Hi. I have a 99 Accord with the V6. 185k
Engine cranks great. Have decent spark. Will run if you shoot it. No power to fuel pump through any key cycling range. Only one terminal on the connector gets power to the test light which I believe is for the sending unit which appears to be working accurately according to the dash gauge. Test light directly to the pump terminals shows nothing at any thrown position of the key.
The fuel pump relay is new and is clicking. All of the fuses inside and out are good.
This car will run and drive intermittently.
I also noticed at one point that the check engine light wasn't illuminating.
There are about a dozen codes in the computer. A couple for evap. One for each cylinder and random misfire. 1705 for the trans. 1259 for vvt.
Yes it's a mess. Trying to help a friend.
could bad Distributor cause all the misfire codes And cause no power to the fuel pump?

 

With that many errors, could the ECU be shot? a dozen codes is a LOT!
Did all of these errors happen at once? Or has your friend been driving and it's been getting worse.

Still think this is a computer error first with so many errors. EVAP, misfires, VVT, transmission makes no sense for commonality.

 

She said the eng light has been on a long time. And seems to run normally when it does run. I'm wondering what gives the fuel pump power

 

If you think it's a fuel pump, first just put a pressure tester on it, you can rent them from the aurto parts store. Should pretty much zero at this point, but it's easy to test.

There is also relay to check.

 

Well yeah it'd be zero, considering there's No power going to the pump. The main/fuel relay is new and clicking.
Today, after having sat overnight with the battery disconnected, it will start and run but only for a minute. It will keep starting but only run for a minute.

Today the check engine light is working in the dash normally also

 

Well...if it's running ,then the pressure it not necessarily zero. Perhaps you can run power to the pump to see if it stays running. Then at least you know it's electrical and can chase in that direction.

 

The problem is obviously electric. The pump is new and so is the relay. The question is, what signals the pump? Does it get power from the ecm? Does the distributor play? Is it an issue with the immobilizer or key?

 

The main relay is used to operate the fuel pump and supplies power to the fuel injectors (there are actually two mechanical relays inside the one main relay).

The PCM needs to supply the ground to the relay coil to energize the coil; so, that the relay contact closes to allow power to the fuel pump. How the mechanical relay works is (a) when relay coil is energized by power and ground then (b) the relay contacts close (think of it like a draw bridge) to power allowed through to the fuel pump

This is a circuit diagram of the fuel supply system where I added some notes and color coding. Red is positive and green is negative.

 

Where do you recommend I start? I have some mechanical knowledge and a test light lol. Today the symptoms are different (see previous posts). Starts and runs but dies after a minute.

 

I would suggest starting at the ECM.

 

I bet dollars to donuts that the ECM is failed. Or more correctly the electrolytic capacitors are either leaking, dried out, or shorted. These items never last much past 20 some odd years without showing issues around this time, all sorts of issues can occur including delayed fuel pump priming.

One of the most common symptoms of the ECM capacitors failing would be if you go to start the car and the check engine light stays on solid and you get no fuel pump prime...
then here's my proof of the problem, if you turn the key to ACCESSORY position, let it sit there, usually in my situation the car will prime after anywhere between 1 minute or perhaps as many as 6 minutes or so. It's very repeatable but doesn't always happen but as time went on it would always take some minutes to prime if the car's ECU wasn't activated by turning the key on for more than an hour or so.

If you have basic soldering skills you can repair your ecu capacitors for just a few dollars and make the unit perfectly serviceable again.

 

I had something similar occur with my 94. The ecu had began to fail, sometimes it would start, other times it would start erratically after a lot of cranking. Basically the capacitors in the ECU were starting to die. Pull the ECU out of the passenger foot well and open the top cover. (5 screws), if it smells like rotting fish or you see nasty goop around any of the 5 capacitors (Cylindrical towers with a "UF" marking) then they have failed. In this case you need to see if any traces are destroyed on the board, if so, then you're getting a replacement ECU from somewhere. if not as mentioned above that you have some basic soldering skills you can replace them for less than 5 or 10 bucks.