When you remove the acsd a lot of people find they need to bump up their static timing a touch to clear up that white smoke on first start up until the engine gets warm. When you think about it, it makes complete sense considering that's what the acsd was automatically doing anyways. Got to be careful though because it increases timing over the whole RPM range not just idle, but most the time that can also be a good thing too as it gives more torque and lowers EGT. If it starts rattling and sounds like you have loose bolts in your rocker cover you've gone to far lol.
The Official 1HD-T/FT Fuel Pump Mod Tuning Thread
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I disagree, but YMMV
White smoke is unburned diesel. It can be due to poor injection spray pattern or bad timing
I'd also have to disagree about these engines being smokey. Visible pollutant emissions from the exhausts of these vehicles are generally really good (especially the FT), They're much cleaner than all the latest spec common rail diesels we have at work lol.
Yeah, I can testify, between the ACSD removal and now I literally saw zero smoke from the car(I also took it to a diesel shop and gave them the FSM and they "advanced" the timing a bit after the ACSD removal. It was night and day from when I first got it. Just left work and didn't notice any smoke at startup, im just going to chalk it up to condensation, it was one of those mornings where there's just moisture all over the car
Do you know what spec they advanced the timing too?
I am pretty sure ACSD advances timing when cold. Which would reduce smoke. When I removed mine there was more smoke when the engine was cold.
My timing is set at .054” which is .001 above the Max Spec
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That's exactly what it does. Once coolant gets up to temp it reduces timing back to normal.
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White smoke doesn't mean underfueled
Diesel smoke typically is according to the below
White - unburned diesel - retarded timing, low compression, bad glow system etc.
Black - excessive fuel - could be a bad tune, poor injectors, insufficient airflow etc - Rich = hot in a diesel, not ideal.
Blue - oil being burnt - lack of rings, turbo problems feeding oil into the intake etc.
I might be a wet blanket but I'd be hesitant to advance the timing by simply adjusting the pump without knowing where it actually was in relation to spec. Seen too many broken engines, (mainly TD42 but still...) Due to questionable timing and tuning.
Count me as a wet blanket too.
A small change to the pump position can have a big impact on timing.
With or without a trained ear, adjusting timing by ear is risky
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On an old petrol, timing by ear is probably fine. The margin for error is too narrow on a diesel IMHO.
Meh, I'm not too concerned anymore about fine tuning the static timing to suit my setup. At first I was really concerned about even touching it after seeing people's comments on here and other sites but after hearing from a few well known Aussie diesel tuners/pump builders my mind was put at ease.
One of the more well known ones said he hasn't used a dial indicator gauge for setting the static timing in years and that when he builds pumps he doesn't generally give an exact spec to set it too as every setup needs a different static timing too achieve optimal performance depending on vehicle mods etc. You can use the dial indicator to get in the right area before you start fine tuning but picking a number to set it to isn't always the ideal it could be.
Yes it can have serious consequences if you get it wrong but I really don't think it's such the scary thing people make it out to be. No one blinks an eye when people start touching the main fuel screw which often ends up doing way more damage than what a tiny about of static timing might do if done incorrectly.
One of the more well known ones said he hasn't used a dial indicator gauge for setting the static timing in years and that when he builds pumps he doesn't generally give an exact spec to set it too as every setup needs a different static timing too achieve optimal performance depending on vehicle mods etc. You can use the dial indicator to get in the right area before you start fine tuning but picking a number to set it to isn't always the ideal it could be.
Yes it can have serious consequences if you get it wrong but I really don't think it's such the scary thing people make it out to be. No one blinks an eye when people start touching the main fuel screw which often ends up doing way more damage than what a tiny about of static timing might do if done incorrectly.
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To each their own - probably risk averse as well but I don't touch the fuel screw without a pyrometer either...
It seems that the 1HDT likes to have the timing advanced. Most posters after advancing ip timing have experienced better fuel economy, less smoke, and improved acceleration.
I have also had the same positive results. One thing I noticed too is that engine noise and vibration increase as well.
Has anyone measured there timing after advancing it? I would be curious to know what range of advance is being used?
What other factors should be considered...
- does the injector crack pressurehave an effect on overall ip timing. If the crack pressure is lower than spec does it have the effect of advancing timing? And visa versa.
