Now starts but battery drain

[bigcaveman]

ok bought this truck 4 months ago. early '99 F-250 7.3 PSD with 101,000 on it. Have been fighting cold starts for awhile. Depending on the temp it would start fine. Colder I would have to give it a shot of ether. I know its bad for it so I use it very sparingly and when I do it is literally a small dose.

I was going to change the GP's in it when I got to reading on her about some one who had their wires swapped on the GPR so I looked and sure enough they were. So I put them right and the truck started and I parked it outside.

2 hours later(truck still cold) the truck was dead. It cranked about 3 times and then clicked. So thinking well the big load from the newly working GP's, killed them. Not knowing when the batteries were replaced last, I went and bought 2 new Interstate 850 CCA batteries and threw them in there this morning. Cranked the truck. Started first time without being plugged in all night. Let it run for about 10 min and shut it off. Came back out 4 hours later and it started right up. Let it run for about 15 min and jumped in it.

Now I looked at the charging gauge and it was about halfway up. Little lower then normal but didnt think much of it. Pulled out and started driving. The gauge just kept drainin so turned around and made it to O'Rielly figuring an alternater. Left the truck running and got the guy inside to come out and ck the output. As soon as we got outside the truck died.

So took my old alternator off and took it in. They ran a test and it passed with flying colors.

I want to mention while I was driving it the gauge did increase when the eng was 1200 and above RPM but wouldnt stay there.

Anyone got thoughts on this? I was thinking the GPR is stuck open and just drawing a lot of amps. I am going to start there when the wife can take me back to the truck. Thanks and sorry for the story.

[ianstew]

sounds like the alternator to me....i've had hit or miss luck with testing alternators at AZ, and places such as them.....put a meter on your alternator at idle and check the voltage.....13.5 is good.

[blk99]

what he said or maybe something is screwy with your GPR and its stayin "open".... but i would think the alt could keep up with it....

[Ryeman2138]

My alt was test and it put out good voltage until it would pop the bench tester. Check your ground cables and make sure they have a good contact and are not loose

[melmount]

any chance any wires are crossed and the glow plug relay is staying on? Just a thought?

[melmount]

the gpr, theres 2 big wires and 2 little ones? I could be mistaken but i thought it did not matter where they were hooked to as long as big stayed to the big terminals and small to small??

[bigcaveman]

Ok got it fixed hopefully. I changed the GPR and jumped the truck and drove it/ran it at idle for an hour and everything worked as advertised. Im guessing it was stuck open. I think it worked to start the truck and shut off like it was supposed to til the truck warmed up. The Contacts expanded and re-energized the plugs. The only reason I think that far into it is bc it ran for about 20 minutes before I started driving it. Then it was like 10 minutes or less and the batteries were dead and the truck died. Im going to leave it unplugged tonight and start it tomorrow and see. It is supposed to be in the low teens tonight, its already 17. So should be a good check to see if it is a permanent fix.

I also ran a charging system check with the truck running and the alternator was putting out 13.05 at idle and above idle(1000 rpm's) it was 14.25 to 14.50.

Yes it seems it does matter how the wires are on the relay. I forgot I have the "Ford" service manual on CD and looked up the wiring diagram. It was for a 2000 but still the 7.3. I think there is a diode or something in the relay because I tried to switch the wires on the new one when I installed it tonight and it didnt work. I could be wrong bc common sense is telling me otherwise. It could have just been my truck too. Still working out the bugs of previous owners.