HELP 1hdt lacking power (1 Viewer)

[jakebarlow123]

Hey legends,


First time posting—been quietly reading and learning here for about 3 years.

I’ve got a 1HDT-powered 80 Series, and lately it’s been feeling sluggish and tired, like it’s not pulling the way it used to. I’ve noticed a slight leak from the intake manifold, but I’m unsure if that would cause this much of a power drop.

It has a fairly new fuel pump, and it felt solid a couple months back—strong and responsive. But now it just feels off. Could the fuel pump timing or setup be slightly out?

Also worth noting:

• There’s a small amount of grey smoke from the exhaust.
• Turbo spools up but the boost feels weak.
• I haven’t checked the fuel filter yet or done a boost leak test, but I will be soon.

Any advice or tips from those who’ve been through this would be seriously appreciated. Just trying to figure out if this is a boost/fuel issue or something deeper like compression

 

[duece71]

Maybe do….
Compression check, fuel pump timing, valve clearance check. Have you had the intake pipe off recently? How did it look inside? How does your coolant look? Learning myself as well.

 

[jakebarlow123]

Maybe do….
Compression check, fuel pump timing, valve clearance check. Have you had the intake pipe off recently? How did it look inside? How does your coolant look? Learning myself as well.

I have nothing to do the compression test and also not sure how to check the timing on my fuel pump or valve clearance

I haven’t taken the pipe off recently/ever but it’s definitely got a leak from it
I might take it off tomorrow and check it out and replace the gasket.

My coolant looks normal and also stays at the same level

 

[duece71]

You could also take off the oil fill cap, turn it over and put flat side down over the valve cover port. Fire it up and see if the cap stays put. Vibration of the engine shouldn’t knock it off.

 

[jakebarlow123]

You could also take off the oil fill cap, turn it over and put flat side down over the valve cover port. Fire it up and see if the cap stays put. Vibration of the engine shouldn’t knock it off.

Nope nothing happens
0 blow by
Thanks for the response again mate

 

[OrangeCrusher]

Have you checked the turbo boost? If I'm remembering correctly the green LED should come on around 1800rpm at full throttle.


I've had it that the wastegate linkage mechanism on the turbo was worn out, and the wastegate didn't close properly. This was on a high mileage vehicle (about 500,000km). I was able to fix it just by rejigging that mechanism, but can't remember exactly how I did it as it was many moons ago.

 

[duece71]

I have nothing to do the compression test and also not sure how to check the timing on my fuel pump or valve clearance

I haven’t taken the pipe off recently/ever but it’s definitely got a leak from it
I might take it off tomorrow and check it out and replace the gasket.

My coolant looks normal and also stays at the same level

Do you have the FSM on the 1-HDT? Yooootooob has a couple of videos on how to check pump timing. You would need an SST and a dial gauge and a new copper gasket for the head bolt.

 

[gilmorneau]

Leak in intake manifold could cause drop of boost pressure, which would show up as lower power. As mentioned above, check boost. (And fix the leak)

 

[jakebarlow123]

Have you checked the turbo boost? If I'm remembering correctly the green LED should come on around 1800rpm at full throttle.


I've had it that the wastegate linkage mechanism on the turbo was worn out, and the wastegate didn't close properly. This was on a high mileage vehicle (about 500,000km). I was able to fix it just by rejigging that mechanism, but can't remember exactly how I did it as it was many moons ago.

My light turns on basically as soon as I give it gas and also my red one doesn’t work

 

[jakebarlow123]

Leak in intake manifold could cause drop of boost pressure, which would show up as lower power. As mentioned above, check boost. (And fix the leak)

I will be getting the new gaskets in tomorrow
Don’t know how to test boost tho

 

[mudgudgeon]

My light turns on basically as soon as I give it gas and also my red one doesn’t work

The red one is an over boost warning light. It will only come on at 14-15psi

The intake manifold has rubber gaskets at the head that fail and can leak boost.

What situations do you see grey smoke?

 

[jakebarlow123]

The red one is an over boost warning light. It will only come on at 14-15psi

The intake manifold has rubber gaskets at the head that fail and can leak boost.

What situations do you see grey smoke?

High revs and cold starts not much at all but it’s there
I think it might be normal