so i did a 305 tpi to a 350 carbed in my 92 Camaro...

everyone said that if i take out ecu and harness, it wont effect speedo....WRONG according to my picture, you can see the YELLOW/purple wire goes into the fender right into the ECM

yes the TPI portion of the harness looks a mess. i got the car and it was like that i organized and labled. i was never going to use agian so i just threw it in a box. thats why it looks like it....

1992 camaro 305 TPI does not have a BUFFER box it is BUILT INTO THE ECM. same goes for the V6 ......

so i need help hooking my speedo up. i know this thread will help others because there is NO answer on this form to how to do it.

i did cut the YELLOW/PURPLE wire so can bypass the ECM if i can, or it might have to go through it...im trying to figure this out... THE VSS is build into the tranny, pushing 4000 pulse, and the speedo is 4000 pulse so i dont see why i cant bypass. i am NOT using crusie control so i dont need to split it.

so is there anyway around this,,,,or just hooking up the PURPLE/ wIRE back up...and cutting all the other wires, to the ecm( besides the red and pink that goes to the CLEAR connecter that connectes the ECU to the car.

please help.

( i spelled through wrong on the pic )

 

Does this help any? http://www.austinthirdgen.org/mkport...F_and_vin8.jpg

I never cut any wires - I just unplugged my ECM. There is a difference in wiring between a TPI car and a TBI car - mine was TBI and everything just worked fine.

 

yeah TBI cars are alot easier to work with..just unplug fender harness...the TBI cars also have a yellow buffer box near the ecm that you could just wire to get the speedo to work also. But in my case i dont...

every one said just unplug from fender...and im just trying to show people the TPI's dont unplug, (well from 90-92 305 TPI anyways) the wires are just hot glued into a clip for the fender/firewall.......

i need to figure this out.

 

this is the same exact question i have, sure hope someone can help us out i have a t-5 and just about to put the 383 stroker in just a few items left

 

As the SD cars only have a single wire ,4000 pulse output from the the ECM , you may need a Digital Dakota box to convert the 2 wire signal from the VSS to suit the 90 - 92 speedo

http://www.dakotadigital.com/index.c...rod&prd126.htm

 

I would be more worried how the T5 is going to live behind a 383

GM didn't make it available behind the 350 for a reason;
TOO WEAK!

 

 

the VSS that is build into the 700r4 is 4000 pulse, the point of the yellow box is to send 2000 pulse to the cruise control. the 92 speedo takes 4000 pulse so i dont see why i cant just bypass the box and go straight to harness under the dash( clear harness) or the speedo itself...?

 

I am having issue with my speedometer as well. The owner took out the 305 adn dropped a 350 with a 2bl CArb. My speedometer is 25 miles off. I have replaced the VSS. That didn't fix the issue. I am looking now at the ECM. My car does have a yello buffer box under the dash. I am also thinking the speedometer is not calabrated correctly. Any help would be greatly needed. Thanks for your time and God Bless.

 

If the spedometer is not accurate you need to install the correct drive and driven gears in the transmission tail housing to correct for rear gear change and tire size. These are becoming harder to find so another alternative would be the dakota digital sgi-5 to recalibrate the vss signal to the ip.

http://www.summitracing.com/parts/DAK-SGI-5/

 

back from the dead, do i have to run separate wires from the buffer box to the speedo or can i plug into the harness and it should work? i hooked into the harness and the speedo isnt getting any power to it. im running phantoms and it was a tbi car with t5

 

If the car was a tbi 5 speed the vss signal goes to the buffer and from the buffer optical 4k ppm out to the speedometer. Not sure what input the phontoms use ? yoou also have the choise of 2k output on the buffer as well.

http://images.search.yahoo.com/image...mb=rtnZiIYol.J

 

i have a similar problem and i have no clue since my searches came up with less than desired results!! please help me just swapped a carbed 350 in a 92 camaro that had a 3.1 v6, speed does not work at all nor does odometer. the speedo Used to work fine, and the rest of the electrical guages are fine, and the car has no other electrical issues, any help would be appreciated as i am not exactly the most mechanically incline individual,. Thanks!

