Slow engine warm up

Topic: Slow engine warm up (Read 1217 times) previous topic - next topic

Re: Slow engine warm up

Reply #25 – August 17, 2021, 08:13:55 am

King Throttle Control could be a suspect.

How about the turbo waste gate and control ?

Is the waste gate controlled by the Fuel Injection Pump on the C8.3--asking for a friend ?

Re: Slow engine warm up

Reply #26 – August 17, 2021, 08:29:44 am

Could be fuel solenoid,could be sticking and just coincidence it unsticks at 150 degrees,if the fuel filters are near changing
mileage change them now and see if it helps,it will eliminate one posibility.Also it would not hurt to remove the air filter and check
over,will eliminate another potential problem.With engine cold you can remove the air intake piping to the turbo and stick you hand
in the turbo and see if the impeller spins freely,may be unsticking when warm,make one change at a time so if it gets cured you know exactly what it was.

Re: Slow engine warm up

Reply #27 – August 17, 2021, 09:51:53 am

OP quote.....
"cannot get more than 2,000 RPM out of the engine and just getting out of the campground in the morning is a struggle "

First question is.....
Is the engine actually at 2000 rpm? or just above idle (1000rpm)
Sounds like the answer is no. This should be easy enough to determine by ear with the window down .

If at 2000 rpm and in first gear, leaving the campground ( most any campground) should not be a problem. Unless he has a transmission problem. (Slipping?)

Is it a fuel or throttle problem? Probably not IF... the tach shows 2000 rpm and it's actually 2000 rpm.

Second question I have is :
What does the Allison shift pad show?
First gear or perhaps a higher gear.

As stated in a post above, if the tach is showing 2000 rpm and the engine actual rpm is much less than that, then there is the problem. Why would it be related to engine temp? Maybe it's just a coincidence.

Would like to know what the OP finds as the problem.

Remote trouble shooting is not the most effective way to diagnose a problem. 🙄

Re: Slow engine warm up

Reply #28 – August 17, 2021, 10:20:32 am

Quote from: Dan & Annie – August 16, 2021, 10:24:01 pm

New speedo and tach are VDO.

http://www.vdo-instruments.com/media/instructions/0%20515%20012%20037%20--%20Programmable%20Tach%20with%20hourmeter(c).pdf

Re: Slow engine warm up

Reply #29 – August 17, 2021, 10:27:59 am

If the brake lights are on, the King Throttle Control will only give 1/3 throttle but
I don't see how this could be related to engine temperature. As Justin said if your
engine RPM is 2000 that's way more power than you need to get out of a campground .

Re: Slow engine warm up

Reply #30 – August 17, 2021, 10:31:31 am

Quote from: CRY42 – August 17, 2021, 08:13:55 am

Is the waste gate controlled by the Fuel Injection Pump on the C8.3--asking for a friend ?

AFAIK, the waste gate on the mechanical C8.3 is controlled by spring pressure, and opened by intake manifold pressure. Spring holds the waste gate closed. When intake manifold pressure exceeds the spring rating, the waste gate opens...usually around 22 PSI of intake manifold pressure (boost pressure) on a stock 300hp engine like mine.

I don't THINK the P7100 fuel injection pump has any direct control over the waste gate actuation, but I could be wrong. The hose that supplies intake manifold pressure (boost pressure) to the waste gate actuator also supplies a boost pressure signal to the injection pump. There is a "T" in the hose so boost pressure goes to both places.

Re: Slow engine warm up

Reply #31 – August 17, 2021, 10:46:07 am

I ordered the BlueFire engine monitoring system this morning, along with the adapter for my old-style 12-pin diagnostic port. That may give us a bit more info.
BlueFire LLC. 9-Pin J1939/J1708 Green Bluetooth Apple/Android/Windows Adapter

Re: Slow engine warm up

Reply #32 – August 17, 2021, 04:15:53 pm

Thanks for you clear description of your low power situation. . . Continue reading if you have a C-8.3 mechanical Cummins engine

"If King Control board cannot see a working ground circuit through brake lamp bulbs, it will not accelerate above minimum RPM.

King Control manages cruise control and on our vehicle also throttle control. Because King Cruise Control needs to turn off when brake lights come on, it wants to be sure it is connected to brake light circuit, so it has a wired connection to the wire that goes to rear brake lamps. If some reason it cannot see a ground, because of wire connection problem or brake bulb filament burned out, or brake bulbs missing, etc, there will be limited throttle.

We also had the same limited throttle when our fuel shut-off solenoid only partly opened due to a problem solenoid. Replacing the fuel solenoid fixed our throttle problem."

Above is our 8-yr old post. Both problems can be diagnosed with easy bypasses.

IF fuel shut off is limiting power, when it happens, manually fully lift solenoid up and hold in place with cable tie. Later when you arrive at destination, cut cable tie to turn off engine.

