HI
I recently fixed my 7 enough to drive it on the streets. A week later I was driving 25mph and hit a bump in the pavement, this caused the 40a fuse (walbro255 fuel pump) to blow.

1) Diagnosing and testing the fuse box with the voltmeter I noticed something, the fuse box slots which connect to the alternator would read high then slowly drop, after a few seconds the reading would be constant with no drop. I unplugged the harness from the back of the FD alt and used the voltmeter to test, the reading was constant with no dropping.

2)The connection at the back of the alternator is bad? The auto parts store ran a test, the alternator failed the "LAMP ON" test, I asked the store workers and they had no further information other then the alternator is bad. I would assume this is why I was seeing the volt drop when the harness is connected

3) While looking over the alternator it seems the pulley sits crooked, it has bent slightly. What effect would this have ? Is this repairable ?

I could pay $240 for a new alt from the autoparts store but, I'm working on a small budget and would prefer to try and repair the alternator myself, does anyone have advice on any of these three issues? thanks

 

Assuming that you need to rebuild your alternator, I've used these folks before.

Pacific Exchange Parts Rebuilders, Inc. - Auto Part Remanufacturing

I seem to recall that the FD alternator is less than $100 to rebuild. See what the shipping will cost you though ... I'm lucky enough to be local.

 

What was the voltage? Tapering down is normal after the car is running.

 

1. I wouldn't worry about it if it is keeping the battery charged.

2. I'm guessing the "LAMP ON" test they're talking about concerns whether or not the alternator will illuminate the Alternator MIL on the dash. Turn the key on (engine off), and if you see the MIL illuminate, then go out when the engine starts running you're fine.

 

I would just rebuild the alternator and have it upgraded to a higher amperage unit. Kill two birds with one stone!

Otherwise you could check the classfieds, they're usually floating around in there.

 

So update, I took the alternator to a specialist. They replaced some internals. Fast forward a couple thousand miles. (2500) my alternator squeals really bad, watching the pfc commander the volts drop to 11.6 - 12.1 during squeal. As soon as the squeals stop, the volts jump back up to 13.6 range.

What are potential causes of the alternator squealing? I have a custom side mount re location of my alternator, my initial thought is that the alternator is binding once I put tension in it.

Any thoughts?

 

bad bearings ... haven't looked in the FD alternator but I would guess one in front and one in the back of the case

 

The front bearing is easy to change yourself. Just take the pulley off and a few bolts out. Don't even need to take the guts out.

 

I have 140 amp upgrades. Let me know

 

I have a spare FD alternator that you can ****** the bearings out for free. Just pm me if anything.

 

How do you know how many amp alt you should get, I've seen some 140 and bigger out there for sale.

 

The fact that the voltage drops during the squeal suggests that something is slipping under load; the belt or pulley. Check those first. A noisy bearing would not cause the voltage to drop.

 

I agree with speed of light. A squeal coupled with a voltage drop indicates belt slippage

 

Stock fd alternator is 90 amps. When you add a bigger fuel pump, gauges, stereo, hid lights, etc it can have a hard time keeping up. I upgrade them to 140 amps. I have seen some as high as 200 amps. The problem with this is its similar to running a larger turbo. To make more amperage the alternator has to spin faster, and will be less efficient at lower rpm. I found 140 amps is the best tradeoff and more than enough for almost any fd.

 

That depends on how much electrical load you've added to the car over stock.

If you're seeing system voltages in the 13.5 to 14.5 range (depending on temperature) then your stock alternator is keeping up just fine.