How do I wire my original gauages to work with my new 4.6 Mod engine & transmission

Skegee, Stang · 10-13-2009

Hi there, Guys & Girls. Will be back in the states soon from Iraq. I am restoring my 1970 Mustang Mach 1. I am going to put in a 4.6 DOHC Mod engine & transmission from a 1996 Mustang Cobra. I am going with coilover so I can natch the shock towers to fit the engine in. I have seen it done by afew people with out going the Mustang II front suspension route. I know that I am going to have to have the ECM re-flash to bypass the PATS, EGR & 02 sensors. What I need to know can I & if so how to wire up my original dish Tech & Temp gauages with the 4.6 Dohc engine & ECM? Also how hard will it be to get the Speedo woking with the new transmission? Can't wait t get started on my Stang when I get back. Any help would be great.

boosted stang · 10-13-2009

i dont think the old speedo would work because the old speedos are cable driven the new one is electronic

Skegee, Stang · 10-15-2009

Thinks Boosted Stang. A friend of mine told me about this product to run cable speedo with new electronic speedo sensors. Here is a link to the site if anyone ealse needs it.

Cable X...Electronic Speed Signal to Mechanical Speedometer Adapter

rj8806 · 10-15-2009

Actually, the '96 model GT's and Cobra's were mechanical speedometer, not electronic. They didin't go electronic until 1999.

You should be able to run a cable directly from the transmission up to the gauge with no problem. In 1969 + up, the gauges were a clip on (meaning the speedo cable pushed onto the head instead of threading on). If you were able to get the speedo cable off of the cobra, it should go up to your gauges and fit fine.
The tail housing on the T45 out of a Cobra has a different mounting pad for the rubber isolator mount than a GT. Some modification of the cross member will be required.

The tach....I'm not so sure and will leave that for someone else to answer.

Richard
Tech Support
Tremec TKO, T45 & T56 Transmission Systems

silver69 · 10-15-2009

Thank you for your service Skegee Stang, please let your buddies know we all appreciate them tramendously! as said the speedos were mechanical untill '99 but the trans still had drive gears till 01 with a blind plug over the hole. If your car has a factory tach you should be able to use a resistor to get your old tach to read form MSD or summit. The oil pressure and temp are no different, the gauges are merely looking for input values. Install the necessary PIPE thread adapeters(if they are even needed) and use the correct sending unit for a 70 with a gauge or a warning light, they are different. If you are going with a 4.6 dohc are you keeping efi or using an after market carb intake? Good luck and hope to see you home soon,
Joe

rj8806 · 10-15-2009

Quote:

Originally Posted by silver69

.....as said the speedos were mechanical untill '99 but the trans still had drive gears till 01 with a blind plug over the hole. .....

Actually, that too is wrong. In '99, when they went to electronic, the plastic drive gear was removed/replaced on the output shaft with a metal reluctor ring with which to run a magnetic pickup for an electronic speedo.

The "hole" in the tail housing was re-designed in '99 and instead of being at an angle, they came straight out instead, thus making it impossible to simply swap the reluctor ring for a plastic worm gear and run it. In order to make this happen, a complete tail housing swap needs to take place as well as replacing the metal ring gear with the plastic worm gear.

We are in the business of rebuilding T45's for use in our kits and I have 50+ cores in house and none of them have both a reluctor ring and a plastic worm gear on them from the factory.

Richard
Tech Support
Tremec TKO, T45 & T56 Transmission Systems

silver69 · 10-15-2009

You are right about the 5 speed manuals RJ, my mistake but the automatics still had provisons for the manual speedo's until late '01, we are running them in our cars as we speak. they do have the reluctor wheel to talk to the trans controllers, elecronic speedo cluster and the worm drive gear on the tailshafts with the plug over it, in 02 the hole was still there but shaft was smooth and in 03 the hole too is gone. at lest this is what I have learned in converting my cars to 4R70W automatics, thanks for correcting my mistake, I hate giving or getting incorrect information.

rbinck · 10-15-2009

When I put the 5.0L EFI in my Falcons there was a tachometer wire in the EFI harness. Hopefully it will work with your stock tachometer, it worked with my aftermarket.

As far as the temp gauge goes, I had to use a '66 temp sensor. On the 5.0L there is a separate sensor for the guage and the sensor for the computer. The guage sensor is in the intake manifold and the computer sensor is in the heater bypass tubing.

Also I have to have the speed sensor connected on my computer or the engine will stall when I come to a stop. It is probably only applicable to automatics, but that is something to look at. I didn't have room in the tunnel for the sensor so I used an underdash sensor that installs in the speedo cable. I got the sensor ('74 Galaxy D4AF9E731) from Autozone and the short speedo cable between the sensor and the speedometer is available at RockAuto.com, their part number Y845.

Skegee, Stang · 10-16-2009

Thinks everyone for your support & advice. RJ thinks for the info on the Speedo. saaving me alot of money that I can put somewhere ealse. Silver69 thinks also with info & yes on the 4.6 DOHC I am keeping the EFI.