Intermittent Non-Start Problem

[fizzkidz]

I have a 2003 Excursion with a 7.3 with 115K miles. For the last eight months I have had an intermittent non start problem. It could happen twice in one week or only once in a month. Every once in a while I will go to start and the starter will just crank with no fire. I will wait a little while and try again. May start may not. Just have to wait long enough. May take a few minutes to an hour but it has eventually always started. Very frustrating. It has never done this from a complete cold start. Always while I am out running around.

I have checked or replaced the following:

1. Batteries are good 6 month old.
2. Battery connections are good.
3. Brand New starter.
4. CPS sensor replaced under recall last month.
5. Wait to start light comes on and goes out as normal.
6. Once it decides to start it fires up as if nothing was never wrong and runs great.
7. No DTC codes.
8. Oil pressure comes up to normal level while cranking.
9. Finally got frustrated enough to take to dealer so they could run diagnostics. As I expected they couldn't find anything. Told me the only way they could figure it out is if it did it there.

Anyone have any suggestions on what else to check or how to check it? Is there a scan tool I can carry around with me so when it does it I can plug it in and read the sensors? Need some help here. Very frustrating!

[woodnthings8]

If you had a scan tool capable of reading the sensors "live data" you could help identify the issue. My Autoenginuity is one that reads this data. NExt time it does not start disconnect the ICP sensor and see if the truck starts up. The PCM will default to a setting of 500 psi when the ICP signal is lost, this will allow the truck to idle if the sensor fails.

The PCM needs to see a few things before it will send a signal to the injectors to fire.
V-Power needs to be 8 volt minimum
RPM needs to be 100 RPM minimum
ICP needs to be 500 PSI minimum
Fuel PW needs to be 1-6 ms

If this criteria is not met the truck will just spin over until the battery dies. You could have a problem with the ICP sensor, the IPR, or low high pressure oil. It is really hard to say on an intermittent issue. Also check the IPR to make sure the nut that holds the solenoid is tight. These often come loose and cause issues.

[fizzkidz]

Thanks for the info. I think I will order the AutoEnginuity and put it on my laptop so I can carry it around with me. Next time it happens I will be able to check it.