Once the entire LS1 conversion harness was connected to the car, plugged into the ECU and all accessories and everything
were bolted onto the car and everything was ready to go, it was time to connect the Battery.

As soon as the battery was connected, the fuel pump started running on it's own. This was without the key being in the
ignition even.

After doing some troubleshooting and looking around I've been able to determine the following things:

-Unplugging the 3-pin connector from the gas tank to the body connector, their is 12V on the fuel pump power wire coming
out of the body connector at all times with or without the ignition turned on
-When you turn the key to the on position, the fuel pump power wire intermitangly cuts power for approximately 2 seconds
then the 12V returns
-Checking the fuel pump relay under the hood shows some really odd results:

**BEFORE SUGGESTING TO TRY ANOTHER RELAY, I HAVE. I'VE TRIED 3x SEPARATE RELAYS WITH THE EXACT SAME RESULTS!**

With Relay Pluged in:
---------------------
1) Terminal 'C' on the relay ALWAYS has 12V. This is an orange wire and appears to be the constant power wire for the relay
2) Terminal 'D' shows 12V for 2 seconds when you turn the ignition into the 'ON' position and then shuts off (goes to 0V).
This wire is green and appears tobe the fuel pump prime/power wire on the relay side
3) Terminal 'E' constantly shows 12V with the relay plugged in no matter what

With Relay Unplugged:
---------------------
1) Fuel pump does not run or turn on no matter what you do
2) Terminal 'C' on the harness side shows 12V no matter what
2) Terminal 'D' on the harness side only shows 12V when the key is in the ON position and shows nothing when the key is OFF
3) Terminal 'E' on the harness side shows nothing at all when the relay is unplugged. Always 0V.


This problem is mind boggling and I don't know where to start looking. In case you forgot here are some specifics about my car
which might be usefull in helping diagnose and fix the issue.


-1989 Camaro Iroc-Z
-Built 6.0L LQ4 w/ a lot of mods which is unimportant or relevant to the situation
-1987 Camaro Iroc-Z TPI Interior Harness was used from the 3rd gen side of things, utilyzing the stock 3rd gen style relays, etc
-1999+ LS1 F-Body engine harness was used and fitted with all the T56 wiring
-Rear 02's, AIR, EGR, EVAP, Skip Shift were all deleted from the harness
-Stock 2000 LS1 6-speed F-Body ECU was used
-Steering column is from my old 1985 Camaro Z28 w/ LG4 305
-harness made by pocket
-Harness was retrofitted with the '3-wire' "1998" LS1 F-Body temperature sensor

I'm at a loss here and can't figure out where to start here. If I step on the clutch I can crank the engine over with no problem
but no matter what the fuel pump runs constantly.

I want to make this CLEAR. Im in no way slaming pocket or putting down his work at all as its top notch stuff. I mention it as I dont want people to think this is a home made harness and every piece of info helps to solving the problem. Im just trying to get to the bottom of this is all and get my car running and any help from anyone im willing to use to slove the problem.

 

i think i would start out by swapping the pins on the relay side that go to D and E. it sounds like they normally closed and normally open positions are reversed. if those pine are at the pump then i am not certain what pins would swap on the relay, but i would still be looking at the normally closed and normally open pins at the relay being reversed.

normally the pump would be off with the battery connected, then when you turn the key it would kick on to prime the injectors with pressure (a couple seconds) then wait for signal that the engine is cranking or running to supply constant pressure.

it sounds like your pump is doing the opposite, which leads me to the output pins on your relay plug being reversed.

 

Can anyone chime in on this??

6SIX6 is a good friend of mine and I took a look at the car and harness and I can't figure it out either...

Pocket? Anyone?

 

If your running your stock third gen to control fuel pump and injectors then what could have changed to cause the pump to become hotwired? Seems odd to me.

It almost sounds like your PCM is not hooked up to the relay at all and its getting excited from elsewhere. Its the PCM is what triggers the fuel pump on/off when the key switches ign on. I would start with the wire ( PIN 9 on the red iirc ) and make sure thats whats run to the fuel pump relay. Then make sure the power source for the relay is connected to 12V+ ign and NOT 12v+ BAT. Somewhere theres a wire hooked up where it shouldnt be

 

The thing is though, when you turn the key to the 'ON' position the relay DOES click on for 2 seconds, then shut off.

Im not sure what you mean by running the stock third gen to control fuel pump and injectors though? The harness was made by Pocket. It is supposed to be a complete Plug & Play LS1 3rd gen conversion harness that utilizes a stock TPI 3rd gen harness and a stock LS1 4th gen harness. Put together its supposed to just connect to everything and work as stock.

The ECU is connected properly and it does function. When I connected it to HP Tuners VIA obd2 connector, HP tuners was able to see TPS, o2, IAT, Injectors, etc and i confirmed it was working by stepping on the gas, it definitely sees WOT.

But turning the key on or off doesnt stop the fuel pump from running. No matter what you do, the fuel pump runs. And as mentioned earlier, with the fuel pump relay plugged in, theres always 12V on 2 different terminals.

 

What I mean is aside from changing the fuel pump wire at the tank and the PCM Fuel pump relay control ( pin 9 red conn ) the rest of the fuel sys wiring on the car should be as per stock third gen. So I cant see how simply switching the trigger wire has now caused the fuel pump to get 12v+BAT instead of 12v+ign instead

 

Have you tested to make sure the pins in the connector to fuel pump relay are not shorted to each other? The 3rd gen connector at fuel pump relay is a known pile of junk and prone to shorting. Sometimes with fireworks.

