Anderzander Posted January 22, 2022 Share Posted January 22, 2022 Could it be the vanes sticking in the turbo and then suddenly releasing? Would it be like this: Its the vanes that control the pressure isn’t it? So if they weren’t opening / sticking you’d have low power and back pressure into the fuel system - which might then suddenly release and spike ? Then once released and free moving you’d be back to normal ? Quote Link to comment Share on other sites More sharing options...
cackshifter Posted January 22, 2022 Share Posted January 22, 2022 Or could the vanes be free but the turbo shaft itself be sticking? Not many moving parts. Quote Link to comment Share on other sites More sharing options...
Maverik Posted January 22, 2022 Author Share Posted January 22, 2022 7 hours ago, Anderzander said: Could it be the vanes sticking in the turbo and then suddenly releasing? Would it be like this: Its the vanes that control the pressure isn’t it? So if they weren’t opening / sticking you’d have low power and back pressure into the fuel system - which might then suddenly release and spike ? Then once released and free moving you’d be back to normal ? It makes sense something in the mechanism is sticking, but I've cleaned the turbo, installed a new actuator and tested all individually and I can't see any issues... Quote Link to comment Share on other sites More sharing options...
Maverik Posted January 22, 2022 Author Share Posted January 22, 2022 6 hours ago, cackshifter said: Or could the vanes be free but the turbo shaft itself be sticking? Not many moving parts. Sticky turbo shaft wouldn't allow boost which is kinda of opposite to what I'm getting, oil pressure is pretty solid throughout the process. Quote Link to comment Share on other sites More sharing options...
Maverik Posted January 22, 2022 Author Share Posted January 22, 2022 Been thinking about this a little more, I think I've got 2 issues, one is the smoke all the time the other is the "sticky" behaviour. Thinking back, the bad smoking started after I rebuilt the head after the timing belt incident - I installed new injector nozzles... these along with the turbo are the only major components taken from the old engine... as the injectors had been rebuilt and tested I'd kinda ruled those out... now I'm not so sure. So before I whip the turbo off I'm going to install some alternative injectors... Quote Link to comment Share on other sites More sharing options...
cackshifter Posted January 22, 2022 Share Posted January 22, 2022 1 hour ago, Maverik said: Sticky turbo shaft wouldn't allow boost which is kinda of opposite to what I'm getting, oil pressure is pretty solid throughout the process. I meant, sticking initially, then frees off as the engine gets going. There isn't much affecting boost other than the turbo, esp making it higher than normal. But, if it was easy you'd have found it long ago Quote Link to comment Share on other sites More sharing options...
Anderzander Posted January 22, 2022 Share Posted January 22, 2022 Is the turbo oil fees all good ? Quote Link to comment Share on other sites More sharing options...
landroversforever Posted January 22, 2022 Share Posted January 22, 2022 1 hour ago, Maverik said: Been thinking about this a little more, I think I've got 2 issues, one is the smoke all the time the other is the "sticky" behaviour. Thinking back, the bad smoking started after I rebuilt the head after the timing belt incident - I installed new injector nozzles... these along with the turbo are the only major components taken from the old engine... as the injectors had been rebuilt and tested I'd kinda ruled those out... now I'm not so sure. So before I whip the turbo off I'm going to install some alternative injectors... Decent injector nozzles? Presumably they were rebuilt and tested at that same time? Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 23, 2022 Share Posted January 23, 2022 You could nip back down to Sheaf Diesel. They will pop test them while you wait. If you book in advance I’m sure they would also clean and work on any that need it, while you walk the Five Wiers or visit the site of the Full Monty canal scene 😄 Quote Link to comment Share on other sites More sharing options...
