1227747 I/O questions

[uncabob]

Presently rebuilding a harness with a 1227747 ECM. Original was after market but worked ok.

Question 1. B+ goes to ECM A6. Should it be continuous or switched from the key?

Q2. B+ to ECM B1. Continuous or switched?

Q3. If neither A6 or B1 are continuous how does the ECM maintain RAM ?

Q4. ECM B10 (P/N signal) needs to be grounded? My engine runs with no wire in B10. Detrimental?

Q5. ECM C9 should see cranking voltage? No wire here either. Detrimental?

Q6. Is fuel prime determined by the ECM or the BIN? I'm using AKAH BIN. Pump runs a long time before I turn the key to start position.
2 seconds should be plenty? 20 seconds max? It's in a 49 Jimmy not a MH.

Thanks for any help. I've got a lot to learn.
Bob.

[dave w]

Post #2 on this tread has schematics and other useful information: http://www.gearhead-efi.com/Fuel-Inj...Information-42

dave w

[uncabob]

Post #2 on this tread has schematics and other useful information: http://www.gearhead-efi.com/Fuel-Inj...Information-42

dave w

Thanks Dave:

That's exactly where I started about a year ago and my schematics and wiring are based on them. That thread is where my questions come from.

I can't find an explanation on where the ECM gets the power to maintain the memory for tune or error codes. Does it have to have continuous power or can it be switched off? But switching it off clears the codes so that wouldn't make sense. Also if the battery is removed the next start seems to run rough until it has been running for awhile.

You have helped me before and I do appreciate the help I get on this site. Maybe my questions were not clear enough? Thanks again. Bob.

[Six_Shooter]

A6 is ignition, B1 and C16 are battery.

For best results the signals for park/neutral should be used, unless you're using a manual bin, and start signal with enabling some of the start parameters.

[uncabob]

A6 is ignition, B1 and C16 are battery.

For best results the signals for park/neutral should be used, unless you're using a manual bin, and start signal with enabling some of the start parameters.

Thanks Six: That's what I was looking for. I had totally missed C16. My injectors are wired to C16 also. Can they have continuous B+?

Using a th400 and had my P/N in series with the start relay (hot side). Now have switch in series to the ground side and to B10 (P/N) through a diode.

Is C9 looking at the battery voltage while cranking or does it just need a signal? I have it wired to the output of the start relay (solenoid input) at present.

Thanks again: Bob

[Six_Shooter]

Injectors should have switched one side and the negative trigger from the ECM on the other...

I don't follow your P/N wiring, drawing up a diagram will help clarify that.

C9 should have 12V while the key is turned to crank.

Study the diagrams in the thread that dave w linked to, all of the info about how things should be connected and to where is in those diagrams.

[uncabob]

Injectors should have switched one side and the negative trigger from the ECM on the other...

I don't follow your P/N wiring, drawing up a diagram will help clarify that.

C9 should have 12V while the key is turned to crank.

Study the diagrams in the thread that dave w linked to, all of the info about how things should be connected and to where is in those diagrams.

Don't know how to add a drawing to a forum but I'll try.NEW ST CKT.zip

[uncabob]

Wasn't quite what I expected but that's the diagram I drew up using the info in the thread you and Dave recommended.
Your comments would be welcome.

Thanks again: Bob