I have an early 99 Superduty 7.3L that won't start. It clicks at the starter relay but thats it. Originally it would click on the first try but then would start after that. I have put two new batteries in, changed the starter relay, and have had the starter bench tested at two places, it passed at both (pulled 18amps and settled down to 11). Am I missing something? Another switch or relay. Any help would be great-already have given the dealership enough money. Thanks

Paul

 

Check your battery cables and connections. If a cable is bad it will not be able to pass the current needed to start the high compression PSD. Other than that I think you have covered the bases.

 

1. Turn on the lights. Are they normally bright (sortof)?
2. Try to start. If the lights dim a little, the starter is pulling lots of juice bit can't turn the engine. If the lights don't dim, check every single cable connection to be sure there is no open circuit in the starter circuit. All battery posts, all battery ground connections. The cable to the starter. Inspect the cables for signs of corrosion (green crud). If that is down in the strands of the cable, replace it. If it still won't turn over, get a voltmeter and a helper. put the voltmeter on one of the batteries; it should read 12.5 volts or more. have the helper turn the key to start. The volts should drop to maybe 11. If that happens and the engine won't turn put the voltmeter between the hot terminal of the starter and ground. It should jump up to the 11 or so volts when the switch is turned. It all this happens and the engine doesn't turn something mechanical is locked up. Check to make sure the starter is properly bolted in squarely. If you have a stick shift, you can try towing it to start; let the clutch out while in a high gear, not low. don't forget to turn the key on. If the engine turns but doesn't start, keep towing it to a good shop.
Good luck and post what happens and the final solution.
Warren

 

I checked the voltages at the battery and relay, they wer 12.8 for the batteries and somewhere around 11 at the relay. Today I will get under the truck and check the starter. The dealership tech said the sarter could have a flat spot on the armature and thats where the starter is stuck. I don't know is that more BS from the dealership to try and get more money? I'll post the results, thanks for the help.

 

A 1.8 volt drop at the relay. You might have a slight ground somewhere or a cable deteriorating inside the sheathing. Probably at or near the wire connections. Use some baking soda and water at these connections. If it starts to foam at the wire, (not the lead connector), it is a good indication. Look at the cable

 

ahhhh yes... the old baking soad and water trick..!

 

Heck any soda pop will work, but heaven's no, don't waste a beer. OK, I won't look

 

If you have 12.8 at batteries and 11 @ relay you either have a lose cable or bad one try attaching a jumper cable to load side of relay and the other end to another hats attached to positive side of battery see if it turns over, use 2 jumpers so you do not spark next to battery. Or put the jumper to line side and positive side of battery and try and start with key. Also if you have an ohm meter you could check the cable that way. My bet is bad cable. You should have pretty close to same voltage heck the cable is less than 10 feet long.
Good luck.
LPR

 

Paul:
You didn't say under what conditions you measured those two voltages. Were they both with the ignition switch turned to start? If so the above guys are right; there's a bad cable or connection at the relay. Or in it. But you said you replaced the relay. Must be a cable. With the switch on start you should have just about the same voltage at the battery all the way to the starter.
About the flat spot; just pull the starter and turn it a little, put it back in and try it. I think thats dealer BS.
Warren

 

if you have it narrow down to the point where you think you might have a flat spot in your starter, just get a new one... there's not much sense in taking your starter out and then put it back if it is bad... i don't know if there is a way to test a starter for a "flat spot"....

 

Paul:
Let us know how all this came out; It'll help the next guy with such a problem.
Warren

 

Well I rechecked all the voltages with a more accurate volt meter. Everything checked out ok per your advice (battery voltage and voltages at the starter and relay) So I went ahead and replaced the starter (250,000 miles on the original). So far it seems to have solved the problem (I guess there was a bad spot). If it happens again should I go after the neutral safety switch (manual trans). Thanks for all the help.

 

I don't believe you have one. There is a clutch safety switch. But on Stick you can start in any gear with clutch pushed in. Good Luck. LPR

 

I am glad you are on your way. It is a pain sometimes to narrow down starting problems, there are so many variables. Happy trails

 

Just saw this thread and thought I'd try it out. What do you guys think could be my problem? I have a 1999 F250 with the 7.3 and 61,000 miles. Always garaged kept in in great shape but here's the problem:
This truck does the exact same thing EVERY time... Turn the key on, wait till the "wait to start" light goes out then try to start it. It will crank for a short time and act like the batteries are going down but not start. Then I shut the key off and immediately try the same sequence again, only the second time around, it starts like a new truck. New batteries and new glow plug relay. Are there any 7.3 gurus out there that can help?? Not really wanting to take it somewhere and spend a fortune for something I might be able to do myself with a little help.
Thanks!!