Maverik Posted February 7, 2022 Author Share Posted February 7, 2022 So here's a wee update. Slightly embarrassing but I might have overreacted in my last post. Now I've had some time to drive the truck I've got a few more reflections. The "general" smokyness has actually improved quite a lot, the smoke cloud is much less with general acceleration, now I only get slight grey smoke when pushing her. Something I didn’t initial post was that the timing was a good bit out when I went to remove the old injector pump, I had to go a good bit past TDC to find the Fuel pump pulley locking hole - which indicates retarded, this probably wasn't helping the situation - she was running really rough at higher revs. So with the new pump in, timed up spot on. - I ran with the factory set boost pin settings and it was pretty gutless and still pretty rough approaching 3000rpm, so I re set the boost pin and off boost setting to match what I had before - this improved the 0-50 type performance, but was still rough on the motorway at 60mph. I then re-installed the boost ring really interesting to see the change in "performance" - really surprised and impressed with how its made the thing run much smother and a fair but more power in 5th and much smoother in the higher rev range (which is what the thing promises ironically). As for the odd booth behaviour this is still here, and is still baffling me. I can drive off in 1st and the engine note is slightly different, I'll move to 2nd hold the boost at 1 bar then after say a 20 seconds the engine notes changes (maybe sounds slightly smoother) and the vehicle starts to accelerate a little and steady's off. After this has happened its got really good accelerator response. So the search continues. The only items out with lumps of passive metal components that are still the same as when the problem first started are as follows. Cylinder head (which has had new valves and stem seals) - can't think of anything here that would cause this type of problem. Turbocharger (which has been cleaned and new actuator installed) - I want to rule the turbo and actuator out as I've tested this using a pump and there is no sticking effect on the actuator or mechanism. Injectors Intercooler - I had a good look in the end tanks and didn’t see any blockages. Exhaust. Boost pin - (I ran the overhauled injector pump with its new boost pin and this behavior was not changed) So a few questions I've been thinking about. Injectors - can a "stuck"/faulty injector cause this odd temporary running behavior? - something I think I've seen is when accelerating hard you don’t get a solid stream of smoke, it looks like its more "puffing" or pulsing all be it very fast. Although the problem started before I had the nozzles changed and got them serviced. Exhaust - would a strange blockage in the exhaust cause a pressure spike like I'm seeing? - should be able to test this by disconnecting the box sections from the exhaust and going for a noisy drive. Quote Link to comment Share on other sites More sharing options...
cackshifter Posted February 7, 2022 Share Posted February 7, 2022 I have experienced an exhaust blockage on a Cavalier gsi, many years ago. Eventually all it would do was tickover on the hard shoulder sounding like an angry snake.So it does sometimes happen. But I was wondering, could it be a leak in a fuel pipe, allowing it drain back when stopped? Then when it does come through, maybe the turbo takes a moment to react hence boost spike, IE it's a symptom, not the cause Quote Link to comment Share on other sites More sharing options...
Maverik Posted February 10, 2022 Author Share Posted February 10, 2022 A bit of progress of sorts. After much deliberation I decided to swap the injectors out for a spare set I had, they looked remarkably good so I don't know why they weren't in an engine but hey ho. Injectors replaced as well as the spill rail as I snapped one of those stupid barb off. And quite surprisingly she runs like a wee rocket once again! after a drive about I didnt see much smoke but its difficult to tell as its pretty windy just now, but first impressions are she pulls much better and idles seemingly smoother. I've never been convinced those injectors where right, and after I replaced the nozzles with some of ebay I'm pretty convinced they're not correct - even though they went to a Bosch specialist too. So I'm smiling again as at least I'm getting some of the performance I expect from the thing after all this rebuild work. Something else new is that she idles about 100rpm higher than she did with the previous injectors, was going to ring the diesel job up whom I got the injection pump from to see if they could shed any light on it. Still doing the boost thing on start-up. - next I'll be disconnecting the exhaust boxes. I'm taking this as a win. 2 Quote Link to comment Share on other sites More sharing options...
Peaklander Posted February 10, 2022 Share Posted February 10, 2022 36 minutes ago, Maverik said: I'm pretty convinced they're not correct - even though they went to a Bosch specialist too. This is all interesting for me as a TDi owner, however I'm a bit puzzled by that comment. When did they go to the Bosch specialist? You replaced the nozzles, then Bosch and then into service? Quote Link to comment Share on other sites More sharing options...
