Low Voltage at dash. Random no start condition
04-05-2015, 02:54 PM
#1
Low Voltage at dash. Random no start condition Ok so I've been trying to tackle this electrical gremlin for a while now, and I haven't had much success. Here's the issue(s) I'm having, and what I've done to try to fix them...
1. Low voltage at the gauge - around 10V.
- I've replaced the alternator, checked grounds, pulled fuses (with ignition in ON position, but car not running) in an attempt to locate some parasitic loss. Voltage at all the fuses comes back to be battery voltage, except for gauge fuse which is maybe .4V less (but is still within spec according to the service manual). I also pulled the starter and checked the exciter wire. The exciter wire was showing voltage when I checked it, and when the car is running, I measure 13.4V across the battery.
- When I first fired up the car after replacing the alt, the voltage jumped to over 13V at the dash, but was swinging. It since has returned to around 10V, and stays there. However, the car doesn't show physical signs of low voltage. No dimming lights, starter is very responsive, car drives fine. I'm not showing any codes related to low voltage.
2. ABS Inop, TCS off, Brake light turn on at random
- This issue just started happening at random. Sometimes they come on and stay on; other times not at all or shuts off after being on briefly. I should note that the air bag light is now always on as well.
3. Gauge cluster does the "sweep" move everytime I turn the car on. My car is a 99, so it's always done this, but randomly. It's just a guarantee every time now.
4. Random no start condition - The car will randomly act as if it has a completely dead battery when I go to start (No dash lights, starter will not turn, etc.)
- This has happened to me maybe 3 times. I have moved wires around to try to replicate this condition, with no success. Nonetheless it is quite concerning. Sometimes I have to let it sit, and this last time it started when I turned the key after the third try and acted like nothing ever happened.
I should note that the low voltage and gauge issues (1 & 3) have occurred since I put the motor back in. I added a supercharger to the engine, and replaced all gaskets, seals, etc. The wiring harness was in good condition except for the starter power wire, which had been burned by the headers, but was still intact. We soldered that section of the wiring and taped it up. I have checked the voltage at the end of that wire to ground, and there is no noticeable voltage drop across the wire ( and again the starter works as if it were brand new).
Frankly, I just am not sure where to go from here. I have spent a ridiculous amount of time trying to fix this with no avail. Any help would be much appreciated.
1. Low voltage at the gauge - around 10V.
- I've replaced the alternator, checked grounds, pulled fuses (with ignition in ON position, but car not running) in an attempt to locate some parasitic loss. Voltage at all the fuses comes back to be battery voltage, except for gauge fuse which is maybe .4V less (but is still within spec according to the service manual). I also pulled the starter and checked the exciter wire. The exciter wire was showing voltage when I checked it, and when the car is running, I measure 13.4V across the battery.
- When I first fired up the car after replacing the alt, the voltage jumped to over 13V at the dash, but was swinging. It since has returned to around 10V, and stays there. However, the car doesn't show physical signs of low voltage. No dimming lights, starter is very responsive, car drives fine. I'm not showing any codes related to low voltage.
2. ABS Inop, TCS off, Brake light turn on at random
- This issue just started happening at random. Sometimes they come on and stay on; other times not at all or shuts off after being on briefly. I should note that the air bag light is now always on as well.
3. Gauge cluster does the "sweep" move everytime I turn the car on. My car is a 99, so it's always done this, but randomly. It's just a guarantee every time now.
4. Random no start condition - The car will randomly act as if it has a completely dead battery when I go to start (No dash lights, starter will not turn, etc.)
- This has happened to me maybe 3 times. I have moved wires around to try to replicate this condition, with no success. Nonetheless it is quite concerning. Sometimes I have to let it sit, and this last time it started when I turned the key after the third try and acted like nothing ever happened.
