The man who says something is impossible, is usually interrupted by the man doing it.
Using a 1227747 ECM to install a TBI on my 1974 Chevy K10. While studying the ECM wiring schematic I see pin C9 with a purple wire coming from the starter solenoid called "crank signal input". Is this to let the ECM know that the engine is cranking and is it needed?
The crank signal should be connected. I connected it to the S terminal of the starter.
My schematic also shows the purple wire going thru a 3 amp fuse. Is this correct?
Thx Dave.
It's not absolutely necessary. I've used the '7747 with and without that connection and haven't experienced any difference in starting.
I mean, it's not a difficult connection to make so add it, but all I'm saying is, if you didn't, you're not likely going to experience issues starting.
The man who says something is impossible, is usually interrupted by the man doing it.
I've already installed it.
I am putting a GM TBI unit in my 1974 K10 and am using the 1227747 ECM. I'm trying to make the check engine light come on and per the ECM schematic I need 12v switched to the bulb and a brown/white wire going to pin A5 which grounds out inside the EMC. I've checked everything I can think of, good bulb that works, 12v to the bulb, and the light won't come on. Does this mean the ECM is bad or could it be something else
In response to your same question on TGO...double, triple, quadruple check your wiring. Idk what schematics you have that would have the A5 spliced to go to pin D on the ALDL... There's some schematics at the following link... http://www.gearhead-efi.com/Fuel-Inj...Information-42
In the 1227747 schematics you sent me, the schematic on the top row far right is the schematic I have which shows the spliced brown/white wire going to pin D in the ALDL.
Found the attached .pdf on the web, looks correct to me.
Okay, thx a lot, looks just like the way mine is currently wired. Now, since my check engine light won't come on, is there anything else that could be causing it to not come on besides a failure inside the ECM?
Ahhhh...I didn't see that and ironically albeit not originally 1227747 but it would be plug and play, my '85 Caballero has a brown/wht wire going to ALDL D. I have no idea if it's spliced as you have said. I keyed on engine off and measured for volts and only got 0.1v. I verified that my ground was good checking volts on the cigarette lighter.
Edit: Wait a minute, the last schematic says it should read 0v with key on eng off but 14v with engine running.
Last edited by stew86MCSS396; 10-21-2022 at 09:27 AM.
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