After the inertia switch the next stop is the fuel pump. As for your test light: when you first turn the key to "on" the ECM will run the pump for a second or so to prime the injectors and then turn off on its own until you turn the key to "start" when it should turn back on and stay running. So, if you see the light turn on then shut down, that means everything is working properly. If the light stays on, that means the pump is running continuously, which it shouldn't be doing.

 

I totally agree with you Maticuno and thanks for the advice. As that is what bewilders me is when I turn the key on if it cycles the test light on and then off signifying normal it will always start, initially anyway. But when I cycle the Ign on and the test light remains lit and does not cycle off. this is when my truck will not start ? So does this mean my pump should be running continuous ? Or does the power go through the inertia switch to one of the fuel/press/pump control modules that are generally mounted under the spare, or is this exempt on the F-350s?
Iam positive at this point having my test light hooked up at inertia switch on fp side that this is the issue when truck won't start. I'll be checking more tomorrow as well as actual fuel pressure with gauge hooked up. Thanks again guy's.........until then !

 

If you have power at the inertia switch, and the switch is working properly, that means the fuel pump is running. There are no other stops on the way. The inertia switch is the last check point. Try hooking the code reader up when it does this. When my ECM went out it wouldn't throw a code, but if the truck wouldn't start or would start and sputter dead, the code reader would be unable to connect to the ECM. To verify: try starting the truck. If it doesn't start or sputters dead, leave the key ON then plug in the code reader. If the code reader can't connect, then it's likely a bad ECM.

 

Ok, my truck has been in the crank but won't fire mode for the last few days so I finally got to check some things. Battery voltage 12.88 volts, through the cable etc. Fuel Pressure 41psi, all fuses good, critical fuses checked for voltage both sides no sig. difference noted. swapped fuel pump relay as well as interchanged other questionable relays as far as computer related, fuel pump etc. With my test light hooked up constant on the fuel pump side of the inertia switch. Key to run position I do not get a pulse, but a constant 12 volts when I turn Ign to run. The fuel pump is running, gauge reads 41 psi even after bleeding off. I took #1 coil power wire plugged into a extra coil I had and to my spark tester, cranking I have good spark at test plug. Now with this dilemma having a constant 12 signal with key on, although I do have a check engine light laminated with key on and I believe when cranking when I hook up my scanner with key off/ then key on my scanner is continually saying attempting to connect but never does ??
This is where I'm going to need some help as what would create a steady 12volt continuous through the inertia switch? I'm going to remove my computer in the morning and remove the super chip that is installed in it to see if there is any results ! Otherwise gentlemen, I'm all ears, stumped, baffled and tired.......till then guys again your thanks !

 

And Johnfist : the original problem I had was dying while going down the highway just like someone turned the key off, rain or shine. As you coasted off the highway and to the shoulder I would sit there, could crank but no start for 10-15 mins. It would then fire up and might run for the next two weeks, two tanks of gas what ever, no rhyme or reason. One time I drove to a friends house about 10-15 miles was there for about 30-45 mins went to leave, just cranked, he had carb cleaner so I fogged it and it fired right up but wouldn't idle on it own. I disconnected MAF it fired on its own, I hurried and got about 3 miles away it died, cranked it nothing, got out fogged it, acted like it wanted to fire. plugged MAF back in and it fired. Made it about a mile and it died and 2would not restart. I had about a hour wait for a tow and had run my battery down so a guy offered me a jump, it fired up and drop remainder home !
And Im50Fast : That was a little sarcasium on my part although be it age of parts or not I'm not a person that hangs parts till problem goes away, ie "parts swapper".And having owned this truck since new, I'm the one that chipped it and have had zero problems with it, but not to say, maybe not damaged like mentioned but chip has given up??

 

A bad ECM can cause weird and random problems. Hopefully for your case it's just the Super Chip making the ECM freak out. When you remove the Super Chip, check the board for damage. On mine one of the capacitors had been bent over when the chip was installed, and that flex on the solder caused it, over time, to loosen up and quit making contact.

At this point I would not suspect the fuel pump relay. If it turns on at all and turns off when you turn the key off, then the relay is doing exactly whatever the ECM is telling it to do.

 

 

Sounds like the computer is "crashing" after initial key-on - anyone taking bets on the Superchip?

 

Either the chip is the direct cause, or installation of the chip damaged something. The symptoms don't point to much else.

 

Nope not on my life and I'm sorry for not getting back to everyone sooner but that's the luxury of a third car ! lol
Any way update, 1) fuel pressure key on not running 42 psi 2) having a test light on the fuel pump side of the inertia switch was huge ! If I turned key on and light pulsed truck always fired right up. If key on and solid signal through switch I had the 42 psi from pump, also had spark to coils when cranking but would not start ? I suspected the signal to injectors wasn't there but didn't want to rig extra wires to check as I was alone and arms weren't long enough to crank as well as check for inj sig with tester. So frustrated I disconnected battery that night to start from scratch with 12v signal to computer next day.
The next day I came down to my shop and before starting with battery I pulled my computer checking all connections but more so to access my Jet Performance Chip I installed on my truck 16 yrs ago when I bought this truck new. Yes I am the original owner and a ASE Certified automotive tech, but a tired and worn out one ! lol.
I had no water damage to the area where the ECM goes through firewall, I removed my Jet chip, loosely installed ECM hooked up battery and turned key to see a pulse, cranked and fired right up !! YIPPY But did I kind of re-flash my computer with battery disconnect or was chip bad ? And keep n mind my original issue was truck would for no reason die while running down the highway to sit on the shoulder for 15 to 30 minutes to fire up again and run for maybe another week or two. I never had a test light or equipment with me to test and it always started up about the time I was ready to test it.
So I have driven it non stop for three days and 3/4 of a tank of gas so far it hasn't missed a beat, restarts every time I come out engine hot or cold, fingers crossed and thanks guy's. But why would my chip completely die after 16 yrs ? I'm contacting Jet Performance as they have a different part # for my truck now and I don't expect it to be under warrantee just want some answers. And yes I still run my K&N air filter, new had oil issues on MAF but I only oil the outside of it as there seems to be some bias in here toward some performance mods or I detected that anyway. So I won't tell you about my high dollar Gibson muffler delete when it rusted out ! I just run the cat with custom duals and it's throaty as hell ! My 2 cents guy's more exhaust stuff coming soon, through all of this I noticed a bold broke off on #3 exhaust manifold so possibly shorty headers and the new style y pipe soon. Thanks again

 

With engine running fuel pressure is 34 psi, regulator bypassed 43 psi just for information. Thanks again Richmo

 

The contacts on the edge-connector on that chip weaken over time and eventually start to lose connection. There could also be a cold solder joint in the chip itself. Crap happens

 

I just thought I would stop in and tell everyone that my truck hasn't missed, died or had any problems since removing the superchip from my computer. It is down just a smidge on performance but not that noticeable. Take care all.....Rich

 

Great news! If you want some power back, get a 5-Star Tune and tuner combo. I got one after removing my defective chip and it's way better.

 

You mentioned getting power back ? Although mine has had a few mods done. Could you possibly elaborate on what is done and cost to turn these 10 chipmunks into some fire breathing gas eaters ? And also how could I flag this thread on the opening page that it's solved so readers don't have to read a novel to see what fixed mine ? Lol thanks again......Rich