Exhaust 'puff' occurring, any ideas of cause?

[Jocklandjohn]

8 hours ago, stevebus said:

I don't know if this might be an issue, and I'm asking the question here, if you had to much air after the turbo/FIP has done its thing, would you get smoke, excessive smoke? The reason I ask, I'm in the throws of rebuilding a 12L and on having some parts vapour blasted the other week including the intake manifold the core plug at the back of it, part number 524765 core plug had rusted through, not massively but there was indeed an hole, I hadn't run it obviously cos the engine is still in pieces, so dont know if that would create excessive smoke, the guy who did the work spotted it, and I've now replaced it, could that be a problem, its not something you'd think of and with your efforts now John this is now in my mind getting to be something silly that you've missed, not that you've missed a lot here, if that's an idiot conclusion tell me to shut up and I'll butt out

Well I'm at the point where any suggestions are welcome however left-field!  Mind you I suspect that a hole in the manifold would result in bad running all the time which I'm not getting. I'll see if I can spot anything with the mirror as I suspect thats an awkward corner to look into. 

8 hours ago, landroversforever said:

A diesel is controlled by its fuel, so can’t really have too much air.

Another reason why I really can’t see this being fuel related. Pile of smoke shouts unburned fuel to me = not enough air. But what I can’t understand is why there’s no smoking gun of something on the intake side blocking up. 

Have you run with a totally different pipe turbo to inlet manifold - bypassing the intercooler and all old intake pipework? What’s the air filter like? I still think there’s something collapsing or some kind of delaminating going on. Are you running a snorkel? 

Removed & replaced ALL the pipes from air intake to inlet. All of it is new. Runs are straighter too as I relocated the filter canister. Canister was the old 19J one, new one is Donaldson, now running the second Donaldson filter element (not knock-off copies) to check its not a filter issue. Also have the small Donaldson filter-meter thing attached which will (crudely but visually) display whether there's excessive 'suck' required thus indicating a blocked filter (or any other intake restriction), and its not showing an issue.

 

I was doing some work for a lad last week and mentioned the POOF issue and he said he'd an engine years ago (he has worked on helicopters/planes/also cars) that had similar symptoms, tried loads of the obvious remedies without success. Eventually discovered a worn woodruff key. Timing was set all bang on, start the engine and torque on start up shifted timing slightly and overfuel was result, when engine settled into 'correct' running excess fuel fired out and steady 'normal' running continued. So ANY stop of the vehicle that involved an ignition start up would repeat this, but any stop where the engine remained idling would not. Which is what I'm experiencing.

Is this likely cause? Would a worn keyway do this? Thinking it over my (non-expert) assumption would be that the timing would be out all the time it was running rather than shifting from correct-off-correct again. But I have no idea!

 

 

[Jocklandjohn]

PS 

One thing I have noticed is that the POOF is occurring lower down the rev/gear/performance range with the new kit than with all the old turbo/pipework/fuel lines. Previously it occurred under considerable load in 4th or 5th gear but getting to that point was sluggish and 'choked' with loads of black smoke. Now with new gubbins throughout its happening earlier, in mid-second gear, at take off speeds. For example - going downhill from house it won't happen through 1st to 3rd gears but will on flat at bottom at top of 2nd or into 3rd gears as load increases, however if I go UP the hill from house it happens in mid-second under the earlier hill-induced load. So its load dependent too. 

(Bearing in mind old pipes had an alloy intake pipe that had a small weld-crack that was losing turbo pressure so once I remedied that things improved dramatically in terms of overall performance - but the POOF issue was still there and things were sluggish until I reached POOF point.)

[Bowie69]

To clarify, and apologies if missed, have you experienced this with a standard turbo?

[Jocklandjohn]

 

 

1 hour ago, Bowie69 said:

To clarify, and apologies if missed, have you experienced this with a standard turbo?

Yes it was occurring with the previous turbo, just not 'clearing' as easily. Poof happens quicker now!

 

[Bowie69]

18 minutes ago, Jocklandjohn said:

 

 

Yes it was occurring with the previous turbo, just not 'clearing' as easily. Poof happens quicker now!

 

To clarify again, by standard turbo I meant not a VGT, I can't see where you have said standard vs 'previous' turbo.

