99SE only getting 5v on fuel pump

[ktmccrary]

Hi, I am new and don't know how to reference previous posts but found a post by "poppeman" on this forum on 02-28-2009, 10:18 AM, that nearly got me to where I need, but not quite. He ended up having 12v on his pump and therefore determined the pump was bad. I have a momentary 12v at pin 30 on the FP relay with the switch to on. I realize this is normal. But on the other end, the gray wire on the 4 pin connector is seeing 5v the whole time the switch is on. I cut the wire behind the connector that attaches to the trunk to eliminate any problems with the connectors themselves and I get 5v when it is turned on and 5v until it is turned off. Also, on the power panel that holds the FP relay, there is NO WIRE at all that comes off the back of pin 30 of that relay. My Haynes manual shows that there is a gray wire that directly connects pin 30 to the fuel pump, so I am at a loss here. BNaylor seemed to be very knowledgeable on this issue, so if you're out there, PLEASE HELP!

[tblake]

You need to find a wiring diagram specific to your year/model. I'll see what I have and post back.

Otherwise you can swap the fuel pump relay with another relay in the fuse panel that is the same shape/color/size to test for a bad relay.

I swapped my Ac Compressor relay with my horn relay when my compressor stopped enguaging. After the swap, the horn still worked so I knew the realy was not my problem.

[BNaylor]

What ground are you using? The wiring coding for '99 SE/GT is the same as far as fuel pump motor feed and ground. Gray at Pin B of the fuel pump assembly electrical connector is the fuel pump motor feed and black at Pin C is ground. Did you have a meter hooked up between Pins B & C?

On the fuel pump relay when the coil (contacts 85 & 86) energizes contacts 87 to 30 make passing 12 volts out to the fuel pump at Pin 30. The 12 volts to Pin 87 is from the fuel pump fuse (15 amp).

And welcome to AF.

[ktmccrary]

Sorry, but I gave misinformation at the beginning of the post because I was on the wrong freaking wires, but there was still a major problem and I finally figured it out. Actually there were two problems. I bench tested the fuel pump right at the pump itself. I didn't try the external connector on the pump module when I had it on the bench. When I finally determined that I actually did have 12v at the gray wire on the connector I had to go back over a few things. I applied 12v directly to the external connector on the FP module and the freaking thing didn't run. Removed the pump again and check at the pump and it runs, but the outer connector it doesn't. Applied power at the upper end of the connector ont the pump while it was disconnected from the module and it runs. The + connector was loaded with varnish from the gasoline and I cleaned the hell out of it, reconnected it to the top of the modlue, applied power directly to the external of the module again and the pump ran. NOT DONE YET!!
I reconnected everything and NOTHING! GRRRRR! I disconnected the connector mounted in the trunk base and applied power directely to that connector and it ran. Checking the other side of that connector I got 12v at the right place. I cleaned this connector and spread the pins to make them tighter and VOILA! Finally it works with everything connected.

I didn't mean to give misinformation, but I was simply on the wrong wire and chasing ghosts. Still, this ended up being a double problem and hopefully my frustration with it will help someone else that finds themselves in a similar situation.

Thanks for trying to help.

ktmccrary
99GP SE 3100