Weird starting problem - The 1947 - Present Chevrolet & GMC Truck Message Board Network

harrdawg54 · 08-16-2007, 07:50 PM

I have a problem with my truck when I go to start it. I turn the key and the motor starts cranking, then when I let off the key it still keeps cranking. I know it's an electrical problem but I don't know what it could be (starter, ignition, ?). Any help?

MrJohnWayne · 08-16-2007, 08:12 PM

I would think it is the switch not releasing after you let go of the key.

cdowns · 08-16-2007, 08:36 PM

try spraying wd40 in the lock cylinder and working it back and forth

zeeklu · 08-16-2007, 08:41 PM

Could be the selenoid on the starter.Theres a copper washer that sticks if cranked too long or it has low voltage. Chris

harrdawg54 · 08-17-2007, 02:05 AM

I did remove, disassemble, clean and then reassemble the starter. I am going to replace the battery and positive cable to see if it makes a difference.

ckhd · 08-17-2007, 01:13 PM

My money is on the starter. You could always try it without using the key. Get a jumper wire and jump from the battery cable to the yellow wire on the solenoid (make sure it's in park or neutral with the e-brake FIRMLY set before you try this). If it still sticks when you do that, you know it has nothing to do with the switch.

Oh, if you do that, it will throw some sparks. Just be prepared and don't jump too high!!

Or, pull the starter out and test it with jumper cables, or take it to napa and have them test it.

**raggedjim** · 08-17-2007, 01:18 PM

Quote:

Originally Posted by zeeklu

Could be the selenoid on the starter.Theres a copper washer that sticks if cranked too long or it has low voltage. Chris

I'm with zeeklu, this is a common problem... Sounds wierd but I had the same thing happen to my old '64.

Rg

sneakysnake · 08-17-2007, 02:52 PM

Sounds like you have the wires swapped on the starter sol.
Double check to see that the purple goes to S. and the other goes to.R

harrdawg54 · 08-17-2007, 09:00 PM

I checked the wiring and everything seems fine. I will remove the starter and have it checked at napa.

Select · 08-17-2007, 09:06 PM

I say it's the solenoid starting to stick and keep it going....Mikey

Rippin-J · 08-17-2007, 09:11 PM

What if:

The motor tries to turn over the second the negative battery cable is connected?

I have replaced the battery, solenoid, and the ignition switch. same thing.

Even removed the ignition switch completely, motor still tried to turn over.

Am at a loss and at the end of the extent of my knowledge - any help much appreciated!

ps - it's a 396 in a '68 c-20.... auto.

centsless · 08-18-2007, 01:16 AM

It needs the starter shimmed. If the starter bendix is too close to the flywheel, it will not release, and keep the solenoid activated. Install a starter shim and it will be fine.

Select · 08-18-2007, 02:03 AM

Ahhhh, the joy of shims.... I've never had to use them and I hope I never have to. Trial and error gets to me sometimes....Mikey

sneakysnake · 08-19-2007, 01:04 PM

Here is a simulation that might help in understanding whats happening inside your starter.

Rippin-J · 08-19-2007, 03:59 PM

great diagram.... thanks for that.

08-16-2007, 07:50 PM	#1
harrdawg54 Registered User Join Date: Apr 2007 Location: Sandpoint, Idaho Posts: 178	Weird starting problem I have a problem with my truck when I go to start it. I turn the key and the motor starts cranking, then when I let off the key it still keeps cranking. I know it's an electrical problem but I don't know what it could be (starter, ignition, ?). Any help?

08-16-2007, 08:12 PM	#2
MrJohnWayne Shadetree Grease Monkey Join Date: Jul 2007 Location: DFW Texas Posts: 17	Re: Weird starting problem I would think it is the switch not releasing after you let go of the key. __________________ John Wayne 2000 7.3 Powerstroke - It's big and it's fast 1978 K10 "Bonanza" - It's peppy 1980 Chevy Scottsdale - One of these days Soon to be project: 1968 C-10 CST

08-16-2007, 08:36 PM	#3
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Weird starting problem try spraying wd40 in the lock cylinder and working it back and forth __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

08-16-2007, 08:41 PM	#4
zeeklu Registered User Join Date: Dec 1999 Location: Northwest NJ Posts: 746	Re: Weird starting problem Could be the selenoid on the starter.Theres a copper washer that sticks if cranked too long or it has low voltage. Chris Last edited by zeeklu; 08-16-2007 at 08:44 PM.