- do higher boost pressures require more or less advance?
- do the modified pumps and injectors being sold run stock timing?
I dont mind experimenting with my engine but I dont know what things impact ip timing in a negative way. How do you tell if you have gone too far?
My new engine is in the truck running finally and I am going to start tuning this week . I am certainly going to play with my timing and fueling.
Fueling adjustments can be observed with AFR, EGT, and tailpipe smoke.
How can we quantify ip timing adjustments to know that we are in the safe range for our engines?
I have also had the same positive results. One thing I noticed too is that engine noise and vibration increase as well.
Has anyone measured there timing after advancing it? I would be curious to know what range of advance is being used?
What other factors should be considered...
- does the injector crack pressurehave an effect on overall ip timing. If the crack pressure is lower than spec does it have the effect of advancing timing? And visa versa.
- do higher boost pressures require more or less advance?
- do the modified pumps and injectors being sold run stock timing?
I dont mind experimenting with my engine but I dont know what things impact ip timing in a negative way. How do you tell if you have gone too far?
My new engine is in the truck running finally and I am going to start tuning this week . I am certainly going to play with my timing and fueling.
Fueling adjustments can be observed with AFR, EGT, and tailpipe smoke.
How can we quantify ip timing adjustments to know that we are in the safe range for our engines?
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by sticking to the figures stated by toyota in the fsm.
most of these engines now will be running retarded due to high miles.
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@Wildnlost Advancing the timing does make a significant difference on the 1HDT - I ran mine at the most advanced end of spec, think it was ~1.3mm of lift and big difference in throttle response, she was very snappy and good on fuel.
Mine was also set to 1.3mm after it got rebuilt but in my testing anything less than this would have cold start smoke issues. After hearing from pump builder it's more to do with how they set up the pump internally than what the exact static timing is, so it makes sense that a rebuilt/modified pump setup with a different test plan will require slightly different specs than a factory pump from the FSM.
I never bothered to measure everytime I adjusted it to know exactly what it's set too, I just scribed a mark at the initial 1.3mm setting so I knew I could always get back to that and use it as a reference. I started off testing retarding it but I didn't go too far due to the bad smoke at cold startup. I did notice the engine sounded smoother/quieter and boost response increase but actual power decreased. On my test hill near home I could normally use fourth gear to maintain speed up a hill but now had to drop to third to get up it.
Oh man, a test hill near my home...I can't even imagine how great that must be, lol! It's a 2 hour drive to a hill that would cause a trans to have to kick down from here!
by sticking to the figures stated by toyota in the fsm.
most of these engines now will be running retarded due to high miles.
@chapel gate your post would suggest that as the injection system collects miles it loses advance to wear I am assuming. Is that correct?
If that is the case it makes sense that many posters see a benefit to advancing timing on there high mileage engines.
So with a rebuilt pump and injectors on a slightly modifed 1HDT running 24 psi boost, intercooler, modified intake manifold , 3” exhaust, Duramax airbox, fresh rebuild .020”o/s pistons and porting.... What would be a good starting point for for pump timing?
I am currently running .054” of lift just slightly above the stock spec. Should I be considering more advance than that ?
The question is.... is more timing than the FSM acceptable? What is a reasonable limit?
What are factors to consider?
What are signs of too much advance?
I don,t mind experimenting but knowing the limit or how to recognize when you are at the limit is my question.
I have tinkered with alot of the mechanicals on my truck and now the task will be to tune it. I think IP timing and advance curve are probably a good part of the tuning process.
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When injectors wear, the springs get weak, and they would inject earlier than they would have with newer, stiffer springs, right? Or am I looking at that the wrong way? That's an opposite shift from the worn pump theory above, what's the net effect?
Does an engine age and gain or lose timing advance?
Does an engine age and gain or lose timing advance?
I would say you are correct on the injector opening sooner so yes advanced.
I wonder if the plunger gets worn in the pump and it bleeds pressure. So it takes more crankshaft rotation to build enough pressure to crack the injectors making the timing late?
I wonder if the plunger gets worn in the pump and it bleeds pressure. So it takes more crankshaft rotation to build enough pressure to crack the injectors making the timing late?
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