: 01 F-150 stock tach sig wire???

03-06-2011, 08:16 AM
Throughout my conversion I've wanted to maintain the factory ford look. Gauge-wise the only thing left is the tach. I got a Dakota tachometer interface for the "W" connection on the alternator. So, the Dakota gets pwr with key, Ground, input from the alt. (pulse). then sends the corrected signal to the tach.
If someone has a real schematic ,
My problem is what instrument cluster input wire or pin goes to the tach for signal?


03-08-2011, 10:59 PM
Sorry but I cannot answer your question about the Dakota tach. However, you can get the factory tach to work with the original crank position sensor and machining some "teeth" into a crank pulley-dampener from a 6BT. There are 35 teeth on a 360 pattern. I can send you a drawing if you want it.

I made a simple mount for the Ford CPS so it will detect the pulses from the tone wheel. The two wires on the sensor go to the original pins on the PCM.

I have a diagram for 2003 and 2004 trucks, but nothing earlier. I bought a DVD from Taylor Automotive which has been an absolute necessity for this project. If you think it will help, I can e-mail the relavent parts to you. Just PM me.

03-09-2011, 05:43 AM
you folks that swapped the cummins into these fords did you have any issues with the pats system? i want to put a 4bt into my 2002 f150, i have the 5 speed so i wont have to worry about the tranny issues but will the computor chipped key function as it should with a 4bt in it? did you guys basiclly keep the stock pcm in your trucks funtioning as stock? thanks That is basically the main issues i am gonna have swapping in the 4bt. I am basically electrically and computor retarded.

03-09-2011, 07:13 AM
Hi cr; Yeah that ship has sailed, I have the motor harness all hacked up, kinda short-sighted. The Dakota should mimic the pulse of the sensor and it is also correctable for the input frequency. I found a pin-out for the 97 model year but the tach wire in the diagram( w/pk) actually ran the oil press gauge , must be year specific. I'm pretty sure once I get the correct wire either on the PCM harness, crank sensor wire or the instrument cluster harness. I think it will work. Thanks

Hey jaybuller; Believe it or not it was not that hard but it was involved and there are things to make work. I removed the box and cab. I bought a motor out of a bread-truck with the ford chassis, that gave me a flywheel and bell adapter in sm ford(big bucks to buy separate). Yours will be the mod pattern with a slight bolt pattern difference. I went with the m5od from a 91 f150 so I had some hyd throw-out challenges. The cross-member was moved to the rear-ward boltholes other than making motor-mounts it was bolt in. wiring was find a hot wire in key start and on for the fuel shutdown and starter wire to solenoid. (mine is a 88 model year motor, not sure how the newer computerized cummins will be). I bought my truck with a blown motor so I never drove it and I don't know if the theft was activated or what. maybe because the pcm has been "lobotomized" . All the motor and trans. sensors and inputs have been removed but the theft lite flashes and I hear a soft tone then it goes out after a while so I think the computer thinks it's stolen but It has no control so it is just a nuisance until I finally clip the beeper and pull the lamp. It was a dog until I turned the star wheel and added the 3200 rpm spring and fuel pin. That made it drivable power wise.

03-09-2011, 08:39 AM
thanks for the reply, yeah i heard that my m5r2 tranny will bolt right up to the ford adapter on the cummins, i could be wrong though. i think i will be able to figure out the whole theft thing by foolin it thinnkin its not stolen. Im gonna get a ppump for the 4bt when i do it so that i can tune it up for about 275 ho or so. Ive been messin with cummins trucks for a while now so i have gotten good at makin them run but this electronic stuff in the 2002 f150 scares me a little.

03-09-2011, 11:12 AM
By the time your p-pumped the electronics are irrelevant.....I would like to figure out my cruise control though??

03-21-2011, 08:59 PM
Hey CR - I'm in the same tachometer boat as taggmann....but just with a '04 f250. :) If you don't mind, I have a quick few questions.

By CPS, did you mean crankshaft or camshaft position sensor? Do you have the pinouts for an '04 F250?

Thanks in advance.

03-21-2011, 11:21 PM
By CPS, did you mean crankshaft or camshaft position sensor? Do you have the pinouts for an '04 F250?

Crank Postion Sensor. Sorry about the ambiguity. The Dodge durango guys needed a cam position sensor, and so I added it when I was having trouble geting the PCM to communicate. As it turns out, I did not need the cam PS for the PCM to come alive. So my Expy only uses the factory sensor and two wires to the PCM to get the tach to work.

I have posted the diagram and the connector pinouts below, assuming you had a 5.4L engine. Looks like your factory sensor is on pins 21 and 22. Let me know if you had a 6.8, since the connector will likely be different.

Hope this solves your problem.


03-22-2011, 05:26 AM
Well it looks like back to the U-pull-it. I will get a motor harness from a donor. So if I; Use The W lead from the alt. to the input on the Dakota tachometer interface. The output of the Dakota to the crank sensor wires imputing the pcm?

03-22-2011, 04:51 PM
Awesome! Thanks CR! Yes I have a 5.4L. I butchered my harness too....so I'll probably be seeing taggman at the U-pull-it.

(And I got the the 35 tooth magneto wheel from destroked....so no dampener machining required here.)

Thanks Yall.

03-23-2011, 02:03 PM
Taggman-- I looked at the Dakota web site for their diesel converter. I'm not sure it will work on your factory tach. It appears that it is a "pulse converter"-- it takes some number of pulses from whatever source you have (alternator, flywheel, other tone ring) and outputs the number of pulses per rev that an aftermarket tach is expecting.

