I have a 99 Lariat witha 5.4 (see mods in signature). It is in the mid 30's today and it took a little bit longer to crank this morning. Ran fine and I parked it for about 8 hours. Got back in and it would turn over but not crank. Before I killed the battery I got out to check fuel pressure at the fuel rail - no problem, got gas all over my hand. Jumped bac in the truck and tried again. It spun for about 10 seconds and cranked. Ran smooth without any hesitation or engine light on the dash.

Ran about 10 miles and came to a stop light and it died. Would not crank. Verified fuel pressure again - no problem. Spun it over multiple times trying to get it to crank with no luck. Almost killed the battery trying to get it to crank - noticed the odometer is reading all dashes [---------]. Tried again and it slowly spun about 5 times befor the dreaded cliking of a dead battery.

The only thing I can think of is the SuperChip may be partially plugged in. I pulled the battery and carried it home to charge it up once the wife picked me up. I am going to try to crank it tommorrow morning (pulling the chip after the first try). If anybody knows anything else that I can try let me know.

Tony
tonytsquared@yahoo.com

 

I know this seems silly - but if you have the original battery, can't help but wonder if that is the problem. Weak batteries can cause all sorts of weird problems with these electronically controlled vehicles. I have a 1999 F-150 5.4 and replaced the battery this past fall just because I thought five years was long enough. Hate to wait until they start to fail and have to troubleshoot the starting problem. Been there, done that.

 

Check your Idle Air Control valve.

 

Battery is less than a year old - It has plenty of power.

IAC has less than 6k on it - they seem to last about 30k for me on this truck.

Put the charged battey in the truck this morning and it fired right up with no problems??? Ran with out any issues and no idiot engine light came on... Don't know why it crapped on me yesterday but I will be keeping an eye on it for a while.

 

It has been running fine until today. It died while running down the road @ 45 mph. No warning, it just shut off and the instruments went dead. The odometer was set to trip mode and it displayed all dashes. I dropped into neutral and tried to crank, it just spun without firing.

I pulled it off the road and turned off the truck, the odometer displayed the total milage (I had not toggled it back), and tried it again - it fired without any problem. Ran 2 miles back to the house and shut it down and tried it again - no problem. No check engine light or other indicators. I borrowed my neighbors OBD II reader and there are no codes stored in the computer.

Any ideas?

 

Take out your Superchip, clean the terminals and duct tape the chip in place.

Fritz

 

I know on the older cars, the alternator runs the engine after it has started. That is why you can pull out a battery with an engine running. I think I remember hearing something about a minimum voltage needed by the computer to run. If the alternator is not putting out the juice maybe it won't start and your battery is not getting charged fully, just enough for it to turn over but not start. It would also give reason as to why the system just shuts off while you are driving down the road. Seeing the dashes reminds me that the odometer is also a part diagnostic tool and if it gives dashes maybe it is not seeing the computer anymore. I would check the alternator for a problem. If it is okay, maybe the computer.

Brian

 

Fritzthecat has the answer. It left me again this afternoon. Would not crank. Removed the Superchip and it started right up.

I have had the chip installed since it had 1k for the past 5 years. The contacts look OK on the chip but I will leave it off until I can get time to pull the computer and clean both the board and the chip. I need to pull the computer so that I can clean the tape residue off the outside of the box anyway....