RPM sensor wires spliced?

[kcinga]

Just bought a 1986 F-350 Diesel with dual wheels. Automatic transmission has been replaced by previous owner, but tachometer isn’t working. When I checked RPM sensor (1-inch nut with 2 wires), mine has 2 additional wires that have been connected to it. It appears that one set of wires goes behind alternator, the other set feeds the dash, I think. Is there a wiring diagram that shows how RPM sensor, alternator and dash hookup should be connected? I’ve ordered another RPM sensor, but I need to figure out if it should connect to wiring that goes behind alternator or the wiring that goes to the dash… then figure out whatever wiring is still unconnected and where it should connect.

[Gary Lewis]

Hello! Glad you joined.

But, before we get to the problem you are having there's the issue of our guidelines. We sent you an email asking you to post an introduction in the New Members Start Here folder before posting elsewhere, but you may not have seen it. The reason we ask you to do that is because that's where we have the guidelines posted and that gives you the best chance to see them, which is important as we hold everyone to them.

So before we talk about the tach please at least let us know you've read the guidelines, if not post an intro in that folder.

[kcinga]

Hello! Glad you joined.

But, before we get to the problem you are having there's the issue of our guidelines. We sent you an email asking you to post an introduction in the New Members Start Here folder before posting elsewhere, but you may not have seen it. The reason we ask you to do that is because that's where we have the guidelines posted and that gives you the best chance to see them, which is important as we hold everyone to them.

So before we talk about the tach please at least let us know you've read the guidelines, if not post an intro in that folder.

Done! Sorry that I missed that step.

[Gary Lewis]

Hello! Glad you joined.

But, before we get to the problem you are having there's the issue of our guidelines. We sent you an email asking you to post an introduction in the New Members Start Here folder before posting elsewhere, but you may not have seen it. The reason we ask you to do that is because that's where we have the guidelines posted and that gives you the best chance to see them, which is important as we hold everyone to them.

So before we talk about the tach please at least let us know you've read the guidelines, if not post an intro in that folder.

You need to get familiar with the 1986 Electrical & Vacuum Troubleshooting Manual, aka EVTM. It is available at Documentation/Electrical/EVTM/1986 EVTM. It shows all of the wiring, but is broken down by system.

In it you'll find the page shown below that gives the wiring to the tach.

But don't miss that the page after that has component locations, and they point you to this page, which might help as well.

[Gary Lewis]

Done! Sorry that I missed that step.

No worries, lots of people do.

[kcinga]

Done! Sorry that I missed that step.

No worries, lots of people do.

Thanks! Still trying to understand what I’m seeing. I see lines 11 and 12 coming from tachometer with color designations (like dg/y=dark green with yellow stripe), but not sure what C130 is and why I’m seeing a wire coming from both ends of RPM sensor. I’m aware of the 1-inch nut with 2 wires for one connector, but previous owner rigged up something else entirely. According to your diagram, I should see DB/Y colors on one end and BK/LG colors on the other end, right? At the moment, I see 2 black wires going from one connector of RPM sensor, which goes behind alternator. Other spliced-in connector (going to dash, I think) has red color from one of its wires. Faintly seen in attached photo. Thoughts?

[grumpin]

Thanks! Still trying to understand what I’m seeing. I see lines 11 and 12 coming from tachometer with color designations (like dg/y=dark green with yellow stripe), but not sure what C130 is and why I’m seeing a wire coming from both ends of RPM sensor. I’m aware of the 1-inch nut with 2 wires for one connector, but previous owner rigged up something else entirely. According to your diagram, I should see DB/Y colors on one end and BK/LG colors on the other end, right? At the moment, I see 2 black wires going from one connector of RPM sensor, which goes behind alternator. Other spliced-in connector (going to dash, I think) has red color from one of its wires. Faintly seen in attached photo. Thoughts?957A99F2-F5EC-4D4C-82C1-E6894DE6BD3C.jpeg

C130 is the connector.

I agree with what Jim said in the other thread, vacuum controls the C6 automatic. The tach should have nothing to do with it.

Does the tach work with those two extra wires disconnected?

Edit: yes you should have dark green with a yellow dash and black with a light green dash hooked to the sensor.

Edit again: looks like your wiring has stripes not dashes. If there’s no stripes on the two black wires, they must be a ground for something.

[Gary Lewis]

Thanks! Still trying to understand what I’m seeing. I see lines 11 and 12 coming from tachometer with color designations (like dg/y=dark green with yellow stripe), but not sure what C130 is and why I’m seeing a wire coming from both ends of RPM sensor. I’m aware of the 1-inch nut with 2 wires for one connector, but previous owner rigged up something else entirely. According to your diagram, I should see DB/Y colors on one end and BK/LG colors on the other end, right? At the moment, I see 2 black wires going from one connector of RPM sensor, which goes behind alternator. Other spliced-in connector (going to dash, I think) has red color from one of its wires. Faintly seen in attached photo. Thoughts?957A99F2-F5EC-4D4C-82C1-E6894DE6BD3C.jpeg

C130 is Connector #130, and if you scroll down to the last page of each section in the EVTM it shows where the connectors are. In this case that's Page 100 and C130 is on the right fender apron, or inner fender.

But I don't know what the PO did. I'd put it back to factory. However, the RPM sensor won't make the transmission shift differently as it doesn't even connect to the tranny.

Also, please go look at Bullnose Forum/Forum FAQ's in the menu to see how to post pics.

[ArdWrknTrk]

Thanks! Still trying to understand what I’m seeing. I see lines 11 and 12 coming from tachometer with color designations (like dg/y=dark green with yellow stripe), but not sure what C130 is and why I’m seeing a wire coming from both ends of RPM sensor. I’m aware of the 1-inch nut with 2 wires for one connector, but previous owner rigged up something else entirely. According to your diagram, I should see DB/Y colors on one end and BK/LG colors on the other end, right? At the moment, I see 2 black wires going from one connector of RPM sensor, which goes behind alternator. Other spliced-in connector (going to dash, I think) has red color from one of its wires. Faintly seen in attached photo. Thoughts?

Can you figure out which transmission controller your PO tried to install?

I hope the E4OD you now have is '89-'91 so it has a tailshaft output that can be used.

I don't think Mark Kovalsky (the former Ford powertrain engineer who developed the E4OD) can help you here but if we knew which controller it is there might be help troubleshooting.

Here's the pic:

[grumpin]

Can you figure out which transmission controller your PO tried to install?

I hope the E4OD you now have is '89-'91 so it has a tailshaft output that can be used.

I don't think Mark Kovalsky (the former Ford powertrain engineer who developed the E4OD) can help you here but if we knew which controller it is there might be help troubleshooting.

Here's the pic:

Also. I would crawl under there and confirm it’s an E4OD.

I’ve seen trucks like this posted for sale as an E4OD and they’re not.

Here’s an id guide.

https://www.jalopyjournal.com/forum/threads/need-to-know-how-to-identify-ford-transmission.1204543/