No Cold Start Assist

[gaylemarlowe]

Hi Guys,

Have a 2005 Newmar Dutch Star with 400 Cat. During cold weather, starting without using the block heater takes forever. If I don't use the block heater it will crank quite rapidly, but won't start firing until it has cranked for 15-20 seconds.Then when it does start firing, it misses quite a bit and smokes a lot. After all cylinders are firing it quits smoking and seems okay.

Cat manual that came with the coach says it has a heater in the intake and a light on the dash that lights up when it is cold enough.

After looking at all the intake hardware, I don't see what could be a heater and I don't get any lights on the dash when I turn the key on and it is cold.

Is it possible this one came without a heater? Or is it somewhere I don't see it and the dash light is there and not illuminating?

I know you guys will educate me very quickly!

Thanks in advance for your responses.

[wolfe10]

Yes, your Caterpillar C9 will have an intake manifold heater (as do all their engines as well as Cummins engines).

There are two things that would be at the top of my list for your symptoms:

1. The intake manifold heater is not working. Locate it (heavy wire going to the intake manifold from a relay that is likely right there on the top of the engine (I have not worked on the C9, so don't know the exact location). Put a volt meter on it, and with the engine cold, turn the key to the first or second position (depends on chassis). In other words the position before the starter engages. In this position, the intake manifold heater should be on-- how long it is on depends on temperature. In very cold temperatures, it can even stay on after the engine has started. Have someone monitor the voltmeter. You could have a problem with the relay, a fuse or wiring from ignition switch. And, yes, you should have a dash light for the heater. Check with your chassis manual or coach manual for its location.

2. Low fuel pressure will cause the same symptoms, and in cold weather, metal shrinks, making fuel systems more leaks prone. If you have the Caterpillar manual primer pump on the secondary fuel filter, unscrew it (turn the knob counter-clockwise) then pump it in/out. It should be very hard to pump, indicating that you are trying to compress fuel. When finished, be sure to push the plunger all the way in and screw it in to lock (clockwise) If it pumps easily, there is air in the system or the fuel pressure has bled off (injector or more likely the check valve in the fuel return port). If this is the problem, pumping the manual pump will give you fuel pressure and a "normal" start.

[gaylemarlowe]

Thanks Wolfe, I will do those checks tomorrow and let you know what I find.

[tbutler]

On our coach the light on the dash is labeled "Wait To Start." When it goes out we can start the engine. That gives the heater time to warm up.

[billbaldwin]

I use the block heater on my Cummins if the temp gets into the teens.

Work great

[tbutler]

I use the tires and the accelerator if the temperature gets into the teens. Get me out of there!

[gaylemarlowe]

Did the checks on the electrical that Wolfe suggested and did not get very far. No voltage to the heating element and no voltage to the relay when the key is turned on. Went thru my Spartan chassis manual looking for a wiring diagram, but no luck.

I have exhausted my talents on this, so will take it to the Cat dealer here in town for a hopefully, easy fix.

Will still let you know what was the culprit after it gets fixed.

[billbaldwin]

I'm with TBUTLER....head south

[BillAdams]

Would the heating element "also" come on or does it only come on when it's a certain temperature outside? If it needs cold, is it currently cold enough where you are?

I know nothing about your engine....just askin'.

[wolfe10]

Bill is correct. If is is 80 degrees F out, the heater may not come on and that may be OK.

Caterpillar Corp (yes in Peoria, IL, not India) can look up at what temperature your intake heater should come on. Call them with your engine serial number: 877 777-3126.

[gaylemarlowe]

Was 48 deg yesterday morning when I checked it, so it should have been cold enough for it to come on. Am getting a wiring diagram from Spartan, should be in email today, but may not help.

[wolfe10]

You will want to locate the wire/terminal on the relay (the one on the engine) that is used to close/turn on the intake manifold heater. Likely it will be a 12 VDC positive, but could be the relay ground. If it is not getting the proper "signal" you have an ignition switch or wiring issue. If it is getting the correct signal, it is likely that the relay is bad.