Fueling issues with 1HD-FT

TurboDennis

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Having some issues with my truck and was hoping somebody could point me in the right direction.

I had my injection pump and injectors rebuilt last summer by a local shop that has extensive experience with Bosch-style pumps and very good reputation.
The engine had 170k KM on it at the time, and there was absolutely nothing wrong with it - i just wanted to service the pump/injectors as preventative maintenance. Was running 1HD-FTE turbo, pushing about 13 PSI. Fuel pump was never touched before, and it ran great.

The guy that was rebuilding the pump said that with factory settings, the 1HD-FT pump would not be able to supply enough fuel for the increased boost that i was running, and it would need to be adjusted. That made sense to me, so I told him to go ahead and do what needs to be done. The guy said I should expect more power and better fuel economy.

I installed the new pump and injectors, and installed a roof top tent at the same time. After a long trip, i noticed that my fuel economy has decreased. Was getting about 10.5L/100KM (22.5MPG) before, and went down to about 12L/100km (19.5MPG). I attributed this to addition of RTT, and didn't pay much attention to it.

However after putting more miles on the truck since then, I'm convinced that the truck is over-fueled. I'm getting noticeable black smoke on startup, at low RPM (before boost), and during full throttle acceleration. EGT's usually climb to around 500-600C (950-1100F) during small hill climbs, but have gone as high as 800C (1450F) during long mountain passes in high gear (at which point i would downshift and back off the throttle). The weight of the truck is close to stock, running 33" tires. I didn't have an EGT gauge before the fuel system rebuild, but i believe these EGT's are way too high for 13 PSI and a relatively light truck.

I have never messed with IP, but i want to try and reduce the fueling a bit. What would be the best adjustment to make, and how much? I asked the guy that did my rebuild how much he adjusted the compensator spring/main screw relative to factory level, and his response was "I dont know. I don't count turns - i adjust by injection volume in CC's on a stand"


Second issue that I'm having, which may or may not be related: After the truck sits for at least a few hours, it starts great and holds the idle perfectly for as long as i let it idle before driving. However after driving it a few seconds (and letting the turbo kick in once), it wants to stall when dropping the RPM's back to idle. There is a stop sign 50 meters from my house, and it always wants to stall at that stop sign. I have to bump the RPM's with pedal to keep it from stalling. It only does this once, and the problem never reappears until the truck is parked again. However this happens VERY consistently, pretty much 100% of the time.

If anyone has any suggestions, I would really appreciate it!
 
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and was hoping somebody could point me in the right direction.
I would be pointing you back to the person who took your money and promised better fuel economy and more power.
 

mudgudgeon

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However after putting more miles on the truck since then, I'm convinced that the truck is over-fueled. I'm getting noticeable black smoke on startup, at low RPM (before boost), and during full throttle acceleration. EGT's usually climb to around 500-600C (950-1100F) during small hill climbs, but have gone as high as 800C (1450F) during long mountain in high gear (at which point i would downshift and back off the throttle)
See below


However after putting more miles on the truck since then, I'm convinced that the truck is over-fueled.
Fuel has clearly been turned up. Over fueled, I'm not so sure.
Was running 1HD-FTE turbo, pushing about 13 PSI.
Are you still running the 1HD-FTE turbo? Bumping boost to 15-18psi would probably reduce some of your smoke, and give you more power. But you'll still see off boost smoke

I'm getting noticeable black smoke on startup,
A little black smoke on start up is ok, so long as it clears once there's a bit of warmth in the engine.
A diesel relies on heat and compression to ignite the fuel. A cold engine is not going to achieve full ignition.

at low RPM (before boost),
A slight puff of dark smoke on initial throttle input before boost is normal. A test for this is while sitting in neutral, with the engine idling, give the throttle a good stab with your foot. You should initially see a puff of dark smoke which clears as the revs come up.
This shouldn't be a big cloud, and shouldn't be a smoke screen, just a visible puff for 2-3 seconds.

I used to see off boost smoke occasionally in my mirror or more often at night when cars headlights pick up the smoke.
The shot of fuel that causes smoke is what is needed to produce hot exhaust to spool up the turbo

and during full throttle acceleration.
as above. Hard acceleration is a scenario where you have a high load, low RPM, and a load of fuel being injected.
It's normal to see a bit of smoke under hard acceleration, but it should clear as revs rise and boost comes up providing more air/oxygen for a more complete fuel burn

EGT's usually climb to around 500-600C (950-1100F) during small hill climbs,
This is entirely safe, and very conservative IF your probe is before the turbo. If it's after the turbo, all bets are off.

but have gone as high as 800C (1450F)
This is still safe if its an upper maximum IF your probe is pre turbo. If you're probe is after the turbo, you should be nervous.

