Smoking issue - need advice (1 Viewer)

[Cothran]

I just recently bought a 91 HZJ77 in LA and drive it 2200 miles back to Minnesota. We had pretty much no issues except for some black smoke at altitude, which cleared up as we descended through South Dakota. I've been daily driving it, and it runs smooth and strong, but recently it has started smoking a lot on warm restarts.

I'm just going to list out the symptoms, fearing the worst, and look for advice/suggestions on how to diagnose the source and how expensive the solution will be.

So I'll start it up in the morning, drive to get coffee and shut it down. When I come back out and restart it, there's a lot of white smoke with a little bit of a stutter, until I've gone about 1/2 mile. Once I'm on the highway, it's fine - no more smoke even under heavy acceleration.

If I leave it running while I'm waiting, I'll turn up the throttle a bit to say, 1100, and at first it didn't smoke but in the last few days it starts smoking within a couple minutes of putting it in park.

Interestingly, if I'm at a drive through, as long as it's in Drive, no matter how long I'm stopped there's no smoke. But put it in park and the smoke show begins.

I just removed the oil cap while running and there are no exhaust gases escaping through the crankcase. I also just checked the radiator and it was down about a liter on coolant. I don't know how full it was when I bought it though, so I'll have to keep an eye on it. It does appear that there is some oil in the coolant. This worries me the most. Dipstick still reads full though, so not burning too much oil.

What are my next steps? Right now I plan on driving my other vehicle until I get this figured out. What's the best place to get 1HZ parts in the US? From all my searches, it sounds like it's either the head gasket, bad injectors, bad valve guides, and so on. It's just perplexing to me because it drives so nicely all the way to work (30 miles) and the only evidence of something wrong is this idling smoke problem.

 

[roscoFJ73]

We’ve been cruising at 125-130 every day. I just looked over and my wife is doing 145 through South Dakota.

This could be why.
Although it is perplexing why its only doing it in neutral. It wont be bad injectors, they smoke furiously at hwy speeds. Valve guide seals are an uncommon problem on 1HZ engines.
I know that 1HZ fuel pumps slip into a different mode below 1300rpm where they only load enough fuel for the charge needed. At higher rpm they load a full shot of diesel and release some to give the correct charge. But that's a bit beyond me and I haven't heard of that being a problem.
I think its most likely a damaged head gasket and possibly warped head, that's not such a dire position to be in, but finding someone to fix it properly could be.

Does your injection pump have an ACSD? From what I've seen Japanese 1HZ automatics do have them. I'm wondering if its affecting the low rpm timing. Long shot.

 

[Cothran]

After I posted that I discovered that the speedo was off by about 10kph. Since I put 33s on it’s only off by about 1-2 mph using a gps app, which leads me to believe the speedo may have been regeared. So at the fastest we were probably only doing 135. Consistently getting about 16.5mpg at each fill up, btw.

I will have to check on the ACSD.

 

[Loober]

Not to scare you but excessive smoke on these engines could mean about 1000 different things. You need to start at square one and check compression, blockages in the intake and fuel lines, etc. You will quickly realize that finding an "expert" in your everyday repair shop is not going to happen. Unless you live near one of the shops that are on this forum you are on your own and will have to become the expert by reading countless threads here and elsewhere as well as studying the FSM.

I was in your boat 1.5 years ago with the same exact problem and vehicle. After a year of frustration, I not only became very knowledgeable in the truck but also what it means to own one of these in the US. At the top of the list is not driving it at 135kph, these are not your honda accords. My problem ended up being a cracked head, don;t get discouraged, it is a labor of love, you will spend countless of hours in the garage scratching your head and even more online trying to figure stuff out. These trucks are simple and the issues most always can be narrowed down to isolated areas, you just have to be systematic, and don't just throw parts at it.

In your case, the coolant level is an obvious sign pointing to a head gasket. Which is not a huge deal, the parts can be sourced easily and with the help of an FSM can be done by yourself.

Cheers

 

[roscoFJ73]

I would be leaning more towards a head gasket. If you can smell the acrid smell of coolant in the exhaust when its blowing white smoke, that would pretty much confirm it. You also noticed the coolant is down and the smoke is getting worse.
You also say it is smoking on warm starts, this sounds like pressure that is either escaping from the combustion chamber into the coolant system, or more likely pressure escaping from the coolant system into the combustion chamber. Probably the latter.
Are your radiator hoses unnormally hard after its fully warmed up? This would indicate pressure is entering the coolant system. I had a car once that had a head problem and the hoses would be rock hard even when the engine was cold.

 

[MauricioR]

If I were you, I just go ahead and give the engine a seal/gasket refresh.
I bought 04111-17021 which also works for the 1HZ.

Water and oil mixed can kill an engine.

 

[mudgudgeon]

You should be able to drive a healthy 1HZ at 135km/hr all day long (assuming you miraculously avoid hills all day!)

I had a cracked head on my HZ (cracked between valves) pushing it at 120km/hr on a summers day cooked it after a few months of random overheating issues

How long are you leaving it at idle?

Start with basics.
Check air filter is clean and clear
Check oil filter is clean and properly sealed (If it sucks in air, it can cause white smoke and a stumble, but usually when under acceleration)
Check radiator cap is good (it's common for a bad cap to allow loss of coolant)
Top up coolant and keep an eye on it.
If it looks like there's oil in the coolant, either get a test kit to test for combustion gas in the coolant, or get an oil analysis done.

