DFIS has my pump and injectors now. They come highly recommended but they are local to me so it made for an easy decision.
Builds OL'BETSY ZX: 1991 HZJ77 (1 Viewer)
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JDM Journeys
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- #442
Well, just did a cold compression test. Temp in garage was around 12*C. Engine hasn't been going for 24 hrs and sat afterwards in -3ish till this morning, when I turned on the heat.
Just as background, I'm sitting at 1100m elevation, 1HZ engine has 260k kms on it.
Here are my COLD results in psi:
#1 - 460
#2 - 400 (430 after I added a little oil)
#3 - 420
#4 - 445
#5 - 460
#6 - 450
Manual says to check comp #s at operating temperature, so I can only assume these will go up somewhat? But my issue is excessive white smoke at cold start unless I advance the timing past factory specs, hence my cold comp #s.
Lower than I'd like, but not at the listed minimum of 384psi, even cold. No's 2 and 3 down so much is concerning, compared to the other 4.
Here are my valve clearances from a year and a half ago (maybe 15k kms or so?)
Any insights from the gallery would be appreciated.
Just as background, I'm sitting at 1100m elevation, 1HZ engine has 260k kms on it.
Here are my COLD results in psi:
#1 - 460
#2 - 400 (430 after I added a little oil)
#3 - 420
#4 - 445
#5 - 460
#6 - 450
Manual says to check comp #s at operating temperature, so I can only assume these will go up somewhat? But my issue is excessive white smoke at cold start unless I advance the timing past factory specs, hence my cold comp #s.
Lower than I'd like, but not at the listed minimum of 384psi, even cold. No's 2 and 3 down so much is concerning, compared to the other 4.
Here are my valve clearances from a year and a half ago (maybe 15k kms or so?)
Any insights from the gallery would be appreciated.
Are you sure it’s fuel smoke and not condensation smoke? Or maybe a combination?
JDM Journeys
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- #444
Like head gasket condensation you mean? I mean... its very diesel smelling, not coolant sweet smelling. I'm familiar with HG white smoke, and it doesn't seem like it. But I'm open to all possibilities right now.
I can add that when I advanced the timing (and I mean advanced) the smoke all but went away after the usual puff (it was cold out).
condensation as in a cold engine start in cold climate, like your gasser does when you start it in the cold. you for sure qualify for cold
you are on average been colder than us here all winter.
you are on average been colder than us here all winter.
JDM Journeys
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- #446
Gotcha. For sure there's some of that, but its excessive, compared to other diesels I've had, and even another 1hz that I had recently.condensation as in a cold engine start in cold climate, like your gasser does when you start it in the cold. you for sure qualify for cold
you are on average been colder than us here all winter.
Yeah we are coming off another cold snap. Although it just increased 20*C in about 12 hours...
Hey Phil, glad you had the time to get the compression test done. Those numbers really aren't that bad at all. Granted, it would be nice to have them all nice even 450 across the board, but as you already stated, the lower 2 are still above spec, and the engine was cold.
At this point, I would be checking the pump pressures, and this is why:
With new injectors, they are going to be pretty tight, crisp, and the pump will need to send the fuel at a higher PSI value than the injectors are set at. The new injectors would most likely be slightly delayed in the injection of the fuel over the older more worn ones you replaced. So, to mitigate this, you need to advance the fuel.
Combine those factors with the possibility that your pump could be pumping at suboptimal pressures, and you have the hair-pulling frustrations you are seeing at now, and having to advance the fuel over factory spec to get it to run half decent.
I figure you do not have all the tools for testing and rebuilding diesel fuel pumps, so what I would suggest is pull the pump, get it tested at a shop that you can trust.
My 2 cents... along with my sorrow for your troubles. But once it is fixed up and you are cruising again, this will be a dim memory...
At this point, I would be checking the pump pressures, and this is why:
With new injectors, they are going to be pretty tight, crisp, and the pump will need to send the fuel at a higher PSI value than the injectors are set at. The new injectors would most likely be slightly delayed in the injection of the fuel over the older more worn ones you replaced. So, to mitigate this, you need to advance the fuel.
Combine those factors with the possibility that your pump could be pumping at suboptimal pressures, and you have the hair-pulling frustrations you are seeing at now, and having to advance the fuel over factory spec to get it to run half decent.
I figure you do not have all the tools for testing and rebuilding diesel fuel pumps, so what I would suggest is pull the pump, get it tested at a shop that you can trust.
My 2 cents... along with my sorrow for your troubles. But once it is fixed up and you are cruising again, this will be a dim memory...
JDM Journeys
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- #448
Yep, its confirming what I was thinking all along. I don't like running it this far advanced.
Wonder if it's worth the trouble to do the comp test again, warmed up? I didn't do warm numbers today since the truck was cold and ambient only reached -17c this morning: pretty difficult to get up to op temp. I'm assuming I'd see slightly higher numbers, once warm? Possibly looser valve clearances will also help a bit with bringing those numbers up even more? Almost all the valves were on the lowest side of spec, and that was the summer before last, so another bunch of k's since then prob means they're even tighter now? I'm not seeing any blue smoke, and not seeing any oil losses, so I can't imagine that one cylinder is making a huge difference.
