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About to play with quantity adjuster... any advice?

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11 hours ago, Sausage said:

Missed this bit, ticking noise when hot = hydraulic lifters as prime suspect.

This sounds like fuel starvation, blocked fuel filter, blocked tank strainer, excess air in the fuel. Try clear pipes between filter and pump.

More of a pinking sound (detonation or early injection). Not 'ticking' really... yeah fuel supply is good. See previous posts.

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Ok pinking isnt ticking LOL, 

Injection timing is too early so engine is fighting itself hence less power would be my guess.

If your cam and pump timing are correct then the pumps internal timing must be out.  There's a solenoid valve on the bottom of the pump that controls SOI isnt there? There will be some volts or ohms within spec etc to test it most likely.

You got any smoke when it is gutless?

Edited by Sausage

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Nah, no smoke ever. Nice clean exhaust. Actually smells ok when hot too. I guess the oxidising cat is doing its job. I did try pulling off the needle lift sensor plug, at which time it belched out smoke like in a turkish nightclub... not doing that again.

My guess is that the timing mech in the pump works... why, well i think injector no. 3 is showing a true reading when the injector needle lifts relative to crank timing. The ecu 'appears' to be adjusting the advance solenoid, becuase you can see the pwm drive varying the timing correctly. On the screen shot above, you can see the expected and measured advance timing matching, with the advance valve being well controlled.

The reason this all started a few weeks back was because of the pinking noise. On older diesel injector engines, you can have leaky injectors, that 'drip'. Before main injection starts, when the piston goes up to compress the air, the tiny amount of diesel that leaked out during the exhaust and induction stroke ignites creating a tiny 'kick' or pinking detonation just before TDC. Usual cure is to swap or service the injectors, which is what i did. It obviously didn't make any difference... then straight after I'd put the new injectors in there was a complete loss of power (and still is). My initial thought was air in the system, so i methodically went through everything. My conclusion now is that the sudden rush of diesel swishing around inside the emptied pump dislodged some particles that got sucked into the plunger assembly and ruined it permanently. I think i've exhausted just about every other option.

I haven't checked the cam timing. Hmmm. If the cam jumped a tooth, surely the valves would be hitting the pistons and game over? I don't think the SDI has a cam sensor does it? That cam cover is coming off first thing!

Edited by mk2
Idea...

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One tooth out it would run I would think, depends on the engine for valve / piston safety but unlikely to be a problem if a tooth out. You'd get some chuffing noises to clue you in that something wasnt right with cam timing though.

You need to check the timing though just to eliminate obvious stuff as maybe just the pump is a tooth out and cam / crank is fine. Doubtful though as your engine seems to run fine up to low revs you say.

But from what you have just said now it seems to be to do with your injector change though (sudden loss of power after injector change).

Have you done compression test?

Try and separate what the ecu is telling you from the maps and what it actually is measuring and knows. I think everything in your chart matches the maps so far, but probably not the real world.

Edited by Sausage

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Cam is spot on. Tensioner spot on. Hot engine compression with glow plugs out is identical in all 4 (pain to check though- what a lot of faff).

Time to swap pump. It arrived today :)

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Got to be the pump tbh, you said early on it had loads of power with the hammer mod and i kind of ignored that thinking it might be placebo down to changed pedal response (doh!).

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I can't wait to pull that old pump out and strip it! I really hope i find scoring on the plunger. I suspect that there's a scratch near slot 1 or gallery 1 (that feeds injector pipe 1), only because of the injector imbalance. The injectors are all good. 

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A few days later...

Ok, so I've swapped out the injection pump for a known good one. Actually, i bought a complete engine with all the bits, as it works out cheaper. And I get lots of spares. Time to find a car for my spare engine... I was taking pictures as I went for another how-to thing, but I've come to the conclusion that this really is too fiddly. There are many many ways a small thing could cause a major disaster. So no how-to. It's not really a DIY job.... Swapping an engine out is easier.

Woah hey, new pump in, everything adjusted to specifications. Quantity adjuster tweaked to get me exactly 2.8mg per stroke at hot engine idle. switch off and then adjust pump position a little, as it was slightly too retarded for my liking. I logged the PWM effort the ecu was using to drive the advance piston, and it got to 95% at high revs, so definitely slightly out (retarded). Now tweaked just right so I get 60% PWM.

Starts and fires up in under 1 rev. Excellent! Problem sorted.

Quick run around the block to check everything. 

Absolutely gutless. Problem sorted?! I don't think so..... No change. Sigh. That was a mountain of effort for nought.

So now what? Summary:

Entire fuel supply system has been thoroughly checked, dismantled and reassembled with new seals, filters, hoses, clamps etc...

ECU wiring thoroughly checked and all connectors examined and relubed with silicone grease. ECU behaving as it's meant to.

All engine sensors checked and swapped to eliminate problems. No change.

Both sets of known to be good, professionally cleaned, pop and leak tested injectors tried, with no discernible difference in output, with new copper washers each time.

Cam and injection pump physical and electronic timing checked. All perfect.

Cylinder pressures, compression tested, all found to be fine. Engine is in pretty good nick from my tests.

Injection pump swapped over, adjusted and correctly set.

No change from before, almost as if there has never been a problem... At least it tells me that I have a good spare pump now- or two dodgy pumps. All injector quantity readings just like before with the same imbalance at idle. Very very odd. I have never ever been defeated by a car. Not yet anyway, but it's looking like this one may have me beat!

 

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I'm going to try the injectors from the spare engine. I cannot believe both pumps are toast. Quick and easy job.

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fuel filter?

does the tdi still have the petrol one floating about at the back?

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Whoops, searched for sdi map sensor and got a hit for Lupo hence me asking above, turned out to be mis labelled air temp sensor. :lol:

Is your egr blanked off, cant remember what's been said now?

Can we have some videos of what it is / isnt doing? Might help.

Edited by Sausage

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Unplug your SOI solenoid under the pump and see what it does. Check the wiring to it.

Your glow plug light works? (will flash for CEL i think) and you have no error codes?

 

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take both on the rolling road.

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33 minutes ago, Rich said:

take both on the rolling road.

very tempting if i can find some free road time. That thing earns its keep....

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Fixed. Full power restored.

it was the injectors.

ok, so all i did is swap the injectors from the used spare engine to the one with the gutless symptoms. New washers again. I bet the threads on the pipe nuts are wearing out the number of times i've done this now... so much for two sets of known to be good injectors. Hmm. 

Ok, I'm going to go back to the guy who cleaned and tested my original set (and the spare set i bought) to find out what is going on. I saw the spray pattern myself, so i know it can't be blocked nozzles. I also read the gauges as they 'popped' and they were all almost identical. This is all most peculiar. 

I'll run with the 'new' injectors for a few days to let everything settle in, maybe chuck a can of purge through the system too, as the nozzles that came out of the old engine were a bit gunged. But i thought, no cleaning; I'm just going to bung them in my engine without doing anything at all to them and see what happens. All good!

then i'll see what the injector balance is like and post my results here.

 

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pinking/ticking sound getting quite loud now and only when on power, silent on overrun. just rebuilt the head with all new hydraulic tappets. still making that tappet sound. So only thing left is to pull the engine out. It has to be a broken ring. but compression is still good in all cyls. slightly down on no4. suspect no4 is gauging away at the liner/bore. breather or blowby still very low. i shall bung the spare engine in.

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