 

[Jocklandjohn]

8 minutes ago, Bowie69 said:

To clarify again, by standard turbo I meant not a VGT, I can't see where you have said standard vs 'previous' turbo.

 

 

Ah ok I understand you point. Previous turbo was the original Garrett that came with the engine when fitted in place of the 19J around 28 years ago but has had a hybrid conversion 15 years ago, new one is the VGT. Both did the poof thing. 

[Peaklander]

I’ve nearly run out of popcorn 🍿 

Please try eliminate the solenoid feed as a cause!

[Jocklandjohn]

4 minutes ago, Peaklander said:

I’ve nearly run out of popcorn 🍿 

Please try eliminate the solenoid feed as a cause!

Yes sir!

[landroversforever]

33 minutes ago, Jocklandjohn said:

 

Ah ok I understand you point. Previous turbo was the original Garrett that came with the engine when fitted in place of the 19J around 28 years ago but has had a hybrid conversion 15 years ago, new one is the VGT. Both did the poof thing. 

So just to confirm.... original Garret fitted with engine conversion - then that same turbo was tweaked with a hybrid unit (assuming different wheels/cartridge unit) - then swapped out for a VGT. 

When it was in hybrid form, has it always done the poof? 

[Jocklandjohn]

2 hours ago, landroversforever said:

So just to confirm.... original Garret fitted with engine conversion - then that same turbo was tweaked with a hybrid unit (assuming different wheels/cartridge unit) - then swapped out for a VGT. 

When it was in hybrid form, has it always done the poof? 

Yes correct.

As far as I can recall, but it was harder to get it to do it, occurring at higher speed and in higher gears, but to be honest I wasn't looking for it, just had an engine that seemed to not perform as well as I'd have expected* and on occasions chucked out a giant poof of black smoke. Now that same poof is occurring earlier with lower speeds (I presume related to the better spread of boost with the VGT?) and as I'm now aware of it and actually looking for it/replicating it I can see its abnormal. 

*I had comparisons - one company I guided for had a couple of 110 CSW with 300tdi's and I'd lug a load of people around in it and it was very quick, unlike mine. So whatever ailment I've got its been there for a long time. 

[landroversforever]

Have you tried a totally standard turbo back on there? I'm feeling like its actually some kind of turbo lag here, or something behaving like lag.

[92a]

Has anyone suggested rather than setting the timing with pins try a dial guage in the back of the pump see exactly what lift you’re getting ( has the flange on the pump been put back on in the correct place there is no key way so it’s possible for it to be out ) 

[Jocklandjohn]

15 minutes ago, landroversforever said:

Have you tried a totally standard turbo back on there? I'm feeling like its actually some kind of turbo lag here, or something behaving like lag.

No not tried that. Doubt its lag though - I can sit at idle and blip throttle and see the boost gauge needle flicker, watch it rise when accelerating etc. And was same issue with both turbos. Crucial thing is if I drive and pass the poof point then slow down and come back to an idle and go off again there is no poof, but if I switch ignition off so engine actually stops and then immediately restart it poofs all over again. So it ONLY poofs AFTER ignition has been switched off and engine actually stops. As peaklander has noted the solenoid could be involved.....    (...but two FIP's and two separate solenoids, and voltage to solenoid *seems* ok, see previous post)

8 minutes ago, 92a said:

Has anyone suggested rather than setting the timing with pins try a dial guage in the back of the pump see exactly what lift you’re getting ( has the flange on the pump been put back on in the correct place there is no key way so it’s possible for it to be out ) 

Timing belt was replaced three weeks ago, all checked and was bang on according to independent LR garage I use. Once past the poof point it runs like clockwork, smooth and clean, but if timing was out I assume it would be pants all the time?

Edited September 9 by Jocklandjohn

[Hawklord]

Just another but maybe silly suggestion.

Could it be a baffle or something else in the exhaust silencer has come loose so that when switching off the engine it "falls" effectively blocking  the exhaust but after starting and revving the engine the exhaust gas pressure moves it to where it should be and restoring power. This could explain why the new turbo clears the problem quicker than the old one as it is producing a higher output. Maybe you could take the silencer off and do a test run.

[Jocklandjohn]

6 hours ago, Hawklord said:

Just another but maybe silly suggestion.

