chaseincats

I completely forgot to update you on this, sorry about that. Wiggling it worked and I haven't had an issue since. What a waste of time changing all those alternators out ended up being lol. Thanks Captain

Correct, you need to modify the box to get it to fit. The general consensus is (this is what I did) getting some literal tin snips and cutting away the metal until you can fit it in. Don't be discouraged by this, it's absolutely worth the effort.

Haha sounds good, I'll wiggle away!

Gotcha. I took it for a drive today and it was behaving, next time it misbehaves I will.

By 'jumper' you mean take an ohm measurement with a multimeter, not stick a wire between the two, right? (please say ohm measurement)

All my measurements are on post #23

The W/R wire that goes to the alternator’s T-connector isn’t included in this check, right? Good catch on the tape flap, I grabbed another shot after giving it a haircut. It does go back into the harness:

Gotcha, it's just odd that it fixes itself everytime I change the alternator out. But I'll give that a look today.

Thanks all, good to know. Before I jump ship on this alternator though, I do want to find the possible issue with my wiring harness

From the pic on the rockauto part page it looks like I'd need to yank the fan off of my current alternator and transfer it to the new one somehow, no?

Could you send me where you got the alternator/2-pin connector? I'd like to keep working on getting the current one working properly since the theory so far is my car's wiring is the issue but that sounds like an upgrade I'd like to make later on

Did you need to do any hardware modifications to the alternator housing or mounting brackets? I know most non-Z alternators need that which I'd like to avoid if possible.

The wire colors differ from my 78 FSM which is interesting but it looks like @Captain Obvious's is more on point. I've attached a picture of my alternator's wiring (I unplugged the T connector for a better view of the wire colors). E: Black wire B: White with red stripe wires (condenser's WR has been connected to the terminal via a ring terminal instead of the original bullet connector) S: White with red stripe L: Blue with white stripe that becomes blue with black stripe after the electrical tape I think (the wires are dirty so it's hard to see)

Since this car is a '78 it is the only 1st gen year that doesn't have an external regulator and uses what became the ZX alternator

I took a look at the FSM just now and it appears that the W/R bullet connector that isn't connected is for the condenser but on remans these days, the condenser is pre-connected to the alternator's B-post using a ring terminal instead of an external bullet connector so it just dangles

Gotcha, so I just took a reading from the alternator body to the small r/w wire which is a bullet connector that isn't connected. I never connected this and just assumed it was a remnant of the 77 and back cars that were externally regulated. Anyway, the voltage from that wire to the alternator body is identical to the battery 12.25v The other w/r wire looks to be a ring terminal and is also sitting at 12.25v

Sorry for the lack of response, all - I've been out of town and just got back. When measuring the sense line to ground (I'll use the negative battery terminal), does the car have to be off, in accessory mode, or running? @Zed Head I don't believe O'Reilly's tests the alternators they get from their reman folks but I could be wrong.

I haven’t, how would I do that?

No but the problem is always fixed after the swap which is why I think it’s always the alternator

To use the frontier alternator you need to do the wiring mods you noted though, right?

That Wai unit being new is interesting, do you know if anyone on here has tried it? It's weird it says new on the page but when you click info it says reman. I'm going to email rockauto and see which is correct...

Hi gang, I’ve gone through 5 alternators in the past 7 years. These are all rebuilt ZX units each of which had different problems (hemispheres not lining up so couldn’t mount, squealing bearing, etc). That said, the vast majority had the internal voltage regulator die and overcharged the battery per the voltage gauge (yes I checked with a multimeter). Because oreilly lifetime warranties these, I’ve just been swapping them but I’m tired of this haha. Are there any drop-in brand new (not remaned) alternators that work? I know there’s a gm alternator that does but that requires permanently modifying the mounting bracket which I’d like to avoid… Any ideas? -chase

Agree that it PROBABLY is the bullet connector on the harness that connects to the temp sending unit - that was my issue a while back as well

Try unplugging the TPS connector temporarily and see if it leans out

Yep, using an o2 sensor and an AEM air/fuel gauge I was able to get it to run stoich after the forum and I worked through this thread. I was actually pretty astonished at how well it holds stoich at freeway speed as long as your TPS is set right - it won't hold it while driving around town, you kind of tune the AFM so that it runs stoich at highway speed (it will run richer around town by design and won't lean-out) Here is how to do it: - get rid of ALL vacuum leaks using the hand pump and cigarette method - once you are SURE all are gone, run through the EFI bible and check all sensors to make sure they're in spec - once all your vacuum leaks are gone, your TPS is set correctly per atlanticz, lean the AFM back 3 teeth (counterclockwise) and it will run stoich at highway speed, sound/feel healthier around town, and smell more like a modern car - I'd HIGHLY recommend doing this with an air fuel gauge/o2 sensor so you can be sure your numbers are right, but if you do everything above, you should be good