Battery: Is This Possible?
Thread Starter
Le Mans Master
Joined: Jul 2004
Posts: 8,142
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From: Time is a great teacher. Unfortunately, it kills all its pupils.
Cruise-In VIII Veteran
St. Jude Donor '07
Battery: Is This Possible?
Went for a tune as my idle suddenly went whack. Idling very rough with AC on and car in gear.
The tuner says I have a problem with the MAF as the air/fuel ratio spikes when he floors it on the dyno and then levels out to normal. I have a new one on order and will be taking the car back to him.
Unfortunately, after 3 pulls on the dyno, everything, and I mean everything, is whacked out now. Idle is worse, the car surges, lurches, sounds like it’s misfiring, gear shifts are horrible, check engine light has come back on and gas mileage has gone completely out the window. I think I’m going to ask that the tuner just restore my original tune.
I talked to the tuner yesterday about how bad my car is running and he is saying it might be my battery. Is that even possible? Stock battery on a 2 ½ year old car.
The tuner says I have a problem with the MAF as the air/fuel ratio spikes when he floors it on the dyno and then levels out to normal. I have a new one on order and will be taking the car back to him.
Unfortunately, after 3 pulls on the dyno, everything, and I mean everything, is whacked out now. Idle is worse, the car surges, lurches, sounds like it’s misfiring, gear shifts are horrible, check engine light has come back on and gas mileage has gone completely out the window. I think I’m going to ask that the tuner just restore my original tune.
I talked to the tuner yesterday about how bad my car is running and he is saying it might be my battery. Is that even possible? Stock battery on a 2 ½ year old car.
Instructor
Joined: Mar 2010
Posts: 212
Likes: 1
From: Pittsburgh PA
My understanding is that if you get three years out of a battery, you're doing good...on my Brand P cars, the German batteries were only good for about that long...now I once had a Sears Die-Hard in an old Jeep CJ that went a long, long time, but I suspect that was a serious flook...
About your MAF Sensor...do you have a K&N style oil impregnated filter on your car? If so, the oil has been known to get deposited on the MAF & screw them up...at least in my previous experience with Brand P, I'm not sure if it applies to Corvettes...
About your MAF Sensor...do you have a K&N style oil impregnated filter on your car? If so, the oil has been known to get deposited on the MAF & screw them up...at least in my previous experience with Brand P, I'm not sure if it applies to Corvettes...
Melting Slicks
Joined: Sep 2007
Posts: 2,597
Likes: 3
From: READING PA
St. Jude Donor '08-'09-'10
Put a METER on the terminal of the ALTERNATOR. See if it measures 12.5
to 12.6 Volts DC without the engine running. with the meter connected wiggel the battery terminals and the heavy lead going to the fuse box also the alternator terminal itself. If the reading is rock steady I doubt your battery is causing this. Start the engine and again look at the meter on
the Alternator terminal . Is it at 14.5vdc. This is a good test although
more comprehensive tests can be done. I would be satisfied with the power system at this point.
Thread Starter
Le Mans Master
Joined: Jul 2004
Posts: 8,142
Likes: 0
From: Time is a great teacher. Unfortunately, it kills all its pupils.
Cruise-In VIII Veteran
St. Jude Donor '07
My understanding is that if you get three years out of a battery, you're doing good...on my Brand P cars, the German batteries were only good for about that long...now I once had a Sears Die-Hard in an old Jeep CJ that went a long, long time, but I suspect that was a serious flook...
About your MAF Sensor...do you have a K&N style oil impregnated filter on your car? If so, the oil has been known to get deposited on the MAF & screw them up...at least in my previous experience with Brand P, I'm not sure if it applies to Corvettes...
About your MAF Sensor...do you have a K&N style oil impregnated filter on your car? If so, the oil has been known to get deposited on the MAF & screw them up...at least in my previous experience with Brand P, I'm not sure if it applies to Corvettes...