All signs seem to be pointing toward the pump. I figured that was the case, but it's good to have a full picture first. At 260k, it seems par for the course. As you said Darren, lower pump pressures combined with new injectors is likely a perfect storm of white smoke on startup. And at 1.09 I can't get it to run cold without clouds of it, and a pretty good stutter.
Wonder if it's worth the trouble to do the comp test again, warmed up? I didn't do warm numbers today since the truck was cold and ambient only reached -17c this morning: pretty difficult to get up to op temp. I'm assuming I'd see slightly higher numbers, once warm? Possibly looser valve clearances will also help a bit with bringing those numbers up even more? Almost all the valves were on the lowest side of spec, and that was the summer before last, so another bunch of k's since then prob means they're even tighter now? I'm not seeing any blue smoke, and not seeing any oil losses, so I can't imagine that one cylinder is making a huge difference.
All signs seem to be pointing toward the pump. I figured that was the case, but it's good to have a full picture first. At 260k, it seems par for the course. As you said Darren, lower pump pressures combined with new injectors is likely a perfect storm of white smoke on startup. And at 1.09 I can't get it to run cold without clouds of it, and a pretty good stutter.
Do the pump to rule it out. Not to scare you but I was having similar symptoms with my HZ, did everything, nothing made a difference. Pulled the head and found the precups cracked, which was messing up the combustion process and causing smoke.
JDM Journeys
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- #450
Well, that is my other fear. But is there a way to test for pre-combustion cup cracks, short of pulling the head and eye-balling it?
Once you rule out pump and injectors, you'll know its something internal, and be pulling the head to see what it is. It could be anything that is effecting how the air and fuel is mixing, like a valve. But my bet its the precups, that's a common failure point on IDI motors, especially if its been turbo'ed. EGTs get too high, precups don't have a lot of meat on them making them most susceptible to heat.
Hey Loober,
do you happen to have any compression test numbers for when your pre-cups cracked? I would have to think they would be below spec at that point? Maybe not, that is why I figured I would ask.
Also, Phil's been thinking about turboing his 1HZ, but he has not yet. The other thing is, when you put an EGT on a NA 1HZ and pin it going all the way up a mountain pass, the NA 1HZ is usually running 1200F the whole way. Granted, a turbo'd 1hz can go north of 1200 quite easily, but unless someone is not paying attention, it is pretty easy to keep the EGT's down.
Don't get me wrong, I do realize after putting a turbo on a 1HZ you are shortening its life, but I suspect it is a combination of the heat - but also from the extra compression.
I suppose time will tell....
Yes I tested compression when this was happening and it was within spec.
Hopefully that’s not his issue but if it is, he’ll be money ahead swapping it over to a DI engine instead of rebuilding the HZ especially if he is thinking about adding a turbo.
Hopefully that’s not his issue but if it is, he’ll be money ahead swapping it over to a DI engine instead of rebuilding the HZ especially if he is thinking about adding a turbo.
I would have to agree with you about swapping for a DI model engine of some sort rather than rebuilding the 1hz.
That is my plan also. However, I am wondering if there were any other issues. As precups will show up cracked on almost all IDI if you pull the head. Now this CAN become a problem if the cracks go right through, and a piece falls into the combustion chamber on top of the piston... yikes
You are correct, there could have been other issues besides the precups. At that point I made the decision of doing a swap, so I did not spend any more energy on the HZ. I was actually able to part it out for about 1/2 the cost of 1HDFT engine.
JDM Journeys
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- #456
I'm going to reach out to dark fox diesel soon. Gotten quite a few recommendations at this point. Even John at @Radd Cruisers recommends them on his site...
Meanwhile I'll do a hot compression test just because I bought the tester. And manual lists hot numbers. Then it's time to yank the inj pump.
Also, my retro stripes finally arrived today. Took over a month but first impressions are that they were worth the wait.
Meanwhile I'll do a hot compression test just because I bought the tester. And manual lists hot numbers. Then it's time to yank the inj pump.
Also, my retro stripes finally arrived today. Took over a month but first impressions are that they were worth the wait.
Жду новую иллюстрацию на борт
Я хочу украсить свою машину
JDM Journeys
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- #460
Redid my compression test today. Did it after taking a drive. So these are the numbers applicable to factory reference...
1 through 6: 480. 435. 445. 485. 480. 460.
Not bad at all. Definitely not enough to adversely affect cold starting in my humble opinion.
Dark Fox Diesel was quick to reply and will have time to re-co my pump in a few weeks. So that's my path forward.
My buddy came by and gave my little pupper a boost up to look at the goings on while I reinstalled the glow plugs. She didn't seem that interested...
1 through 6: 480. 435. 445. 485. 480. 460.
Not bad at all. Definitely not enough to adversely affect cold starting in my humble opinion.
Dark Fox Diesel was quick to reply and will have time to re-co my pump in a few weeks. So that's my path forward.
My buddy came by and gave my little pupper a boost up to look at the goings on while I reinstalled the glow plugs. She didn't seem that interested...
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