Strange 1986 Bronco electrical issue.

[ArdWrknTrk]

Looks like we were all on the same page! I went through and tested in various conditions. It reliably blows fuses when the diode is installed. Also the diode gets wicked hot after the fuse blows. I'm sure that has to be it.

Thanks for the help, guys! Looks like the "fuses blowing" issue is taken care of.

The "gauges rising" issue is still slightly in play. I took these pics to illustrate. First one is without AC on, second one is with AC on. This is WAY less of a change than what used to happen, so I think the ground helped. But having a direct ground straight to the battery should have cured it entirely, right?

I'm not sure about Carpenter's ICVR. I don't know anything about how it operates.

The factory one is basically a flasher unit.

Do you get pulsing current from your new and improved ICVR?

Perhaps the AC clutch thing is messing with its reference voltage or ground?

I only really know about the SWAD-J regulator mod that Gary has documented both here and on FTE.

 

[ArdWrknTrk]

Looks like we were all on the same page! I went through and tested in various conditions. It reliably blows fuses when the diode is installed. Also the diode gets wicked hot after the fuse blows. I'm sure that has to be it.

Thanks for the help, guys! Looks like the "fuses blowing" issue is taken care of.

The "gauges rising" issue is still slightly in play. I took these pics to illustrate. First one is without AC on, second one is with AC on. This is WAY less of a change than what used to happen, so I think the ground helped. But having a direct ground straight to the battery should have cured it entirely, right?

I forgot to ask about your tach situation?

Was it helped with a new cab to engine ground?

Is there a way to program your EFI to step up the idle speed when the AC is operating?

I know the carb engines use a solenoid kicker throttle stop, but I know nothing about the aftermarket EFI.

[Nickelplate]

I forgot to ask about your tach situation?

Was it helped with a new cab to engine ground?

Is there a way to program your EFI to step up the idle speed when the AC is operating?

I know the carb engines use a solenoid kicker throttle stop, but I know nothing about the aftermarket EFI.

Yeah, the Carpenter unit does give the same pulsed output as the old ones. Its main thing is that there are no adjustments needed like with the old ones.

The tach seems to be behaving better now that I have added the extra ground AND grounded that second post that switches it to 8cyl mode.

I'm not sure if this is just how they are supposed to work, but it hovers around 500 when idling (when it's actually at 800), then have to bring it up to actual 1000 before it budges from 500 and moves up and down with the RPMs. It is about 500 under what the actual RPMs are. I can see the actual numbers when I have my phone bluetooth-connected to the Edelbrock EFI ECU.

There is no way to let the EFI system know when the AC clutch is engaged, but it actually detects the slowdown and compensates for it. The compensation looks like a couple of surges while it "finds idle" and then evens out again around 800. It's pretty impressive.

Now that I got the fuse-poppin' issue taken care of, I should be able to drive the truck with the AC on and see how everything is working.

[Gary Lewis]

Yeah, the Carpenter unit does give the same pulsed output as the old ones. Its main thing is that there are no adjustments needed like with the old ones.

The tach seems to be behaving better now that I have added the extra ground AND grounded that second post that switches it to 8cyl mode.

I'm not sure if this is just how they are supposed to work, but it hovers around 500 when idling (when it's actually at 800), then have to bring it up to actual 1000 before it budges from 500 and moves up and down with the RPMs. It is about 500 under what the actual RPMs are. I can see the actual numbers when I have my phone bluetooth-connected to the Edelbrock EFI ECU.

There is no way to let the EFI system know when the AC clutch is engaged, but it actually detects the slowdown and compensates for it. The compensation looks like a couple of surges while it "finds idle" and then evens out again around 800. It's pretty impressive.

Now that I got the fuse-poppin' issue taken care of, I should be able to drive the truck with the AC on and see how everything is working.

Interesting. Ford's EEC-V system has an input for the A/C clutch and I could up the idle speed immediately when the compressor kicks in. However I like the 640 RPM idle even with the A/C on and didn't tell it to increase the speed. But there's no bobble at all in RPM change when the compressor kicks in.

As for the tach, it sounds like it might be sticky, and/or need calibration. Mine shows 500 when it is actually 640, but then is pretty close from there on.

[Nickelplate]

Interesting. Ford's EEC-V system has an input for the A/C clutch and I could up the idle speed immediately when the compressor kicks in. However I like the 640 RPM idle even with the A/C on and didn't tell it to increase the speed. But there's no bobble at all in RPM change when the compressor kicks in.