I should note that the low voltage and gauge issues (1 & 3) have occurred since I put the motor back in. I added a supercharger to the engine, and replaced all gaskets, seals, etc. The wiring harness was in good condition except for the starter power wire, which had been burned by the headers, but was still intact. We soldered that section of the wiring and taped it up. I have checked the voltage at the end of that wire to ground, and there is no noticeable voltage drop across the wire ( and again the starter works as if it were brand new).
Frankly, I just am not sure where to go from here. I have spent a ridiculous amount of time trying to fix this with no avail. Any help would be much appreciated.
04-05-2015, 03:14 PM
#2
couple guesses.....
1. try replacing the main battery cables if you haven't. maybe big 3 upgrade or at least new stock wires. Corroded or worn wires will cause major issues similar to bad grounds or worse. The wiring will show its weakness anytime a decent load is on the system. My ac will cause my volt to flux big time but only randomly. Ive got a big 3 in my future as well.
2. its might be bcm related. most bcm problems are the one cracked solder joint that affects the windows and radio power. ive had to solder mine multiple times....but if I hit a bump just hard enough it will "reset" my bcm and all my gauge lights cycle again. I never lose power but its an example of what a shitty bcm will act like.
1. try replacing the main battery cables if you haven't. maybe big 3 upgrade or at least new stock wires. Corroded or worn wires will cause major issues similar to bad grounds or worse. The wiring will show its weakness anytime a decent load is on the system. My ac will cause my volt to flux big time but only randomly. Ive got a big 3 in my future as well.
2. its might be bcm related. most bcm problems are the one cracked solder joint that affects the windows and radio power. ive had to solder mine multiple times....but if I hit a bump just hard enough it will "reset" my bcm and all my gauge lights cycle again. I never lose power but its an example of what a shitty bcm will act like.
04-05-2015, 03:40 PM
#3
I have not replaced the main cables, but what better time to do it then now. Any suggestions for a good place to get them? I might as well get thicker wires at this point....
Is there a definitive test I can do to determine if the BCM is bad? I haven't had any radio or window issues that sound BCM related. I did pull it some time ago and checked it and everything looked ok, but I probably would need to be a little more in depth checking it to be sure.
Is there a definitive test I can do to determine if the BCM is bad? I haven't had any radio or window issues that sound BCM related. I did pull it some time ago and checked it and everything looked ok, but I probably would need to be a little more in depth checking it to be sure.
04-05-2015, 05:03 PM
#4
I just ordered the big 3 kit from innovative as an upgrade. but you could make your own for a cheaper and sloppier alternative. the stock wires were bare minimum adequate at best.
I dunno of a real test for the bcm...and mostly likely this is all due to ground issues. but most of those will be done/checked with a wire replacement.
I dunno of a real test for the bcm...and mostly likely this is all due to ground issues. but most of those will be done/checked with a wire replacement.
04-06-2015, 08:28 AM
#5
1) The gauge is not worth much to you here. You need to see what the battery says. If the two don't match that will help zero in on the problem or loose cable.
What kind of alternator did you put in? Is it new or reman? The swinging needle would point to a bad alternator, exciter wire, or loose belt.
2) All of these are a problem. You need a special scanner to scan the ABS system to see what codes have been thrown. Same for the SES/airbag system.
3) The sweep points to a low voltage condition.
4) Could you jump the car in these situations?
What kind of alternator did you put in? Is it new or reman? The swinging needle would point to a bad alternator, exciter wire, or loose belt.
2) All of these are a problem. You need a special scanner to scan the ABS system to see what codes have been thrown. Same for the SES/airbag system.
3) The sweep points to a low voltage condition.
4) Could you jump the car in these situations?
04-06-2015, 09:51 AM
#6
1) The gauge is not worth much to you here. You need to see what the battery says. If the two don't match that will help zero in on the problem or loose cable.
What kind of alternator did you put in? Is it new or reman? The swinging needle would point to a bad alternator, exciter wire, or loose belt.