IF King control, find with King wiring diagram, the single wire that is connected to rear brake light positive wire, which will turn off cruise if 12v+ is sensed, and put throttle in limp mode if 12v-negative is NOT sensed. A stuck brake light switch will turn on brake lights and will keep throttle from working.

Some LED brake light bulbs have been known to cause King limp mode.

You could do what we have done, which is to add a new incandescent 12v bulb to outer front of bed panel, with a good ground and connecting the 12v+ side of bulb to the brake light positive wire. We know when brake lights are on from driver's seat.

Re: Slow engine warm up

Reply #33 – August 17, 2021, 05:03:15 pm

We have 98 U270 with late 97 C8.3 325 hp. A partially sticking fuel solenoid was keeping us from making power pulling away from our campsite in June. I first changed both fuel filters, no improvement. Then verified my King throttle was giving full throttle. Checked turbo plumbing. Pulled air filter. Next grabbed fuel shut off butterfly valve after start with my hand It was stuck halfway. Your rpm values seem off to me. 1850 RPM is 65 mph for me. Good hunting.

Re: Slow engine warm up

Reply #34 – September 17, 2021, 12:57:34 pm

Problem solved. I read up on the King Controls electronic throttle system, and how it delivers only 1/3 power when there is problem with the ground feed from the brake system. That sounds like it might be what's going on so I lifted the bed and watched the function of the actuator as my wife pressed on the accelerator up front. It only pulled about a half inch of cable. I reach in and advance the throttle by hand, and RPM's shoot way up. That's it.
I checked the brake lights out back, all good. I pulled the main power and control panel wiring connections apart and checked things with the multimeter, as directed in the trouble shooting guide. Found nothing obvious, but when I plugged those harnesses back together, the problem resolved. I'll check again in the morning when things have cooled down, but my thinking is that it's not the engine temp per se that keeps me from getting power from the engine, but rather bad contacts inside the electrical connections to the King Controls, and it's not until the engine runs long enough to warm the compartment under the bed and thus the plastic wiring connectors so they reform and make better contact.
So question: What can I do now to ensure better contacts inside those connectors? My understanding is that dielectric grease is a non-conductive insulator so I'm not sure I want to use that, but is there something else I might apply?

Re: Slow engine warm up

Reply #35 – September 17, 2021, 01:16:21 pm

Contact cleaner often helps and if the connector is too bad remove the
connector and replace it with another type of connectors.

Re: Slow engine warm up

Reply #36 – September 17, 2021, 02:04:51 pm

Nothing wrong with dielectric grease, particularly in a wet location.

The metal to metal contact conducts the current. The grease keeps water in dirt out.

Been doing that on marine wiring (think salt environment) for decades.

Re: Slow engine warm up

Reply #37 – September 17, 2021, 02:16:26 pm

I spray my connectors with ATF . Works fine . Makes a little mess.

Re: Slow engine warm up

Reply #38 – September 17, 2021, 06:07:18 pm

Look at reply 26 again,give Larry b's a call on Ebay,he may have the connector or know the brand and source.

Re: Slow engine warm up

Reply #39 – September 20, 2021, 02:39:14 pm

I cleaned the connectors with CRC contact cleaner, applied dielectric grease and put them back together. I really think this was the problem. It's been working fine for 3 days now.
Thanks everybody for your suggestions, especially those who mentioned the King Controls as a possibility.

Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 12, 2025 ...

Re: Slow engine warm up

Reply #25 – August 17, 2021, 08:13:55 am

Re: Slow engine warm up

Reply #26 – August 17, 2021, 08:29:44 am

Re: Slow engine warm up

Reply #27 – August 17, 2021, 09:51:53 am

Re: Slow engine warm up

Reply #28 – August 17, 2021, 10:20:32 am

Re: Slow engine warm up

Reply #29 – August 17, 2021, 10:27:59 am

Re: Slow engine warm up

Reply #30 – August 17, 2021, 10:31:31 am

Re: Slow engine warm up

Reply #31 – August 17, 2021, 10:46:07 am

Re: Slow engine warm up

Reply #32 – August 17, 2021, 04:15:53 pm

Re: Slow engine warm up

Reply #33 – August 17, 2021, 05:03:15 pm

Re: Slow engine warm up

Reply #34 – September 17, 2021, 12:57:34 pm

Re: Slow engine warm up

Reply #35 – September 17, 2021, 01:16:21 pm

Re: Slow engine warm up

Reply #36 – September 17, 2021, 02:04:51 pm

Re: Slow engine warm up

Reply #37 – September 17, 2021, 02:16:26 pm

Re: Slow engine warm up

Reply #38 – September 17, 2021, 06:07:18 pm

Re: Slow engine warm up

Reply #39 – September 20, 2021, 02:39:14 pm

Affiliate Notice