On the way home last night my 01 7.3 went about 1/2 mile then ran rough and then stalled. I havn't been able to start it since. It will crank but will not start. I have checked the fuel filter, and changed the CPS. What else should I try???? It is a stock truck with only 78,000 miles.

 

CPS??? is my first thought. Second, fuel! You might open the drain on the fuel filter and then turn the key on. The fuel pump would continue to pump fuel, ok? Also, check your oil level, low oil level and truck won't run.

 

Can you describe the rough running a little better? Let's start with the basics. Is the engine oil clean and full? How much fuel in the tank when this happened? If you open the drain valve of the fuel filter bowl with the key on, do you have a strong steady steam out the drain tube?

How long did you try to crank it before you changed the CPS? Could you have worn your batteries down to the point where the IDM doesn't see enough voltage to fire the injectors? Any smoke or smell out the tail pipe when cranking? Have you checked all your fuses?

 

^^^^^What he said.^^^^^^
Make sure the fuel pump is running when you turn on the ignition, etc.

 

Thanks for the help! Chris, a discription of the rough engine was it seemed to be missing and lossing power then stalled. It happened fairly quick almost like it was starved of fuel. The week previous it ran rough too but never stalled.

I did open the fuel filter with the key on and there was some fuel coming out but it wasn't a stiff steady stream. The truck was cold when all this happened. It was about 15 degrees that day. The fuel tank is between 1/2 and 3/4 full. Chris had a good idea to check the battery voltage level after I changed the CPS. It was still cranking fine so I didn't think to check that. At what voltage will the injectors stop firing? The engine oil I use is Rotella 5W40 synthetic due to the cold climite where we live. It is changed every 5,000miles and I think I am getting close to changing it again. Another issue I thought of was fuel possible gelling however I have been adding Stanadyne every fill up. Anyway let me know what else I can try. Thanks for all the help!

Matt

 

If power drops below 10.5 volts while cranking the injectors won't fire, no matter how well the engine sounds like it's spinning.

If you don't have a stiff steady stream coming out of the drain with the key on, then it sounds like a fuel delivery issue. Possibilities would include a bad pump, shorted wires, or obstruction in the tank (including the possibility of gelled fuel).

You can take some of the treated fuel from your truck and put it in a glass or plastic jar. Leave it outside and check it in the morning. You'll be able to tell by looking at it if that's a problem.

When the key is first turned on, you should hear the fuel pump humming for 20 seconds. The pump is attached to the frame below where the drivers seat is. If it's not running or doesn't sound like an electric pump should, check the voltage on the wires going to the pump.

If you want to check for obstructions, the easiest way I know is to disconnect the line off the front of the pump and stick a short hose on there. Turn the key on and watch how the fuel comes out. Then disconnect the fuel line from the back of the pump, put a hose on the back end and dip it into a small container of fuel. Repeat the key on observation and see if you notice a difference. If the pump level seems weak in both cases and the voltage is good, you'll need a new pump.

You'll need a fuel line disconnect tool to get the lines off the fuel pump.

 

Thanks Chris!

I will try these things. Isn't there a fuel pump also in the tank as well as on the drivers side frame rail? Where can I get the fuel line disconnect tool?

Another questions is...on start up how is fuel supplied to the engine after the fuel filter since there is not any high oil presure to the injectors? When this all happened I opened up the fuel filter and it was full of fuel.

Is Stanadyne a good fuel lube for the Low Sulfur gunk we buy now? Also do you know if it does well as an anti gel additive. I have heard that it is what the injector pump shops recommend. What do you think?

Thanks again for the help!

Matt

 

Some of the cab & chasis models have a fuel pump in the tank. The rest of us only have the one on the frame rail.

The electric fuel pump is an always on (or at least supposed to be) pump that supplies the fuel to the filter bowl. Excess fuel is returned from the bowl through the tank controlled by a FPR (fuel pressure regulator) When the fuel leaves the bowl, it is pumped into fuel rails that are integral to the heads. Fuel is pumped through the rail into the injectors. The HPOP (high pressure oil pump) sends high pressure oil (up to 3000 psi) through another rail in the head which is used to send the pressurized fuel into the cylinder. That's why we don't have an injector pump.

Stanadyne is a great product. I wouldn't hesitate using it. I know they offer different products, so you'll have to wait for someone else to chime in regarding the anti-gel properties. We don't use anti-gel stuff down here, and run #2 year around. Sunny and 82 today.

 

Sunny and 8 degrees here this morning!

My cab/chasis combo is 2001 F350 6-speed XLT 78,000miles and all stock still.

Does anyone ever have problems with the HPOP not sending 3,000 psi to the injectors and what would the symptoms look like? lHow do these injectors fire when the truck is not running and there is not any oil pressure on start up. Is this HPOP mechanical or electric? Is there any maintence to be done up in this area to make the injectors and oil pump last longer?

Thanks again for all the help I am off to the hagar to try some of these things!

Matt

 

Steel tank? There have been issues with the coating coming off the inside of the steel tanks and plugging the fuel pick up.