I have a 4.2 v6 f150 XLT extended cab with 170,000, no remoteless key entry. I am having an intermittent starting issue. The problem is getting worse.

I can drive the car all day, in and out with no starting problem at all. Then it happens. I get in, all the lights and gauges work, but it won't start. No crank, just silence. I replaced the fuel pump a year ago. Replaced the transmission almost 2 years ago. The battery is good I had it checked today. I removed and checked the starter it worked fine. I replaced the solenoid on the firewall. The truck started just fine. Made 1 stop, truck started fine. Made a 2nd stop at the grocery store, got back in the truck and nothing. No start, no clicking, lights and all are good.

What are my next options?

 

Automatic transmission? I'd suspect a flaky or misaligned MLPS (neutral safety switch). Try putting it in neutral to start it, wiggle the lever up and down and see if it will catch.

Manual transmission? Clutch pedal safety switch.

 

If it's intermittent and only happens after you use the starting system,, it's possibly a heat issue in one of the components???? Also could be like glc said too.

If you check stuff on a bench test it after you use it when it is hot or used .

 

I'm confident that it's not the neutral safety switch. I jiggled the handle around and attempted to start in neutral several times. No luck there.

 

I don't think it is a heat issue either. The truck has sat overnight and still won't start. I had to have it towed home again. I'm leaning more toward an electrical issue. I do appreciate all the advice and tips, please keep them coming.

thanks,

david

 

I think the battery cable may be corroded somewhere along the line. Not sure exactly where though. I will replace it Monday. I will keep this udpated.

david

 

Moving the gear selector won't do anything if the DTR ( Digital Transmission Range ) Sensor is where the problem is at.

Instead of random parts replacement, how about a step #1

When the key is in the start position, the DTR should pass + VDC to the starter motor relay on the firewall.

The Tan w/ Red stripe wire will have + VDC on it when the key is in the start position and the DTR is aligned to a park or neutral position ( as long as the DTR has not shifted on the trans or the connector corroded ).

Use a known good ground to the meter and to the lug the Tan w/ Red stripe wire is on.

If this is functioning, next is to make sure the Starter motor relay is closing.
- There are 2 large AWG wires on it, one is to the starter, the other to the battery via the fusible links.
Check that the side to the battery has + VDC on it.
If the Normally Open contacts are closing, the other side will also have + VDC on it.

If not, that shows the starter motor relay is bad.

 

SSCULLY, thank you for your advice. I've only replaced 1 part so far, the starter relay on the fire wall.

I will test the DTR tomorrow.

Thank you,

david