I have a Vararam CAI and it has an oil impregnated filter. The guys at the shop thought the same as you did and pulled the MAF and cleaned it to no avail.
Thread Starter
Le Mans Master
Joined: Jul 2004
Posts: 8,142
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From: Time is a great teacher. Unfortunately, it kills all its pupils.
Cruise-In VIII Veteran
St. Jude Donor '07
Thread Starter
Le Mans Master
Joined: Jul 2004
Posts: 8,142
Likes: 0
From: Time is a great teacher. Unfortunately, it kills all its pupils.
Cruise-In VIII Veteran
St. Jude Donor '07
Doubt its the battery. A loose connection perhaps. Though its a fact our corvette batteries are not lasting as long as yesteryear.
Put a METER on the terminal of the ALTERNATOR. See if it measures 12.5
to 12.6 Volts DC without the engine running. with the meter connected wiggel the battery terminals and the heavy lead going to the fuse box also the alternator terminal itself. If the reading is rock steady I doubt your battery is causing this. Start the engine and again look at the meter on
the Alternator terminal . Is it at 14.5vdc. This is a good test although
more comprehensive tests can be done. I would be satisfied with the power system at this point.
Put a METER on the terminal of the ALTERNATOR. See if it measures 12.5
to 12.6 Volts DC without the engine running. with the meter connected wiggel the battery terminals and the heavy lead going to the fuse box also the alternator terminal itself. If the reading is rock steady I doubt your battery is causing this. Start the engine and again look at the meter on
the Alternator terminal . Is it at 14.5vdc. This is a good test although
more comprehensive tests can be done. I would be satisfied with the power system at this point.
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Burning Brakes
Joined: Aug 2004
Posts: 1,207
Likes: 147
From: St. Louis MO
Doubt its the battery. A loose connection perhaps. Though its a fact our corvette batteries are not lasting as long as yesteryear.
Put a METER on the terminal of the ALTERNATOR. See if it measures 12.5
to 12.6 Volts DC without the engine running. with the meter connected wiggel the battery terminals and the heavy lead going to the fuse box also the alternator terminal itself. If the reading is rock steady I doubt your battery is causing this. Start the engine and again look at the meter on
the Alternator terminal . Is it at 14.5vdc. This is a good test although
more comprehensive tests can be done. I would be satisfied with the power system at this point.
Put a METER on the terminal of the ALTERNATOR. See if it measures 12.5
to 12.6 Volts DC without the engine running. with the meter connected wiggel the battery terminals and the heavy lead going to the fuse box also the alternator terminal itself. If the reading is rock steady I doubt your battery is causing this. Start the engine and again look at the meter on
the Alternator terminal . Is it at 14.5vdc. This is a good test although
more comprehensive tests can be done. I would be satisfied with the power system at this point.
Do this: Put the voltage meter on the battery as suggested, but also put a small 12v light bulb across the battery. Something like a backup lamp, #1157 or similar. If the voltage drops under 12v, and heads deeper into the 11v range every few seconds, = bad battery.
If it drops a 10th of a volt or two and holds, = reasonably good battery.
Test the alternator with the engine running, yes, but with the headlamps on also. Low voltage with headlamps means a bad charging circuit.
Cheers!
Last edited by fnbrowning; Jun 15, 2010 at 01:40 PM. Reason: spelling
Burning Brakes
Joined: Dec 2005
Posts: 819
Likes: 3
From: Flowery Branch Ga
With all respect, testing the battery with an electrical meter can be misleading. Many times, a battery with a bad cell will read 12+ volts, but with a load, it will cr@p out.
Do this: Put the voltage meter on the battery as suggested, but also put a small 12v light bulb across the battery. Something like a backup lamp, #1157 or similar. If the voltage drops under 12v, and heads deeper into the 11v range every few seconds, = bad battery.
If it drops a 10th of a volt or two and holds, = reasonably good battery.
