87 D21 wont start mornings

[Dattebayo]

Hey everyone.

I had a new issue pop up today (of course) when I was on my way into work this morning.
I could hear the starter relay click near the fuse panel to the left of the steering wheel when I turned the key all the way forward, but could not get the solenoid to click or the starter to turn over the engine. I replaced the old starter with a brand-new unit one month ago or so, so I know it's not that.

I turned the key to the "on" position and took a piece of wire to bridge the solenoid connection directly to the battery positive, and the engine starts! But after I turned the key off, I cannot re-start the engine again with the key. I pulled the starter relay to check it with a multimeter and I can verify the coil has the proper resistance, but I don't know the coil voltage to test the switch operation... anyone know what that is so I can put it to bed?

I even replaced the female spade terminal on the harness solenoid lead as well to no avail. SO I just started it by the by-pass method and went to work.

BUT WAIT- After I drove the car for about 30 minutes, I was magically able to start it normally using the key in the parking lot of the store I was working at. Huh. Anyone have an idea what this could be? Thanks-

-Dave

[DrewUth]

My 92 D21 had a similar issue that took me nearly a year of intermittent no-starts to diagnose. Turned out to be my ignition switch.

However...just because the starter is new, don't rule it out. Put a test light on the solenoid signal wire (that small female terminal) and have a friend hit the key. If that wire is getting 12v when the key goes to the start position, the issue is the starter. I have had many "new"/reman starters fail quickly.

[Dattebayo]

Okay, thanks. But by that reasoning, if it were a bad solenoid, why would a jump from the signal wire terminal to the positive terminal start the engine if the solenoid was bad?
I should have said that I used the signal terminal more specifically in the first post.

Besides, I tested it first and it had no voltage on it when I tried. (I thought I said that in the first post, I guess not exactly after re-reading it, derp) It was the first thing I did...

BTW, what I meant in my first post was I turned the ignition to the "start" position, not "on" as I mis-typed up there. Sorry to confuse.

[Kompresshun]

Dave you probably should replace the ignition switch. You may have to buy it as a whole assembly with the lock cylinder, but I had this issue with two of my Ford Rangers in the past and it sounds just like you're describing. Different vehicles I know, but that solved my issue both times.

[Dattebayo]

I really do appreciate your help, I really do! And I understand what you're saying, but I'm still hung up on this: The starter relay was engaging.

Doesn't that mean the ignition switch was still working like it's supposed to?

[Dattebayo]

I just found the FSM, and it looks like there's a fusible link, diode or the inhibitor switch somewhere that may be the culprit. Crap, this is why I hate automatics...

Well if it happens again, I'll report more so I can get a real idea.

[Dattebayo]

[DrewUth]

Well...is this a no start or a no crank issue? I was under the impression that it is a no crank. The starter works pretty simply, and you seem to know that- there is a heavy 12v hot wire practically straight from the battery on the solenoid, and when the signal wire from the ignition switch is hot it slams the solenoid shut, allowing the 12v from the battery to spin the starter motor. You said you have 12v at the signal wire when you turn the ignition to start, so the only other piece of the puzzle is the 12v hot lead from the battery. A solenoid is just a "switched switch"- when it gets the signal from the ignition start, it closes to allow the high-amp current from the battery to the starter motor.

I have never owned an automatic. In 5spd cars, there is a switch behind the clutch pedal that wont let the engine crank if the pedal is not depressed- however, it interrupts the signal from the ignition switch, not the hot lead from the battery to the solenoid. I always jump those anyway. I know that automatics need to be in Neutral or Park to crank, and I wouldn't recommend trying to jump that switch. If there is a fuseable link between the battery and the solenoid, that is the next place to look for sure. Hell, you could just run a heavy battery cable from the positive terminal down to the starter/solenoid to test/eliminate the extra points of failure and simplify the entire setup.

Looking at that wiring diagram, if one of the inhibitor thingys was inhibiting, it would be stopping the signal from the ignition switch from getting to the solenoid- which is why you can jump the 12v from the hot side of the solenoid to the signal side and the motor cranks. A quick and dirty fix would be to buy a cheap 12v relay and push button starter switch from the auto parts store and wire them up to the signal side of the solenoid.

[Dattebayo]

You said you have 12v at the signal wire when you turn the ignition to start

Nope, you missed this:

I tested it first and it had no voltage on it]

So I'm thinking the fusible link or the inhibitor.

[DrewUth]

Ah, gotcha. Well there ya go. Sorry!

[Dattebayo]

Any chance those diodes could cause the problem, you think? There could be a miniscule chance someone crossed the battery terminals at some point in it's life...

[david29]

Could be ignition switch, relay next to battery or the clutch push button switch on clutch pedal.

[Dattebayo]

We've ruled out the ignition switch already through the course of this thread, and as said earlier, its an auto so it doesn't have those other things. Also, there is no relay next to the battery.