It's above the 750⁰c that most people consider a safe limit. You can run them to higher maximums. 750⁰c is actually quite conservative. (Gas engines run EGTs of ~1300⁰c at stoichiometric air/fuel mix, or all the time)

I ran mine to 8-850⁰c regularly, and would see peaks up to 950⁰c. When the engine was apart, there was no sign of combustion heat being to
high.

during long mountain in high gear (at which point i would downshift and back off the throttle)
Do EGTs keep climbing if you don't back off?

A lot of people don't drive turbo diesels appropriately. They are happier at high revs than they are at low RPM, wide open throttle struggling to keep revs up. They'll run happily all day at 3000rpm. (Your ears may be less happy).
Better to hold speed in a lower gear at 3000rpm than it is to bury your foot in the floor in top gear with the engine at 2000rpm.

Also, be prepared to downshift before hard acceleration. Stir the pot, keep things cooking, keep revs in the sweet spot where you are on boost and have power in reserve, and not expecting the engine to accelerate hard from low RPM, low boost in too high a gear


Obviously, I can't see how much smoke you are seeing, so you have to make a judgement on this.

A bit of smoke is the trade off to having more power available.

Fuel economy is dictated mostly by your right foot.
 

TurboDennis

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I would be pointing you back to the person who took your money and promised better fuel economy and more power.
You're right, i should've done something about it right away. But like i said, i thought that the decreased fuel economy was due to addition of a RTT at the same time as installing the new pump, so that kinda threw me off. At this point (a year later), the best i could probably hope for is him offering to bring him the pump so he could re-tune it on a stand. I don't feel like pulling the pump again.
Are you still running the 1HD-FTE turbo? Bumping boost to 15-18psi would probably reduce some of your smoke, and give you more power. But you'll still see off boost smoke
Thanks for a detailed response, i really appreciate it!

Yes, running brand new (as of this summer), original FTE turbo at stock boost. I dont have a boost controller on it. The increase in boost over stock is due to a 3" exhaust.
Maximum power is not my priority. Long term reliability is, so i don't want to stress the turbo by turning it up any higher.
A little black smoke on start up is ok, so long as it clears once there's a bit of warmth in the engine.
A diesel relies on heat and compression to ignite the fuel. A cold engine is not going to achieve full ignition.


A slight puff of dark smoke on initial throttle input before boost is normal. A test for this is while sitting in neutral, with the engine idling, give the throttle a good stab with your foot. You should initially see a puff of dark smoke which clears as the revs come up.
This shouldn't be a big cloud, and shouldn't be a smoke screen, just a visible puff for 2-3 seconds.

I used to see off boost smoke occasionally in my mirror or more often at night when cars headlights pick up the smoke.
The shot of fuel that causes smoke is what is needed to produce hot exhaust to spool up the turbo


as above. Hard acceleration is a scenario where you have a high load, low RPM, and a load of fuel being injected.
It's normal to see a bit of smoke under hard acceleration, but it should clear as revs rise and boost comes up providing more air/oxygen for a more complete fuel burn
The way i see it is this: black smoke means unburnt fuel. Unburnt fuel that comes out the tailpipe is wasted fuel. Yes, i do understand that it may be preferable from a performance standpoint to have more fuel than needed. But as I've said before, long term reliability is my main concern. Fuel economy is a close second. Performance was perfectly adequate for my driving style before, and i was not interested in increasing it (certainly not at a cost of reliability and fuel economy). Besides, i cant say that there is a noticeable improvement in performance. There may be some, but it's marginal at best. Im trying to keep my truck very light, i never tow anything with it and the areas where i do 95% of my driving are completely flat, so i don't want to sacrifice anything for more power.

The truck didn't smoke AT ALL before the fuel pump rebuild. Fuel economy was ~15% better. EGT's were probably lower (i didn't have a gauge at the time, so i cant say for sure, but i think it's safe to assume that more fuel at the same boost will usually raise the EGT's)
This is entirely safe, and very conservative IF your probe is before the turbo. If it's after the turbo, all bets are off.


This is still safe if its an upper maximum IF your probe is pre turbo. If you're probe is after the turbo, you should be nervous.

EGT Probe is pre-turbo

It's above the 750⁰c that most people consider a safe limit. You can run them to higher maximums. 750⁰c is actually quite conservative. (Gas engines run EGTs of ~1300⁰c at stoichiometric air/fuel mix, or all the time)

I ran mine to 8-850⁰c regularly, and would see peaks up to 950⁰c. When the engine was apart, there was no sign of combustion heat being to
high.

I wish i knew what the EGT's were before the fuel pump work. I don't think they would go to 800+...


