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300Tdi wont rev


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Posted here, as the engine came from a Disco.

We got a replacement 300Tdi engine for a 90 that was previously upgraded to a 300Tdi but threw a bearing. The engine had been sitting for some time and we never saw it running.

Fitted everything, with a new timing belt and the FIP from the old engine, as the replacement had EDC.

We had some problem at first start-up to get all the air out, afterwards it starts fine every time. But, it wont rev up and has no power at all. 25mph was about the best we got out of it. Lots of smoke, white-grey, pointing to unburned diesel. Very rarely a black puff, usually when backing off the throttle. Idle is fine, car moves off without applying power, but once you try and raise the revs, it starts smoking and boggs down. We tried about everything we could think of:

- fuel filter has been replaced and we're now running it from a jar of fresh diesel, with some added cleaner, to rule out dirty diesel and/or blocked pipes.

- lift pump reused from the old engine, as it was replaced recently. We get a good steady flow from the return pipe, no signs of air.

- injectors swapped with those from the old engine, no change. We get fuel at all 4.

- compression checked, above 21 on all 4.

- disconnected the air intake at the manifold, to rule out turbo or intercooler problems. No apparent change in behavior, still smoking and sluggish to rev.

- double checked timing and tried advancing the FIP a bit, to little effect.

- valve clearance seems OK.

I'm sure Elbekko will add anything I might have forgotten. Really at wits end...

Greetz,

Filip

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Might be worth checking the boost fuel pin, it sounds like it might be stuck down so as soon as you  rev it's dumping too much fuel in. 

It's odd as there isn't a lot to TDi's and if they start they usually work OK for everything else.

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- Camtiming was checked by Elbekko and myself when replacing the timing belt, not afterwards.

- Haven't had time to do further checks, but the boost fuel pin sounds plausible as it's definitely dumping too much fuel. Does the FIP need to come apart or can it be checked from outside?

Thanks!

Filip

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When you disconnected the turbo feed from the manifold was there normal flow from the turbo as revs rise as much as it could ?

Is running evenly on all four just with no power/rpm ?

The colour of the smoke does suggest timing issues although it's hard to see how with your checking

cheers

Steve b

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21 hours ago, steve b said:

Is running evenly on all four just with no power/rpm ?

Yes. It revs smoothly but very, very slowly. It shakes heavily on overrun.

I agree on timing, all signs point to that. Guess we'll pop the cover off and verify. The only thing I'm not 100% sure about (only 99%) is the crank timing, it has a 2.5TD bellhousing on, which doesn't have the hole in the bottom, so I set it with the notch in the crank pulley.

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  • 2 weeks later...

Last weekend we finally found the courage to have another look at the engine...

Started by resetting timing, though it appeared to be quite good. We had already tried to advance it a bit with the cover on, so it was not spot on. We advanced it a bit, using an 8.5mm drill bit instead of the usual 9.5mm bit. This stopped the smoke, but still very low on power. We then played around with the boost pin, by increasing the preload (and thus fuelling at low boost). Again some improvement, but not quite there yet. Finally replaced to boost pipe from the turbo to the FIP. It didn't seem blocked, but not much pressure could be felt when revving (under no load) either. And that seemed to be the cure, she now revs as should, power not great but very much acceptable for a 300Tdi that had been stood for some time. We'll do some more finetuning and then we'll be very very glad to see this car go back to its owner. :-) To see it again on the Gentlemen Drivers Rally in May.

Thanks for all the tips!

Filip

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Filip

Have you "played" around with the Android setting or checked the Diaphragm for leaks

Mark the direction how you remove it/ on the deepest it will give you a full movement of the pin..

Put grease/Vaseline on the conical and rev up and after opening again you will see how far it travelled

download.jpg

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Yeah, we tried different setting of the boost pins and different preload.

Good tip to apply grease to see how far it moves, we didn't do that. But as it runs OK now, I think I'll leave it alone.

Filip

  • Thanks 1
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Get a dial gauge and set the timing that way.  Do not trust the pin method at this point.  This needs to be step 1 and then adjust fueling second.  Set TDC by looking at the slot through the drain hole and not with the timing pin.  There is too much play with a flywheel timing pin.

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There is no drain hole to even put a timing pin in, as they've used a 2.5 NAD bellhousing. So it's purely set by the mark on the crank timing pulley.

I've never seen a guide about setting timing with a dial gauge, how would that be done?

Either way, it runs pretty well now, the biggest problem will have been the boost pipe.

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14 hours ago, Red90 said:

 Set TDC by looking at the slot through the drain hole and not with the timing pin.  There is too much play with a flywheel timing pin.

I’m a definite amateur at this stuff but even so, having done the job once, I’m surprised at this advice. Can viewing really be more accurate than using a pin (or reverse gear switch)? Surely the pin locates centrally and holds the flywheel slot in the middle of the hole doesn’t it?

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The pins allow for a fair bit of movement, so are not the best for accuracy.  Normally people rotate it to get in in which puts the crank a bit past TDC and you end up with retarded timing, which gives you the telltale white smoke.  When you look through the hole, you can get it much closer.

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  • 2 months later...

An update, to provide closure to this topic.

Our initial optimism proved unfounded, as the car still didn't pull as it should. 50mph max on a good run, so not usable on motorways or such. After going over everything once more (checking timing, confirming boost, adjusting boost compensator, ...) we decided to take it to a diesel specialist to have the injection pump checked. The verdict was a worn but usable pump, and they could adjust the pressure settings to give reasonably good power with just a wiff of black smoke. When driving it back, I actually had to brake for a speed camera, so everything seems good. 🙂

What's puzzling is that the FIP appeared to do a good job on the old engine. Yet once transferred to the 'new' engine, performance was poor. Totally unexpected, which is why we ignored the pump as long possible, as it was supposedly a known good item.

All's well that ends well, a shame it took so long... The owner did get to borrow my Lotus Excel a couple of times, for a classic car run he intended to do with his Defender.

Filip

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  • 3 years later...

Hi I’m having the same problem with my 300 tdi the minute u start it it goes straight to 2k revs and won’t rev , i bypassed the fuel stop soilnoid by braking the tamper proof cover off and just broaght a live wire to it any ideas on what it might be ?

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