the fueling on the pump came off, it goes from pump to the rear of the inlet if this is of any help?,.
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facebook: rodney dean / rd transport  |
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Oct 15, 2011 21:02:09 GMT
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this old truck still going?? I was on a job in a one night when it lost power and lost speed , the vacum pipe for the fueling on the pump came off, it goes from pump to the rear of the inlet if this is of any help?,. It is indeed ;D Slowly at the minute though  Hmm... Interesting. Will investigate this pipe tomorrow. Cheers matey. |
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Oct 15, 2011 22:30:01 GMT
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Have you done a compression test yet?
Also like others have said, check for air in the fuel and make sure the turbo is spooling up and the wastegate isnt siezed.
I'm guessing this would be too old to have an EGR valve right?
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R.S. Autotech. Servicing/Repairs/Diagnostics.
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Oct 16, 2011 10:12:40 GMT
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Without knowing the intricacies of the type fitted to your engine, I'd say it could be one of two things:
1: advance piston sticking, if the revs wont advance past a certain point with any real power, it's usually because the fuelling isn't being advanced properly
2: internal pump pressure. If this isn't getting high enough, either through a broken vane pump (bloody rare!) or the pressure regulator on the fuel return fitting is letting too much fuel back. No internal pressure = no timing advance
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You're like a crazy backyard genius! |
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It has recently had a new fuel filter (one on the engine as the bottom one under the passanger footwell has been bypassed) and I drained a little off today to make sure there was no water there, which there wasn't.
