Engine barely turns over, need help |
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Engine barely turns over, need help |
solex |
Jun 20 2020, 10:41 AM
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#1
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Senior Member Group: Members Posts: 789 Joined: 12-January 05 From: Long Island, NY Member No.: 3,439 Region Association: North East States |
I have done a lot of work and had the car running fine for serveral but now I have an electrical problem that I cannot seem to find.
Symptoms: Starter will turn a few degrees but will not turn over the engine when I release the key the starter will turn over a few more degrees as though I still have the key in the start position. What I checked:
Recent work done (may not be relevant):
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solex |
Jun 20 2020, 10:48 AM
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#2
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Senior Member Group: Members Posts: 789 Joined: 12-January 05 From: Long Island, NY Member No.: 3,439 Region Association: North East States |
I just went out to check the distributor and turn the engine over and noticed that the accelerator cable in the engine compartment was hot...
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yellowporky |
Jun 20 2020, 10:51 AM
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#3
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Member Group: Members Posts: 427 Joined: 18-October 09 From: Martinez, Ca. Member No.: 10,948 Region Association: Northern California |
If you cross the main power lug and the terminal with the yellow wire from the ignition switch will the starter crank fine?
If no you have an issue with the starter If yes you have something wrong with the ignition switch or the feed from it. Good luck |
falcor75 |
Jun 20 2020, 10:52 AM
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#4
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Senior Member Group: Members Posts: 1,579 Joined: 22-November 12 From: Sweden Member No.: 15,176 Region Association: Scandinavia |
Check your ground between engine/gearbox and body. put a startercable between the gearbox and body to rule it out being poor.
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Spoke |
Jun 20 2020, 11:38 AM
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#5
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Jerry Group: Members Posts: 6,986 Joined: 29-October 04 From: Allentown, PA Member No.: 3,031 Region Association: None |
I just went out to check the distributor and turn the engine over and noticed that the accelerator cable in the engine compartment was hot... The accelerator cable is now the ground for the engine/starter/distributor for some reason. That's why it's hot. As others have said, check the cable from the trans to the chassis. If you want to measure the bad ground, connect your voltmeter between the engine case and chassis and crank the engine. Likely you'll see several volt drop. |
solex |
Jun 20 2020, 12:07 PM
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#6
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Senior Member Group: Members Posts: 789 Joined: 12-January 05 From: Long Island, NY Member No.: 3,439 Region Association: North East States |
Thank you for the suggestions.
yellowporky: I bench tested the starter and it works fine, bridging the power to the ignition results in the same problem, this has be puzzled Falcor75: The ground between the body and the transmission is relatively new and has been thoroughly cleaned. I just ran an endoscope up an down the center tunnel and other then rust I do not see any obvious shorting. |
solex |
Jun 20 2020, 01:10 PM
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#7
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Senior Member Group: Members Posts: 789 Joined: 12-January 05 From: Long Island, NY Member No.: 3,439 Region Association: North East States |
I cannot believe that the ground strap was the problem. I replaced it two years ago.