Maverik Posted February 10, 2022 Author Share Posted February 10, 2022 1 hour ago, Peaklander said: This is all interesting for me as a TDi owner, however I'm a bit puzzled by that comment. When did they go to the Bosch specialist? You replaced the nozzles, then Bosch and then into service? So last year prior to the paper towel incident I noticed the engine was really starting to smoke, after I rebuilt the head and as I had the injectors out I bought some new bosch nozzles from ebay and rebuilt the injectors myself with the new nozzles. On putting the head back on and sorting out the damage from the paper towel I put the rebuilt injectors in, it ran rough and really smokey, so I re-pulled the injectors and took them to a Bosch specialist who "set" them and painted them black. I Put them back in and the smoke was less but still bad. As it was still smoking and breathing pretty badly I assumed I'd damaged some piston rings with the paper towel incident. Sooo I rebuilt the engine... same head and injectors... Quote Link to comment Share on other sites More sharing options...
Peaklander Posted February 10, 2022 Share Posted February 10, 2022 Oh, so a Bosch injector specialist who didn't do the job in a specialist kind of way. At least that's what the evidence suggests. Was it where you got the pump overhauled? Quote Link to comment Share on other sites More sharing options...
Maverik Posted February 10, 2022 Author Share Posted February 10, 2022 5 minutes ago, Peaklander said: Oh, so a Bosch injector specialist who didn't do the job in a specialist kind of way. At least that's what the evidence suggests. Was it where you got the pump overhauled? No, injectors where done in a place near Southampton, pump was from South Yorkshire. I'll drop the apparently dodgy injectors to them too see if they can find anything wrong with them. The nozzles: Quote Link to comment Share on other sites More sharing options...
Peaklander Posted February 10, 2022 Share Posted February 10, 2022 9 minutes ago, Maverik said: pump was from South Yorkshire Yes I know where you got the pump done - that's why I was wondering. It's where mine were overhauled during the work to replace a piston, caused by the injector spray going wrong I think. They have been OK since. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted February 10, 2022 Share Posted February 10, 2022 I had a set of injectors done by diesel bob in the summer, Mav, the tick over speed on mine increased on fitting and I just adjusted it back to where it should have been. It runs much better at lower revs such as on laning. Mo Quote Link to comment Share on other sites More sharing options...
Nonimouse Posted February 11, 2022 Share Posted February 11, 2022 11 hours ago, Maverik said: No, injectors where done in a place near Southampton, pump was from South Yorkshire. I'll drop the apparently dodgy injectors to them too see if they can find anything wrong with them. The nozzles: That's very cheap 1 Quote Link to comment Share on other sites More sharing options...
Popular Post Maverik Posted February 11, 2022 Author Popular Post Share Posted February 11, 2022 Well after a good long run including some motorway work and I can confirm all smoke has gone, pretty chuffed I've solved that issue as it was bothering me quite a bit. Pretty miffed it's taken me so long to figure it out and a seemingly rebuilt set of injectors are duff. Hey ho put that down to a learning experience. Bloomin expensive one mind... 5 Quote Link to comment Share on other sites More sharing options...
Maverik Posted March 30, 2022 Author Share Posted March 30, 2022 Just to close the boost spike initial problem. I never quite got to the bottom of the issue, in way that I decided to remove the VNT and put back to standard in which I now have and she runs as she should. I suspect the problem is with the angle the boost actuator rod works on the vane actuator on the turbo, that it was not a smooth action, I plan to do some bench tests when I've got nothing better to do to hopefully confirm this, suffice to say she drives perfectly well with the standard turbo all be it with the fueling tweaked up a bit and a boost ring installed. I'm also planning on increase the boost pressure by shortening the rod a turn or two to take it up to 0.8-0.9bar. Should improve hill climbing and EGT top temp. Quote Link to comment Share on other sites More sharing options...
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