AFSOC_Commando

Car: 80 Rex... New starter (thought the old one was bad)

This is the problem,

Starter does not disengage when I take the key out or after starting.


I bought this car for a steal from a young kid, installed a gas tank and rebuilt the carb... New battery and she started right up! But it didn't run for to long before it was dead... No DC power... So I charge the new battery up and try again, she starts fine again... But soon starts sputtering and dies. Well I go to try to restart and the starter turns the car over but to slow to start, like a dead battery again (Brand New Battery) So I pull the key out of the ignition and the damn thing is still trying to turn over...

I'm thinking the ignition is shot.... So I pull the ignition lead at the solenoid... No power for the relay now... But the damn thing is still engaged and trying to start!!! The only lead on the starter at this time is the Hot from the battery, I pull the battery lead at the battery and hear the starter disengage and the gear click as it retracts back....

Now this has occured with 3 starters... I am furious, The car runs but with the starter sucking high current and not disengaging it is sucking the battery dry not to mention melted 2 hot leads so far before I went 2 Gauge on the damn thing.

Anyone have any ideas? The only way to get the starter to disengage is to pull the hot lead at the battery.

The starter rebuild folks claim that once the starter is engaged that the solenoid stays hot while the gear is out, but that doesn't make any sense....


HELP!!!

85RX7GS

iTrader: (1)

Is the solenoid new? If not, replace it.

AFSOC_Commando

Yes, Solenoid is new also... Everything tests perfect when not in the car. Only when mounted into the tranny does it exhibit this weird problem!!

two79rx7's

I had an identical problem with an early 79

one day after starting the car after 23 years the
starter cranked the engine but did not disengage.
And the engine reved up to ,,,Well if felt fast,
like 4k rpm. I never rev the engine up on starting
past 1.5 to 2 k with the choke.
I immediately turned the key off and I still heard the starter or something going (it was the starter. I was lucky that the batery cable was loose enough to pull by hand. and I quickly did so
as I knew how much current was being pulled.

when I would reconnect very high current would flow at any time, in any ignition key position.

I had to work under the car to disconnect the soleniod and starter wire...hmmm maybe it was just the solenoid wire. but in either case no current would flow once i did this - which is what i wanted.

Answer to one of your questions _ no current should flow to starter or soleniod once key is off ig. position. How else could you park the car and expect to drive it away the next day or week!

I reconnected the battery + cable,push started the car and drove home.
I did not bother testing my starter or solenoid. I
got a new starter solenoid combo, cleaned everything up and installed it.
The car started so much better with the new starter/ soleniod. It was obvious to me the old starter was drawing excesive current (partially shorting i guess) all along for many years and taking away from the ignition circuit efectiveness.

that was it.
since your problem continues and you are getting your starters from a reputable rebuild place or like a pep boys, it most likely is your soleniod

ideas,
you have tried 3 starters but only one soleniod. try another solenoid and test it with an ohmmeter or continuity tester. Look at the wiring diagrams to see how it should work.

a short between the hot on the starter and the hot on the soleniod.

!!!!!!!check voltage and current flow at the hot
wire for the solenoid in all ig key positions.

it may very well be there!!!!!!!!!
that wire should only be hot to engage soleniod when starting the car.

if it is work your way back and find out where the supply to this wire is comming from and correct it.

If I am in error with any of this please post.

AFSOC_Commando

two79rx7's

Each starter had a new solenoid. I did check the ignition switch hot lead to the solenoid and it only supplies dc when the ignition is in the start position like it should be.

I am at Witts END!!!

85RX7GS

iTrader: (1)

Battery cables

RotorMotorDriver

iTrader: (1)

Ok, do RX-7s have external relays? Cause when you turn the key, it sends power where? To a relay? Or directly to the solenoid? Maybe a relay is sticking somewhere and causing the starter to think your still holding the key in the start position...My friends Jeep did that to him...

~T.J.

AFSOC_Commando

Like I said, once it is stuck and trying to turn over the engine I can pull the lead to the Solenoid and it continues to turn over, The only lead at this time would be the hot lead from the battery connected to the solenoid. It tests perfect outside the car but when mounted refuses to disengage from the flywheel.

If I can't fix this then I'll just part the damn thing out... Or swap the tranny and flywheel to see if it fixes it...

Strider

I'm pretty sure that this is the cause:

Your starter bendix gear is sticking in the out position, engaged to the flywheel.

