Solenoid Relay Wiring
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=50453
Printed Date: April-28-2024 at 5:51pm
Topic: Solenoid Relay Wiring
Posted By: jmesser
Subject: Solenoid Relay Wiring
Date Posted: January-23-2022 at 9:23pm
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So I rcvd an engine. It is a late 80's PCM 351. I saw it run on the stand. the gentleman disconnected it and I brought it home. I have an old pigtail to plug into the harness (he let me have it). I went to wire it up and crank it in my garage. And I reviewed the plethora of diagrams on this site and others and have come to the conclusion that the solenoid is wired up wrong. ...Yes, but I said to myself, I just saw it run like this. So, sanity check please. 1st pic is my solenoid compared to a diagram form CCF. (Yes I do have a newer starter with the 2 wires running back to it). I don't have the battery positive hooked up yet. 2nd pic is another diagram basically showing me the same thing. 3rd pic- yes mine is still wrong Also, none of the diagrams show the use of the "I" terminal. But mine is hooked up. My questions- Are "A" and "B" terminals (not that they are labeled) interchangeable (I am led to believe they are NOT)? On my solenoid, the "I" terminal goes to the ballast resistor. Is that right? Or no matter? ...any input appreciated!  ------------- Johnnie Messer |
Replies:
Posted By: KENO
Date Posted: January-24-2022 at 6:57am
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About that third picture.........it doesn't seem to have shown up. By your description, you have a PMGR starter so what's shown in your first picture will work just fine once you hook the battery cable to the bottom lug that has the big Red cable to the starter and has the pinkish, reddish wire going to the main breaker hooked to it.
PCM never used the "I" terminal on the points equipped engines, but not knowing if you have points or an electronic distributor, I'd leave it just as it is now. It can't hurt and can only help. With the wire from the "I" terminal hooked to the ballast resistor, it's providing maximum voltage to the coil when the key is taken to the Start position (it's a short direct path from the "I" terminal to the coil without going up to the dash to the key switch and back to the engine again) and when the engine starts and the key is i the Run position, then the alternator is supplying plenty of power to the coil. The "I" terminal is only energized internally when the key is in Start. If you check voltage at the "I" terminal with the wire in place and the engine running, you'll have voltage there. It's being fed externally, backwards from the connection at the ballast resistor. If you got rid of the wire completely, the engine would have less starting voltage to the coil and some electronic systems don't like that and won't make a spark If you were to check voltage at the "I" terminal with the wire removed while the engine is running, you'd get zero volts since it's only energized when the key is in Start like mentioned above. So.............leave it hooked up as it is, hook up the battery cable as mentioned above and you're all set  PS the A and B terminals are interchangeable functionally
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Posted By: TRBenj
Date Posted: January-24-2022 at 11:33am
| That bracket also looks alien to me… zoom out a bit and take another? |
Posted By: Hollywood
Date Posted: January-24-2022 at 11:46am
| Please? |
Posted By: KENO
Date Posted: January-24-2022 at 2:09pm
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Well if we're looking for "alien" looking stuff, those cylinder heads are alien to an 89 PCM engine Looks like later gt40 heads on your new to you engine
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Posted By: Jonny Quest
Date Posted: January-24-2022 at 2:22pm
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KENO doesn't miss much. Those look like GT40 “3 Bar” heads… JQ
------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: jmesser
Date Posted: January-25-2022 at 9:00pm
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Thank you! You are so fast with response. I apologize, I'm stretched for time daily and getting back as soon as I can. ...You'll kill me, but I haven't jumped in to research anything on the engine yet as far as year and model. Im sure there are some threads on here that will guide me in. I'm gonna make some cables and hook here up soon, but in the mean time here are a few more pix of what I have.
gotta tell ya, I'm good with computers, but this image upload set up is a struggle, ha! Finally got em uploaded... unfortunately sideways.