Could it be a baffle or something else in the exhaust silencer has come loose so that when switching off the engine it "falls" effectively blocking  the exhaust but after starting and revving the engine the exhaust gas pressure moves it to where it should be and restoring power. This could explain why the new turbo clears the problem quicker than the old one as it is producing a higher output. Maybe you could take the silencer off and do a test run.

Thanks for the suggestion, it's not silly at all. In fact the exhaust was mentioned as a possible cause earlier in the thread and if the current 'fixes' (solenoids, injectors) don't remedy it then the exhaust is next. I have another exhaust in the shed I need to weld new clamps onto, so I have an alternative. It certainly is a possibility and is 'out of sight' sufficiently to be overlooked. 

Edited September 9 by Jocklandjohn

[vulcan bomber]

14 hours ago, Jocklandjohn said:

Thanks for the suggestion, it's not silly at all. In fact the exhaust was mentioned as a possible cause earlier in the thread and if the current 'fixes' (solenoids, injectors) don't remedy it then the exhaust is next. I have another exhaust in the shed I need to weld new clamps onto, so I have an alternative. It certainly is a possibility and is 'out of sight' sufficiently to be overlooked. 

Just pull the down pipe off and do a couple of miles with it like that. It won't harm anything.

[Jocklandjohn]

2 hours ago, vulcan bomber said:

Just pull the down pipe off and do a couple of miles with it like that. It won't harm anything.

I didn't think that was a useful strategy! Know it's not going to do any real harm, but I assumed it would simply not replicate the running performance of a vehicle with an exhaust, and then any odd air/fuel related behaviour would be masked by the absence?

[Bowie69]

No harm in trying it.... 

[steve b]

When will Electro-Diesel be one with the FIP?

Steve

[Jocklandjohn]

36 minutes ago, steve b said:

When will Electro-Diesel be one with the FIP?

Steve

Boss John said they've got a line of various Emergency Services vehicles and RNLI and a few marine customers to get through so current turnaround is about 3 weeks. That was end of August and pump got there on the 4th Sept so it'll be a couple of weeks.

[steve b]

...that should have been "done" but maybe that is more in keeping with the general theme 

Dodgy D key ...

I still feel this is the key element to all this.

Steve

[Jocklandjohn]

On 9/2/2024 at 10:46 PM, Peaklander said:

This gets more and more bizarre.

It’s no good, then clears with a little bit of power and is ok forever.

You stop, switch off and then in only one second, with, I suggest, no time for anything physical to happen, it reverts to ‘strangled’.

What happens if you leave the ignition on and stop the engine by unplugging the fuel pump solenoid feed? Then restart without loosing ignition feeds.

Ok - I put a wire in the line to the FIP solenoid and out of the engine bay to the dash so I could easily disconnect it.

Ran van up the hill slightly 'strangled', got a poof in 2nd gear and it immediately ran better, came to a halt leaving everything running, set off, no poof and still running well. 

Stopped again. Switched engine off. Switched on and ran, slightly strangled then poof in 2nd and then ran better.

Stopped again, disconnected solenoid leaving ignition on, restarted, strangled again then poof in 2nd and ran better.

Repeated several times and each time the same poof issue.

So it *seems* that disconnecting solenoid and leaving ignition on has no effect.

 

On 9/3/2024 at 8:55 AM, Bowie69 said:

Not really, a low voltage to the stop solenoid is quite plausible, especially if the vehicle was originally petrol with a ballast resistor. 

Then checked voltage to solenoid, using the same wires. Getting the full 12+V and once started 13+V. Then put meter on glowplugs, all four one after the other. 0V before ignition and bangs up to 12+V when the engine turns over, then goes back to 0V almost immediately. And 0V when running. So that *seems* like normal behaviour, no relay issue with glow plugs, as previously suggested. 

On 9/3/2024 at 8:47 AM, Peaklander said:

Whilst it sounds mechanical, whether fuel or air supply, in or out, the mention of just one second to cause a reset almost makes it electrical.

I know that’s highly improbable on a 300tdi but I suppose it’s an easy check. I do realise that two solenoids are involved so makes that implausible but it’s almost like your voltage starts low and then surges to normal.