 

[augirthedude]

You should be able to drive a healthy 1HZ at 135km/hr all day long (assuming you miraculously avoid hills all day!)

I had a cracked head on my HZ (cracked between valves) pushing it at 120km/hr on a summers day cooked it after a few months of random overheating issues

How long are you leaving it at idle?

Start with basics.
Check air filter is clean and clear
Check oil filter is clean and properly sealed (If it sucks in air, it can cause white smoke and a stumble, but usually when under acceleration)
Check radiator cap is good (it's common for a bad cap to allow loss of coolant)
Top up coolant and keep an eye on it.
If it looks like there's oil in the coolant, either get a test kit to test for combustion gas in the coolant, or get an oil analysis done.

Do you mean fuel filter instead of oil filter? I’ve used clear fuel line temporarily between the filter and fuel pump to detect air in the fuel supply.

 

[mudgudgeon]

Do you mean fuel filter instead of oil filter? I’ve used clear fuel line temporarily between the filter and fuel pump to detect air in the fuel supply.

Yep, fuel filter.

 

[roscoFJ73]

You should be able to drive a healthy 1HZ at 135km/hr all day long

They usually start sucking up oil into the air intake, never a good sign. And the engine in question is 27 years old and he was going through hills.

 

[IanB]

How about a video showing the smoke issue. It could be nothing to be concerned with at all, or it could be something worth digging into. There are zero emissions devices on these old diesels, fingers crossed you just need to calibrate yourself with what "normal" is.

If it's "normal", there's things you can do to help the situation. Whenever I change the fuel filter, I fill the new filter with seafoam and that seems to help the smoke at idle on mine. Different brands of fuel can have an effect as well.

 

[mudgudgeon]

They usually start sucking up oil into the air intake, never a good sign. And the engine in question is 27 years old and he was going through hills.

So let's all assume 135km/hr was on the downhill runs then

 

[mudgudgeon]

They usually start sucking up oil into the air intake, never a good sign. And the engine in question is 27 years old and he was going through hills.

So let's all assume 135km/hr was on the downhill runs then

 

[mudgudgeon]

They usually start sucking up oil into the air intake, never a good sign. And the engine in question is 27 years old and he was going through hills.

So let's all assume 135km/hr was on the downhill runs then

 

[Cothran]

I do have some video I’ll try to get up later today. I’ll be taking it in Thursday or Friday to have the oil and coolant analyzed for exhaust gasses, check compression, etc.

 

[roscoFJ73]

So let's all assume 135km/hr was on the downhill runs then

Ive always maintained the stock cooling systems fastidiously on the 3 1HZs Ive owned, but once you go over 120 the temp starts rising, even on the flat WA roads. You can get away with a quick dash to 130 overtaking road trains.
The engine rebuilder I used told me the biggest killer of 1HZ is overheating at high speed for extended periods. Eventually they blow a radiator hose and at high speed you don't notice it until its too late.
I have one of those ENGINE WATCHDOGS on the coolant outlet with the alarm set to 110c, it can go from 95 to 110 in less than a minute going up a hill.
They have top speed of a 135-140, driving any engine at top speed is being cruel. They are not fitted to a sleek aerodynamic body, so they are pushing 2 tons in 5th gear with a big air dam in front of them.
We pulled an old truck that weighed 12 tons with a HZJ75 for 40klms after it lost engine power. The 1HZ could do that all day in 3rd and 4th gear with the rpms under 3000.

 

[Cothran]

Sorry - that took a long time. Finally got a video though. Fyi, since I last posted, I took it into the shop and had them test the coolant. It tested positive for exhaust gases. For better or worse, I decided to try a bottle of Bar's Leaks Blown Head Gasket Repair since it seemed to be running fine with zero overheating issues. I drained the coolant, added the Bar's, added new coolant and let it idle until it reached operating temp. Stopped it, topped off coolant and then followed the instructions to let it idle at 1200rpm for 15 minutes.

No smoke this entire time, btw, and no increase in temp. After that, I let it cool, topped off radiator (which didn't need any), and continued to drive it to work for the next week.

This morning, I drove it in and as I put it in park and got out to get my ticket, it started smoking and wouldn't stop. Ran slightly rough, too.

After work I started her up - no smoke - drove home 30 miles and took this video as I was almost home. So I'm open to interpretations of how serious this is and what exactly the problem might be. For now I assume I'm going to pull the head and have it checked. I just don't understand why - if it's a head gasket - it doesn't smoke while driving or stopped, but only once it's put in park. Wouldn't a bad head gasket produce smoke constantly?

 

[Mighty690]

When it comes to questioning a HG integrity, I can't think of a cheaper or simpler thing than getting an oil sample analyzed. You might have to wait a week or so to get the results. You'll also get lots of other information.

 

[roscoFJ73]

I just don't understand why - if it's a head gasket - it doesn't smoke while driving or stopped, but only once it's put in park. Wouldn't a bad head gasket produce smoke constantly?

It might have something to do with exhaust gas temperature and/or compression. At idle the temps are cool and the vapour is visible, at higher rpm the vapour may still be present but not visible or because the increased compression is not allowing so much coolant to enter the combustion chamber.
Either way it needs the head to be pulled and checked. I wouldn't be driving it. I would be worried that as it gets worse you may get a pool of water accumulate on top of a piston overnight and really do some damage when you start the engine. Although I cant recall that happening to a 1HZ.
You must be able to smell burnt coolant by now?