------------- Johnnie Messer |
Posted By: jmesser
Date Posted: January-25-2022 at 9:02pm
 ------------- Johnnie Messer |
Posted By: jmesser
Date Posted: January-25-2022 at 9:03pm
------------- Johnnie Messer |
Posted By: jmesser
Date Posted: January-25-2022 at 9:05pm
------------- Johnnie Messer |
Posted By: jmesser
Date Posted: January-25-2022 at 9:06pm
------------- Johnnie Messer |
Posted By: KENO
Date Posted: January-26-2022 at 6:41am
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I'm gonna guess that your engine is a handful of years newer than you or the seller think and that it was a ProTec equipped engine And the gt40 heads were original to a 285 HP ProTec engine It looks like your yellow/red wire from the engine mounted solenoid turns into a black wire on it's way to the starter solenoid. I'll guess that you got more engine than you paid for or were expecting. |
Posted By: TRBenj
Date Posted: January-26-2022 at 8:02am
| Yup, what keno said… that’s a 93-94 vintage PCM, originally a Protec. Looks like a 40i (1:1) trans and some off brand mounts. Wonder if the engine is RH or LH… |
Posted By: jmesser
Date Posted: January-26-2022 at 2:47pm
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Hey good news! I'll take it. Yes sir, the yel/red wire turns to black on the starter. And it is a LH engine. I need to research the GT40 heads now since I have some. Thanks guys! ------------- Johnnie Messer |
Posted By: TRBenj
Date Posted: January-27-2022 at 8:07am
Bummer |
jmesser wrote:Posted By: jmesser
Date Posted: January-27-2022 at 10:29pm
 ACC to the number 3 pin (Starting) IGN to the number 6 pin (Ignition) BAT- I haven't hooked to anything. I didn't get any response. no click or any gauge movement from the makeshift guage panel. I stopped, and jumped on here and it's not clear on how to hook up the switch. At some point the "ahh ha" bulb will hit. But for now, do you guys see what I am missing? ------------- Johnnie Messer |
Posted By: KENO
Date Posted: January-28-2022 at 7:01am
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The ahh-ha bulb lighting up should tell you that you need 12 volts fed to the BAT terminal. You should have a switch with a BAT terminal an IGN terminal and a SOL terminal. With 12 volts to the BAT terminal, when you turn the key to START, you'll send 12 volts to both the SOL terminal and the IGN terminal. This will power the starter and power the ignition system and the engine starts. After it starts and you let the key return to the RUN position, only the IGN terminal has power and the engine stays running and the starter is deenergized So............run 12 volts to the BAT terminal and you should be good to go. It's hard to tell from the picture, but hopefully your temporary positive and negative cables are something like 4 ga or larger to handle the starter motor current.
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Posted By: Duane in Indy
Date Posted: January-28-2022 at 12:42pm
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KenO, IIRC the only reason that the SOL terminal is hot when in start mode is to bypass the ballast resistor and supply full 12 volts to the coil. Am I correct???? ------------- Keep it as original as YOU want it 1978 Mustang (modified) |
Posted By: Jonny Quest
Date Posted: January-28-2022 at 1:23pm
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Duane: I think that the "I" terminal is to supply 12V to the ballast resistor. JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: Hollywood
Date Posted: January-28-2022 at 1:36pm
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Which is not 12V to the coil… I to ballast resistor S to coil Coil is dual fed during start |
Posted By: Duane in Indy
Date Posted: January-28-2022 at 2:10pm
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OOPS again, you guys are correct. Thanks ------------- Keep it as original as YOU want it 1978 Mustang (modified) |
Posted By: KENO
Date Posted: January-28-2022 at 5:48pm
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Here's a rather sloppily marked up version of the TRB diagram for a mid 80's to early/mid 90's carbureted 351 PCM with a later PMGR starter like Johnny Messer has. It shows what's hooked to the BAT, IGN and SOL terminals on the key switch and also what's hooked to the different terminals on the slave solenoid on the back of the engine. (The A,B, S, and I terminals) Normally PCM hooked nothing to the "I" terminal on the carbureted stuff with points but the sloppy blue line shows how the "I" terminal can be put to use to maximize coil voltage during cranking. The blue wire from the "I" terminal on the solenoid can go to either the ballast resistor as shown or to the (+) terminal on the coil if you have an electronic ignition and got rid of the resistor for example. The yellow/red wire from the key switch to the neutral safety switch to the "S" terminal on the solenoid is white on some of the engines. Johnny's engine has white as an earlier picture of his in this thread shows
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Posted By: jmesser
Date Posted: February-20-2022 at 3:46pm
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KENO, Ahh haa! Yes sir you were right as usual! I went over those diagram a hundred times.... You want to know my problem, I hate to advertise it... But will. On the switch I bought at O'Reilly's it had 4 positions (screws). The 3 around center were BATT/ACC/IGN. I held that switch in my hand for a long time and last night after going through it all again, I realized there was a screw in the middle with an S (Start). I was so embarrassed. Anyway, I hooked it up again and here are the results (https://www.youtube.com/watch?v=3rwBv9bt4AY). Thanks again for all!
------------- Johnnie Messer |
Posted By: jmesser
Date Posted: May-09-2023 at 9:36pm
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I now have multiple copies of this diagram in the garage. Used it many times. Thank you! ------------- Johnnie Messer |