My understanding of newer instrument panels (don't know about your 2001 though), is that the needles are rotated by a little tiny stepper motor. The stepper motor driver lives on the instrument circuit board, and gets some sort of analog signal (variable DC voltage) from the PCM. The driver converts the analog signal to a certain angle of rotation. In the case of my Expy and Stoner's '04, the pulses from the 35-tooth tone wheel are sent to the PCM for counting and processing. The PCM also looks at the cam position signal to determine TDC and other things . The PCM sends a signal (not a pulse) to the instrument panel so the tach needle can move appropriately.

My thinking is that if you want to use the factory tach, then the most straighforward way is to send it the signal it is expecting from the PCM.

I have some diagrams from the 2003 F150 DVD manual that I have posted below. There is a 3G alternator and a 4G alternator. If you look at pin1 on connector 102b (bottom of diagram), you can see that it comes from the stator and is an AC signal. This should have a pulsed signal that varies with rpm. This would be your "W" terminal that you could connect to the Dakota converter. Note that it is a "jumper" connector and joins pin 1 to pin 2. If you use this, you will have to connect your own line to it somehow (have not seen this on my alternator-- your's may be different too). If you have a 4G alternator, there does not appear to be a connection to this pin, although there might be.


Here are the pinouts on the 3G alternator connector for the '03 F150

Below is the instrument panel overview diagram. Look at the box inside of the box. There is no standalone signal identified for the tach. It appears that any device not specifically identified with its own wire(s) is communicated by the Data Link Connection.

I can't say enough about the Ford DVD manuals. They are really good. I bought mine from Taylor Automotve ( http://4door.com/default.html), but it looks like they don't have the newer ones listed on their site anymore. You might look here http://www.diyrepairmanuals.com/products.asp?cat=2363

The $75 I spent has saved me so much time. Here is an example of the manual for troubleshooting the charging system on a 2001 F-150:

My manual covers all Ford cars & trucks made in 2003-2004. This includes Lincoln and the commercial trucks too. Truly a good buy.

There was a pirate website up a few years ago that put them up for free downloading-- I think it was fordcds.com, but it has been taken down. I got a free CD for my '96 Lincoln Town Car and saw how good they were. When I needed one for my newer Expy, I did not hesitate to buy a legal one.

03-23-2011, 07:38 PM
Hey CR,
Thanks for all the info, yeah I have my doubts about how the pulse signal will convert in the pcm and also if the voltage is right to not cook the pcm, (that is kinda why I wanted to go straight to the tach) and if the Dakota will have the necessary compensation range to make it accurate. My local starter/alternator guy said the terminal that leads to the light will give a pulse signal and if that doesn't work he will hook to the pre-rectifier stator wire for a signal?
I bought a CD manual for my 05 dodge on E- for if i remember 3 bucks and it is pretty complete(don't know about legalities) could not find it for the ford though. Right now we are getting snow so when the weather breaks I will hit the u-pull-it for the motor harness and see what happens. Meanwhile got some reading to do, I will keep you posted.
Thanks; Taggmann

03-27-2011, 04:23 PM
Just made an interesting discovery....my destroked tone wheel (actually purchased through autoworld) has 58 teeth--not the 35 teeth CR machined on his balancer. As it turns out, the cps tone wheel should have 35 teeth for a 5.4L, 39 teeth for 6.8L, and 58 teeth for a 6.0L.

Looks like autoworld sent me a 6.0L tone wheel and not a 35 tooth one I need. :( My assumption is that this is putting the pulse readings out of range.

03-27-2011, 04:46 PM
You are correct; the readings will be out of range. The Ford PCM for the 5.4L expects 35 pulses on 10 angles of rotation. When it "sees" the missing tooth at 360, then it recognizes or counts one revolution. If you have access to a CAD program, you can likely copy all the dimensions and features on the 68-tooth wheel except for the tooth pattern, then send it back. Find a sheet metal shop that can water-jet cut you a new wheel with 35 teeth and you are in business. I would avoid laser-cutting, since that could warp the sheet metal and affect balance or the distance between the teeth and sensor.

03-27-2011, 05:17 PM
Cool. As it turns out, I'm friends with the guy at work that runs the water-jet.:dustin: I'll draw one up in ProE and buy him lunch....and I should be good to go!

Question on the missing tooth, did you machine your balancer on a 36 tooth spacing and just leave one tooth off? Or did you machine it with the 35 teeth evenly spaced? (I'm assuming the first way...I just want to be sure and not have to have him cut out a second wheel b/c I drew it wrong.) thanks

03-27-2011, 09:55 PM
Yeah, I used a 36-tooth spacing (one every 10), but with one missing. Here is the quote from the Ford service manual DVD:

The crankshaft position (CKP) sensor is a magnetic transducer mounted on the engine block adjacent to a pulse wheel located on the crankshaft. By monitoring the crankshaft mounted pulse wheel, the CKP is the primary sensor for ignition information to the powertrain control module (PCM). The trigger wheel has a total of 35 teeth spaced 10 degrees apart with one empty space for a missing tooth. The 6.8L ten cylinder pulse wheel has 39 teeth spaced 9 degrees apart and one 9 degree empty space for a missing tooth. By monitoring the trigger wheel, the CKP indicates crankshaft position and speed information to the PCM. By monitoring the missing tooth, the CKP is also able to identify piston travel in order to synchronize the ignition system and provide a way of tracking the angular position of the crankshaft relative to fixed reference


03-28-2011, 05:51 AM
Thanks man! You've been a huge help.

(If you lived closer, I'd buy you a round of beer.)