Idle Speed : Toyota 4 cylinder (1 Viewer)

[knuckle47]

After doing a few things I probably didn’t need to do immediately, I finally did get my 14B Toyaota running very well. Got rid of the excessive white smoke, idle is way down from the near 2000rpm on startup. She starts up with 3 seconds of cranking when cold.

HOWEVER, I am still not fully satisfied that the idle is correct. My Conventional gasoline engine experience is substantial and I am not afraid to go bare block and rebuild. On a diesel …it give me great trepidation since I am not experienced in injection pumps, injection timing, or even the process of ignition on this truck. I would be unable to bring this vehicle somewhere to undo the screw-ups I create so I am really looking for answers on what I can minimally look into to get this properly adjusted.

an optical tach is arriving soon so I’ll have more exacting information.

As on a conventional carb, there are mixture adjustment, Accelerator pump etc…. Are adjustments like this or the equivalent used on diesel Injection systems?

aside from the throttle speed adjustment screws for minimum idle and maximum engine speed, I must be missing something…
@mudgudgeon , @duncanrm
and @bj70bc took me a very long way to this point with their thoughts and I do thank them

 

[ATL Cruiser]

This picture should give you a bit of help.

Guide: 1HZ - GTurbo + PDI intercooler + 3" exhaust

Documentation on adding a bit more power to my 1992 HZJ77. This entire turbo install is based on multiple guides across the internet, namely the Safari guide, which is absolutely fantastic) ' Safari Diesel Intercooled Turbocharger System for the Toyota Land Cruiser 1HZ diesel engine -...

forum.ih8mud.com

 

[knuckle47]

@ATL Cruiser that is a detailed list…thank you. I am not sure that I have a fuel screw too. Meter the fuel across the operating rpm range. This is a good weekend for me to dig into it a little

 

[mudgudgeon]

There will be a main fuel screw. From factory they are fitted with a pressed metal shroud once the pump is calibrated to prevent tampering. It can make them hard to spot.

The throttle lever on top of the pump housing (your picture) is connected to a series of springs and levers inside. Fuel delivery is controlled in part by throttle position, but is not a rigid connection. The actual fuel delivery position is controlled by the governor weights which move with RPM changes.
Kind of similar to a carbie, fuel delivery changes as vacuum through the venturi changes.
The main fuel screw has a tapered end (similar to needle and seat). Adjusting it simply opens up the passageway for fuel going into the pump. Once you set its position, it doesn't move.
Measure and record how much the main screw is protruding from the pump housing, and you can return it to the same position. You can't mess up anything mechanical.

Tuning these pumps is pretty rudimentary.
You have
Main fuel screw adjustment.
Idle screw
Max throttle position screw ( maximum RPM is controlled by the governor, changing this screw has no effect on the governor)
Injection timing.

That's about it.
All of it is largely external to the pump. You won't screw up anything internally with the pump.
Settings can be restored IF you record the position of stuff before adjusting

 

[knuckle47]

I have been outside all day. Added some Prestone radiator cleaner and let it heat up. After flushing the block and radiator, I took off the hoses, changed the clamps and filled it with water. The mud like gunk inside cleared and the inside looked pretty clean. Flushed again with water and tossed the thermostat housing into the glass beader. The original gasket is a composite and in bad shape. Scraped it off vacuumed the scrap and of course….no thermostat. Put in a new thermostat with o-ring gasket and filled it with only water.

keep in mind I have been trying to troubleshoot the temperate gauge which appeared dead. Took the truck for a quick ride up the street and back and as I get to my driveway…the temperature gauge is reading and working. with nothing but free flow, the thing never got hot enough in the few short tests I did.

I noticed that the idle is now perfect, no smoke, acceleration is not bad and I parked it until tomorrow, it starting to get dark. Found that the windshield wiper actually work with a pull on/off switch on the dash and not the arm on the steering wheel.

I wish I had some logic to say why this all came together tonight. It’s running very well and while I have the parts to rebuild the injectors…I’m just letting it alone for a few weeks.
@mudgudgeon …this is a great dissertation on the injection pump. I have set the throttle at about 750rpm , left the max speed alone and have printed out your notes.. again, thanks !!!

 

[mudgudgeon]

I'm glad you feel like you've made some progress. Frustrating when you feel like you're chasing your own tail.

they are not that different from a petrol engine. Obviously there's differences, and new stuff to wrap your head around.

I have set the throttle at about 750rpm

This sounds good. My diesel 80 series would idle smooth at 650rpm, or 900rpm. FSM said to set idle at 750-800.
I set it at 650, and never had any issues

 

[knuckle47]

@mudgudgeon chasing my own tail was all I felt in the last 3 weeks. It is rewarding to have it back to normal… however, I would love to know why. All I can think of is the sir in the fuel system…I never ran it more than 2-3 minutes so likely since I never ran it long enough to pump air and purge itself, the problem just persisted. The best surprise is the temp gauge working because of the new thermostat. There are more than a few dead cut wires in the harness that had to have done something at some point. Tracing wires is probably my most limiting skill. My thoughts are to just remake a harness for the areas like directional signals and wiper/washer…tap into a 12V feed and let it work independently.

thanks again for the interest in helping me move through this .

 

[knuckle47]

Another small surprise…. Aside from discovering the temp gauge actually does work, I added 4 gallons of diesel to the tank (new vehicle to me since I got this truck I have not yet taken it anywhere…) and found the gauge reading 1/4 full. That saves another 2 hours tracing wires

 

[4Ruster]

I hope this helps.

 

[4Ruster]

Note: Idle will go up with the fuel screw *and* advancing the static timing.