87 5spd Out for a spin - weird idle during ride - battery dead
01-16-2012, 06:29 PM
#1
Burning Brakes
Thread Starter
87 5spd Out for a spin - weird idle during ride - battery dead
I had the day off and decided to take the shark out. Last time I took her out was a couple months back. I have started her and let her idle over this time, but the battery had drained on me.
I jump started according to the manual and after about 10 minutes of idle she shut off. I thought alternator, but the voltage indicator was reading above 12.
On the restart she sounded weak, like there wasn't enough to turn the starter but then she fired up and then died again.
I checked the battery (switch off) and I had 7 Volts. I tried jumping again and let it sit for about 20 minutes. During the charge I had 14.7 volts at the battery
She fired up and the voltage was 13 Volts at the dash and at the battery on the meter.
I let her warm up and I went for out for an hours ride. Taking it slow at first as she was a little rough. The dash voltage indicator read just over 14 and with blinkers on it moved up and down slightly. I also ran the heater and fan the entire ride and the voltage gauge stayed 12-14 the entire trip.
Near the end of the ride and after a spirited but short free way run, I stepped on the pedal lightly and I could feel a jolt each time no matter what speed I was going. At a the next stop sign, the engine was revving from 0 to 2300 rpms. I tried goosing the pedal, but this continued until I turned the car off in my drive.
before shutting her off I opened the hood and checked the throttle and it seemed okay. I turned her off and then tried a restart. She tried to turn over, but the battery seemed to weak again
I checked the voltage again with ignition off and I had 10 Volts at the battery.
I cleaned all grounds not long ago and the battery and ground strap looked good. I checked the grounds that I could see and they looked okay.
I would have thought that if the alternator was not charging that the car would have stalled on me given the heater and blower running the entire trip.
As for the Idle. MAF? Computer? I had the MAF rebuilt in 2010.
Thanks
I jump started according to the manual and after about 10 minutes of idle she shut off. I thought alternator, but the voltage indicator was reading above 12.
On the restart she sounded weak, like there wasn't enough to turn the starter but then she fired up and then died again.
I checked the battery (switch off) and I had 7 Volts. I tried jumping again and let it sit for about 20 minutes. During the charge I had 14.7 volts at the battery
She fired up and the voltage was 13 Volts at the dash and at the battery on the meter.
I let her warm up and I went for out for an hours ride. Taking it slow at first as she was a little rough. The dash voltage indicator read just over 14 and with blinkers on it moved up and down slightly. I also ran the heater and fan the entire ride and the voltage gauge stayed 12-14 the entire trip.
Near the end of the ride and after a spirited but short free way run, I stepped on the pedal lightly and I could feel a jolt each time no matter what speed I was going. At a the next stop sign, the engine was revving from 0 to 2300 rpms. I tried goosing the pedal, but this continued until I turned the car off in my drive.
before shutting her off I opened the hood and checked the throttle and it seemed okay. I turned her off and then tried a restart. She tried to turn over, but the battery seemed to weak again
I checked the voltage again with ignition off and I had 10 Volts at the battery.
I cleaned all grounds not long ago and the battery and ground strap looked good. I checked the grounds that I could see and they looked okay.
I would have thought that if the alternator was not charging that the car would have stalled on me given the heater and blower running the entire trip.
As for the Idle. MAF? Computer? I had the MAF rebuilt in 2010.
Thanks
01-16-2012, 06:42 PM
#4
Rennlist Member
Rennlist Site Sponsor
Starting and idling is not good for an engine. If you don't get it fully up to temp, it is better to not start it.
Appearance means absolutely nothing on grounds and electrical connections, even if you disassemble it to look at it. A battery connection can look like perfectly clean metal and still have a layer of insulating oxides. If you use a knife or metal cutter on the lead portions, a dirty terminal/post will feel "crunchy" as you clean it.
Each major connection needs to be disassembled and mechanically cleaned. This includes both ends of the ground strap (which is often bad as well), every connection on the positive post, the connections on the starter, the connections on the alternator, the connections on the jump start terminal, the connections on the top of the Central Electric Panel, the engine-to-chassis ground strap, the engine grounds, the grounds at the Central Electric Panel, etc., etc., etc.
The alternator belt needs to be tight - tighter than you would expect.
The electrolyte level in the battery should be checked.
There are other possible causes for your problems, such as a failed battery, but I hope that you begin to get the idea...
Appearance means absolutely nothing on grounds and electrical connections, even if you disassemble it to look at it. A battery connection can look like perfectly clean metal and still have a layer of insulating oxides. If you use a knife or metal cutter on the lead portions, a dirty terminal/post will feel "crunchy" as you clean it.
