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200tdi will not run propperly


Landowner

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Got a real problem with the Disco engine that I can't solve.

The 200tdi was running fantastic until one day the power began to fall off. Over about five miles of city driving the power slowly dropped away until the engine would only tick over and would not drive at all.

The engine will start instantly but when the throttle is applied it will struggle up to about 1500revs or so and it is lumpy. Release the throttle pedal and she drops back to idle and ticks over normally.

I've checked the pipe from the tank to the lift pump.....OK

New lift pump fitted and working.....OK

Checked filter housing and new filter fitted.....OK

Fitted clear pipe from filter to injector pump and fuel going through.....OK

Replaced injector pump with known good one that has been re - timed / set up.....OK

New timing belt fitted and all timed up.....OK

Injector pipes clear.....OK

Injectors checked today on machine.....OK

Fuel pressure at injectors.....OK

Rocker cover off and rockers working .....OK

Compression seems to be OK but checking properly when gauge arrives.

Diaphram on top of pump working.....OK

Engine still running with the same problem as it was when we started so nothing left to replace or check.

Any ideas please I'm completely stuck. :unsure::unsure::rolleyes:

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I agree with Les, I've seen the same symptoms on a couple of classics, blowing down the pipe is a red herring because it moves the crud away so gives the appearance of a clear pipe.

I have had the engine running with the lift pump sucking from a can of diesel to eliminate the tank, also plenty of diesel pumping to injector pump.

:)

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What colour smoke do you get at the 1500rpm misfire ?

Have you checked the air intake system for blockages/collapsed filter/de-laminated and collapsed pipework?

And similarly is the exhaust free to flow? to check unbolt at downpipe to 1st box joint and run it up

hth

Steveb

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To check fuel delivery: With engine ticking over, briefly Loosen Banjo on both fuel intake and outlet on the Bosch fuel pump (check each banjo separately).

Fuel should squirt out "vigorously" (I watched a mechanic do this on my 300TDi last week - I had similar issues). For me - turned out to be wastegate push-rod had detached from it's ball joint. Clearly, that ain't you issue though.

Also, remove air pipe into Plenum Chamber. Put you hand over pipe - rev engine, there should be a rush of air - you should have to struggle to keep you hand on the pipe.

If you're getting air at the plenum chamber (the point of delivery), and you get a good squirt of fuel from the pump's outlet, then you know it's probably timng, valves, compression, or the exhaust (given that you said you have checked the injectors).

Best of luck!

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Plenty to think about then,

The only things left are exhaust blocked or something to do with turbo on exhaust side (blocked),as it's getting plenty of fuel and air and it's timed up so something stopping it from functioning properly.

The smoke is white by the way so unburned diesel.

Going to have a go at it on Monday, I'll take the exhaust off for starters and see how we go.

Ta for the suggestions :)

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Maybe , the waste gate is basically a butterfly that directs the exhaust gases either thru the turbo impellor on the exh side thus driving the air intake impellor or , when boost pressure is reached the flow is opened to exit direct to downpipe, it should move about a 1/4 of a turn with some grips on the arm.

Is the small boost pressure pipe connected properly to the IP diaphragm ?

Too much diesel/not enough air is usually black smoke

edit to add compression check may be a good idea when you get the tester , or a 'sniff test kit' to check coolant for exhaust gases

cheers

Steveb

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The smoke is white by the way so unburned diesel.

as steve b said. black sooty smoke is unburnt diesel.

blue smoke is oil

and white smoke is either your burning water or a big air lock in the fuel system i believe....

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as steve b said. black sooty smoke is unburnt diesel.

blue smoke is oil

and white smoke is either your burning water or a big air lock in the fuel system i believe....

No water in system for checks between rectification remedies, just run the motor for a few seconds to check if it's repaired.

No air locks as whole fuel system overhauled and bled, new leak off pipes as well.

Sounds like the problem could be on the exhaust side with a restriction of some sort as that would stop the motor picking up and cause the smoke.

