Lazy Cold Start Advance

[HammerDown]

Noticing the 'cold start advance' has become (for lack of better words) lazy.
Meaning, at initial 'cold' start-up it no longer engages immediately ... as it once did.
Now I have to hold the fuel pedal down a little until raising the RPM's until the 'cold advance' kicks in/grabs and then it holds RPM up until engine temp comes up and it kicks-off.
Any ideas as to what's causing the issue?

 

[Nero]

The solenoid could have a wear in the push rod and it's hanging up. Had one that did that. Rotated it 1/4 of a turn and it fixed it for a while. Could be a tired solenoid too.

 

[HammerDown]

The solenoid could have a wear in the push rod and it's hanging up. Had one that did that. Rotated it 1/4 of a turn and it fixed it for a while. Could be a tired solenoid too.

I've never messed with it, way back in maybe 2008 I tool the IP off and sent it to Mel and he did his "baby moose" deal and shipped it back. I remember there was just a little wear on the advance piston. I remounted the rebuilt IP and took it to him to time it.
So... if I remove the cover is it easy to get a hold of to spin?

 

[IDIBRONCO]

You don't need to remove anything. All you need is an open end 1/4" wrench. Put it on the hex part that goes up against the part that the throttle cable attaches to. It's threaded inside the solenoid.

 

[captain720]

When I start mine it idles lower than normal and “clatters extra” and goes up when warm, but I can hear a noticeable change when it gets warm and something clicks off is mine somehow working wrong? Hopefully I’m not thread jacking it seemed related.

Maybe worth noting it starts up fine and idles smooth although the coldest I have started it yet was about 35 degrees F no block heat.

 

[chillman88]

Sounds to me like you're confusing the cold timing advance with the high idle solenoid?

Cold timing advance is in the pump, it sounds like what you're talking about is the high idle which is the small solenoid that pushes against the throttle lever next to where the throttle cable attaches. It has nothing to do with the advance piston and there's no cover to remove because it's not technically part of the IP.

 

[IDIBRONCO]

When I start mine it idles lower than normal and “clatters extra” and goes up when warm,

The extra clatter when cold is normal. That's the timing advance working like it's designed to. The idle speed sounds like it's working opposite of how it's supposed to. Before you do a cold start, do you press the throttle pedal part way down? You're supposed to do that to set the fast idle speed. If you're not doing that, then maybe, it could idle a little bit slower than normal. The idle speed may raise because maybe the engine vibrations may help the fast idle solenoid push the throttle on the pump far enough to idle faster. I don't know if that's what's happening, but only a guess.

I can hear a noticeable change when it gets warm and something clicks off is mine somehow working wrong? Hopefully I’m not thread jacking it seemed related.

Now this is perfectly normal. The fast idle and the timing advance both stop working when the coolant temperature gets to about 120*. Your glow plugs also won't come on or won't stay on very long at or above this temperature. That's also normal. That is unless you have your glow plugs on manual control.

 

[captain720]

Thank you everyone, fantastic advice as usual. Turns out it’s just user error, I forgot to mention the idle comes up if I hit the pedal once so it turns out I was just supposed to be hitting the pedal to set the fast idle just like I’ve always done with my carbs. Thanks again @chillman88 and @IDIBRONCO

 

[HammerDown]

Sounds to me like you're confusing the cold timing advance with the high idle solenoid?

Cold timing advance is in the pump, it sounds like what you're talking about is the high idle which is the small solenoid that pushes against the throttle lever next to where the throttle cable attaches. It has nothing to do with the advance piston and there's no cover to remove because it's not technically part of the IP.

I believe 'you' know what I'm referring to lol
On a dead cold start, pedal down 1/4 to 1/2 way, glow the plugs and fire it up... normally the the RPM's would be held-up then, as water temp hit 100 or so the 'thing' would kick-off and normal lower idle would be attained.
So, that is called... the "High Idle Solenoid"?
Can it be tested and or repaired?
Easy to replace?
Part number?

 

[IDIBRONCO]

So, that is called... the "High Idle Solenoid"?

Yes. most on here call it the high idle solenoid. I call it the fast idle solenoid simply out of habit. That's what we called it at the shop I used to work at.

Can it be tested and or repaired?

I don't think that it can be repaired. There's very limited testing that you can do with it. Basically you can put 12v power directly to the spade where the wire attaches to see if it works. If there's more testing that you can do, I don't know about it.

Easy to replace?

Yes. One wire, one double (from the factory) spring to remove, and two 1/4" bolts with 7/16" heads on them. The mounting bracket can be adjusted slightly so if you replace it, your idle may be higher or lower than it is now.

Part number?

I don't know that they are available new.

 

[chillman88]

@IDIBRONCO beat me to it and summed it up pretty good. The only thing I will add for clarity is it's not supposed to push the throttle open, but should hold it so if you're testing it you'll have to push the throttle lever up by hand but it should hold it up as long as it has power.

If it tests out good it's possible the temperature switch has gone bad (or possibly just gotten bumped and come unhooked).

Part number?

No clue but I think Classic Diesel Designs had some on his website at one point. I don't know if he still does or not.

 

[HammerDown]

Thanks fellas... is the "temperature switch" actually 'on' the fast idle solenoid or, is it a remote deal with a wire tapped into a water jacket?

 

[Nero]

It's remote, tapped into the water jacket, just left of the IP gear cover, it's a 2 pin sensor.

 

[HammerDown]

It's remote, tapped into the water jacket, just left of the IP gear cover, it's a 2 pin sensor.

Left of the IP as on the drivers side? (trying to picture where it's at) I've been looking at my 7.3 since new in 88 but never encountered this issue.

 

[IDIBRONCO]

If it tests out good it's possible the temperature switch has gone bad (or possibly just gotten bumped and come unhooked).

Or even just a dirty/bad connection. I've had that happen. I wiggled it and it started working and is still working 9 years later.

It's remote, tapped into the water jacket, just left of the IP gear cover, it's a 2 pin sensor.

It's right underneath the thermostat housing. It's underneath the lowest part of your upper radiator hose.

Left of the IP as on the drivers side?

Passenger's side instead of left.