I removed the strap, checked the resistance at 0.1 ohm, cleaned up the strap (it did not need much cleaning) replaced the nuts and washers with stainless, chased the threads on the chassis stud, the car started right up... Thank you all for the quick replies, I was getting really frustrated, all I wanted to do about 3 weeks ago was dial in the timing with my new digital timing light and it turn into a likely unnecessary starter rebuild and tearing in to my interior showing me the minor rust I need to repair. Have a happy fathers day all. |
dr914@autoatlanta.com |
Jun 20 2020, 01:34 PM
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#8
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914 Guru Group: Members Posts: 7,885 Joined: 3-January 07 From: atlanta georgia Member No.: 7,418 Region Association: None |
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Superhawk996 |
Jun 20 2020, 02:00 PM
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#9
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914 Guru Group: Members Posts: 5,875 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
0.1 ohm is too high of resistance
Ohms Law voltage = current x resistance Stating can draw several hundred amps Let’s use 100 amps to keep the math easy 100a x 0.1 ohm = 10 volt drop You can see how even a 50a starter current will drop 5 volts across that strap. Not good. |
solex |
Jun 20 2020, 02:21 PM
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#10
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Senior Member Group: Members Posts: 789 Joined: 12-January 05 From: Long Island, NY Member No.: 3,439 Region Association: North East States |
0.1 ohm is too high of resistance Ohms Law voltage = current x resistance Stating can draw several hundred amps Let’s use 100 amps to keep the math easy 100a x 0.1 ohm = 10 volt drop You can see how even a 50a starter current will drop 5 volts across that strap. Not good. I just checked the specs on my meter and 0.1 is the lower limit of the meter so I would need to get a better meter to confirm the actual resistance of the strap but will order a new one |
Spoke |
Jun 20 2020, 02:21 PM
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#11
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Jerry Group: Members Posts: 6,986 Joined: 29-October 04 From: Allentown, PA Member No.: 3,031 Region Association: None |
I cannot believe that the ground strap was the problem. I replaced it two years ago. I removed the strap, checked the resistance at 0.1 ohm, cleaned up the strap (it did not need much cleaning) replaced the nuts and washers with stainless, chased the threads on the chassis stud, the car started right up... Thank you all for the quick replies, I was getting really frustrated, all I wanted to do about 3 weeks ago was dial in the timing with my new digital timing light and it turn into a likely unnecessary starter rebuild and tearing in to my interior showing me the minor rust I need to repair. Have a happy fathers day all. Good news! (IMG:style_emoticons/default/beerchug.gif) Likely it wasn't the strap but it was the connections to the chassis. It doesn't take much dirt, oxidation or rust to create a very large resistance even if the bolts are tight. You did exactly the right thing by cleaning up all the metal around the connection. One thing you didn't mention was if you wire wheeled the chassis around the stud. About the 0.1 ohm resistance of the cable, it is very difficult to accurately measure resistances below about 0.5 ohm. Many times touching the 2 probes together will yield 0.1 or 0.2 ohm so the DMM has to be zeroed out. At least you didn't measure 5 or 10 ohms. |
solex |
Jun 21 2020, 09:25 AM
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#12
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Senior Member Group: Members Posts: 789 Joined: 12-January 05 From: Long Island, NY Member No.: 3,439 Region Association: North East States |
Thanks Spoke, I cleaned the pad with 220 grit and steel wool. Seems to be running well.
Again thanks for all your help |
Bartlett 914 |
Jun 21 2020, 10:55 AM
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#13
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Advanced Member Group: Members Posts: 2,216 Joined: 30-August 05 From: South Elgin IL Member No.: 4,707 Region Association: Upper MidWest |
0.1 ohm is too high of resistance Ohms Law voltage = current x resistance Stating can draw several hundred amps Let’s use 100 amps to keep the math easy 100a x 0.1 ohm = 10 volt drop You can see how even a 50a starter current will drop 5 volts across that strap. Not good. I just checked the specs on my meter and 0.1 is the lower limit of the meter so I would need to get a better meter to confirm the actual resistance of the strap but will order a new one I would agree with that. Measuring very low resistance has too many variables and is often unreliable. I am sure the cable is fine but the problem was properly cleaned and seated connections. Glad you are up and running |
Mark Henry |
Jun 21 2020, 11:48 AM
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#14
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
Buy a spare accelerator cable, in certain areas the cable itself has a teflon like plastic coating to make it slippy and snag free, you likely melted that coating. The cable will eventually fail.
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solex |
Jun 22 2020, 04:40 AM
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#15
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Senior Member Group: Members Posts: 789 Joined: 12-January 05 From: Long Island, NY Member No.: 3,439 Region Association: North East States |
Buy a spare accelerator cable, in certain areas the cable itself has a teflon like plastic coating to make it slippy and snag free, you likely melted that coating. The cable will eventually fail. will do, looks like the clutch cable took a shot at being the ground as well, fortunately I have one in stock. |
ClayPerrine |
Jun 22 2020, 08:21 AM
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#16
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Life's been good to me so far..... Group: Admin Posts: 15,498 Joined: 11-September 03 From: Hurst, TX. Member No.: 1,143 Region Association: NineFourteenerVille |
I like to add a second ground cable from the right front corner of the motor to the stud where the negative battery cable attaches to the body.
Just in case.... |
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