EFI relay unplugged

[rcb280z]

Anyone that has read my "I think I'm getting somewhere post" and other EFI post's know that I am chasing a fuel pump shut off issue. My question is; is it normal for the fuel pump to run with the EFI relay unplugged? That's both the white and black connectors unplugged. The fuel pump still runs in the "on" position, engine not running. As you can tell I'm drawing at straws right now because I'm running out of things to test using my FSM. I'm always able to find and fix any problem with my cars but this one is baffling. Appreciate any help at this point.

Bob

Edited January 14, 2012 by rcb280z

[SteveJ]

Did a previous owner hack into the wiring?

[rcb280z]

Steve, I am the second owner since 1985 and don't think the PO hacked into anything.

[Zed Head]

The harness has several connections under the carpet next to the right side of the passenger seat, the fuel pump power runs through them. Easy to get to and one possible spot for a "hack" or even a short. According to the wiring diagrams, the only power supply to the fuel pump wire runs through the combined EFI and Fuel Pump relay. All you can do is try to trace it out.

The 76 diagram shows a green wire with blue stripe all the way from the pump to the plug you disconnected, through the C8 and C3 connectors.

[rcb280z]

Zed Head. That is correct! I remember this all to well when I replaced my carpets about 12 yrs ago. I will be checking that next and update this post on my find. I'm going to look through my FSM again to find this info as well. Thanks.

[rcb280z]

Thanks to all that helped me with this. Zed Head you hit it on the head, no pun intended, when you mentioned the harness along the passenger seat. I had forgotten about that harness. I pulled the passenger seat out and pulled up the carpet and started tracing the harness. I wasn't expecting to find a thing. Well, I did! Someone, I sure don't recall doing this, ran a jumper wire from the fuel pump bullet connector behind the passenger seat up to the back side of the fusebox! I fixed that problem, pulled the starter lead and turned the key to "on" position and no fuel pump sound (like I was getting before). Then on to "start" position and the pump came on. YES, it's fixed! Now I still have to trouble shoot why I'm still getting 7.39 ohms resistance at 39 & 36 of the AFM connector. Any ideas there?

[Zed Head]

Groovy. I'm taking a gold star.

The main reason I thought of it is because that's where I jumped in to the fuel pump power line to supply the "brake warning lamp check relay", after I installed a ZX alternator. And I too have found a long jumper wire in my car, running all the way from my ignition switch to the fuse box, to take the place of a rusted out relay. Once I fixed it, my accessory position on the ignition switch started working again.

If you're measuring at the AFM connector, back through the harness, then what you're seeing is probably the resistance of the solenoid in the relay. 6- 7 ohms is about right for a relay solenoid.

One down...

[Arne]

I merged this second thread into the original where it belonged.

[rcb280z]

Okay Arne. Sorry about that.

[SteveJ]

Thanks to all that helped me with this. Zed Head you hit it on the head, no pun intended, when you mentioned the harness along the passenger seat. I had forgotten about that harness. I pulled the passenger seat out and pulled up the carpet and started tracing the harness. I wasn't expecting to find a thing. Well, I did! Someone, I sure don't recall doing this, ran a jumper wire from the fuel pump bullet connector behind the passenger seat up to the back side of the fusebox! I fixed that problem, pulled the starter lead and turned the key to "on" position and no fuel pump sound (like I was getting before). Then on to "start" position and the pump came on. YES, it's fixed! Now I still have to trouble shoot why I'm still getting 7.39 ohms resistance at 39 & 36 of the AFM connector. Any ideas there?

Gee, so someone hacked into the wiring?

[rcb280z]

Yep. I don't know why because everything is working properly now without the hacked in jumper wire. The only reason I realized I had the issue was because of another post here on this site regarding fuel pump operation in the "on" position of the ignition switch. I'm just glad it's fixed. On to fixing my leaky injectors, then leaky front trans seal, then weak struts, then...........and so on, and so on. I'm glad I love the Z car.

[rcb280z]

UPDATE......OK she is running pretty good now. Found out there was a jumper wire to the fuel pump to bypass the EFI relay. Another story for another time. Everything seems to be working correctly except for cold start up. And I mean over night cold start up. After sitting over night It cranks over and starts good but after a minute of idling it starts running rough, coughing and chocking. If I rev it up a little it gets worst as if it is starving for fuel. So maybe a lean condition? She doesn't smell rich during this time so I'm thinking lean. The AAR doesn't seem to be working right away either? If I baby the throttle for a couple of minutes the AAR starts working. It seems like the AAR doesn't get any signal until well after start up. The AAR, Thermotime, WTS, and connectors are all new The confusing part of this is if I start it a few hours later (after sitting for awhile) it starts better and immediately goes to a higher idle like it should after sitting over night. Which means the AAR is working but why does it not work right after sitting over 10 or so hours. I replaced the AAR 2 years ago with a new one from MSA. The 2 things I'm going to check next is vacuum leaks when cold (not there when the engine is warm) and charging system during engine warm up. Maybe battery voltage is dropping to low after sitting over night and spark is weaker? Not noticeable when cranking though. Oh, and go back through the FSM "unstable idle" during warm up test procedures. I'm sure I forgot something here but I figured I would post this to see if you all think I'm heading in the right direction. Thanks