From the video I agree with Fred, that it seems fine when the voltage is around 14, and stumbles when the voltage dips, and that's when the squeal occurs. Almost sounds like the belt slipping, which may be causing a reduced alternator output. Maybe the tensioner is responsible.

 

You're hearing everything backwards. The screech is the alternator belt. The constant whine that goes away at 14v is the pump. The pump dies, causes the car to stumble and nearly die, which causes the voltage to drop, and the pump to kick back on, which makes the car pick back up and the belt sqeal

 

you need to rewire pump with ignition power and a relay sounds like yours is wired from alternator

 

No sir, wired from the pcm

 

Do you really mean the fuel pump gets 12V from the PCM? I don't think so, but that's what you appear to have written.

You indicate you have a relay because you say you measured the voltage between the PCM and the relay. The PCM driver is intended to supply a low amp 12V signal to the signal coil of the relay. 12V high amp power to the load side of the relay in the factory setup gets 12V from an ignition switched 15A fuse that also supplies the PCM and the theft deterrent module.

 

The pump is not shutting off. It's just changing pitch because of the sagging voltage. You have another problem causing that.

 

So if the pump isn't shutting off, why does the car die when the pump noise goes away? If the pump isn't whining, the car will not run. If you are trying to drive it will kill it nearly every time. Pump goes away, car dies. But yeah Injuneer, you are probably correct. I hadn't actually thought about that being a trigger wire from the pcm, not a feed. I'll have to go back over everything Saturday when I get the chance

 

The PCM can definitely not be the power feed to the fuel pump. You must use a relay. The pump is a high current draw device. The PCM and wiring is not meant to handle that load and could potentially cause harm to both.

 

There you have it. The alternator diode(s) are probably shorting out, which draws a huge amount of current through the armature and puts a huge load on the belt. I doubt that the pcm relay output could short out and cause that big a load. Or could be a shorting battery.

 

Ok, I now realize that I was informing you guys in the first place. Pump is, however, wired correctly. I think. I know the factory fuel pump relay engages it. And the belt slip is because this car has an alternator only bracket with no tensioner. Belt is loose enough I can spin the idler with my finger, with nearly no effort. Going to pull it off and machine a slot where the current hole is, and then drill and tap for an adjusting bolt so that I can keep good tension. Not sure I could believe that this is the root of the problem, but I suppose it is as likely as anything. Had the battery checked yesterday, it's good. :/ waiting sucks

 

Ok. I've had time to go through and look everything over again. It is just as I said it was the first time. The wire running the pump goes DIRECTLY to the fuel pump relay under the dash. Nowhere else. There is no direct battery power to it. I tried to upload a picture, but I don't have enough service. The FPR is two inches from the pcm. All wires going into it come direct from the pcm, and then the pump power wire comes straight out of the FPR, and back to the pump.

 

Btw, since I last posted, I've machined the alternator bracket so I can tighten the belt, put a new alternator on it (old one tested bad), tested and charged the battery, new coil, new icm. Nothing.

 

Wire it correctly, with a 12V source to the load side of the relay and the PCM pump permit signal to the control side of the relay. See this diagram:

http://shbox.com/1/1995_pcm3.jpg


You mention "All wires going into it come direct from the pcm" - is there more than one wire running from the PCM to the relay?

It's hard to understand what function the relay even serves or how they connected it, if the only line going into it is the one from the PCM, and the only wire coming out of it is the line to the pump. Basically, it would just be a junction block.

 

Yeah, there are 5 wires going into it including the pump powe wire. This relay is only supposed to be the trigger for the pump power relay. I have now rewired it as such. There is a dedicated relay on the firewall now, with power direct from battery, a dedicated ground, and I split the original power wire, running it from the pcm relay to pin 86 as a trigger, then from 87 out to the pump. Low and behold....no change. Idk. I'm yanking the tank Wednesday night, cleaning it, and replacing all the old rubber hose. If that doesn't work...idk

 

I really can't follow your description. Doing the math, if the relay had five wires going to it, 1 feeding the pump, and all the wires (the other 4) came from the PCM, WTF were they connected to on the PCM.

On the other hand, maybe someone smarter than I am can follow what you are saying. It's obvious I can't help you.