2) All of these are a problem. You need a special scanner to scan the ABS system to see what codes have been thrown. Same for the SES/airbag system.
3) The sweep points to a low voltage condition.
4) Could you jump the car in these situations?
What kind of alternator did you put in? Is it new or reman? The swinging needle would point to a bad alternator, exciter wire, or loose belt.
2) All of these are a problem. You need a special scanner to scan the ABS system to see what codes have been thrown. Same for the SES/airbag system.
3) The sweep points to a low voltage condition.
4) Could you jump the car in these situations?
2. I've got a friend who is a mechanic who should be able to scan this. I'm going to try to get it to him this week.
3. This is what I suspect also.
4. I didn't try to jump the car. It happened in my garage, so I never bothered.
A side note: I pulled the ground on the back of the driver head yesterday, and realized all 3 ground wires were connected to one bolt, and not two as it was originally. When I pulled the motor last year, this is how it was on the car, so at the time I didn't think twice about it. I'm hoping that this is the problem, and is causing the issue at the PCM. I'm going to try to pick up another bolt today and see if that resolves the issue. With my luck though, I'm not too positive it will solve the problem.
04-06-2015, 10:13 AM
#7
I wouldn't count an exciter wire problem out yet, then. They can cause intermittent issues but I think the grounding thing could be more promising.
I'd give that a shot also. If you have a bad battery or a battery problem, a successful jump can help point that out.
What is your issue with the PCM? Are you thinking the ABS and SES stuff? Those are in different modules.
What is your issue with the PCM? Are you thinking the ABS and SES stuff? Those are in different modules.
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04-06-2015, 12:31 PM
#8
I wouldn't count an exciter wire problem out yet, then. They can cause intermittent issues but I think the grounding thing could be more promising.
I'd give that a shot also. If you have a bad battery or a battery problem, a successful jump can help point that out.
What is your issue with the PCM? Are you thinking the ABS and SES stuff? Those are in different modules.
I'd give that a shot also. If you have a bad battery or a battery problem, a successful jump can help point that out.
What is your issue with the PCM? Are you thinking the ABS and SES stuff? Those are in different modules.
I'm just trying to rule out whether or not the voltage issue lies with the PCM itself.
04-06-2015, 12:47 PM
#9
Moving the connector for the exciter wire could brake/make the contact, but yes - usually when its bad you won't see a voltage at all.
04-06-2015, 01:00 PM
#10
If there was, I would not expect that you'd see a low voltage on your gauge cluster.
When you show 10V on the gauge cluster and the car is not started, what does your battery measure?
Moving the connector for the exciter wire could brake/make the contact, but yes - usually when its bad you won't see a voltage at all.
When you show 10V on the gauge cluster and the car is not started, what does your battery measure?
Moving the connector for the exciter wire could brake/make the contact, but yes - usually when its bad you won't see a voltage at all.
04-07-2015, 07:47 AM
#11
Voltage is between 12.3-12.4 across the battery when the car is off. I get the same voltage at all the fuses (with the exception of the gauge fuse in the inside box, which is slightly lower but much better than 10V). I've had the battery tested twice and both times it was good. It's fairly new also.
04-07-2015, 06:22 PM
#12
Last night I removed the screw on the back of the block and started to remove the manifold. There was no way I was going to get back there with it on top the engine. With the ground disconnected, I hooked the battery back up and put the ignition to the on position. I was able to finally replicate the no lights/no start condition. This afternoon I was able to get two ground bolts on the back of the head. One of the connectors was a little flimsy though. NO sweep on the gauges and voltage was reading battery voltage (12.X).
put the manifold back on, but before I get it screwed in and set, I decide to try again....
works at first, then I hear a fizz sound and everything goes out. That flimsy connector arched itself out. My guess is that having 3 wires on one bolt and the metal being weak was the perfect combination for a bad ground condition
Now I just have to try to figure out the best way to get a new connector on there. It looks like it's going to be a PITA.