Here is how a starter works:

The solenoid is nothing more than an electric coil. Once a small current is applied by the ignition key, a magnetic field is produced that physically moves the starter gear out to engage with the flywheel teeth, AND CLOSES the contact between the high tension lead from the battery and ground. In a real way the solenoid acts like a relay, as the major current at that point is going directly from the battery to the starter motor and then to ground back to the battery.

Once the ignition key is released and no current is being supplied to the solenoid, the magnetic field dissapears and spring force in the bendix gear assembly retracts the starter gear from engagement on the flywheel, AND OPENS the contact from the high tension battery lead.

The battery lead is always directly to the starter motor and is hot, key on or off. You can try this: Grab an insulated screwdriver, then bridge the gap on the solenoid between the key ignition terminal and the high tension battery lead. SURPRISE! You motor turns over without the key in the ignition. (I used to have a VW bug that required this method of starting all the time, until I finally tracked down the faulty wire in the starter circuit.)

So what is the solution? Determine why the starter gear is getting hung up and not retracting. Is the return spring assembly intact? Is the motor properly aligned when it is mounted?

AFSOC_Commando

Strider,

Thanks for the excellent explanation... I will check the engine alignment with the tranny... It doesn't appera that the flywheel is warped or that the Bendix gear only catches certain sides.... I did aplly a little grease to the gear but it didn't really help.

I have considered shaving the starter a little to give me a little wiggle room to move the bendix gear teeth a little further from the flywheel.

bobbitt

http://www.nellump.net/peri/epi/gen7Techs/starters.html
Saw this the other day, didn't read it though...it may help.

Manntis

Not all starter 'solenoids' operate by magnetic field (some are inertial throwout (Chrysler), some are electromagnatic clamp-type (Ford) etc...

Not sure what the Mazda one is

two79rx7's

AFSOC_Commando
you mentioned...
1. I pull the battery lead at the battery and hear the starter disengage and the gear click as it retracts back....
AND
2. Each starter had a new solenoid. I did check the ignition switch hot lead to the solenoid and it only supplies dc when the ignition is in the start position like it should be.
AND
3. Like I said, once it is stuck and trying to turn over the engine I can pull the lead to the Solenoid and it continues to turn over, The only lead at this time would be the hot lead from the battery connected to the solenoid.

This is what I an thinking.
the fact that when power is cut from the battery the soleniod retracts. this means that mechanically the starter gear is not held engaged to the flywheel and it is an electrical problem.

I am wondering, if I had to bet, I would say you checked the solenoid hot lead at the ingnition switch side and not at the solenoid terminal. Another words you checked the connector near the ignition on the igniton side at the time the connector was detached to be able to hook up your meter and you did not hook up your meter on the hot solenoid terninal.!? there must be a hot short that occurs once the soleniod activates that keeps the soleniod terminal hot even if the ignition switch is on an off start position. As you did mention.... even when the ignition was off, the starter was still cranking.

You can try this experiment:

1. install everything.
disconnect the cars' soleniod hot lead at the soleniod.
2. get a long enough piece of appropriate gage insulated wire with a safe and convienient lug to connect directly to the soleniod hot terninal and reach to the + bat terminal. KEEP THIS WIRE AWAY FROM THE BATTERY FOR NOW OR ANY POSSIBLE HOT - JUST KEEP IT PROTECTED AND SECURE FROM EVERYTHING. Lets call this wire the TEST WIRE.
3. TRANSMISSION IN NUETRAL OR PARK PLEASE!!!!!!
4. Move the ignition switch to the run position.
then walk over to the battery and touch the other end of the TEST WIRE to the + terminal of the battery. The starter and soleniod should be active only for as long as you keep this TEST WIRE connected to the + battery terminal. Do this at first just for a split second to hear and notice that the soleniod activates and the retacts as it should and the starter starts and stops. If the TEST WIRE is held long enough, the engine should start. again here too when the engine has started once the TEST WIRE is disconnected from the + battery terminal the soleniod and starter should retract and turn off.

The reasoning is this. the starter cuircut has been removed form the cars system and put under your direct control. all else has remained the same for conditions to start the car.
If your problem continues the problem must be internal to the starter soleniod even if you used many. The fact that your setup works right when not in the car and you have checked your ign. switch, supports the test above you will do. Then you will look for a hot short between the connector near the ignition switch and the soleniod. Look at a schematic to see what cuircut components are between these two points.

I would highly recommend you not use your car at all with such high current drain melting battery gage wire. you are likely to have a car fire. The cost of the test wire is far cheaper thean your cars' value.

hope this helps
two79rx7's