Need help to wire this up on a 92 vette with LT1, i get 4 red blinks. Says I'm missing the est wire signal. Where would this wire be? Car cranks but doesn't start.

 

Do you have the instructions:

https://www.camaroz28.com/forums/lt1...ctions-882760/

On the 1993 F-Body: EST is the white wire from the ECM pin A12 to the ignition control module pin B:

https://www.camaroz28.com/forums/lt1...ctions-882760/

Y-Body should be similar (except for ECM pin ? ?) but I don't have a wiring diagram handy for the 92 Corvette

 

i have this but in not very tech savvy

 

Look at the LTCC module pinout list on page 2 of the instructions I linked above. Pin "F" - EST input from PCM (white) > @ ignition module.

I have the Corvette wiring diagrams in my "Corvette Fuel Injection" manual. It is the same diagram you show marked up above.

For 1992-93 Corvette LT1, the pinout is the same as the 1993 F-Body (Camaro/Firebird). The ignition control module (ICM) has 4 pins on the connector. They are labeled A-B-C-D (unfortunately in the wiring diagram they show a different order).

ICM:

A - pink black wire from coil
B - white wire from ECM (labeled "EST" on the ECM diagram)
C - black wire from engine ground
D - white wire from coil (shows white/black on Camaro diagram)

You only need the white wire from ICM connector pin "B". That gets attached to to pin "F" of the LTCC. Make sure you take the white wire out of pin "B", Not the white wire shown connected to pin "D". The connector should have the letters A - B - C - D in exactly that order.

I can see where the marked up diagram you have is confusing.

 

like this?

 

The two adjoining connectors appear to be for the coil. That is not the ICM. If the Corvette is the same as the Camaro, the ICM is on the same bracket on the front of the driver side head. Looks like this:

http://shbox.com/1/coil_loc.jpg

The 4-wire harness connector is at the very top of the picture, right under the “e” in the word Module. You can see the white wire in the connector position “B”, starting from the left side of the connector, the pink wire is in position “A”, next wire is the white wire you need to connect to pin “F” on the LTCC module. If the Corvette ICM is not located in the same place, I don’t know where it would be.

 

ok now i get it! I'll snap a pic once I'm off work just to make sure.

 

hooked up the pink, there are two white wires, is it the wire next to the pink or the one next to black?
Wire 1.pinkblk connected
wire 2. White connected
​​​​​​wire 3. black
wire 4. white

 

You asked where the EST was. I explained that - pin “B” on the ICM. I gave you a little table showing what color wires are in the ICM connector. The ICM connector should have embossed letters A - B - C - D. I gave you a table with the color of each of the four wires that attach to the ICM connector. I indicated “YOU ONLY NEED THE WHITE WIRE FROM THE ICM CONNECTOR From pin “B” “.

Did you connect the white wire from pin “B” to “F” in the LTCC harness?

Did you look at the instructions I linked above? You need to do that.

The first 5 pages of the instructions are for the original design of the LTCC (lettered terminals). The last two pages are for design revision 3.00 to the LTCC (numbered terminals). WHICH VERSION OF THE LTCC DO YOU HAVE? Maybe that's what is causing all the confusion.

At this point, I think you need to contact Bob Bailey for clarification. There's an email link on his home page:

Bailey LTCC setup

 

i have Version 3.00
I did message bob no reply. Tach filter wire I'm not sure where that goes either

 

also just looked at the pin and it is correct thanks, just need to hook up the tach filter wire unsure where thats at though.

 

According to the diagram for the Corvette you posted in post #3, the tach filter is connected to a white wire on the gray connector for the coil. That is just the opposite of the Camaro diagram which shows the white wire coming from the black connector at the coil. The important thing is there is only one white wire on the coil connectors. Trace the white wire from the coil connector to the tach filter.

I don’t have the slightest idea what the tach filter looks like - in my 94 they deleted the tach filter and wired the tach from the PCM.

When you find the tach filter it will have the white wire from the coil connector running into it, and another white wire coming out of it, running to the instrument cluster. According to the diagram in post #3 you want to connect a “white/black” wire to the wire that goes to the instrument cluster, but it is totally unclear to me what “white/black” wire they are talking about. Is there a loose white/black wire in the LTCC harness? This is not shown in the written instructions.

It is clear from the wiring diagram in post #3 that the ICM, coil, and tach filter are no longer used with the LTCC. But at this point I'm as confused as you are.

 

tach filter looks like this

 

yeah its connected, cranks but wont start. I'm starting to look at maybe the coils arent grounded well it looks like theyre grounded on the coil. It should crank up. And then the wire for the tach i found it think but need to verify with the car on and running.

 

Did the red LED stop blinking (except one second on power up)? Is the green LED on?

Coils ground to engine block.