a55bruce

I knew that, I was trying to keep the post simple & short.
That's what I said, well, sort of...Wait for the brain meltdown when I try to get Ted to backprobe the connectors on the PCM.

mountainmanjoe

so you did. I should read more carefully
yeah I was saving the backprobing for last

Ted K

First of all, thank you very much for your help! 1. Terminal 85 has power all the time. 2. I don't have any power at #86 3. The crank fuse is getting power in the crank command from the ignition switch and the fuse is good.
There is obviously something that I don't understand about the start/neutral safety switch powering the ign E switch, since there is power there even when the shifter lever is in drive and reverse. Anyway, I'm ready for that brain meltdown gentlemen!

mountainmanjoe

very good. Ignition switch works. Getting closer.

Good. So 85 must be the positive side of the coil. It also means IGN E fuse is good, and PNP switch is good.
Now measure resistance between socket #86 and battery ground. Should drop to around zero when key is turned to crank.

If still no luck, we move on to the PCM. Connector end views should be in that same manual. Were you able to find it?



you mean the IGN E fuse? If you look near the top of the schematic it always has power when key is in run or start position.

a55bruce

My mistake My post #9 incorrectly said "all the time", the IGN E fuse will have power when the ignition switch is in the run or start position.
The relay terminal 85 should loose power when the shift lever is moved out of park or neutral.
Don't forget to put the relay back in it's socket.
Did you check the connectors at the PCM? Unplug, check for corrosion, loose pins, chewed wires, etc...
Plug them back in. Try to start one more time. Sometimes unplugging/plugging the connectors will clean the pins/sockets.

PCM Connectors
Using a paper clip from the back side of the connector will permit you to check for proper voltages.
Green connector, terminal 59, purple wire, should get power when the key is turned to START.
Blue connector, terminal 39, yellow / black wire, should have 12v with the key in RUN position. 0 volts when key is at START.
Grounding this terminal should crank the engine.

Ted K

I typed my diagnostic findings above in red. TK.

mountainmanjoe

how much did it read?

perfect. Now follow Bruce's instructions for "PCM Connectors".
Hopefully it's just some corrosion on the PCM pins.

Ted K

Greetings, not sure if I was supposed to remove the blue and green connectors from the PCM to perform the above diagnostic steps, but I did. If that isn't right I'll have to redo this. It was easier with the connectors removed so I chose that path. As it worked out, I removed the Blue connector first and the green connector was still attached. So blue connector, terminal 39 had 12 volts in the RUN position. It also had 12v in the start position. Grounding that terminal did make the engine crank.
Green connector, terminal 59, purple wire, had no voltage when turned to START.
So correct me if I need to redo the test with the connectors hooked up to the PCM. Thanks, TK.

Ted K

Thanks again! I don't think the pins are corroded. The seals were good between the connectors and the PCM and everything looks good with the pins. I just responded to Bruce and I'll see what he says. TK.

mountainmanjoe

yeah PCM has to be plugged in. That's why bruce suggested shoving a paperclip wire into the back of the connectors. This may or may not be possible depending on the connector construction. Photos would help big time.