Auto Knackered?

I did a bunch of work to see if I could solve this, along with a failure to start one morning.
So a few weeks ago I:
- replaced air bleed and non-return on filter head. no change
- changed MAF for new one. Didn't solve the lag on take off
- checked and lubed wastegate arm. no change
- new fuel pump (VDO). no change.
- loom (there was some oil seepage recently), o rings and sealing washers. no change

Nanocom still gives me no hints. Throttle position voltages appear correct, unless there is a 'lag' or they are noisy, but can't tell that from nanocom update rate.

This leaves:
- intercooler pipes, I've looked at all of them and they all seem fine.
- blocked exhaust - going to drop all the exhaust off today and see how it feels. I know the TDi wasn't especially noisy with zero exhaust
- turbo issue?
- injector issue?

I hedging towards exhaust and turbo at the moment, it seems fine above 2000, and the injector balance values appear OK, so I'm thinking it's not injectors or pipes.

A blocked exhaust might really hamper spool up and if the turbo has some issue this might cause slow spool up.

Since I get about 1.18 bar (about 17psi) at full boost I'm hoping exhaust.

Update
I ran without an exhaust at all for a day or so, ever so slight improvement, though nothing I'd say fixed it.
Also, if you're doing this test, it does pump out a LOT of heat into the engine bay, a few of my wiring protection covers were looking second hand after the test. It did clean the oil off a treat though.

Exhaust back on it doesn't feel a lot different, it feels a bit better, not much than before. I did check for play on the turbo, but I couldn't say it felt good or bad. No end float, but definitely some movement.

I also noticed that the exhaust was chuffing a bit of blue smoke at about 1300 in the garage. I hadn't noticed this before at all and it looks like it clears up once warm.

So... I bought a AC/DC Clamp probe ($100) to connect to my fancy oscilloscope and did a relative compression test. I've never heard of this before seeing a nugget over on LR4x4 that mentioned it in passing. It's pretty simple, you put the clamp on the starter motor main +ve, you set the scope for it and record the engine turning over. The scope shows current draw following a sawtooth to triangular waveform, the peak being the max compression on each cylinder (the starter motor draws more as it hits compression and then relaxes on the downward stroke).

If you are going to do this test:
o Disconnect fuel pump relay
o Disconnect the ECU relay

Then turn over the engine, I used a variety of time bases and amp ranges to look at 4 or 5 complete cycles and just 2 really closely.
On mine, this drew about 300Amps peak and varied by about 20amps across all cylinders. The key point about this is it's a *relative* compression test not absolute.
I'm taking from this though that the chance of having all 5 cylinders with low compression, yet start easy, pull higher revs and speed easy is low to none.

I could now do a compression test on 1-4 and be pretty confident about how far No.5 is out, but I'm think it's not the issue.

So... is the blue smoke from 5 before glow plugs get going? Is it perhaps the turbo? There is oil in the inlet, it's not excessive, or wasn't when I last did it.

I have another check I need to get around to, when shifting back to park I notice that the engine revs go up to 1000 for a moment and then drop back to idle, though sometimes they stick.
I'm wondering if there is a particular issue with the pedal sensor, the numbers look OK in Nanocom, but that is at 1 second sample rate. I'm wondering if the tracks are getting tired and the signal is noisy to the ECU (like an old volume knob with all the crackling and stuff when you turn it).
I've tried feeding the throttle in (rather than just going to 100% from standing) and I've convinced myself that it's seems a bit more progressive on the power.
I might probe it up on the scope and do a few test presses and see if maybe it is noisy. It's another 10 year old part and may just be getting old and/or have had a bit of water on it through the years.

If that doesn't suggest anything I'm starting to home in on turbo and that the spool up is slow. But that's an expensive repair by replacement to confirm or deny. On top of that, if I was going to do that I'd probably buy a VNT and a map... which might mask the issue anyway.

Attachment 108387

Did you really run around with your exhaust removed:wacko::wacko:
Ac/DC clamp probe would be good if you didn't have a nanocom ( cyl balance test) . if the head has been refitted at some point the cam timing could be out , but by fitting a low stall torque converter without a remap there will be a much bigger lag in your case because the engine is under load before the turbo can spool up effectively, get td5 inside to do you a map to suit , but check cam timing anyway, you can also shorten the wastegate rod a couple of turns to help things along , try for around 1.3 bar and see how you go.

The thing you have to bear in mind with nanocom is sample rate. It's all at 1 second intervals....
I've looked at cylinder balances and they seem good, but I also heard tell that looking at cylinder balance at anything of idle is a bit suspect.

Exhaust wasn't too bad, bit throaty, but I think I've heard worse from the subaru across the road ;)

It's not like when the D2 V8 sheared it's extractor and I took it for a quick spin with no exhausts on either side. *That* was loud, when it started the kids at the bottom of the street ran to the end of the driveway and looked our way, only 100m away....

