85 Alternator not working until I give gas
06-20-2021, 06:00 PM
#16
If you are running the car without the voltage light bulb in place, what you are seeing is normal.
As has been said, the one bulb that shouldn’t be replaced with led is the charge bulb.
As has been said, the one bulb that shouldn’t be replaced with led is the charge bulb.
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dukenukemx (06-21-2021)
06-21-2021, 04:24 PM
#17
Chronic Tool Dropper
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A reminder that there's a separate resistor on the cluster backplane, in parallel with the bulb, that's needed to provide the proper initial excitation to get the alternator going from a start.
The typical culprits of your symptom are connections at the 14-pin under the hood, and connections or maybe wire damage at the alternator. It's pretty easy to see if the bulb is working -- on key on but prior to start, the lamp by the volt meter should be lit up. Since the bulb depends on a good current flow path to the alternator, it will be weak or won't come on if anything in that flow path is weak. So not seeing the light on is much more likely something else that isn't the bulb. Might be the card edge connector at the cluster, a connection at the CE panel, the 14 pin under the hood, or the wire or connection at the alternator. Some in-circuit testing with a DMM will quickly help you identify what's not working.
Of course, you'd know if you just replaced the cluster bulbs with LED's, and whether they might be a cause of your symptom. If you had good charging and suddenly didn't, it's unlikely that someone snuck LED's into your cluster. Of course, this is also a reminder to look at the last things you worked on. Anything related to or close to the cluster connections, the CE panel, the 14-pin and front-of-engine harness, or the alternator and local wiring would be a candidate. Ignition switch or local wiring worked on recently? You get the idea.
The typical culprits of your symptom are connections at the 14-pin under the hood, and connections or maybe wire damage at the alternator. It's pretty easy to see if the bulb is working -- on key on but prior to start, the lamp by the volt meter should be lit up. Since the bulb depends on a good current flow path to the alternator, it will be weak or won't come on if anything in that flow path is weak. So not seeing the light on is much more likely something else that isn't the bulb. Might be the card edge connector at the cluster, a connection at the CE panel, the 14 pin under the hood, or the wire or connection at the alternator. Some in-circuit testing with a DMM will quickly help you identify what's not working.
Of course, you'd know if you just replaced the cluster bulbs with LED's, and whether they might be a cause of your symptom. If you had good charging and suddenly didn't, it's unlikely that someone snuck LED's into your cluster. Of course, this is also a reminder to look at the last things you worked on. Anything related to or close to the cluster connections, the CE panel, the 14-pin and front-of-engine harness, or the alternator and local wiring would be a candidate. Ignition switch or local wiring worked on recently? You get the idea.
Currently the cluster is in pieces and hardly has any bulbs in it. I'm trying to repair the gauges and I just got the voltage gauge working and noticed it wasn't charging until I gave it gas. I'm currently installing LED's because I like LED's. I always find the old fashion incandescent bulbs to melt things over time. I'll finish today and see how the alternator acts.
If you haven't already, do a search for Ed Scherer's PWM dash illumination controller for the LEDs. The original rheostat current controller won't work well with the LEDs. Just a heads-up!
06-23-2021, 06:35 PM
#18
Electron Wrangler
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Sounds like something I'll get to during the week because I plan to remove the intake system of this car and replace vacuum hoses and bad connections. Some of the connectors have crumbled apart and left nothing but wires. The car also runs very rich and stinks of gas when it runs. I wonder if that has to do with the aftermarket fuel injectors I installed?
Alan