I asked this once before but never got a reply from the list, or if there was a reply I missed it. So... the car stopped running in the driveway, fortunately not on the Interstate or downtown etc. It had misbehaved a time or two prior but only briefly, then self-corrected after a few seconds. This time it was for real. I'd already gone around and around with fuel pumps seeing as how this one was new, having already been replaced earlier. Twice. This one is an AC/Delco and not chineseium. Fuel pressure almost nonexistent. Finally got to nicking the harness at the pump/sending unit and measuring the voltage. Required creative voltmeter positioning while I cycled the ignition. I got 5 volts tops, although it varies every time the switch is cycled. Sometimes I got less than 1 volt. I dug through the manuals and noted this interface wire harness that connects to the harness section coming out of the fuse panel, and leads back to (supposedly) the rer of the car where it evidently plugs into the section of the harness that plugs into the sending unit/pump power. 12 volts at the FP fuse, dependably. I got the car from around front into my behind the house shop by soldering a long wire to the downhill side of the FP fuse and draping it across the car to the tank sending unit which then connects to the power feed wire to the pump, bypassing the wire harness. Car starts right up. I've NOT been able to find any details about this pair of connectors in the harness that leads to the fuel pump, as in where the Hell they might be. I don't have a lift so a detailed search isn't gonna be that easy and I sure as hell won't try to drive it to somewhere with a lift I could use. Does ANYBODY know where to look for these two connectors in that harness so I can either bypass the corroded part or maybe just clean whichever one is bad?? Or does this piece of harness go through the body proper and is likely next to impossible to troubleshoot, kinda like one of the harness sections in an F-16 that has the airframe built around it? I have no intention of buying one of those Rube-Goldberg style bypass harness kits, cuz I'm cheap and cuz it offends my sensibilities. Did I mention cheap?

So, anybody know where to look for these connectors?

 

Knowing the year of the car would be helpful. Have you checked that the fuel pump relay is good?

 

My bad, assumed that posting in a C4 discussion group would get me where I need to be. The car is a 1984 xfire, fairly low miles, and the FP relay seems OK since running a wire from the fuel pump fuse to the fuel pump makes the car start. Recall my saying that the FP fuse always has the voltage it's supposed to have yet the pump would not see more than a few volts if anything at all. Thus, it's a wire harness issue, likely one of those two connectors between the fuse and the pump. And nobody seems to know where the two connectors are or how to find them.

 

I had fuel pump wiring problems in my 86. Easy enough to follow, just pull out the passenger seat and lift the carpet. It's inside under the carpet all the way to the back.

 

I thought so too, but it turns out there are differences in these cars from year to year, sometimes significant! Did you make any progress since your last post?

 

-to RWDsmoke -- THANK YOU sir. Now I have a clue as to where to actually start looking before heading underneath while perching the car on jackstands trying to fathom the wiring. Wish I had a lift... :-) Interesting that evidently there are enough Corvettes (C4s among others) that have this issue that some outfit is making/marketing a harness bypass kit for them. Not terribly cheap. Rather fix what's in the car first. Thanks again.

 

Thanks to RWDsmoke I had a clue where to start looking. I did manage to find out that the FP motor feed wire goes from underneath the dash all the way to the pump where there's the one connector that is fine (new fuel pump). The factory wiring harness diagram tends to be a bit misleading. It appeared in some prints to show what looks like an interface cable harness that looked like it would be between the fuse box and the pump, thus I was looking for another connector somewhere in the body proper. Nope. It's just one single cable from the fuel pump connector all the way up to where it disappears under the dash, confirmed after I pulled out seat/carpet/brackets etc along with a batch of screws just to insure I missed nuthin'. So: All that's left is a 15 pin connector identified as an I.P. Harness Connector, aka C209. It's better at hiding out that Bigfoot. Since it's been raining on and off for the last couple of days here I'll be taking a break until I can get under the dash to fish out C209 and either bypass the offending pin connections or repair them. It sticks in my mind how GM's design engineers put the C4 together for ease of manufacturing and not for servicing... and they all musta been short guys; I'm wearing a notch in the side of my head from the left side of the roof trying to fall into this thing. I'm not a small (over 6 ft) guy so I'll be pulling the targa roof off and get stabbed in the back by the seat mount studs while cussing GM for the nonsense they perpetrated on these cars, with the words of Ian Malcolm ringing clear... "They were so preoccupied with whether or not they could they never stopped to think if they should." Yeah, they could have done it better.