[PontiacMatt72]

Had an issue with the starter yesterday on a 70 400. (in Dad's 70 GTO).

Has been starting fine for a few months now, but been trying to get it tuned right and in doing so, the car has stalled out several times on us. Saturday, it started getting harder to start, was sluggish starting, then it wouldn't start at all. just would give an electrical "hum" when turning the key over, wouldn't engage gear or even spin it.

So pulled the starter, took it to Autozone to have it tested, and it tested good on their bench tester.

bring it back home, put it back on the car, go to start it tonight and - "whiirrrr". gear is spinning, but will not engage the flywheel. loosened it, put it back on, tapped it with a hammer - nothing helped.

Bought a new starter from Autozone. Tested it on the starter at autozone before bringing it home, tested perfect. Bring it home, put it on the car - "whiirrrr". Same dang thing - gear spins, but won't kick out and engage the flywheel.



Any ideas?? 2 starters, same issue.

There are 4 wires connected to the starter - 2 red (one large for battery, and one little smaller, probably a 10-12 gauge wire?), one yellow wire going to the "R" stud, and one purple going to the "S" stud. I guess it's got to be an issue at one of these, but I've had it for tonight... hopefully can get some good ideas of what to check.

Trying to get this car road worthy = one step forward, two steps back.

[stellar]

If the starter gear is engaging into the flywheel and you hear the whiirrr it is a bad starter drive gear assembly. If the starter gear is not engaging the flywheel it is a bad solenoid or the purple wire is touching the 4th post on the solenoid.

[chrisp]

Use a screwdriver under the car to jump the solenoid . If that works then starter / solenoid is good . You have a bad connection somewhere . Have seen the heavy gauge solenoid wire actually melt in the firewall bulkhead connector from excessive long cranking , heating up the connector . If that is the case run a new 12 gage wire from the ignition to the starter solenoid to eliminate the possible bad bulkhead connector .

[PontiacMatt72]

Had a time with that bulkhead connector... put a new engine wiring harness in the car, was completely missing one wire, and now possibly have this going on...

Thanks for the ideas fella. I'll check in to the purple wire, which I guess is the solenoid "switch"/power wire. I'll try to test it to see if/what kind of voltage it's getting at the end (where it meets the starter).

[2002Z4CSS]

Maybe the new starter needs a shim.

[RAIV55]

If the solenoid is engaging the drive into the flywheel and the starter motor spins without cranking the engine, my money is on a bad starter drive.

[72LuxuryLeMansLa.]

I'm voting on a bad ground somewhere. My LeMans occasionally did something similar to this and it turned out to be the Negative battery cable. There was something wrong with the shielding. If I moved it so that there was no contact between the cable and the battery case the car would start. If the cable was touching the side of the battery it would not start. I never figured out the technical cause but took the hint. I made sure the cable didn't touch the case of the battery and the problem is gone.
Point being, check all wires in the starting circuit. Sometimes just moving one will identify it as the culprit. Bad grounds are the source of most electrical problems.

Karl

[PontiacMatt72]

The gear that should be engaging the flywheel is just free spinning where it rests, it won't extend out to engage the flywheel.

I don't think it's a solenoid or starter issue, because i have 2 starters (one new from autozone), and both do the exact same thing. it must be a wiring/grounding issue.

[FrankieT/A]

The purple wire comes from the neutral safety switch. The "S" terminal on the solenoid is what energizes the solenoid/starter.

[stellar]

If it kicks out on a bench test, and does not kick out on the car, the only possibility would be the purple wire is touching the solenoid 4th post. The one that is directly connected to the starter field.

[FrankieT/A]

Originally Posted by stellar

If it kicks out on a bench test, and does not kick out on the car, the only possibility would be the purple wire is touching the solenoid 4th post. The one that is directly connected to the starter field.

I agree, the one to the field has a metal strap(actually two)coming out of the starter itself going to that terminal. That can be the only explanation since inside the solenoid is a disc that contacts the heavy battery cable to the field connection only when the solenoid is activated.

[Schurkey]

Originally Posted by PontiacMatt72

The gear that should be engaging the flywheel is just free spinning where it rests, it won't extend out to engage the flywheel.

I don't think it's a solenoid or starter issue, because i have 2 starters (one new from autozone), and both do the exact same thing. it must be a wiring/grounding issue.

Have you SEEN that the gear does not push out into the flywheel?