I’m rambling.

See above. Voltage is all in the normative range as far as I can establish everywhere I've metered.

 

So....now it gets 'interesting'. I got a set of injectors from Mo Murphy, took them to a different diesel shop and had them tested and all 4 nozzles replaced. Put them in the van a few days ago and I have a different vehicle! 

Virtually no smoke on start up and overrun, (unlike before) incredibly clean when running and I can actually pull away *almost* properly (I still have the stuck FIP fuel pin). EGT's are unbelievably low too. Its very smooth and has that solid diesel 'clatter'.

So, the previous set of injectors were obviously goosed.

But...they were serviced and had new nozzles fitted relatively recently by the same place that did the problematic FIP - the folks who sent the pump out twice with the stuck fuel pin (I checked it again today, and its still stuck - I thought it might free itself with use but no luck).

I do recall after installing that last set of injectors that the van was less brisk but with so many other issues I was trying to resolve it was hard to tell for sure. However this confirms that whatever they did to the injectors they were performing nowhere near as well as they should. So much for using a proper Bosch dealership.

Now, did the good injectors make a difference to the poof?

No. The poof still occurs and pretty much same as before. I repeated the solenoid test and ignition off/on etc with new injectors and it's just the same.

With the new injectors though I can pull away far more briskly and the poof point gets reached more easily. After it poofs the running is lovely - even considering that I'm not really getting proper fuel delivery because of the stuck fuel governor pin in the FIP, which means it runs out of oomph if you really push it, but, poof issue aside, when the FIP is sorted it looks like it will be running infinitely better than its done in a long time. If I could only track down the poof cause...sigh. 

I

 

[Peaklander]

Interesting as you say. I like the improvement using different injectors. I don’t like the huge smoke I have at startup. I’m sure it was much less than this 55k miles ago when I bought the vehicle. Mine have been overhauled too. Maybe I should splash out.

@vulcan bomber suggested pulling the plunger in the solenoid to totally take that out of the running.

It doesn’t seem to be that you have a lower voltage at the solenoid but you could stick a meter on the cable now it’s easy in the cab, just to see. Or are those readings taken during the poof transition?

Also there’s the quick eliminate exhaust test that was also mentioned, by removing the downpipe. Can you do that without annoying the locals?

[Jocklandjohn]

1 hour ago, Peaklander said:

Interesting as you say. I like the improvement using different injectors. I don’t like the huge smoke I have at startup. I’m sure it was much less than this 55k miles ago when I bought the vehicle. Mine have been overhauled too. Maybe I should splash out.

@vulcan bomber suggested pulling the plunger in the solenoid to totally take that out of the running.

It doesn’t seem to be that you have a lower voltage at the solenoid but you could stick a meter on the cable now it’s easy in the cab, just to see. Or are those readings taken during the poof transition?

Also there’s the quick eliminate exhaust test that was also mentioned, by removing the downpipe. Can you do that without annoying the locals?

Injectors got a clean up by the errant Bosch shop and the van seemed less sprightly. If you recall a few years back there was an ad for injectors tips several folks got - well I did too and got them fitted and performance was even worse afterwards! This current set have literally transformed the vehicle (poof aside.)

Access to the solenoid is a pita! But....

My *other* pump at the shop in Exeter - boss John emailed an hour ago to say its all been inspected and was absolutely fine apart from the alteration to the boost pin - which is what I did to reduce the smoke I was getting (thanks to carp injectors!) but I have asked him to check solenoid operation before it comes back.

I'll need to do the metering during poof as so far I've only done it at a standstill. 

Removing exhaust will make me very unpopular! Small quiet village and a well-known vehicle with a high probability I'll get finger-wagged! I have a solution though - I've a stainless exhaust in the garage that needs new clamps fitted so I thought I'd get stainless ones and do that, and that'll save a load of faff in another few salty winters time. The exhaust thats on is fine but the clamps are about to give up so it makes some sense. 

[landroversforever]

14 hours ago, Jocklandjohn said:

If you recall a few years back there was an ad for injectors tips several folks got - well I did too and got them fitted and performance was even worse afterwards!

If its the ones I'm thinking of, sold by folk who haven't a clue and just sell them as bigger holes = better when the pump they're designed for is set up differently.