Truck REFUSES to charge after 6.0L GP harness install?

[franklin2]

The white wire on the controller is technically not a ground like you would think. The stud the white wire was on is the negative terminal of the glowplug relay, and the white wire hooked to that stud leads into the brain of the controller.

So to activate the glowplugs via the glowplug relay, the brain does ground this negative relay terminal with the white wire. Same as putting a manual pushbutton in the same location to ground this terminal and activate the glowplugs. If you ground the white wire terminal all the time, the glowplugs would be on all the time.

I do agree this connection should have nothing to do with the alternator charging.

 

[crash-harris]

I kinda doubt it. The white wire on the GP controller is the ground. The GP controller turns on with key on power. If the glow plugs are not connected, you get rapid clicking.

I disconnected what I thought was power to the GP controller and got the clicking with the key on. 2 larger yellow wires on the rear most large stud, yes?

I dislike mobile wiring with the way it's wrapped and routed. I've been putting all the wiring I've installed in loom with maybe some electrical tape every 12" or so. Makes it so much easier to get back into if need be.

 

[icanfixall]

Yes... The top rear most stud gets the two yellow wires and are connected in the same terminal.

 

[crash-harris]

But isn't that power to the GP controller?

 

[Macrobb]

The glow plug contoller(7.3 style) needs two sources of power - heavy gauge wire that's always hot to one of the big relay terminals(other is hooked to the squiggley strip of metal). Key-on power is hooked to one of the small terminals as well, and the controller grounds the other small terminal to actuate the relay.

if you only have power to the large terminal, the controller does nothing.
If you have power to the small terminal only, the controller will short-cycle and just click the entire cycle time.

(Also of note - on an OBS truck, you can hotwire the engine by just providing power to the small glow plug terminal. It will backfeed to the FSS, and the cold advance/idle stuff)

 

[crash-harris]

Gotchya, so just standard relay wiring there, just without the constant positive, the controller just keeps trying to actuate the relay, hence the rapid clicking.

IIRC, the only thing connected to the strip of metal on mine is the GP harnesses (at the bottom end, top end on the other large relay post).

I'll be driving the truck around town tomorrow to grab some things, so I guess I'll see how it acts there/around/and back.

 

[riotwarrior]

1st we are dealing w 2 dissimilar circuites....

1 energizes
1 consumes....

Agreed?

Get truck running good and hot so no gp needed to start any longer.

Disconnect gp system from being able to be used....now start and test charge circuit....is it working?

If so its gp system effing 2ith you....if o charge...it is strictly charge circuit.....

Make sence?

Stop chasing yer tail and isolate

JM13.5VW Eh!

 

[crash-harris]

Al, that's just the thing. The GP controller was connected yesterday when it was charging at 14.4V at idle (even warm idle).

It seems intermittent, but that white wire was the only thing I could find that was loose. Nothing is rubbing or pulled out of a connector or anything. Since the exciter wire is connected to the bulb in the instrument panel, maybe that wire is rubbing under the dash or something? Or maybe the bulb just vibrates/bounces loose, removing that, what, 510 ohms of resistance? Therfore the alternator never gets the signal to engage.

One of the things I'm having tomorrow is a short, pre-made ground cable for the alternator case. Gotta grab a bunch of Type F for a PS pump replacement. It decided to go in the middle of all this as well (1/2" forward/back play and hard, loud growling).

 

[crash-harris]

Seemed like everything was fine. About a mile down the road the voltage dropped from 14.4V to about 14V. A mile later it was back to 14.4V. After leaving the off ramp in town, it dropped back off to battery power only. Sitting in the Autozone parking lot now and even verified that there is 12.6V at the exciter wire while running. I back probed the weatherpack harness that the exciter wire it connected to near the fender.

So I'm getting the signal to the alternator, unless the plug to the regulator itself has something going on. It's not loose, but was a new replacement harness.

 

[typ4]

I found the aftermarket stator connector doesnt always make a good connection, I had this exact same issue, Make sure it is down on that pin very well, thats the single connector in the alt plug.

Also I ended up going with a motorcraft replacement alt plug, the cheap ones dont fit right.

 

[crash-harris]

I said to hell with it and pulled the alternator to throw it on the tester while I was at autozone. Ended up pulling the plastic connector off that stator wire. Alternator failed the test.

The manager that was at that store when I worked there didn't know/never informed us about this, but the current manager pointed out that there is an electric impact in a drawer under the starter/alternator test machine. So I pulled another alternator off the shelf for the warrenty and tested it, tested good, and swapped the pulleys. Tossed the new one in the truck and was hitting 14.6V at idle and on the highway.

So now I'm wondering if the worn/loose belt on the first 3G caused a big power spike, tripped the breaker and I ended driving too much with the alternator producing power, but it not going anywhere. Maybe the breakers are just junk and tripping before their designated amperage rating and killed the second one. I left the cables previously attached to either side of the breaker on the same post to eliminate the breaker and added ground cable from the back of the alternator to the filter head bracket. We'll see how it does I guess.

 

[crash-harris]

Seemed to charge well at 14.4V+ at idle and 14.5-14.8V max on the highway on my trip yesterday. Went to see @Nick382 and he hooked me up with an IDIT (thanks again!). Truck only dropped voltage a bit after dropping the engine off at my old shop, but it kicked back up soon after. Both the factory dash gauge voltmeter and my cheapie digital one mounted on the console are inaccurate. Dash reads high and digital reads low when tested with the multimeter.

So next step is PS pump, then balljoints/TRE's/alignment, then pulling the heads off the IDIT. I could feel the driver's wheel and knuckle starting to shake on the way back. Going to grab a 2 ton hoist and stand from harbor freight for the IDIT since I'll have to swap heads in frame by myself. As long as the cylinders in the IDIT are in decent shape, I'm going to start rebuilding it when I can. Probably be down the road a bit, but I'm a bit tired of having vehicles with a questionable bottom end. Got a hair-brained idea to chop the bronco frame when I get it torn down and use the front half for a test stand

 

[typ4]

Put new valve springs on the heads while they are off.

 

[crash-harris]

Put new valve springs on the heads while they are off.

Already on it. Got 910's to go in. I've got the valley pan already, just need 6.9 head gaskets, new head bolts and valve stem seals. I'm planning to load it with new valves as well and check for guide wear and flatness. I'll have to dig out that bag of o-rings I got from you. Should I soak your rebuilt injectors in ATF or diesel kleen after I pull them out of my current heads?

 

[Nick382]

Just for the record, I believe that's a NA block that had a factory turbo kit added to it. Not sure that changes much with your plans but is worth clarifying.


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