Starter thumping, won't start
Thread Starter
Racer
Joined: Aug 2002
Posts: 369
Likes: 11
From: NV
Starter thumping, won't start
Last week shut it off at gas station. 5 minutes later she goes dead. Not a peep, nothing on on the DIC...just dead. I again turn key and it turns slowly, barely, but enough to start and then no further problems until today. Today, put in a new battery and it immediately again acted like a dying, or dead battery. Connections tight, voltage 14.2 (yellow top Optima). Dash, headlights, interior lights, Windows, etc all work fine. A second attempt gets a barely cranking engine but starts. Drives great, everything working and no codes. After driving half hour, I shut off in driveway and immediately try to start and get a solid thump, thump, thump as I turn and hold key......but it is not turning over, just a solid thump, thump, thump as long as I hold key. I suspect I have something going on at starter giving me intermittent shorts. Anyone have ideas or suggestions? I've never heard this sound before, usually hear a bad battery still slowly cranking, but this just thumps solidly.
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
Sure sounds like the starter. They tend to work better when cold but once hot from engine and exhaust heat the windings and solenoid can have issues. A classic--- started fine/OK and went for a drive and stopped somewhere and would not start again.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
A couple of things to check:
Are the battery terminals properly tightened? If you can move them by hand, they are TOO LOOSE.
The connections on the solenoid need to be clean and tight. Check those and the wires.
Bill
Are the battery terminals properly tightened? If you can move them by hand, they are TOO LOOSE.
The connections on the solenoid need to be clean and tight. Check those and the wires.
Bill
Thread Starter
Racer
Joined: Aug 2002
Posts: 369
Likes: 11
From: NV
So....my starter looks brand new. Shining away with perfect contacts, no corrosion, oil, grime....literally clean enough to eat off of. The battery cables were tight but not so tight that I could not move them.......especially the ground. Tightened them both as much as possible and well, so far so good. The simple things right? For the last several weeks I had been plagued with AH codes. New tires, newly aligned, functioning yaw and lateral sensors. But driving it for 45 minutes tonight, not one popped up. So, let's see how she does this week. Thanks again guys.
Thread Starter
Racer
Joined: Aug 2002
Posts: 369
Likes: 11
From: NV
So no go. The battery is discharging within hours. So...I rigged up the old light trick of cable to light to battery and got a bright steady light. Then started pulling fuses..at #25 the light went out. Bummer for me....BCM/IPC. Anything fixable in there?
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
Maybe. However 2001 reman BCMs BCMs are plentiful and not expensive. You will need to do the relearn "handshake" for the BCM PCM interface. After that you may need to use a Tech 2 to add any needed RPOs for your car if the BCM does not have them.
Relearn:
1. Turn the key to ON for 11 minutes.
2 Turn the key to OFF for 30 seconds.
3. Repeat 1&2 two more times.
4. Turn the key to ON for 30 seconds.
The car should start and run with the new BCM.
This will sync the PCM to the New BCM
Mr. Sam
Relearn:
1. Turn the key to ON for 11 minutes.
2 Turn the key to OFF for 30 seconds.
3. Repeat 1&2 two more times.
4. Turn the key to ON for 30 seconds.
The car should start and run with the new BCM.
This will sync the PCM to the New BCM
Mr. Sam
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
When conducting a current draw test on ANY modern day vehicle,, The old light bulb test WILL NOT WORK! The BCM and some other modules continuously draws current for theft control, memory and remote function monitoring. The bulb will remain on all the time.
You need to actually use a DC AMP Meter in series with the negative battery lead and battery terminal.
You will be looking for close to 20 milliamps Thats the ONLY way to see if there is an excessive current draw and to remove fuses and see if it reduces the draw.
NOTE.. The BCM must go into SLEEP MODE to achieve the 20 ma draw. If you bring the BCM out of sleep mode, it can take as long as 10-12 min for it to go to sleep. You can watch the meter and see the draw step down to sleep mode. Most of the time it takes 1-2 min.
The 10-12 minutes comes into play as an example; when you leave the hood up and the light doesn't go out for a long time (10-12 min)
Give that amp meter a try and see where your are.
Bill
You need to actually use a DC AMP Meter in series with the negative battery lead and battery terminal.
You will be looking for close to 20 milliamps Thats the ONLY way to see if there is an excessive current draw and to remove fuses and see if it reduces the draw.
NOTE.. The BCM must go into SLEEP MODE to achieve the 20 ma draw. If you bring the BCM out of sleep mode, it can take as long as 10-12 min for it to go to sleep. You can watch the meter and see the draw step down to sleep mode. Most of the time it takes 1-2 min.
The 10-12 minutes comes into play as an example; when you leave the hood up and the light doesn't go out for a long time (10-12 min)
Give that amp meter a try and see where your are.
Bill
Last edited by Bill Curlee; Nov 15, 2015 at 02:33 PM.
