Real world advice - tuning a smoky 1hdt

[finderscuba]

I have a 1990 HDJ81 with 168,000 km on it. I've had it now for 8 months. My objectives are to lower smoke output, raise power and smooth out operation.

The truck is pretty smokey on gear changes on even low acceleration. It's more of a grey smoke, but black if I really punch the throttle. The smoke is almost non-existent until the engine warms up. It also seems to be lacking some power especially evident when towing a 2000lb trailer. I'm not expecting great performance while towing, but it is unlikely I could tow much more weight and still maintain speed. It seems a bit rough when rpms are over 2500.

I don't know all the history behind this truck, but everything looks pretty clean and well cared for. It starts right up in non-freezing temps, has good oil pressure and idles smooth.

I have the FSM and have studied all the sections related to fuel and boost. But I'm new to diesels and need some advice on where to start adjusting.

When towing the trailer I was seeing EGTs up to 1250°F and climbing. This plus the black smoke leads me to believe that the fuel is set too high. But if I turn it down, won't my power go down as well? Boost maxs out at 10 psi. I'd think that 12-14psi is possible. But where do I start?

Should I get the timing checked and adjusted? Injectors serviced? Or should I just adjust fuel and boost? Could the ACSD be affecting the smoke since it seems better before the engine warms up? How would I go about testing the operation of the ACSD? Will removing the ACSD affect winter starting?

I'd really appreciate some advice from the experts out there.

 

[lshobie]

Don't adjust the timing, I don't believe you would have to do that. Getting a smoky HDJ81 in canada after it comes from Japan is not a rare thing.

There are two possibilities - boost compensator and the amount of fuel going in - oh and injectors. If you think the injectors are fine then dont bother rebuilding them.

A local guy has the same issues here in Ottawa, we will be making some adjustments shortly, his smokes all the time and has plenty of power - I think it is overfuelled. The key is to keep the power while reducing smoke using.

Will let you know what I find works best.

Louis

 

[finderscuba]

Quick question: when adjusting the "full load set screw" (pg FU-75) do you turn counterclockwise to decrease fuel or clockwise? The FSM seems to think we should know this.

 

[Tapage]

IIRC counter for decrease .. but I should recomend adjust the boost compensator too if you are experimenting low rpm under aceleration black smoke ..

I'm running 14PSI .. but don't spect it do miracle for your powa if you decrease your fuel .. you can add an intercooler to help to ..

But see it simple .. turbo and boost are just to keep your EGT safe .. the diesel it's the key.

If you are pushing black smoke .. means your a diesel injection problem related ( IP or injectors ) or simple you are in the top of the power performance of your 1HD-T ...

More will be add ain propper bigger intercooler and other turbo .. ( somethink bigger )

Edit. just read in your sign that you are in 35" .. maybe a re gear will be a great idea if you are in the towing section.

 

[R2HKS]

You could leave the pump alone and increase the boost instead which will give you more power and reduce the black smoke which is what you are after.

 

[Enigma]

Edit. just read in your sign that you are in 35" .. maybe a re gear will be a great idea if you are in the towing section.

I'm interested to see how this turns out, mine is smokey as well, but more of a blue, doesnt seem to burn any oil though. My boost maxes out at 12 psi.

And what Tapage said, either regear or go smaller tires if you want to tow. Stock tires are 31", that extra 4" makes a big difference on towing/power relations.

 

[9180ltd]

I'm interested to see how this turns out, mine is smokey as well, but more of a blue, doesnt seem to burn any oil though. My boost maxes out at 12 psi.

Just a lil bit of my experence here, take it as you will. If you are getting a bit of blue smoke and not burning any between changes, your beating your head against the same brick i was. I would get large bluish clouds specialy for the first 5-10 km every morning, as well i noticed oil driping onto my front diff that looked like it was coming from the turbo. I figured ....great turbo seals are gone. After further inspection (after dealing with it for 6 months) i found that the blue was indead coming from oil and yes it was going through the turbo but the turbo was not the problem. The problem was the the crank case vent. Under normal opperation since these motors are "enviromentaly responsible" and re-burn there blow by gasses through the intake pre-turbo rather than vent it into the atmosphere like older normal diesels, they slowly slober small abounts of oil into the air filter suction tube before the turbo. When warmed up and running its not as bad , but let it sit over night and even if it is 0.05 of a liter or just oil residue runs down the tube and sits in the turbo housing. This (on mine at least) caused it to look like my turbo was leaking and when you started up in the morning and got on the throttle, the turbo essentialy attomized the oil with the air charge and created a fogging effect of blue smoke.
After looking into a couple options, Racor had a very nice system called a CCV system (closed crankcase ventilation) that separated the oil from the blow by gas, returned the oil to the crank case and returned the "clean" blow by gas to the intake . This system was to rich for my blood at 350$ So i opted for a MORROSO vacuum oil catch can. This can still separates the oil from the gas but it vents the gas into the atmosphere and holds the oil in a can for you to drain.
My truck did not exhibit any oil loss between 5k change intervals, so it goes to show you how little oil it takes to create this problem. As i said before take it at face value, this was just my experience and it had rectified my oil drip and smoke problems 100%.

