1HD-T noises / high idle (1 Viewer)

clay763

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All,

Could use an assessment from the wise folks. A while back I adjusted my throttle / kickdown cable, and put my idle into spec per the FSM (750-850 in N, at operating temp). Since then, the only thing I have done to the engine is changing the oil, but the idle has crept up as of late. Now it sits about 950 to 1000 at idle in neutral, with that has come a lot of vibrations and a loss of power. Today I went to adjust the idle back down, but even with the idle adjustment screw all the way down, it still sits high. Throttle cable has appropriate slack, not contacting the idle screw, but still high. I'm hesitant to touch the fuel screw, as many threads have advised against it, so I'm wondering if there is anything else to try.

On the noise bit, she has had a tick ever since I got her. At idle it seems randomly spaced, but under load it increases frequency linearly with RPM. Hard to hear in the video, but it is loudest when driving by something on the side of the rig (a wall, gate, truck, etc). Tick has gotten louder as of late. ACSD is about to be removed once the kit comes in.

Youtube video for the tick...

Thanks,
Clay
 

clay763

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ACSD, that’s where I would look.

Cheers

Yea, ACSD is leaking, it's getting blanked off as soon as the kit arrives. I'm wondering if it isn't introducing air into the fuel system as well, contributing to the vibration. I'll update when that is blanked off.

As for the A/C, that is another strange condition. There is no increase in RPM corresponding with engaging the A/C. FSM says to check the variable switching valve, havn't had a chance to look at that. I don't think the 1990 1HD-T has an A/C idle up, unless that is what the FSM is calling a VSV.
 
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Do you have another video of the ticking sound? I spent over a year chasing mine down so im curious to see what yours sounds like...
 

Squash

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ACSD is immersed in coolant and therefore cannot add air to fuel other than advancing or retarding the IP.
Get the blank installed and take her for a ride.
A tick can be so annoying, it comes, it goes , it disappears and then it's back. Driving a man to paranoia. My cure is a good hard run on a winding dirt forestry road. Pour on the coal, a little drifting, shift manually. Once back let her cool down at idle and just listen to that engine purr like a well loved woman.
Remember that an engine clanks, moans and ticks while differing metals warm or cool. I'm reminded of this every time I fire up my wood stove.
 
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clay763

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ACSD is immersed in coolant and therefore cannot add air to fuel other than advancing or retarding the IP.
Get the blank installed and take her for a ride.
A tick can be so annoying, it comes, it goes , it disappears and then it's back. Driving a man to paranoia. My cure is a good hard run on a winding dirt forestry road. Pour on the coal, a little drifting, shift manually. Once back let her cool down at idle and just listen to that engine purr like a well loved woman.
Remember that an engine clanks, moans and ticks while differing metals warm or cool. I'm reminded of this every time I fire up my wood stove.

It seems to be leaking fuel once the rig gets warmed up, at least it smells like diesel. I assume it is from the mating between the IP and the ACSD? But alas, I'll be out of the country for the next six months, and the ACSD kit arrived the day after I left, so it will have to wait.
 

clay763

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Do you have another video of the ticking sound? I spent over a year chasing mine down so im curious to see what yours sounds like...


Here is a different one. There is a consistent tick that can be heard, not worried about that, seems to be normal. The concerning one is off beat, random, and can be best heard when I pan back towards the firewall behind the turbo. It seems to be loudest behind the turbo, and even down under the drivers door. It can only be heard when I have the window down, and pulled up against something on the driver side (wall, car etc).
 
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Ive heard a few 1HZ make sounds like that. Im wondering if it some kind of expansion/contraction noise from the 2 piece exhaust manifold joint.
Mine only made the noise about 10 mins after start up.
 

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