Test the alternator with the engine running, yes, but with the headlamps on also. Low voltage with headlamps means a bad charging circuit.
Cheers!
Do this: Put the voltage meter on the battery as suggested, but also put a small 12v light bulb across the battery. Something like a backup lamp, #1157 or similar. If the voltage drops under 12v, and heads deeper into the 11v range every few seconds, = bad battery.
If it drops a 10th of a volt or two and holds, = reasonably good battery.
Test the alternator with the engine running, yes, but with the headlamps on also. Low voltage with headlamps means a bad charging circuit.
Cheers!
Melting Slicks
Joined: Sep 2007
Posts: 2,597
Likes: 3
From: READING PA
St. Jude Donor '08-'09-'10
With all respect, testing the battery with an electrical meter can be misleading. Many times, a battery with a bad cell will read 12+ volts, but with a load, it will cr@p out.
Do this: Put the voltage meter on the battery as suggested, but also put a small 12v light bulb across the battery. Something like a backup lamp, #1157 or similar. If the voltage drops under 12v, and heads deeper into the 11v range every few seconds, = bad battery.
If it drops a 10th of a volt or two and holds, = reasonably good battery.
Test the alternator with the engine running, yes, but with the headlamps on also. Low voltage with headlamps means a bad charging circuit.
Cheers!
Do this: Put the voltage meter on the battery as suggested, but also put a small 12v light bulb across the battery. Something like a backup lamp, #1157 or similar. If the voltage drops under 12v, and heads deeper into the 11v range every few seconds, = bad battery.
If it drops a 10th of a volt or two and holds, = reasonably good battery.
Test the alternator with the engine running, yes, but with the headlamps on also. Low voltage with headlamps means a bad charging circuit.
Cheers!
He did say he took it to the garage and they cleaned the MAF SENSOR.
I wonder if the Garage put a scanner on to read the CEL's Thats the next thing I would do. i think the tuner could have said a little more than he did. If he is getting CEL's and should be with his description of
how the car is carrying on.
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
What will affect it will be the voltage. Poor connections, low voltage output from the battery will affect sensors and how the car runs.
However, from the symptoms you have outlined, I strongly suspect a poor job by the tuner.
However, from the symptoms you have outlined, I strongly suspect a poor job by the tuner.
Last edited by Mez; Jun 15, 2010 at 02:47 PM.
Melting Slicks
Joined: Mar 2007
Posts: 2,391
Likes: 23
From: Santa Barbara CA
An easy test here would be to simply unplug the MAF so the ECM goes into a substitute mode where (from what I know about the LS engines) it uses the MAP sensor instead. An otherwise healthy engine will run completely normal with the MAF unplugged.
I'm a BMW tech and have seen problems like this caused by a bad (or oil soaked) MAF. Unplugging it eliminated the problem and is a sure way to diagnose the meter.
Andy
I'm a BMW tech and have seen problems like this caused by a bad (or oil soaked) MAF. Unplugging it eliminated the problem and is a sure way to diagnose the meter.
Andy
Melting Slicks
Joined: Sep 2007
Posts: 2,597
Likes: 3
From: READING PA
St. Jude Donor '08-'09-'10
An easy test here would be to simply unplug the MAF so the ECM goes into a substitute mode where (from what I know about the LS engines) it uses the MAP sensor instead. An otherwise healthy engine will run completely normal with the MAF unplugged.
I'm a BMW tech and have seen problems like this caused by a bad (or oil soaked) MAF. Unplugging it eliminated the problem and is a sure way to diagnose the meter.
Andy
I'm a BMW tech and have seen problems like this caused by a bad (or oil soaked) MAF. Unplugging it eliminated the problem and is a sure way to diagnose the meter.
Andy
Melting Slicks
Joined: Sep 2007
Posts: 2,597
Likes: 3
From: READING PA
St. Jude Donor '08-'09-'10