bad gasoline? (not!)

JD1964

Master Mechanic
Thread starter
Dec 31, 2014
254
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Oh, on the injectors, the stock LT1 injectors were tossed during the swap and Bosch style from Fuel Injection Connection were installed.
 
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JD1964

Master Mechanic
Thread starter
Dec 31, 2014
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I went to do voltage checks and discovered the alternator is not charging. I have a gauge and if this were happening all along I can't believe I overlooked it. Either way, before I continue to diagnose I certainly need to get the alternator back online. It has a CS130 style and the exciter wire is run through the gen light in the inst cluster. I noticed the bulb is now not lit with koeo. So that is probably why the alternator is not charging. (burnt dash bulb)

I'm going to rewire the exciter wire through a dedicated resistor so I don't have to worry about charging system failure when a dash bulb goes out.

I suppose that lower voltage caused by non functioning alternator can cause sensitivity issues with engine control electronics and cause the stumbling problem but I dont know for sure.

I'll keep you posted.
 
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64nailhead

Goat Herder
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Dec 1, 2014
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Upstate NY
Personally, I'm a fan of the idiot light (guess why ;) )
 
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edfiero

Not-quite-so-new-guy
May 2, 2022
9
1
Just one thought about the original idea that it was bad gas. You indicated the problem started within 15 seconds of starting up. It seems unlikely to even burn through the old gas already in the gas line within 15 seconds. I would think it would take at least a minute for 'new' gas to even reach the fuel injectors. But sounds like you are on the right track it chasing down other possibilities.
 

JD1964

Master Mechanic
Thread starter
Dec 31, 2014
254
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I would think it would take at least a minute for 'new' gas to even reach the fuel injectors.

Thanks for your thought and its worth touching on just for the sake of understanding they way this, and many other fuel injection systems deliver fuel to the engine.

The pump pushes fuel from the tank to the rail and back to the tank in a constant loop as soon as you turn the key on. The regulator on the rail allows a specific pressure to build in the rail then sends the excess back to the tank, constantly.

Bottom line is on this car and many others, whatever is in the tank gets to the injectors pretty much right away.
 

JD1964

Master Mechanic
Thread starter
Dec 31, 2014
254
63
Personally, I'm a fan of the idiot light (guess why ;) )
Ultimately I’d like to have a functional idiot light and a gauge but have some redundancy to the exciter wire so I won’t loose charging if the bulb burns out.
 

64nailhead

Goat Herder
Supporting Member
Dec 1, 2014
4,471
113
Upstate NY
Ultimately I’d like to have a functional idiot light and a gauge but have some redundancy to the exciter wire so I won’t loose charging if the bulb burns out.
IIRC it won't light the bulb and work correctly with both the resistor and idiot light in the circuit. Perhaps someone else can correct me if I'm wrong.
 
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g0thiac

G-Body Guru
Sep 6, 2020
701
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IIRC it won't light the bulb and work correctly with both the resistor and idiot light in the circuit. Perhaps someone else can correct me if I'm wrong.
From a standpoint of basic theory, that should be the case.

I’ve never tested both. However someone can either use the ohm load from a resistor or the bulb because if the two values combined, exceed what was intended by the manufacturer it may not even function as intended.
 

JD1964

Master Mechanic
Thread starter
Dec 31, 2014
254
63
I figured out the reason for no charging. It's actually two issues.

1. Its not the dash bulb that's burnt. Instead its the printed circuit on the back of the inst cluster. Its worn I suppose and the socket wont maintain good contact. Same condition is affecting intermittent function of other dash bulbs such as the left turn indicator. Not sure how to fix this but at least I know this printed circuit wont be a reliable source for regulator triggering.

2. The connector on the back of the alternator is not maintaining reliable contact. It's probably a poor quality connector and I plan to replace it with a better quality one.

Nonetheless, I wiggled things and got it charging there in the driveway and let it warm up real good. Still doing the stumble with good charging system so rule that out. Although once I get the new alternator wiring in I may reset the PCM and let it relearn. Maybe it will teach itself how to behave again. I actually had to do this previously after fiddling with and fixing MAF issues.
 
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g0thiac

G-Body Guru
Sep 6, 2020
701
63
1. Its not the dash bulb that's burnt. Instead its the printed circuit on the back of the inst cluster. Its worn I suppose and the socket wont maintain good contact. Same condition is affecting intermittent function of other dash bulbs such as the left turn indicator. Not sure how to fix this but at least I know this printed circuit wont be a reliable source for regulator triggering.

2. The connector on the back of the alternator is not maintaining reliable contact. It's probably a poor quality connector and I plan to replace it with a better quality one.
You can always try adding a few bits of solder to each side of the light bulb, so it’s more tightly secured.

I would clean the connections. But like the cluster I was working on for my other car, the oxidizing damaged the traces which meant I had to jump them with wire.

As they do wear out over time, but it’s pretty much an easy fix.

Indeed though, replace your alternator pigtail lol 😎💪
 
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