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Discussion Starter · #1 ·
Hello,

I've recently acquired an 03' F250 7.3L with 190K on the clock (automatic transmission). I'm having issues with the starting system. Its noisy when it starts and it may be running on.

The previous owner had issues where he had the flexplate and starter replaced. He mentioned that the starter would loosen and he kept checking it.

I examined the new flexplate, and teeth are beginning to round. I filed away the burrs hoping it was from a previous 'loose starter' condition. I noticed the two bolts holding the starter did not look original and one did not have a lock washer. I ordered the correct parts from the dealer, which subsequently did not fit (too small diameter). I added a lock washer to the existing bolts and had hoped I would improve the issue. The bolts threads look rounded over, which is concerning.

It did not. I'm suspecting the starter and flexplate may be symptoms and not the cause (with the bonus ailment of whatever happened to the mounting bolts). I'm now investigating the possibility of something upstream causing the issue, ie TSB for ignition cylinder etc. I removed and cleaned the lock cylinder with no improvement.

This evening I started checking the starter relay. Oddly enough I'm seeing around 4.5VDC (reference to the metal frame by the fuse panel) on contact 86 (coil) of the relay. This is present even when the key is off! The voltage remained when I removed the lock cylinder. First question, any ideas where this may be coming from?



I also noticed that inside the slot that the ignition cylinder fits, there is a metal tab recessed in plastic. The plastic looks shot. I read around 10VDC on this tab, it may or may not short to metal around it. What does this function? What would it be called so I can figure out how to replace it?



This thread has a lot of good info on similar problems:
http://www.thedieselstop.com/forums...f-not-solved-time-i-part-out-my-truck-295529/

I plan on measuring the thread pitch on the starter bolts and figuring out what size they actually are, and replacing them with new. I'll also check the grounds and power wires running to the starter in case the bendix is not engaging fully (the teeth are mainly rounded in the first half closest to the starter). I'm also hoping for some thoughts on this relay. I may try to check the flexplate runout with a dial indicator, but would like to rule out some of these other issues first.

Any help is appreciated!
 

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I recently found my starter loose as well. I check it every oil change and last time it was hanging half off. Now that its firmly back in place, I get some louder than usual noises starting. I'm going to wait until it gets worse before swapping flex plates.

As to the little tab in your ignition switch, that's the contact that lets you know you've got your key in the switch. It's what activates the dinger circuit when your key is in and door is ajar. As soon as that plastic wears a little more and that copper tang slides over and makes contact with the housing, that dinging noise is going to become a constant annoyance. Better make plans to replace the housing now.
 

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Discussion Starter · #3 ·
RT, thanks for getting back to me. That is good to know that is the dinger circuit. I'll have to look into replacing it.

I've been thinking about that 5VDC on the relay. The previous owner put an aftermarket radio in, maybe he somehow installed it incorrectly. I'm not sure what else would source 5VDC. I'll update if I learn anything, and am still open to any ideas.
 

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Discussion Starter · #4 ·
I've gone back and replaced the bolts that were holding the starter on with the Ford parts. Sometime in its past it had two bolts, looks like they are from the help! section starter kit, that were 3/8 x 16 instead of the proper M10x1.5mm. Extra points go to the person who put these in as they are different sizes (must've bought one of the autoparts 3 different size packs...) The 3/8 size bolt will go in and feel tight but has no actual retaining capability.



The bolt on the left is the correct part from Ford. The other two are not right at all.

So now that I have the starter being retained properly, I still need to figure out where the rattling is coming from. It may be due to the wear already caused to the flexplate, but I suspect it may have to do with the 5 Volts on pin 86 of the starter relay. The only thing between the relay and the central junction box is the DTR Sensor. If I shuffle the automatic transmission through the gears, I see the 5V when its in park and neutral, otherwise it goes to ground, so that leads me to believe its upstream of the DTR. The next thing inline I see is the ignition switch. The 5V shows up when I put the key in and select run. The voltage jumps up to 12 when I move the key to the start position. The 5V remains when I turn the vehicle off. It stays for about a minute after I shut the doors and lock with the keyfob. This is probably a pretty good clue, does the PCM have some sense wire sneaking in that could be pulling this line up to 5VDC?

I found one reference to 5V on the starter relay at the end of this thread:
http://www.thedieselstop.com/forums/f24/still-replacing-starters-flex-plates-cant-keep-up-308048/

The previous owner did say he had the starter and flexplate replaced at a shop that supposedly specializes in PowerStrokes. I don't have any reason to doubt this. If I had definitive proof that they put the wrong bolts back in when replacing the starter, I'd definitely have to leave a warning about them!

Any thoughts on what to check concerning the starter circuit would be appreciated. I'll keep digging and update what I determine.
 

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Discussion Starter · #5 ·
I've been able to narrow down where the voltage is feeding from. If I remove the F2.34 Fuse, the 4.5-5V goes away. F2.34 controls the following:

F2.34 10A Brake pedal position switch (13480), Passive anti–theft transceiver module
(15607), Electronic Automatic Temperature Control (EATC) module
(19980), Four–wheel drive control module, Brake pressure switch (2B264)

I'll check out each of these modules next.
 
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