How "HIGH" should the high idle be at initial startup?

[blakpete91]

Almost every morning before I head out to class I start my rig up and let her warm up to operating temps before I move her. It will idle normally for the first 10 seconds then it kicks into "high idle" mode, my guess is to help warm up. It revs up to around 2100 RPMS and holds there for 5-8 min. then clicks off and returns to normal idle RPM's. Is this normal or is it to high?

 

[Hydro-idi]

That is not normal. Your high idle solenoid should be set right around 1200 rpm and normal idle should be around 700 rpm. The high idle can be set by tapping the pedal right after initial startup. 2100 rpm is way too high

 

[91idi]

^^x2!
1200 is as high as it needs to be. Are you sure the tac is correct?

 

[hesutton]

High idle is typically 800-900 RPM. Gotta adjust the plunger on the solenoid.

Heath

 

[blakpete91]

Tac is correct no doubt. Truck is stock. I turned my IP up half a flat but it was doing this before I messed with anything. How should I go about diagnosing this or changing the high idle?

 

[mblaney]

look at the throttle lever on your IP. there is a solenoid that holds the higher rpm when cold, and drops it down on the idle adjust screw when warmed up. the solenoid plunger has a hex head where it contacts the throttle lever, just screw it in to adjust. IIRC I think it takes a 1/4" wrench.

 

[stumiister]

FWIW I have my truck set at 900rpm high idle when cold and when its at operating temp the idle is at 600rpm or 650 I just dont remember, but 2100 is defenitly way too high

 

[icanfixall]

About all the above postings are correct. Your cold idle setting is way too high. The proper way to set it when you attempt a cold start is to turn on the kry. them step on the throttle peddle to set the cold rpm. Reason for stepping on the peddle is the solenoid is not powerfull enough to set this by itself. You will overload the solenoid and burn it out if you don'r Hhelp it" by pressing on the peddle once. Now for making any adjustments. Its true the hex is a 1/4 inch heax. I like useing a 1/4 inch drive wrachet and socket. This is a very fine thread so lots of turns may be needed. Another way to sometimes adjust this is the solenoid bracket. Loosen the two bolts that holds it to the pump and move it towards the firewall to increase or towards the radiater to decrease the rpm. There is a little play in the bracket bolt holes and many times this is all thats required for adjustments. I have found after removing this bracket to make more room when adjusting the timing I have to readjust the cold rpm. I now have make adjustments with the bracket in the forwards or backwards postiton so all changes will result in the same cold rpm setting no matter what pump I install on my engine.

 

[whalebus]

Do not want to hijack the thread but what controls the cold idle soliniod? I have manual glow plugs and Im guessing one of the wires to the controller was for that right?

 

[justinray]

Do not want to hijack the thread but what controls the cold idle soliniod? I have manual glow plugs and Im guessing one of the wires to the controller was for that right?

No, its the coolant temp sensor, and a little solenoid like power door locks use.

 

[homelessduck]

Gary- You're saying we should always use the cold idle advance to prevent the solenoid from burning up?
I rarely use it because my truck starts up and idles smooth even when it's super cold out. I didn't stop to think that the solenoid was overloading trying to push the throttle lever.

 

[icanfixall]

Yes. Always push down on the throttle peddle after the key is turned on waiting for the glow plug lite to turn off. That fast idle solenoid can't make enough force to open the throttle. So our foot has to help it along. We don't have a throttle plunger like a gasser carb has. So no amount of "pumping" the throttle will gat any fuel enter the engine. Remember we have an injectable fuel source thats only working when the engine is turning over.

 

[IDIDieselJohn]

I always fire mine up cold without touching the throttle, let them low idle for 10-20 seconds, then tap the gas to get it on high idle.

My 7.3 idles cold at 900RPM and warm idle at 600.

 

[homelessduck]

I always cringe at the thought of a cold engine with all the oil in the pan revving high, even though the high idle doesn't even rev that high . I'll start doing that though, I don't want to burn up the solenoid.

 

[franklin2]

You will not burn up the solenoid by not tapping the throttle. As long as the metal plunger is in the center of the coil of the solenoid, it will be fine. It will not hurt it to be pushing on the throttle, but not being able to physically move it.

Which brings up a question on the original post that started this thread; From his description, he starts the engine normally, it idles normally, and then revs up to 2100rpm. How can that be? We all know the solenoid doesn't have enough power to open the throttle by itself. So why is the engine rpm flaring up on it's own?

I also believe the best way to set the high idle speed would be with the engine fully warmed up. The initial rpm is drastically affected by the temperature and the viscosity of the oil you are using. I don't have mine hooked up, but I can hold my foot steady on the throttle, and as the engine runs for a few minutes, it's going faster and faster at a gradual rate as the oil and everything else warms up.