As for the tach, it sounds like it might be sticky, and/or need calibration. Mine shows 500 when it is actually 640, but then is pretty close from there on.

I looked for an "AC to computer" wire when I installed the Edelbrock system. Turns out that they used to include one in the older versions, but it was causing folks a lot of problems to hook up. I think it had to do with some systems having the diode or a solepot, or a straight wire. The thing I read on the Edelbrock site said that in order to simplify the installation they removed the wire and updated the software for AC.

They do have a CAN bus connector on there, but I'm not sure if that could be used that way, and I know almost nothing about CAN.

[Gary Lewis]

I looked for an "AC to computer" wire when I installed the Edelbrock system. Turns out that they used to include one in the older versions, but it was causing folks a lot of problems to hook up. I think it had to do with some systems having the diode or a solepot, or a straight wire. The thing I read on the Edelbrock site said that in order to simplify the installation they removed the wire and updated the software for AC.

They do have a CAN bus connector on there, but I'm not sure if that could be used that way, and I know almost nothing about CAN.

Ford used the same basic computer on everything from little 2.0L engines to my 7.5L, so needed some way to tell the computer when the additional load was coming on.

But I can see that some people might not understand the need for nor the orientation of the diode, so that could cause problems.

[mat in tn]

Ford used the same basic computer on everything from little 2.0L engines to my 7.5L, so needed some way to tell the computer when the additional load was coming on.

But I can see that some people might not understand the need for nor the orientation of the diode, so that could cause problems.

maybe im off base here but what alternator is on this? you changed to serpentine so you had to change that also. what wiring mods were done?

[Nickelplate]

maybe im off base here but what alternator is on this? you changed to serpentine so you had to change that also. what wiring mods were done?

I have the Powermaster 200a 3g alternator right now. I have had a 3G alt on this thing for probably 15 years, but I had to switch to a transverse mount one with the new serpentine stuff.

The wiring is:

I have a 4 gauge charge cable with an inline 200A fuse that goes to a power distro lug. The power distro lug also has the battery positive, the starter relay/solenoid, and a few other power leads.

The alternator leads from the old 2G went to connector #610 which is on the passenger side fender well.

C-610

655 R-O - This wire is capped off

654 Y-LG - This wire is capped off

904 LG-R - This connects to the green wire from the 3G alternator harness

37 Y - This lead is the main power to the fuse panel and remains unchanged. It connects to that same power distro lug as the other big wires.

There is also the voltage regulator yellow/white lead from the alternator, which I have going to the power distro lug.

All the other wiring from the 2G alt is gone, which means my Ammeter in the gauge cluster does not work. I'm eventually going to convert it to a voltmeter.

[FuzzFace2]

Now that I got the fuse-poppin' issue taken care of, I should be able to drive the truck with the AC on and see how everything is working.

Did I miss what the fix was on the fuse popping was?

I have not looked into a issue I have on my 81 F100 (factory wiring / no computer) where when the AC compressor kicks on & off, be it low charge or temp, the dash turn signal lights flash.

You can only see this when it is dark, I leave for work between 12am & 4am, I do not see this in day light as the flash is to quick. I should also point out I have LED dash lights.

I know all my grounds are in place but being everything has been painted they may not be 100%and I need to check this someday.

It is not a big deal for me but just something that is along the same strange line with the AC as yours.

Dave ----

[Nickelplate]

Now that I got the fuse-poppin' issue taken care of, I should be able to drive the truck with the AC on and see how everything is working.

Did I miss what the fix was on the fuse popping was?

I have not looked into a issue I have on my 81 F100 (factory wiring / no computer) where when the AC compressor kicks on & off, be it low charge or temp, the dash turn signal lights flash.

You can only see this when it is dark, I leave for work between 12am & 4am, I do not see this in day light as the flash is to quick. I should also point out I have LED dash lights.

I know all my grounds are in place but being everything has been painted they may not be 100%and I need to check this someday.

It is not a big deal for me but just something that is along the same strange line with the AC as yours.

Dave ----

Yeah, the fuse pop was caused by the diode. It was no longer needed since the ecu was no longer attached. It was causing a short.

Your issue sounds like a ground as well. Though Reverse voltage through an LED shouldn't technically work.