 

I'm going to make this easy:

EVERY F-BODY PRODUCED BETWEEN 1990 and 92 THAT DOES NOT HAVE A TBI ENGINE RUNS ON THE 1227730 ECM. THEY ALL BUFFER THE VSS SIGNAL TO BOTH THE CRUISE MODULE AND THE INSTRUMENT PANEL. YOU REMOVE THE ECM, YOU NEED TO ADD A BUFFER MODULE OR YOUR SPEEDO AND ODOMETER WILL CEASE TO FUNCTION. Enough said.

Easiest thing to do is to leave the VSS wires intact and add the buffer from either a pre-90 (but post-86, IIRC) Bird with the electronic speedo or from a 90-92 TBI car. Wires in like stock (except the speedo out wire is green/black where the 730 output is gray), and works like stock. Other than that, Dakota Digital is the only way to go (but a lot more expensive).

 

Technically no you dont need to wire in a buffer, now if you are trying to retain cruise control yes, but otherwise you just need to wire the vss to ground and to the wire in the C207 that goes to the gauge.

And the speed output wire from a tbi buffer is brown, not green/black.

 

bump , i still need any advice, just spent 160 at a shop today for my 91 and they couldnt get it done except for installing a missing drive gear in the tranny.
They said the sensor is working and has output, but between the sensor and the guage cluster itself there is an electrical problem. is there an adapter box or module dohicky that i can buy to splice into the two wires from the speed sensor on the trans and wire up directly to the electronic guages? idk why this is a hard problem for shops to figure out.

 

Did your car start out as a 6 cyl or a TBI V8 ?

 

Hi I have a problem and maybe someone can help. I have a 92 rs Camaro that I put a 350 in and a turbo 350 trans I was trying to get the speed odometer hooked up. I bought a speed sending unit from summit, part number sum-g2887, I'm trying to hook it up but am very confused I took out my dash cluster and its electronic so there's just the 2 plugs I need to know what wires I need to hook the speed sending unit too. There is instructions but very bad it just say red to 12v power source and black to a ground and white or clear to(16 pulse/revolution,square wave and that's it. If anyone could help me please message me at bigtrucks94@aol.com thanks. And one more thing could someone tell me which wire in the back of the dash cluster would make the tach work by that I mean to hook up to negative on coil.

 

That brown speed output wire is for the ECM... The red one is for the cruise control (half output) and the green one is for the speedometer head. If you connect that brown wire to the speedo head, the speedo is going to read half speed as that output is also halved (92 FSM).

I suppose the rest could be possible, but until someone actually does it, I wouldn't count on it.

 

I don't believe you can make the Hall effect work even with a Dakota digital sgi-5. If your cars was tbi you can just but a 2k ppm vss and wire it up to the vss buffer to get the 4k optical signal to the speedometer. If you need to adjust the speedometer for incorrect speedometer gear in the th350 or tire change or rear end gears you should uses a retrofit 2k magnetic vss and a Dakota digital sgi-5
http://www.austinthirdgen.org/mkport...ter_pinout.jpg
http://tpiparts.net/inc/sdetail/7586

 

Not to hijack the thread, but I am in trouble and desperately need help. I have a 6 speed in my 85 Trans Am with the stock 870 ECM. How would I use the SEN-820 from TPI Parts to get VSS to my ECM? I was planning on swapping a later model gauge cluster in, so to feed my ECM I would need the SGI-5 along with the SEN-820 correct? According to the diagram a brown wire comes off the VSS and goes into A-10 of the ECM from pin A of the VSS. Pin B is ground, and pin C goes to the gauges, and pin A of the ALCL. So would it be enough to plug in the 6 speed VSS output to a SGI-5 and then take the SGI-5 output to pin A-10 of the ECM? Or would I need more? Sorry this is long, I just wanted to give as much detail as possible.

 

I'm trying to understand all of this speedo fix with the DD Sgi-100bt. I've read so much on the forum and no one can seem to have the same opinion or a solution similar to mine.
I have a 1990 Firebird V6 car. Replaced V6 with a SBC and Transmission with a 700r4. The speedometer is maxing out now when in drive. I purchased and installed a DD Sgi-100bt. Took the purple and yellow vss wires from the ecm and used them into the DD input and ground. The brown wire from the ecm from the speedometer to output #3. This does not stop the speedo from maxing out to allow any adjustments. I've tried different settings in the DD Sgi-100bt and different outputs for the speedo.
Can someone that understands this offer me some help?