08-17-2007, 02:05 AM	#5
harrdawg54 Registered User Join Date: Apr 2007 Location: Sandpoint, Idaho Posts: 178	Re: Weird starting problem I did remove, disassemble, clean and then reassemble the starter. I am going to replace the battery and positive cable to see if it makes a difference.

08-17-2007, 01:13 PM	#6
ckhd Registered User Join Date: Oct 2000 Location: St. Johns, Arizona Posts: 2,660	Re: Weird starting problem My money is on the starter. You could always try it without using the key. Get a jumper wire and jump from the battery cable to the yellow wire on the solenoid (make sure it's in park or neutral with the e-brake FIRMLY set before you try this). If it still sticks when you do that, you know it has nothing to do with the switch. Oh, if you do that, it will throw some sparks. Just be prepared and don't jump too high!! Or, pull the starter out and test it with jumper cables, or take it to napa and have them test it. __________________ my 2¢ - t.i.o.l.i. Bowen 1968 K20 fleet 1969 K10 swb fleet 1972 K10 Suburban 1972 C10 lwb step 1992 K1500 'burb 1995 K2500 'burb 1997 C1500 'burb 1999 K1500 2000 K1500 'burb Why do I own so many Suburbans? Last edited by ckhd; 08-17-2007 at 01:14 PM.

08-17-2007, 02:52 PM	#8
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	Re: Weird starting problem Sounds like you have the wires swapped on the starter sol. Double check to see that the purple goes to S. and the other goes to.R Attached Images

08-17-2007, 09:00 PM	#9
harrdawg54 Registered User Join Date: Apr 2007 Location: Sandpoint, Idaho Posts: 178	Re: Weird starting problem I checked the wiring and everything seems fine. I will remove the starter and have it checked at napa.

08-17-2007, 09:06 PM	#10
Select Friday's Toy Join Date: Nov 2006 Location: Ovilla, TX Posts: 574	Re: Weird starting problem I say it's the solenoid starting to stick and keep it going....Mikey

08-17-2007, 09:11 PM	#11
Rippin-J OurLadyofBlessedAccelerat ion Join Date: Aug 2007 Location: Denver, CO Posts: 148	Re: Weird starting problem What if: The motor tries to turn over the second the negative battery cable is connected? I have replaced the battery, solenoid, and the ignition switch. same thing. Even removed the ignition switch completely, motor still tried to turn over. Am at a loss and at the end of the extent of my knowledge - any help much appreciated! ps - it's a 396 in a '68 c-20.... auto.

08-18-2007, 01:16 AM	#12
centsless sufficiently talented fool Join Date: Jun 2006 Location: Forest Hill, MD Posts: 2,231	Re: Weird starting problem It needs the starter shimmed. If the starter bendix is too close to the flywheel, it will not release, and keep the solenoid activated. Install a starter shim and it will be fine. __________________ "it's impossible to be surrounded by idiots when you are part of the circle" 2003 Suburban 2002 Pontiac Montana 1981 Corvette 1966 Impala Convertible Click here to support the board

08-18-2007, 02:03 AM	#13
Select Friday's Toy Join Date: Nov 2006 Location: Ovilla, TX Posts: 574	Re: Weird starting problem Ahhhh, the joy of shims.... I've never had to use them and I hope I never have to. Trial and error gets to me sometimes....Mikey

08-19-2007, 01:04 PM	#14
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	Re: Weird starting problem Here is a simulation that might help in understanding whats happening inside your starter. Attached Images

08-19-2007, 03:59 PM	#15
Rippin-J OurLadyofBlessedAccelerat ion Join Date: Aug 2007 Location: Denver, CO Posts: 148	Re: Weird starting problem great diagram.... thanks for that. __________________ _______________________________________________ 1968 Chevy C-20 w/ 396 1997 HD Sportster 1200 street tracker 1994 Chevy 1500 Silverado



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