OK, this is on our '99 Ram 3500. After sitting for awhile, the truck doesn't want to start right away. It just turns over and over, but never actually firing up. We noticed that the "wait to start" light doesn't light up. If we cycle the key a few times and even bump the starter, then the "wait to start" light comes on and then it'll start.

Now for what we've done: Fuel pressure is good, 13 psi and better. Checked and replaced IAT sensor. Checked all relays and fuses. Preformed a APPS reset. Checked for codes; which shows none. Replaced the IP return check valve. Checked all fuel lines and banjo's for leaks and air leaks. Replaced fuel filter. We did buy a new APPS, but at $500, we are gonna wait intill ALL other avenues are explored.

Oh, this is on a completely stock '99 3500 2 wd service truck. The IP and LP were replaced by the dealer 3 years ago. Of course they installed an in-tank lift pump.

I'm thinking it has something to do with the heater grid system. The relays checked out ok, but what triggers them?

Please help. Please throw some advise at us. This has three Cummins and Cat certified mechanics STUMPED!!

 

If you have to cycle the key a few times to get the light to come on, have the switch checked out.

 

I wouldn't think it's the switch. Everything else works just fine from the switch. In fact when cold, if you just turn the key all the way forward, the starter will turn the motor; it just won't fire up and run.

 

Actually, I didn't state the above sequence correctly. If cold and we just turn the key all the way foward, the starter will turn the motor and it'll not start running. But if we floor the throttle while cranking on the starter, it'll cough to life.

Any ideas?

 

I would say grid heaters are not coming on as well. I know the relays for them are triggered by the ecu and are located right below the drivers side battary. You may check that relay if you havent already. One of mine stuck on but have heard they can stick the other way as well.

 

I know I'm SoCal now and never even think about the cold start procedures and the "wait to start" light, but if you're having problems and you don't think the heater grid is working, put the throttle at about halfway and crank it-- once upon a time I lived in Eastern Washington state after that, Baltimore-- it should fire to life; it will sound like there are about 40 little demons with jackhammers slamming away inside the engine, but it will run. I know that's not the answer, but it's a quicker way to get it running and the oil flowing. On an outside thought, as a crutch, have you thought about plugging it in?