Do EGTs keep climbing if you don't back off?
I dont know. I would back off the throttle and downshift (slow down) when i saw 800. I didnt have the balls to keep pushing it further.

A lot of people don't drive turbo diesels appropriately. They are happier at high revs than they are at low RPM, wide open throttle struggling to keep revs up. They'll run happily all day at 3000rpm. (Your ears may be less happy).
Better to hold speed in a lower gear at 3000rpm than it is to bury your foot in the floor in top gear with the engine at 2000rpm.

Also, be prepared to downshift before hard acceleration. Stir the pot, keep things cooking, keep revs in the sweet spot where you are on boost and have power in reserve, and not expecting the engine to accelerate hard from low RPM, low boost in too high a gear
That's good advice!

Obviously, I can't see how much smoke you are seeing, so you have to make a judgement on this.

A bit of smoke is the trade off to having more power available.

Fuel economy is dictated mostly by your right foot.

I wouldnt say that the amount of smoke is EXCESSIVE. But again, there was NONE before. Fuel economy was noticeably better (with identical driving habits). And power is more or less the same... So i would prefer to detune the pump back to factory spec. Or maybe half way between what it is now and factory spec. The problem is that i have no idea which adjustments he made, and how much exactly.

I suppose that if i remove the aneroid, i would see if there was another (second) scar mark on it from the plunger and i could turn it back to that spot. But what about the main fuel screw and the spring preload? Is there a way to determine the factory settings for those?
 

mudgudgeon

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The way i see it is this: black smoke means unburnt fuel. Unburnt fuel that comes out the tailpipe is wasted fuel. Yes, i do understand that it may be preferable from a performance standpoint to have more fuel than needed
Yes, you are correct, in an ideal world.

There's limitations in tuning a mechanical fuel pump. There will be times when you will get some dark smoke, is just a fact of life with these old diesels.
You need enough fuel to drive the turbo to produce boost to then fully burn fuel.

It does sound like you could detune and be happy.

15% change in economy is huge. How confident in that figure are you? Have you tracked economy, it just estimating it?
 

TurboDennis

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Yes, you are correct, in an ideal world.

There's limitations in tuning a mechanical fuel pump. There will be times when you will get some dark smoke, is just a fact of life with these old diesels.
You need enough fuel to drive the turbo to produce boost to then fully burn fuel.

It does sound like you could detune and be happy.

15% change in economy is huge. How confident in that figure are you? Have you tracked economy, it just estimating it?
Pretty confident. I drove it for close to two years with that exact drivetrain combination, and would always average around 10.5L/100km with mixed city/hwy driving. +/- 0.5L.
After the fuel system refresh (and driving it for a year), i average 12.0 L/100KM. I have never seen numbers in the 10's with the new pump/injectors.
As i've said before - the only other "variable" is a roof top tent which i added at the exact same time as the fuel system work, but it's the slimmest design possible (aluminum hard-shell), mounted almost touching the roof. I doubt it would have THAT much of a negative impact on fuel economy..
 

Akella

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I wouldnt say that the amount of smoke is EXCESSIVE. But again, there was NONE before. Fuel economy was noticeably better (with identical driving habits). And power is more or less the same... So i would prefer to detune the pump back to factory spec. Or maybe half way between what it is now and factory spec. The problem is that i have no idea which adjustments he made, and how much exactly.
It sounds like you are over-fueling, You can turn fuel down by adjusting the fuel screw. you would need 10mm wrench and flat screwdriver and street to test drive until you are happy with EGT and power and smoke. Just adjust the screw 1/4 turn at a time and after finetune accordingly.


Also, you can ask the rebuild shop for a printout of the pump number when he run it on the bench and compares it to factory numbers. Also, the 1hd-ft fuel system had 2 different pressure settings depending on the year if I remember correctly. Hopefully, he set injectors and pumps to the same settings.

I might be in Toronto later next week and I can stop by and help you.
 
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Pretty confident. I drove it for close to two years with that exact drivetrain combination, and would always average around 10.5L/100km with mixed city/hwy driving. +/- 0.5L.
After the fuel system refresh (and driving it for a year), i average 12.0 L/100KM. I have never seen numbers in the 10's with the new pump/injectors.
As i've said before - the only other "variable" is a roof top tent which i added at the exact same time as the fuel system work, but it's the slimmest design possible (aluminum hard-shell), mounted almost touching the roof. I doubt it would have THAT much of a negative impact on fuel economy..
You might be surprised how much that RTT could affect fuel economy. I saw at least a 0.5 l/100km drop when I took the aluminum roof rack off my truck. I had nowhere to store it, so I had it on the roof full time for 7 years. I took it off when I bought a house, so I had a lot of data to compare to and saw and obvious difference.
 

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