Grants Full Cage Goblin - '06 LT NA Donor

[Ark :D]

Do your lights all work? Turn signals, headlights, brake lights?

When you turn the key to the "on" position, does your fuel pump prime and does it sound like the engine will start if you crank?

If that last question is a yes (pardon me, I didn't take the time to read back in this thread), then make sure you're in neutral, turn the key on, and jump the 12v pin on the starter. That should result in an engine crank.

I had similar problems as you, and my problem ended up being poor contact between one of the fuse box block connectors and the pins inside the fuse box. There was one pin in there that the ECM was grounding at crank, but since the pin wasn't making good (or any?) contact, the crank relay was never receiving ground and thus, no crank. I fixed it by splitting the fuse box and bending many of the pins slightly to force better contact. Unfortunately these connectors were not designed to be separated and reconnected dozens of times.

 

[Ark :D]

I just looked at the first post and now I remember, you don't have any lights hooked up. I asked that question to see if there might be a problem with your BCM.

You should use a meter to find out if your lighting wires get 12v when they are supposed to, to eliminate a BCM problem. I was thinking it may lack power or ground.

 

[GrantSmith6]

Ok, in answer to your question about turning the key to the on position and the fuel pump priming, it does not. I will check for 12v on my lighting and see if I get that 12v signal. I am just so confused because it seems that half the things are working but half are not. Could it even be a faulty relay for my fuel pump? I would guess not but just trying to throw out some ideas. Maybe I'll try pulling fuses 1 by 1 and check for poor contacts like you said you encountered.

 

[Gtstorey]

Trying to determine what is wrong in a partially wired car is next to impossible. To many possibilities on what is not hooked up. You will have to either finish the wiring or start the tracing of wiring to figure out what is missing. If you are able to use wiring diagrams and have a fairly complete idea of how the systems interconnect, you might be able to find the problem. But trying to fix this on a guess off of the internet is going to take a long time. That’s hard enough with a stock vehicle where everything should work. Take a partially connected, modified harness and the number of possibilities go through the roof. I would suggest continuing wiring and the try and track it down. Otherwise you have to start somewhere tracing until you get to the problem. At some point you will get to the point that something isn’t getting a signal or ground or power at the right time.

 

[Robinjo]

As always when it comes to electical, Gtstory is right on with this statement.

This very much sounds like a ground issue but that’s not worth much from me.

 

[Gtstorey]

As a numbers thing, the odds are a ground problem. But that’s just based on my car won’t start problem and it turns out to be a ground problem.

 

[Robinjo]

As a numbers thing, the odds are a ground problem. But that’s just based on my car won’t start problem and it turns out to be a ground problem.

Mine acted the same when I the new ground installed under the fuse box when my rear ground stud broke. Once I cleaned and tightened it properly these
TB functioned but not much else.

OP- do you have the turn signal switch hooked up? I think that is what stopped a start on the Goonzquad videos.

 

[GrantSmith6]

Update and its funny that you say that about the turn signal switch as I tried that and it worked and even ran a little bit!!! Unfortunately I didn't see what you said until now and just happened to figure that out earlier today. Now the only problem is that it seems that my fuel pump isn't working fully as the engine only runs for a second. When I turn the key I can't hear it prime but if I use a jumper than I can get it to pump. Any ideas on whats causing this? I used a multimeter on all 4 pin locations, found the 12v, ground, and then I get a 0.5 volt from one and a 7.5 volt signal from the other pins. Maybe the pin thats showing 0-0.5 volts should also be ground? I'm not sure.

 

[Gtstorey]

You have to give pin numbers or at least wire colors. Specifics matter.

 

[Robinjo]

How many times have you started and it dies at the first starts? 1 or 2 is normal. 5 or 6 is not. Even with priming the pump a few times there is still air in the lines.

 

[GrantSmith6]

I tried to start it in the ballpark of 5-6 times, even with a jumper in place of the fuel pump relay and it just dies. I'm not sure why it wont idle when I bypass the relay but it also seems like the relay isn't working either. I tried replacing it and it didn't help. I was tracing wires and the grounds all check out, my only thoughts are the green wire with white stripe that controls the fuel pump relay might not be working inside the ECM. Maybe some part of the cars security system is preventing it from running? I will make a diagram with all the voltages I'm reading and which ports/wires they are associated with later today. I was also doing some digging and I replaced my alternator but I still get the warning to check the charge system. Could all this be caused by a bad battery? I am reading 12.5-12.8 volts from the battery so it seems good to me but not sure.

 

[Joebob]

I chose not to prime the fuel system by jumping the pump and it took a good 12 times til it would run. The pump will prime for 1 second and not turn on again until it starts. Get a towel, turn the key to run and prime the pump. With the towel over the shraeder valve on the fuel rail, vent the pressure which should be mostly air. Doing that a few times helps purge air from the system. If it starts and runs for 1 second and then dies, that is a good sign all is well wiring wise, just need to purge the air out of the system.

Joe

 

[GrantSmith6]

Ok gotcha but my problem seems to be that it wont even prime for 1 second when I turn the key to the run position. That is what leads me to believe it is some sort of wiring problem. I don't think that the relay is getting the signal voltage to close and run the fuel pump. I ran out of time and couldn't work on the car yesterday so I will try to test those voltages like I said today.

 

[Gtstorey]

Check battery voltage when trying to start the car for a better idea of battery health.
Did your donor have the battery amperage sensor on it and if so do you have it wired in?

If you jump the fuel pump relay incorrectly, you can burn a trace up inside the fuse box. But I think this typically causes a problem with the starter circuit. It’s possible that your trace might burn out in a non-typical location if you did short it jumping the relay.

 

[GrantSmith6]

I don't believe I have the battery current sensor wired in so I will take a look at that when I get home. Could that be responsible for the fuel pump issues? Also what would be the best way to search for burnt traces within the fuse box?

 

[Gtstorey]

No battery sensor could cause the charging sensor warning.

Best way to determine burnt trace is using the wiring diagrams with the connector views to determine if power is where it’s supposed to be.

 

[GrantSmith6]

I wired up the current sensor and was still unable to get the fuel pump to knick on. The car will run if I jump the fuel pump but it runs very rich and I need to feather the throttle to keep it running. I will check more in depth to try and figure out why the fuel pump relay still won't activate but I am really confused on what the problem is. Time to do some more digging.

 

[Gtstorey]

How are you investigating this problem? Do you have the wiring diagrams for your donor?

The battery current sensor was to possibly fix your charging warning. It had nothing to do with the fuel pump.

 

[GrantSmith6]

Yeah I just was hoping maybe it caused some other electrical issues. I've been using ALLData for wiring diagrams with a multimeter and testing for continuity and voltages.

 

[GrantSmith6]

I have made some progress and I think that one of the grounds in the fuse box that is responsible for closing the fuel pump relay is not working. I think that perhaps the connection like you said somewhere internally of the fuse box is bad. I wired in a solution and now the relay can close, however it still struggles to run. It sounds good on startup but seconds later when it attempts to idle it really struggles. I also have been really careful to turn it off when it starts to struggle as I don't want it to backfire (it already has a time or two). Its running really rich so is this problem just common during first startup? I have bleed the fuel lines so I don't think that is what is causing the problem.