Been a while for any updates, anyway, I loaded a remap and then went back to the UK and while I was there picked up a few more bits.
* TD5 Inside map. This had an effect, though lag definitely still there. Stall test now showed a rise to 1500, stop/slow, then a big surge after about 1800, topping out at 2300 (so at or above the number expected for HD torque converter).
Just having the extra power made it drive better, but lag was still noticeable.

* I changed the MAP sensor and this didn't appear to make any difference.

* I changed the intercooler hoses, no effect.

* Replace downpipe to decat and removed mid box. This didn't make much, if any, difference to the off the line lag. I have noticed though that at speed (say going 80kph ish up the local steep hill) it breathes a lot easier. It's easy with the map and straight through to cruise up in 4th locked at 80 and a bit. So a bit of a win.

I did a stall test again at the end and, again, not much, if any, difference 1500-1800-2300 combo.

So, my list of things is now down at:
* Pedal sensor (still need to probe and check)
* Turbo

I've priced TD5Inside VNT (which targets the low end spool) and it's tempting, however I should do the free pedal sensor check first.

BTW, as others have stated, the decat and no mid box is just on the verge of too loud. The novelty is still strong, but I've not done any long trips yet, it might be that the novelty wears right off.

mine use to be very laggy from take off .I just thought this is how the car drives .eventually my lag got worse and worse .so I replaced elentronic boost sensor and cleaned down all other sensors

no difference I did a hard reset made some difference but then fell back into lag mode again .I then purchased a new genuine MAF sensor made no difference

I then deleted my EGR with a blanking plate and removed all the actuators that sit onto the intake manifold now I just have a straight through pipe leading to manifold .I suspected one of the butterfly's flaps was sticking

while I was there I also removed all electronic vacuum actuators that controlled the EGR

since I removed all of this my engine feels more responsive and I now can actually pull away with out waiting for the big gap in traffic

also when cleaning my MAP sensor the probe on the map sensor measures temps while the small pin hole measures boost I also cleaned with brake cleaner and sprayed into the hole there was allot of dirt come out

So, an update.
We went to the Eyre Peninsula at xmas and did a decent size trip and it looked like, certainly on the way back we were getting around 16L/100, which was high even for towing a trailer.

I had a working theory that around town I'd seen economy about what I'd expect, certainly nothing I'd freak out about, but the long journey seemed worse or the same. This got me thinking that for urban driving the turbo efficiency isn't in play as much as a long continuous trip and that perhaps the turbo was the cause of the pause, with low spool up and lower efficiency. Maybe the ecu throwing more fuel in to get pressure.

I'd noted the turbo had play on the shaft before, however I didn't know how much is too much, especially with a fluid bearing, while not under pressure it can be expected to perhaps be a bit sloppy.

I ummed and ahhed about what to do, options being replacement turbo, VNT from TD5 inside or a turbo cartridge. I didn't like wasting money and I wanted to try and do a back to back compare so I ended up going with the cartridge, $170 on ebay from China, the company would appear to send the same units to Powertec in Northampton, UK. Arrived in 4 days as well.

I stripped the exhaust side down (note, if you do this remove air con compressor, then turbo, then go at the manifold, it will save loads of time) to do a few extra jobs. I dewebbed and slotted the holes on 1 and 5, as well as finally tapping for the EGT probe before the turbo.
The turbo strip down was easy, the only thing you will want to do is mark alignments on the old item as LR didn't do any alignment dimples or anything. The exhaust side will generally align due to the actuator, but the inlet side needs to be about the right spot.
Put it all back together (which took a lot less time since I'd read the *second* procedure for manifold removal in Rave) and started up with no issues.

I took for a drive and there wasn't a night and day difference to me, but it did seem better. The old turbo did have wear, so not too surprising. I did a stall test and this was marginally better, a bit easier to 1500 and a bit less time before tearing away above 1800. Top out was a bit higher, 2300.
I'll admit I was disappointed, I was hoping to have a fairly smooth increase through the range, not the same two stage test.

I logged the car on the way back to the house and gave it a bit of a chance to push the turbo. On reflection it appears that the car does pull away a bit easier now, it's more laggy and less pausey is how I'd describe it. The power kick in seems a bit more progressive now, before it was almost like a switch thrown in at 1800. The final thing of note is that previously after a drive, if I dropped into park the revs would on a fair few times dip then raise to 1000ish and stay there until I blipped the throttle. This has disappeared so far.

I am unaware of any adaptive strategy in the ecu, but this makes me think that it was compensating for poor turbo with more fuel, the offset staying in after moving to park until triggered to reset. I think petrol ecus have this, long term fuel trim and short term fuel trim IIRC.

So, my jury is still out on whether it's fixed or whether there is still a problem, this could now be down to the HD torque converter.
Turbo pressures, from ones I quickly looked at showed a stall test with 16psi max before and a drive after with 19psi, I don't recall seeing above 17psi on any other captures, so peak boost looks correct with new turbo.