I have no clue if this is a valid idea. Just brainstorming with you.

 

First to confirm, I am assuming when you remove the fuel pump relay, the fuel pump itself stops?

If it does NOT stop: The TPI fuel pump had a fuel pump bypass circuit in its oil pressure sensor, which when oil pressure was sensed provided 12VDC to the fuel pump, regardless of the fuel pump relay state. I am assuming you removed the TPI oil pressure sensor in your swap, but confirm this for us. If it was removed and these wires were tied/shorted together, your fuel pump would run continuous when the battery was connected even when the relay was removed.

 

When I remove the relay it does stop. I will try all of these ideas for sure on the weekend. If anyone else has an opinion please chime in as the more I can use the better as I need my car running ASAP.

 

6, just throwing this out there, but could the issue be with the racetronix hotwire kit? i remember you posting a thread about it. having a 4 gen hotwire kit, could that be the culprit?

 

It has nothing to do with the racetronix kit. If you read the original post, their is power on the fuel pump feed power wire on the 3-pin body connector with the plug from the fuel pump/tank unplugged. Thus by-passing the tank and all tank wiring.

We both thought the same thing so we tested it without the racetronix kit even connected. When we unplugged the 3-pin body connector there is still power coming to the actual body connector, so the problem lies between the body connector and the fuel system wiring and/or relay, ECU, etc.

 

Oh! I remember this guy now. https://www.thirdgen.org/forums/ltx-...-question.html

 

With the relay installed under the above condition, does the fuel pump stop for the 2 seconds then start again?

If it does, I highly suspect the fuel pump relay has been wired to the N/C contact instead of the N/O contact. Post up your fuel pump relay wires and colors.

 

Thats what happens, I will get a pic of it when i get a chance to go see the car as ive been pretty sick lately

 

Yeah thats me but the hotwire kit isnt even connected at all at the moment and its acting up. I completely unplugged the tank wiring on the hump on the outer side of the car. I am testing it from there and its got to do with the relay wiring for sure. Something is just not right at allbut since Ive been sick the last week i havnt been able to work on it at all.

 

I put a few minutes into this hoping to help out. According to the schematic in my old Chilton's manual, the 3rd gen fuel pump relay has:

Orange (terminal E): 12V constant. B+ side of relay contact for normal operation.
Red (terminal D): Fuel pump prime. Interconnected to the oil pressure switch. You may or may not be using this any more depending on if you kept the 3rd gen oil pressure sender.
Tan/White (terminal A): Switched side of relay contact. Power that goes to fuel pump. This can be powered by Orange or Red, depending on the state of relay and the oil pressure switch.
Green/White (terminal C): B+ for relay field control. Comes from engine PCM and controls state of relay.
Black/White (terminal B): Ground for field control. Grounded to chassis.

You said Terminal C is always 12V. That's your problem. It should go to the LS1 PCM terminal 'Red 9' and should not have voltage with key switch off. You might have another problem but get that one sorted out first.

Also, the Racetonix kit has another fuel pump relay. It's just not a good idea to use one relay to drive another relay. I would have scrapped the stock 3rd gen relay, but that's up to you I guess.

 

My personal guess is that the relay wiring is correct, but the LS1 PCM switched power sources are wired straight to battery in the fuse/relay panel. This would cause the PCM to always think the key switch is ON.... and fuel pump to run.

 

Can you post a picture of the relay and a pic of the relay connector?

It dose sound like the relay is wired incorrect. you say it turns off for 2 seconds when key it turned on this is opposite what it should be doing. Like others have said maybe your relay is wired up normally closed instead of normally open.

 

I will post up pics for everyone to see.

Pocket got back to me and told me a solution so I will try his out first as he made the harness. If it doesnt I will try everyone elses for sure

 

so did you get this issue sorted out?

 

No I havnt been able to work on the car in the last week or so as its been -20C at night. So working in the garage is out but I hope to work on it tomorrow night as its gonna be warmer and I got a new heater for the garage. I will let everyone know if I sort it out

 

You make me feel like a weenie for not wanting to be in the garage when it is 0C.

 

LOL thats alright man. I work outside for a living so I really dont feel like messing with the car when I spent 8hours already out there. I might be nuts tho for working on it in those conditions but ive been without it for 4 years now and i want it back

 

Finally had a day I could work on it and as it was +6 yesterday it made it bareable. Anyways A friend (z28metalhead) and I got it running last night. Its a very healthy and sounds mean. We just redid the relay wiring and got it goin

 

Congrats man. I'm glad to hear you got it worked out and running.

 

Betcha that felt good. Thumbs up dude

 

Glad to hear you got it sorted out!

hope you get to enjoy it soon!

 

If i had a utube account and a video editing program I would have posted the video. It was taken on a friends iphone and photobucket doesnt like quicktime at all

I will be enjoying it and Cam im almost there for a trip to cayuga now LOL

 

good job getting it going!

 

Heres a video of it running

http://www.youtube.com/watch?v=2Ewi7...42AUAAAAAAAAAA

 

Congrats Ray, I been quietly following your build, and I know you went through a few cars and motors, to get to this point, so to see you at this point is well deserved man, congrats!!

 

WOW Man long time now hear from. yeah its been too long and now its time to enjoy finally