So this might just be the last glitch in my 383/T56 swap. I have the SGI-5C box hooked up to the ECM, tried all the various recommended Output 3 and 4 configurations = no speedo. The only Output the speedo moves at all on is Output 1, with switches all off. Speedo reads maybe triple actual speed (120 mph at 2000 rpm in 4th gear with 3.70 gears.)

According to the SGI-5 manual the only application for Output 1 is for a 64,000-250,000 ppm signal; a T56 is 25-40,000, correct? Something's not making sense here. Most of the searches turn up an answer that just doesn't quite apply to my combo.

Any suggestions?

 

What year is your T56?

If its a 93 the reluctor ring is different than the 94-02 T56s and requires a different setup than just about every other thread on these forums.

 

I think it may be. What then?

 

Post up how you've got it wired, everything.

It sounds like its wired improperly.

 

Which ecm are you using?

 

7730 ECM.

12v Power, Ground, Transmission VSS directly to Signal in and Signal Ground. As I said, OUT 1 is the only output that will generate movement on the speedo. All other OUTs read zero, no matter the switch settings. All 4 switches currently set to OFF.

Light on SGI flashes green when moving.

 

Switch 3 should be set to ON

You *should* be using out4, though its been about 8 years since I've last setup one of these with the same config you're doing.

Also i'd run a jumper wire over to the main ground from your signal ground connection.

 

TTT. Regrounded as per suggestion. No other outputs will work. I've noticed that occasionally the speedo will drop to zero when driving and the car starts running HORRIBLY. After awhile it will shoot back up to its (incorrect by 250%) reading and run like butter.

Car is parked for another week or two, but thinking about this again for Spring. Do you think the speedo issue is the cause, or a symptom?

Should I buy and try another SGI-5?

 

What kind of different setup?