There isn't much left to investigate:
* throttle pedal - not holding out much hope, checks out in nanocom, so looking for short transient issues only
* intercooler - maybe blocked? leaking?
* injectors - not high on my list, all 5 would need a similar fault since it runs smoothly.
* compression

I did a relative compression and all showed about the same values, so again not sure I'd expect all 5 to save the same loss. I did find a good idea for doing a compression test on TD5, do the relative compression test with the current clamp, but measure the actual pressure on one of the glow plug fitted cylinders and record a sync pulse (injector pulse would be good). You can then work out that xxxA on cylinder 1 was 400psi and then use the current readings on the others to determine their actual psi, even 5. Saw a video and he got pretty good accuracy down in the 180psi region.

Also I saw some interesting checks for the alternator, looking at AC ripple which can cause ecu issues for sensors with AC signals (e.g. the CPS). I'll check those over the next few days and make sure the alternator doesn't have an issue, I'm also going to check hot as I swear the car can drive 100% when cold at times and I noticed we had quite a drop off in the heat over xmas, sometimes as low as 13.7V.

If you have play in your turbo then I'd recommend the cartridge option, $170 is not far from what I paid for the MAP sensor and you can keep the old one.
I did dismantle mine as I considered it scrap and found witness marks on the bearing faces and some abrasion to the compressor side. My new desk paperweight after I clean it all up I reckon, can go alongside the destroyed S3 Diesel piston :)

Quote:

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Originally Posted by Roverlord off road spares

Have you tried a simple adaptive reset on the Trans with Nano or a Hawekeye.
It restores it to factory default. Then the trans ECU will learn again as you driver.
Usually a good idea to do one after fiddling and replacing parts.
Cheers, Mario

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Mario... is an adaptive reset available on nano 1 or only on the later unit with colour screen?

Well, I was around a mates helping with an injector seal replacement and we came to the adjuster setting. Thus ensued a bit of back and forth with him about the method. He was about to fully depress the injector, screw in the adjuster all the way and then back off. I told him he was barking and that wasn't how you did it, instead explaining standard tappet adjustment method (which I don't think he's ever done). I even explained I was confused by the fact that Rave didn't provide a clearance like 5 thou or something - but instead the one turn back statement (see I had read it!).

Short version is that he was exactly right, the adjusters are done with the cam at full lift.

Now, I had done my injector seals about 12 months ago I reckon and had adjusted as tappets (i.e. wrong). I even have this old school tool where you don't actually feeler gauge the clearance, it clicks as you back off and this tells you how many thou you just cleared, I remember noting that the 1 turn was exactly standard LR tappet clearance as well.

I took the rocker cover off yesterday and, as I remembered, I had adjusted the free play. In fact, even worse, some had way more clearance than I would have left (I can only assume that it might depend on how much fuel pressure is there if you screw up like this). So, adjusted away and took for a run.

I think this is the fault, the pause appears to be gone from stationary, it still laggy but nothing beyond what I would expect. A stall test showed no pause at 1500, it span up to it 1300 quickly, slowed but steadily climbed with a bit of extra speed at 1800 as boost kicked in. Much more believable.

Changing from drive to park saw the revs remain rock solid, no few seconds increase or even rising to 1000 and sitting there.

Cylinder balance was now all +/-1 (previously might be +/-4).

It's too early to tell if low down power has improved (or even now evident) or if fuel economy has been improved. I might also be fooling myself, though I had the other half do a blind test and she thinks that it drives like a normal car now.

The D2 has had this pause since the very first test drive (I just thought maybe they were all like that) and, dredging my memory I swear that when I did the seals the injectors were maybe of the same adjustment. I'm working on the story that some work was done in the past and the mechanic did the same as me, read the procedure to get the numbers he was interested in but didn't read the procedure without preconceptions, after all it looks like a duck, sounds like a duck but it actually isn't a duck.

So, if you have this pause or excessive lag in that idle to 2000 range, it would be well worth the time to do an injector bump adjustment and see how you go.


A side note, we had a yarn about how much difference adjusting at the top vs the bottom would make and it is way more than you think:
* Correct adjustment appears to have only around 4 or so threads left. Tappet method had most threads exposed, that's probably 10mm difference
* Correct adjustment keeps the injectors depressed even off cam. Tappet method obviously doesn't
* Correct adjustment stroke length will almost certainly be longer, maybe 5 thou maybe more. However, the injector inlet/outlet ports might not be closed as quickly, reducing the effective length and almost certainly injector pressure.
* Correct adjustment keeps the oil gallery bango like area in the rocker arm. Tappet method will most likely not.

The methods are definitely NOT interchangeable and it's a great surprise to me that with so much difference we still had a pretty good running car.