Starter passes bench test---not car test
Thread Starter
Racer
Joined: Sep 2011
Posts: 414
Likes: 55
From: Humboldt county Ca
Starter passes bench test---not car test
Can a starter work on the bench and not when bolted up? Bendix worked great, motor sounded great (brand new, not rebuilt, American made starter) lasted 2 weeks, went to start one morning and nothing. Lights dim when key is turned so power is getting to the starter. Shorted across the posts while in the car----just sparks, no slam like the bendix is engaging. Ground good, cables good, batt good. I do get a click from the somewhere behind the center instrument cluster when the lights dim.
Help is appreciated.
Thanks,
Roy
Help is appreciated.
Thanks,
Roy
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
The starter is not likely to be your problem, since it bench tested OK.
Your problem is probably with the starter solenoid or with the battery or ground wiring going to the starter. It could also be a problem with your neutral safety switch, if it just does nothing when you turn the key to 'start' position.
Your problem is probably with the starter solenoid or with the battery or ground wiring going to the starter. It could also be a problem with your neutral safety switch, if it just does nothing when you turn the key to 'start' position.
Melting Slicks
Joined: Oct 2012
Posts: 2,156
Likes: 273
From: Dunedin NZ.
A worn key switch can also cause this condition (at least it did to me) but if you jump the terminals on the solenoid you are bypassing the key switch and it should turn over okay. If it doesn't and it worked on the bench I would be looking at the earth connections and the main cable from the battery as 7T1vette said.
Thread Starter
Racer
Joined: Sep 2011
Posts: 414
Likes: 55
From: Humboldt county Ca
Thanks for the suggestions guys. I did replace the neutral safety switch and tested the ignition switch. I will go back through the cables. I'm not much on electrical since I took my dad's hair clippers apart at the age of 7 and plugged the motor in without the case being on as an insulator. He asked if I learned anything. I learned that I know next to nothing about electrical stuff and that you can curl your hair without a trip to the stylist.
Roy
Roy
Drifting
Joined: Jul 1999
Posts: 1,542
Likes: 43
From: Plano TX
Yes it can test good on the bench and not on the car. As another poster mentioned it could be a worn ignition key. It takes a lot of current to engage the solenoid and pull the gear in when the starter is also trying to turn over the motor.
I took the start wire from the solenoid (wire from switch) and now have it trigger a relay. The relay then applies battery 12 volts directly to the solenoid start terminal. This solves the ignition switch/older solenoid issue completely.
Now on my 80 it also had a connector for the starter harness near the distributor. These terminals can corrode and break down which can also case a similar issue if you have this connector. For big current wires I pulled them from the connector and spliced them together to resolve this.
I took the start wire from the solenoid (wire from switch) and now have it trigger a relay. The relay then applies battery 12 volts directly to the solenoid start terminal. This solves the ignition switch/older solenoid issue completely.
Now on my 80 it also had a connector for the starter harness near the distributor. These terminals can corrode and break down which can also case a similar issue if you have this connector. For big current wires I pulled them from the connector and spliced them together to resolve this.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Since your lights dim when it won't start, that means that significant current IS being drawn. But it may be only the current required to power the starter solenoid (several amps). But, the contacts in that solenoid may be carboned-up/corroded or damaged so that a poor connection is made and little current being passed on to the starter. I suspect the starter solenoid is not operating as it should.
The other possibility is that either the main [positive] starter wire or the big ground wire [from frame to motor mount/starter bracket] has a problem with a connection or internally with the wire. Old wire can become weak and increase in resistance if it is exposed to the atmosphere (near connection joints). Check wiring CAREFULLY and examine the wire strands if you can actually see them.
My assessment: 80% probability of a bad solenoid; 15% probability of some wiring defect; 5% probability that it is "something else".
The other possibility is that either the main [positive] starter wire or the big ground wire [from frame to motor mount/starter bracket] has a problem with a connection or internally with the wire. Old wire can become weak and increase in resistance if it is exposed to the atmosphere (near connection joints). Check wiring CAREFULLY and examine the wire strands if you can actually see them.
My assessment: 80% probability of a bad solenoid; 15% probability of some wiring defect; 5% probability that it is "something else".
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Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
I think that you may actually have a starter problem itself. YES...as '7T1vette' mentioned...the solenoid can be the issue...without a doubt.....but also if the armature is not spinning true and rubbing against the field coils...it can do what you have going on....because I recently had one that was cooked internally. AND I do not care if it is NEW or any of that. STUFF HAPPENS.
I seriously doubt at all if it has anything to do with your key switch in your column....if it is turning all the way to start...it has nothing to do with that....BUT...it can have something to do with the IGNITION SWITCH that the key switch actuates. SO....what you can do is disconnect eh purple wire at the solenoid...the one closest to the engine block and have someone turn your key and with a voltmeter...so if you are getting battery voltage to this terminal that you removed from the solenoid. You know that is not the issue. BUT that does not mean that you still do not have a problem in the solenoid itself or the threaded studs that come out of it are loose or broken internally.
DUB
I seriously doubt at all if it has anything to do with your key switch in your column....if it is turning all the way to start...it has nothing to do with that....BUT...it can have something to do with the IGNITION SWITCH that the key switch actuates. SO....what you can do is disconnect eh purple wire at the solenoid...the one closest to the engine block and have someone turn your key and with a voltmeter...so if you are getting battery voltage to this terminal that you removed from the solenoid. You know that is not the issue. BUT that does not mean that you still do not have a problem in the solenoid itself or the threaded studs that come out of it are loose or broken internally.