Could be wrong though. :)

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hi we had this problem on a bmw turned out the CAT was completly blocked we removed the lambda and it reved up fine, im not sure if a 200tdi has a CAT so i would, unbolt the downpipe and try rev the engine.

if that doesnt work then unbolt the inlet and exhaust manifolds and start the engine and see if it revs up (just dont run for too long without and inlet on) if it still struggles then you have bigger engine problems (possibly headgasket)

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as steve b said. black sooty smoke is unburnt diesel.

blue smoke is oil

and white smoke is either your burning water or a big air lock in the fuel system i believe....

Black smoke is excess (burnt) fuel.

White/grey diesel-smelling smoke is incomplete combustion - I've had this on very cold mornings when glow plugs haven't been working.

White non-diesel-smelling smoke is more likely to be water.

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As you seem to have covered everything else have you considered you may have a dodgy 12V supply to the fuel cut off solenoid?

Could be worth trying a feed direct from battery and see what happens.

Tried it with the plunger taken out of the fuel solenoid and no difference. :)

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Black smoke is excess (burnt) fuel.

White/grey diesel-smelling smoke is incomplete combustion - I've had this on very cold mornings when glow plugs haven't been working.

White non-diesel-smelling smoke is more likely to be water.

No water in system whilst fault finding :)

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Would that block the exhaust ?? :)

No, but it would stop the turbo spooling up and cause lack of power.

However, if the turbo didn't spool up, there would be no excess fuelling provided by the injection pump, so I doubt it would be causing your misfire & smoke. Worth checking all the same though.

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No, but it would stop the turbo spooling up and cause lack of power.

However, if the turbo didn't spool up, there would be no excess fuelling provided by the injection pump, so I doubt it would be causing your misfire & smoke. Worth checking all the same though.

Right.....we can eliminate that one then because the engine is being tested at the moment without the intercooler pipe connected. I'll have a look whilst the exhaust is off on Monday though and make sure the mechanism is free to move.

All that is left now is a collapse in the exhaust system, it has two boxes one of which is new but I will check them both anyway.

I have undone the three nuts at the turbo and loosened the downpipe, it's come away about half an inch so that should be enough to confirm the exhaust blockage when I fire it up after replacing injectors etc.

If that fails then it must be mechanical but I'm thinking that a mechanical fault would have come on suddenly or slowly over a longer period, this problem came about over a fifteen minute or so period and the engine went from perfect to only tickover with no ability to rev without missing and smoke, and that with a struggle.

There are no problems with the fuel system as every thing has been cleaned , cleared , tested or renewed. The cam timing is spot on as is the injector pump timing, the injectors have been tested and are delivering fuel, there is loads of pressure at the injectors.

The engine is breathing straight to atmosphere so turbo and pipes eliminated , there is no water in the engine so not leaking into cylinders, and the engine is not using any oil, the oil is clean from a change

a few weeks ago.

No blockage in fuel tank, stop solenoid tested and plunger removed to check. fuel filter by passed and lift pump / injector pump fed from a can to by pass any filter housing problems. Rockers going up and down and new cam belt fitted and checked, removed and checked and fitted again but still problems.

It will be interesting to see exactly what the problem is if I ever find it, I'm going to put the timing belt cover back on and refit water pump and radiators over the weekend and prepare to start the engine without an exhaust fitted on Monday in hopes that it will have mended itself, otherwise the engine will have to come out and a 300 tdi is going in (if it will fit to the gearbox that is) :blink:

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If that fails then it must be mechanical but I'm thinking that a mechanical fault would have come on suddenly or slowly over a longer period, this problem came about over a fifteen minute or so period and the engine went from perfect to only tickover with no ability to rev without missing and smoke, and that with a struggle.

There are no problems with the fuel system as every thing has been cleaned , cleared , tested or renewed. The cam timing is spot on as is the injector pump timing, the injectors have been tested and are delivering fuel, there is loads of pressure at the injectors.

it sounds just like it's 1/2 a tooth out on the timing i know you've done it but is there any chance it could have slipped

as you seem to be running out of things you can fix, change.

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