Each major connection needs to be disassembled and mechanically cleaned. This includes both ends of the ground strap (which is often bad as well), every connection on the positive post, the connections on the starter, the connections on the alternator, the connections on the jump start terminal, the connections on the top of the Central Electric Panel, the engine-to-chassis ground strap, the engine grounds, the grounds at the Central Electric Panel, etc., etc., etc.
The alternator belt needs to be tight - tighter than you would expect.
The electrolyte level in the battery should be checked.
There are other possible causes for your problems, such as a failed battery, but I hope that you begin to get the idea...
01-16-2012, 06:53 PM
#5
Burning Brakes
Thread Starter
Starting and idling is not good for an engine. If you don't get it fully up to temp, it is better to not start it.
Appearance means absolutely nothing on grounds and electrical connections, even if you disassemble it to look at it. A battery connection can look like perfectly clean metal and still have a layer of insulating oxides. If you use a knife or metal cutter on the lead portions, a dirty terminal/post will feel "crunchy" as you clean it.
Each major connection needs to be disassembled and mechanically cleaned. This includes both ends of the ground strap (which is often bad as well), every connection on the positive post, the connections on the starter, the connections on the alternator, the connections on the jump start terminal, the connections on the top of the Central Electric Panel, the engine-to-chassis ground strap, the engine grounds, the grounds at the Central Electric Panel, etc., etc., etc.
The alternator belt needs to be tight - tighter than you would expect.
The electrolyte level in the battery should be checked.
There are other possible causes for your problems, such as a failed battery, but I hope that you begin to get the idea...
Appearance means absolutely nothing on grounds and electrical connections, even if you disassemble it to look at it. A battery connection can look like perfectly clean metal and still have a layer of insulating oxides. If you use a knife or metal cutter on the lead portions, a dirty terminal/post will feel "crunchy" as you clean it.
Each major connection needs to be disassembled and mechanically cleaned. This includes both ends of the ground strap (which is often bad as well), every connection on the positive post, the connections on the starter, the connections on the alternator, the connections on the jump start terminal, the connections on the top of the Central Electric Panel, the engine-to-chassis ground strap, the engine grounds, the grounds at the Central Electric Panel, etc., etc., etc.
The alternator belt needs to be tight - tighter than you would expect.
The electrolyte level in the battery should be checked.
There are other possible causes for your problems, such as a failed battery, but I hope that you begin to get the idea...
01-16-2012, 07:48 PM
#7
Team Owner
clean the battery connections and the ground connections..
Also on your list you should remove the voltage regulator on the back of the alternator and inspect the brushes,
inspect and clean the 14 pin connector wires at the hot post,
get a muti meter and see what the voltage is after you do all of these cleaning and inspections,
you should,have over 13.5 at 1500 RPM if its lower than this then you may have a blown diode
and or the voltage regulator has worn brushes.
Warning dont try jumpstarting the engine you will eventually blow a diode or fry a computer or damage the voltage regulator.
If you decide to replace the voltage regulator only use a Bosch part not the one you can buy from Autozone for 25.00
Also on your list you should remove the voltage regulator on the back of the alternator and inspect the brushes,
inspect and clean the 14 pin connector wires at the hot post,
get a muti meter and see what the voltage is after you do all of these cleaning and inspections,
you should,have over 13.5 at 1500 RPM if its lower than this then you may have a blown diode
and or the voltage regulator has worn brushes.
Warning dont try jumpstarting the engine you will eventually blow a diode or fry a computer or damage the voltage regulator.
If you decide to replace the voltage regulator only use a Bosch part not the one you can buy from Autozone for 25.00
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01-16-2012, 08:33 PM
#8
Rennlist Member
Check that ground strap, too. Some have seen corrosion under the rubber insulator to the point resistance will skyrocket.
Clean up those grounds! We had a great tech session on that at Frenzy last year. If you don't have the guide rixter wrote, I can probably lay my hands on it.
Clean up those grounds! We had a great tech session on that at Frenzy last year. If you don't have the guide rixter wrote, I can probably lay my hands on it.
01-16-2012, 08:47 PM
#10
Rennlist Member
And when it's time to pull her back in, I find a good excuse to go for a drive!
Yea Charles, battery. When was it last replaced? What to make sure we address root cause here.
Also, get yourself a trickle charger to stay away from these jumppost style hot charges.
01-16-2012, 10:41 PM
#11
Rennlist Member
I had an interstate battery that tested good at the local interstate battery store. My mechanic put in a new battery to make sure that was it before spending a bunch of my money and his time troubleshooting and all the problems went away with the old battery.