 

[9180ltd]

pic didnt stick!

 

[Enigma]

That's probably the case with mine, although I have zero oil leaks.

 

[Cancruiser]

9180ltd:
what model MOROSO vacuum oil catch can did you buy?? They got quite a few here:
Moroso : Category Display

Cheers

 

[canucksafari]

So the vapours are just vented under the hood via the airfilter? I thought they are somewhat corrosive and contaminating. Why not vent them into the intake post turbo?

 

[sandcruiser]

you would need to be pushing a lot of crankcase pressure to exceed turbo pressure, wouldn't you?
even with a check valve, it seems dodgy.

I think that is why they go pre-turbo in the stock configuration, that's the closest thing to "vacuum" that you find in the intake system.

if you filter the oil out of the crankcase vapors, it should be pretty clean air. Maybe traces of unburnt fuel, but only traces.

This is a guess. I don't know the answer.

 

[9180ltd]

The can has a series of baffles on the inlet so i have found it dose a better than expected job of separation. As far as corrosive it would be the exact opposite....... were filtering different oils here. I thought about re-routing back pre-turbo but believe it would limit the amount of separation that could take place with the turbo basically sucking the gasses faster than the oil vapors could fall into the can. After all we are talking vapors here, that said only accumulation causes problems. If any thing i will take the filter off and run a tube down beside the frame and let the "clean" vapors vent onto the ground like all the other diesels (older cummins, cat, izuzu, toyota etc.)
I'll have to check my bill for the part ## , I bought it from Mopac in Langley if that helps anyone but any high performance auto parts store that carries morroso should have it (from what i remember it was a common one)

 

[9180ltd]

By the way , i have had this system hooked up now for about 10,000km and as far as the contamination goes i have had none. The filter sits about 2 inches under the fabric acoustical mat under the hood and there has been no saturation or discoloration what so ever. I have even done oil sampling to assure no condensation was entering the valve cover via this system , and there was none.

 

[sandcruiser]

i looked online, seems the morroso catch can is under $75 at jegs
adding it to the list of things to add to the truck.

as for corrosion: I'd rather have "corrosive" air hitting my firewall than have corrosive air w/oil and gunk hitting my turbo.

 

[CMH83]

I made a catch can out of an aluminum water bottle with copper dish scrubbers inside. It is going back to the intake pre-turbo like the stock routing. It seems to have helped with the blue/gray smoke I was getting.

Also on a simpler note when I got my truck it had some kind of K and N re-usable air filter. I just changed it to a Wix paper filter and I have even less smoke now.

 

[sandcruiser]

pictures?

I made a catch can out of an aluminum water bottle with copper dish scrubbers inside. It is going back to the intake pre-turbo like the stock routing. It seems to have helped with the blue/gray smoke I was getting.

Also on a simpler note when I got my truck it had some kind of K and N re-usable air filter. I just changed it to a Wix paper filter and I have even less smoke now.

 

[Dutchie]

Nice, i'll look in to this too as mine is indeed smokey on stratup when cold. Once nice and warm it's pretty much gone (unless I floor it)

 

[Toyole]

Smoke from the hd-t?

 

[gbentink]

Looks like over fueling to me. I would remove the aneroid pin and see what profile is being used - easy to see because there is a distinct wear mark, but you can use a marker pen on the pin and put it back, drive it and pull it out again to check to be sure.

Make sure that it is riding as high as possible on the pin for off boost, increase boost to 14psi, drive it. If smoke too much increase preload spring tension on the aneroid (by turning the toothed wheel CCW when looking down at it). Keep increasing until smoke is acceptable.

If it turns out that acceptable smoke is unacceptable power, then you have other issues.

Generally, if clean under low load, smooth and easy to start from cold, it is simply over fueled.

Black smoke can mean excessive advance, but this is unlikely if the car starts and runs and sounds otherwise good.

Hope that helps