Pump Timing (1 Viewer)

[roaminglost]

I had my pump and injector rebuilt, and we are trying to fine-tune it to run as well as we can.

Some initial thoughts were that it is running high EGTs, with little change from before. It seems that it climbs faster.
There's not much smoke, but still some, less than before.
When stepping on the gas, it almost has very low power till it gets into some RPMS.

The pump rebuilder says to check timing before anything and recommends that it "Should be 1.39-1.45 plunger lift at TDC for mild/increased boost." (I'm at 18 PSI)

Has anyone dealt with timing a pump, and if so, any recommendations?

1990 HDJ81
1HDT
700C peak

 

[mudgudgeon]

It would be helpful to know what vehicle and engine you have.

What have you done to try and tune it?

What mods do you have?

What peak EGTs are you seeing?

 

[roaminglost]

It would be helpful to know what vehicle and engine you have.

What have you done to try and tune it?

What mods do you have?

What peak EGTs are you seeing?

updated the post, but has a green wheel gturbo and pdi intercooler

 

[mudgudgeon]

I would start with setting the timing as recommended by the pump builder.

Then find the G-turbo Tuning Guide in the RESOURCES section in the drop down forum menu. I posted it there, i think someone else also did too

So what you can with tuning fuel settings before changing the timing.
I would leave the main fuel setting as its too until you have tweaked boost compensator settings.

700⁰c peak EGT is conservatively safe. Assuming your probe is in the manifold BEFORE the turbo and not in the dump pipe.
750⁰c peak EGT, pre-turbo is widely considered safe. Personally I think it's still conservative.

If it's a true peak, there's room for more fuel overall. But start with boost compensator settings. This is what has most impact on the torque and power delivery (assuming your pump builder did his job well).

By true peak, I mean peak EGT had been tested repeatedly with the engine at WOT under heavy load, all the way from low RPM, right through the rev range to 3800+ RPM. Something like pushing it hard up a long steep hill in D ( auto) or 4th ( manual) , or pulling a loaded trailer. If you really push it, is that as high as it gets?

You say there's not much smoke. Is this on acceleration?
Its normal to see a puff of dark smoke under acceleration, it should clear as boost and RPM come up. You should not see a smoke screen behind you.

If you stab the throttle for a couple of seconds, while sitting at idle, in neutral, do you see a puff of dark smoke? Does it clear quickly?
Again, you can expect to see a puff of smoke if you do this.
If there's not a puff of dark smoke, you need to tune in more fuel with the off idle screw on top of the boost compensator. This changes initial throttle response when you step on it at low boost. Or as it comes off idle, and builds boost.

After that, look at star wheel adjustment. Changing the boost compensator spring preload via the star wheel changes how quickly additional fuel becomes available as boost builds.
Less preload means fuel will ramp up early, and run out of legs early. More preload will delay the increase in fuel which could mean a lag in boost and power increasing.


The boost you are seeing can be limited either with wategate settings, or by limiting fuel.
Did it boost higher than 18psi previously?
If you saw higher PSI previously, and haven't changed the turbo or wastegate, this indicates you might need to add fuel.

Boost is produced with heat energy from the fuel burnt. Reduce the fuel, you reduce the amount of combustion heat, and reduce the amount of energy available to drive the turbine.

 

[Eurasiaoverland]

To statically time the injection pump, you need a dial indicator and cantilever tool (if the engine is installed in the vehicle). The tool is available from Toyota, or you can buy generic versions which work fine. See a workshop manual for the procedure.

If you have the engine out in a stand, you can also use a simple threaded attachment and long needle in the dial indicator. Remember to disable the ACSD if you have one.