VTESPEED

iTrader: (12)

Im trying to get the stock gauge cluster in my 90 LX to work with the LS1 swap.

Im running a th350, so a local speedometer specialist shop made a custom end that hooks the factory speedo cable to the th350 with right calibration.

Now I want to get the factory tach to work with the LS1. What would you guys do to get this to work right.

Do I need to use a msd tach adapter on the ls1 and hook my tach wire from dash to the to that? I just dont want to spend the money if im not sure if itll work.

Im going to reuse the factory mustang oil pressure sender into the side part of the oilpan. I will hook the voltage wire to the alternator. I have the factory gas tank sender hooked up with my aeromotive fuel system. I also think i can figure out a way to get the factory water temp gauge hooked up.

I just want everything to work like factory to make for a nice clean install...and i really hate putting a get monster tach in the car.

Brains

iTrader: (7)

to get the tach to work, you can program the tach output of the LS1 PCM to fire in an 8 cyl. pattern and just wire it up. If you wire it up as-is, the tach should read 1/2 actual RPM.

VTESPEED

iTrader: (12)

wow..alright...wire direct up.

Where can I program the tach output of the ls1 pcm? I have HP Tuners and have never noticed a section for changing that.
I thought it was like hooking up an autometer tach, where you just use a tach adapter and cut the wires for a 4 cyl...


Any additional info would be great to avoid having to buy a tach adapter.

Brains

iTrader: (7)

There should be a section where you can alter the crank pulses per revolution.

dragon93308

iTrader: (1)

Wouldnt that change the way the computer reads RPM and change tons of stuff ??

Have you actually done this and it worked or do you think it will work.

Brains

iTrader: (7)

I haven't done it yet, but others have done this with other conversion cars. That doesn't change the way the computer reads RPM, only the way the tach output wire works -- so the car will still run normally.

The only small roadblock we might have is if the Ford tach won't trigger from the 5V output from the PCM. If that is the case, I can post plans to build a simple tach driver.

1dirtyZ

iTrader: (1)

Cool , keep us posted.

do you know what table or section in ls1 edit would i find this ?

mramay

iTrader: (4)

Take a look at http://www.dakotadigital.com/

They have electronic adapter units that allow changing the pulse rates for tachs and speedos. Might have one that will do the Mustang. Their description sounds like what you'll need.

This is the link to the Universal Tachometer Signal Interface
http://www.dakotadigital.com/index.c...rod/prd127.htm

"The SGI-8 Tachometer Interface Unit is designed to allow a factory tachometer to function accurately after performing an engine swap to an engine with a different number of cylinders or tach signal. If you are swapping out a V-6 for a V-8 and you need to recalibrate the tach signal from the V-8 to make it read accurately on the factory V-6 tachometer, the SGI-8 will do the job. The SGI-8 is capable of recalibrating tachometer signals for nearly any engine swap combination"

No affiliation, etc. Used their speedo adapter successfully in my Benz after I installed a new differential.

ls1coupe

iTrader: (2)

Get a tach out of a 4cyl mustang. I don't rember off the top of my head but I think you need to wire the white wire into the light green/red wire on the left side plug on the back of the cluster.

Brains

iTrader: (7)

only problem with the 4cyl tach is the lower RPM overlay. I think it only reads to 6k right?

ls1coupe

iTrader: (2)

Yes, but you will have a stock working tach.

Brains

iTrader: (7)

The V8 tach will work as well, simple PCM configuration change

sparkwirez06

iTrader: (18)

I have a ls1 in my typhoon, the guy that did my harness sent me a tach module to change the pulse rate, don't have it hooked up yet, cost $79.

1dirtyZ

iTrader: (1)

spark wire, post some pics!
is the awd functional? and do all the other guages work?

sparkwirez06

iTrader: (18)

I didn't get my tach module yet, he was temporarily out of them, the other gauges work. the cars not complete yet.yes it's awd, see pics at turbols6.com click on gallery, scroll down to typhoonz06, there are 2 other tys on the web site. take a look.

1dirtyZ

iTrader: (1)

heres a related question, if i remove the ford pcm and accompanying harness, will that affect anything left over after the swap ( i.e. oil pressure guage, fuel level , windows??)

sparkwirez06

iTrader: (18)

i have to post a correction, i just got the pcm back, i had to send it in, he didn't disable the vats,it would run for a minute then stop, anyway,i put it back in and the tach works correctly,i haven't talked to him but he must have programed the pcm to output for the 6cyl. tach!!