Check Engine Light

[Steve Huber Co-Admin]

Mike,
The C9 is designed to run hot to help meet emissions requirements. Thus one has to watch it when climbing hills, etc. The side radiator has a wax valve that will control fan speed based on engine temperature. When climbing hills, you don't want to lug the engine. Additionally you don't want to run the RPMs any higher than needed as all that does is generate more heat with no benefit. When climbing grades, take it out of cruise control. Target your RPM for max torque. Specs show that  max torque for a C9 is about 1500 RPM. I find that I get the best results running 1700-1800 RPM when climbing. Watch your engine temp on the Aladdin. It will normally increase a few degrees as you start to climb. If it continues to increase and RPM drops, downshift to keep RPMs in the 1700-1800 range. Don't worry about speed. Drive to manage RPM and temperature.
Steve

[Mike McGill]

Thanks Steve this is a big help when Dave ran his report it showed I was lugging the motor a lot so I'll manage the RPMs thanks
Mike

[Eric Maclean]

Mike some codes (circuit related) should set even when the key is turned on only  but most have to be set by reaching a predetermined criteria programed into the ECM ( data related).

Engine lugging may account for the high intake temperature especially on a C9 at 400HP but it is a good idea to keep an eye on
The radiator stack as the side radiators tend to pick up a lot of dust and dirt from the road and can plug the radiator and
 CAC (charge air cooler )fins deminishing the cooling ability of the stack.
And as Steve explained the cooling fan is regulated by a wax pellet valve that controls the hydraulic fan motor speed but even with full engagement the fan speed is still directly proportional to engine RPM so as you can see when lugging the RPM are pulled down as the  engine luggs down there is more heat generated than there is air flow pulled through the cooling stack to deal with and as a result intake and eventually engine coolant temperatures start to climb .on your aladin you can monitor this as you climb hill the first thing to happen is the intake air temperature with start to climb and several seconds later ( long climb) the coolant temperature will start to raise this is normal to an extent but lugging can drive the temps into an over heat situation.

How ever Keep in mind these coaches have side radiators and there fore don't benefit from the ram air effect of the vehicle moving through the air like a car dose with the rad up front and the only air which goes through the rad on our coaches is pumped through so to speak by the fan so it is important to keep the rad stack clean and the fan shroud has to be intact and complete to insure the air is being pulled through the rad and not in from the sides.
Lugging is to be avoided.

Hope some of this helps
Eric

[Mike McGill]

Yes I does thanks Eric I will keep you guys posted as I work through the wires today

[Mike McGill]

Ok a quick up date both oil sensors are down behind the blow by hose so I remover the hose to dig in a little deeper. the wires on both sensors look in good shape and had no corrosion. Im not sure where to look to follow these wires to the next connection its a little tight in the engine compartment and I'm kind of a full figured guy ha. I'll keep digging tomorrow. BTW the forum has really been a lot of help.

[Eric Maclean]

Mike
In post #3 in this thread I included a link to a diagram which shows the location of the coil pressure sensor and the ECM plug they are both on the passenger side of the engine block and the wire harness is shown as well the harness is quite short between the oil pressure sensor and the ECM.
Eric

[Mike McGill]

Steve and Eric first thank you both for your time and staying with me on this problem. I wanted to give you a up date my local Diesel tech ( Good Guy )came out to check out my coach.
He looked at all the wires connected to the oil sensors back to the Computer.
All connections look good all wires also good With this in mind he felt the next thing to do was to go ahead and replace the Cat oil sensor witch I already had. He said he had this problem on another coach and this fixed the problem. So I hoping this fixed the problem.
I will be heading out at the end of the month and send you both a up date.
Thanks again
Mike McGill
Beaver Montray
Cat C9
Solvang Ca

[Mike McGill]

A quick up date on my check engine light we replaced the oil pressure sensor and the coach is running great. Thank you to Steve and Eric and the Form for all your direction and help.