The stock Delco starters are set up so that the motor does not get power (cannot crank) unless the shift fork/plunger is pulled into the solenoid, which means that the other end of the shift fork--the starter drive--MUST be extended into the flywheel. The typical issue--as has been mentioned--is that the starter drive is hash, the starter motor spins like a siren when you turn the key (RIIIIIINNNNNNNNNNGGGGGG!), but the engine doesn't crank. The starter drive IS extending into the flywheel, but does not transfer power.

A worn shift fork can reduce the amount of starter drive extension. Extremely common. I suppose that the plunger/shift fork/fork pivot could be broken--but on two starters in a row?

WHAT IS THE VOLTAGE AT THE BIG STARTER + POST WHEN CRANKING? You better have AT LEAST 9.7 volts, more is better--and in the summer, I'd be looking for 11-ish. Performing voltage-drop testing on the battery/starter will confirm ground problems.



Is this a stock-type Delco starter, or some aftermarket mini-starter?

Is the engine seized? Can you turn it manually with a breaker bar--or by grabbing the fan belt(s)?

[PontiacMatt72]

It's possible the purple wire is touching a different post... I was holding the starter up while dad connected all the wires. I didn't check to make sure he did it right, just assumed. Will definitely look into that, as that would be a super easy fix.

Shurkey, I'm 100% certain the gear does not extend in to the flywheel. like i said, on a bench tester, both starters work perfectly. Only when on the car did they both have this same issue - gear sounds like it's spinning, but no extension into the flywheel.

It is a stock style Delco (reman) starter, both the 2 in question. the engine is not seized, i actually spun the engine by breaker bar just to make sure the gear wasn't misaligned somehow with the flywheel.

[Schurkey]

Originally Posted by PontiacMatt72

Shurkey, I'm 100% certain the gear does not extend in to the flywheel. like i said, on a bench tester, both starters work perfectly. Only when on the car did they both have this same issue - gear sounds like it's spinning, but no extension into the flywheel.

Flywheel installed correctly? Broken/worn teeth on the flywheel? Starter drive teeth worn?

It's essentially impossible for the starter motor to get power through the copper disc of the solenoid unless the plunger is pulled in; and if the plunger is pulled in...the shift fork MUST move the starter drive. So problems with the plunger/shift fork and fork pivot would seem to be something to look at.

[PontiacMatt72]

I thought i'd responded to this already... oops.

Haven't had a chance to dig back into this yet... workin two jobs leaves little time.

Shurkey, I'm certain the flywheel has been installed correctly... car has started fine at least 20 times the past few months. no broken teeth on the flywheel or starter. as mentioned before, have a NEW (reman'd) starter on the car now, to eliminate that as the culprit. but it has been resulting in the same result thus far.

Will try to get it back down tonight to double check that purple wire, and also may try removing the yellow wire ("R" terminal on solenoid), to see if that changes anything.

What is that "R" terminal for anyway?

[archerytony]

Originally Posted by PontiacMatt72

I thought i'd responded to this already... oops.

Haven't had a chance to dig back into this yet... workin two jobs leaves little time.

Shurkey, I'm certain the flywheel has been installed correctly... car has started fine at least 20 times the past few months. no broken teeth on the flywheel or starter. as mentioned before, have a NEW (reman'd) starter on the car now, to eliminate that as the culprit. but it has been resulting in the same result thus far.

Will try to get it back down tonight to double check that purple wire, and also may try removing the yellow wire ("R" terminal on solenoid), to see if that changes anything.

What is that "R" terminal for anyway?

Got to be a bad switch or conection

[bnorris_74]

Post 13 has a diagram

http://forums.maxperformanceinc.com/...d.php?t=724387

[PontiacMatt72]

Got it fixed. It was the purple wire - has a spot where insulation had split and was touching another wire/terminal.

Stellar, you nailed it.

Thanks for the help guys!

[stellar]

That was an easy one, but if you have other problems take a GOOD look at Schurkey's posts. He is one of the VERY BEST at solving these types of problems. The test procedures he shows are something everyone should pay attention to and do on occasion to find and prevent problems. The voltage drop test he has shown in this thread should be committed to memory as it is very useful. If you have a high resistance connection this test will find it and if you move the test probes along the circuit you can pinpoint the exact location of a problem. You may want to read Schurkey's other posts as he has offered a lot of great advise and tests with diagrams.