new to forum and IDI fords charging issue.....

[1990idi]

hey yawl i picked up a really nice 1990 F-250 7.3 idi E4OD with 66000 miles 2 months ago for 4000 dollars. it looks like it just rolled out of the showroom. long story short an older gentleman owned and rarely used it. friend of the family so that is the actual milage and not rolled. anyways i have an electrical issue. a month ago my battery gauge was showing 11.5 volts so i threw a new alternator and external regulator on and all was well for another month. now it has started again with the voltage hanging around 11.5 volts. both times the voltage has occasionally gone back to normal. seems to be an issue when the temperatures are colder our mostly. the lights are obviously dimmer when the gauge is reading 11.5 volts. i have checked my battery connections and they are good, it also has new batterys in it that are about 3 months old. the alternator is 100 amps and the regulator are from oreilly's. any help will be greatly appreciated! i am not used to working on older vehichles, but i am no stranger to diesels i have worked for several big truck dealerships.

 

[Agnem]

You should test the output of your alternator by disconnecting the regulator, and full-fielding the alternator. Simply locate the alternator field wire and apply full battery voltage to it. Measure the output at the batteries, and you should see slightly over 14v at 1500 RPM.

 

[HS108]

The gauges are ok to go by, but you should really get a volt meter on it when the voltage drops if you can, so you can see the true volts.




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[1990idi]

how do i locate the field wire? is it going to be pin f on the regulator? if i do get 14.5volts the alternator is good then. so what would i do next?

 

[1990idi]

also i have been reading posts about the glowplug controller staying on.... how do i know if the controller is staying on?

 

[franklin2]

how do i locate the field wire? is it going to be pin f on the regulator? if i do get 14.5volts the alternator is good then. so what would i do next?

If you get around 14v at the battery, then you are good, you don't need to do anything. I have noticed my truck runs at around the old 13.8v. It still works fine, the old school regulators seem to be set at this little bit lower voltage. I also notice after starting my truck, the volt gauge will be low till the batteries catch up. When the batteries have caught up, my factory guage points straight down. If they are behind the gauge pointer is a little bit to the left. But like someone else said, these factory gauges are only a rough indicator, do not spend money on parts because of what any factory gauge tells you. I have you heard that your factory oil pressure gauge is a "fake" and is not really a true gauge? What does that tell you?

 

[franklin2]

also i have been reading posts about the glowplug controller staying on.... how do i know if the controller is staying on?

Watch your factory voltmeter in the dash when you glow the plugs. The needle will swing way over to the left, down to the 8v mark. The glowplugs draw a lot of current. After the engine starts, the controller may cycle the plugs. If you see the gauge swing back and forth, and if you have the headlights on and they go dim and then bright right after you start the engine, thats the controller cycling the plugs.

The later model controller you have is not known for keeping the plugs on all the time, I believe the older ones on the 6.9 had that problem.

 

[OLDBULL8]

how do i locate the field wire? is it going to be pin f on the regulator? if i do get 14.5volts the alternator is good then. so what would i do next?

With a VOM meter, set the voltage reading to 50 VDC, or whatever is over 12VDC setting.
The alternator is marked with an F, at least most are, with the regulator disconnected, start the engine, with a jumper wire, jump from the battery POS+ to the F terminal on the alternator, with the VOM meter, Black probe on the battery NEG- terminal and the Red probe on the large Red wire on the alternator, you should have 14.5 VDC output or maybe a little more.
Obviously if you have 14.5+ VDC output on the Alt. when full fielding then the Alt. is good. With the regulator connected to the alternator, check the voltage at the battery terminals, should be 12.3 VDC +/- .2. Start the engine, at 1500 RPM engine speed, it should read 13 VDC to 14.5+ VDC, turn headlights ON and Heater blower on HI, alternator output should maintain at least or more than 13 VDC, if not, then the regulator is defective.
For your intermittent problem, the connector/plug to the regulator could be corroded contacts, corrosion at the starter relay wire junction..

You can disconnect the NEG- terminals on the batteries, and see if the alternator puts out somewhere around 150 volts, of course doing that, it will BLOW any and all electronics connected, but you'll know the alternator is really good.

 

[1990idi]

alright i jumped from f to battery positive, ran the truck and still no charge. i suspect it may be the belt this time maybe. it is worn pretty badly and is pretty loose. i will replace that and maybe that will be the end of that issue. a new problem has arrived though. 2 months ago all the fuel connectors, injector return hoses and all 8 injectors were replaced. there is now a fuel leak at number 1 cylinder between the fuel supply line and the plastic connector..... it literally started while i was looking at the charging problem. is it possible that the line needs replaced?

 

[1990idi]

well put the new belt on and was able to retorque the fuel line and all is good now. i feel like an idiot for not catching that belt earlier.... so are there any known issues with these trucks and engines that need to be corrected?

 

[franklin2]

well put the new belt on and was able to retorque the fuel line and all is good now. i feel like an idiot for not catching that belt earlier.... so are there any known issues with these trucks and engines that need to be corrected?

Since you are messing with the wiring, look at the wires that run from the pass side of the engine compartment over the pass side valve cover to the rear of the engine. About in front of the A/C box(if you have A/C) there will be a connector there. There will be small wires and two larger wires(unless your truck has the updated harness). Check the plug over carefully if you have the two larger yellow wires still running through the connector. See if it's melted in that area. If it is, I would recommend you cut the larger yellow wires out of the connector, and splice them together bypassing the plug. This is a well known problem, these two wires are what feed power to the glowplug controller.

I recommend you put the wires back together in a way that makes them easy to get apart. It's handy to unplug the wires here when replacing the valve cover gaskets or pulling the engine. I used 4 ring connectors and small bolts to bolt the two wires together so they could be taken apart.