DUB
Race Director
Joined: Apr 2007
Posts: 11,152
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From: South Western Ontario
You tested it wrong if you jumpered the big posts together.
Burning Brakes
Joined: Jan 2012
Posts: 943
Likes: 73
If you have a DC digital voltmeter, what is the exact voltage of the battery now?
If you don't have one, look thru your car magazines for a HarborFreight coupon for their free one. You may have to make a small purchase like hand soap, I don't remember.
If you don't have one, look thru your car magazines for a HarborFreight coupon for their free one. You may have to make a small purchase like hand soap, I don't remember.
Last edited by BlackC3vette; Apr 8, 2015 at 01:07 AM.
Thread Starter
Racer
Joined: Sep 2011
Posts: 414
Likes: 55
From: Humboldt county Ca
I'm replacing the solenoid as I just replaced the shifter switch after this problem. I folded a blanket in the wiper channel, hooked jumper cable from batt pos to starter lug along with the orange starter wire. Connected the purple to the s post, grounded the neg cable to the starter case and hooked to the batt neg post. I laid the starter in the blanket, Turned the key and the starter cranked and the bendix popped out just fine. The starter went from there into the car. No start but dim lights when I hit the key. That's when I shorted across the lug and post and got nothing from the starter----and, yeah, I well know how to jump a solenoid.
Thanks for the comments.
Roy
Thanks for the comments.
Roy
Burning Brakes
Joined: Jan 2012
Posts: 943
Likes: 73
I'm replacing the solenoid as I just replaced the shifter switch after this problem. I folded a blanket in the wiper channel, hooked jumper cable from batt pos to starter lug along with the orange starter wire. Connected the purple to the s post, grounded the neg cable to the starter case and hooked to the batt neg post. I laid the starter in the blanket, Turned the key and the starter cranked and the bendix popped out just fine. The starter went from there into the car. No start but dim lights when I hit the key. That's when I shorted across the lug and post and got nothing from the starter----and, yeah, I well know how to jump a solenoid.
Thanks for the comments.
Roy
Thanks for the comments.
Roy
Thread Starter
Racer
Joined: Sep 2011
Posts: 414
Likes: 55
From: Humboldt county Ca
Well, first thanks to all for the comments and helpful advice. It appears that the starter need some shimming. I've replaced starters twice now and none had shims so I went right back to a non shim setup. What surprises me is that the starter made no dragging noise or other abnormal noises prior to shutting down. I was pulling the starter and had dropped one bolt out on the outboard side and slightly loosened the inside bolt. Forgetting what I was doing, I had lunch and then reconnected the battery, reached around and tried the key. Yowee! The car cranked! I double shimmed the outboard bolt and things seem fine now. We'll see what happens once the brace is hooked back up.
One tip: don't forget about using jumper cables to bypass and check ground and hot connections. Really came in handy for me on lots of testing.
Thanks again,
Roy
One tip: don't forget about using jumper cables to bypass and check ground and hot connections. Really came in handy for me on lots of testing.
Thanks again,
Roy
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
Roy,
They make specific starter shims ( staggered or straight bolt patterns) that you can buy at an auto parts house...because I would NOT shim just one bolt more than the other. They BOTH need to be shimmed the same...so the starter housing is flush against the block...thus the aluminum end housing is tight against the shims....due to the torque...you do not have a problem down the road...and this is regardless if you are still using the support bracket to the engine block where it attaches to the end of the starter housing
BUT ..do as you like.
DUB
They make specific starter shims ( staggered or straight bolt patterns) that you can buy at an auto parts house...because I would NOT shim just one bolt more than the other. They BOTH need to be shimmed the same...so the starter housing is flush against the block...thus the aluminum end housing is tight against the shims....due to the torque...you do not have a problem down the road...and this is regardless if you are still using the support bracket to the engine block where it attaches to the end of the starter housing
BUT ..do as you like.
DUB
Thread Starter
Racer
Joined: Sep 2011
Posts: 414
Likes: 55
From: Humboldt county Ca
Dub- thanks buddy. I do have some long, double bolt shims. As soon as I get everything back in place I intend to shim both sides. I'm at the stage now where I cleaned up a bunch of PO's butchered wiring and I'm running down wires that were cut and had as many as 3 splices of different colors in an 18" run. I thought I was a shade tree guy but it looks like somebody has me beat!
Thanks again for verifying what I figured needed to happen!
Roy
Thanks again for verifying what I figured needed to happen!
Roy
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
Roy,
You never wrote what year you have....and if you are messing with the wiring that goes to the solenoid....just be aware that GM installed a fusible link at the solenoid area.
Can not add information/suggestions any more unless I know what year you are working on because there are some other issues in later year models also.
LASTLY...just to also let you know...just in case you did not know....the BLACK wire with the large eyelet terminal DOES NOT go on the large stud on the solenoid where your positive battery cables attaches....even though it looks like it can....it is the ground wire for your wiper motor ad blower motor.
DUB
You never wrote what year you have....and if you are messing with the wiring that goes to the solenoid....just be aware that GM installed a fusible link at the solenoid area.
Can not add information/suggestions any more unless I know what year you are working on because there are some other issues in later year models also.
LASTLY...just to also let you know...just in case you did not know....the BLACK wire with the large eyelet terminal DOES NOT go on the large stud on the solenoid where your positive battery cables attaches....even though it looks like it can....it is the ground wire for your wiper motor ad blower motor.
DUB
