Fuel Pump Relay & Kill Switch?

bonomax

Member
Dec 27, 2011
223
1
18
Hermitage, PA
no duramax has fuel pump or fuel pump relay. they only have injection pump aka CP3 pump. its locating in the valley of the motor up front. post picture of what 4 wires you are referring too. Im betting its the glow plug relays.
 

magnethead494

go fast crew chief
Dec 29, 2013
222
0
0
35
Fort Worth, Republic of Texas
no duramax has fuel pump or fuel pump relay. they only have injection pump aka CP3 pump. its locating in the valley of the motor up front. post picture of what 4 wires you are referring too. Im betting its the glow plug relays.
in the under hood relay box, there's a relay called FPMP right below IGN1. We're wondering if it goes to something, or if there's no reason for it to even be populated with a relay.

I'm just looking for 4 different wires to put kill switches on. Race rigs are stolen about once a week here in DFW. A friend had his LMM dually stolen from his apt complex, surveillance showed they didn't even pop the hood, just crawled underneath, broke the door handle off (same way our dodge got broke into), got in and left.

I'm thinking interrupt ignition power, fuel injector power, and ideally 2 more power lines- tail lights maybe (make more obvious to police/others)? Where else can be cut off? If there a place in the fuel line that a ball valve can be installed so that the CP3 can't draw fuel?
 
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duratothemax

<--- slippery roads
Aug 28, 2006
7,139
10
0
Wyoming
A friend had his LMM dually stolen from his apt complex, surveillance showed they didn't even pop the hood, just crawled underneath, broke the door handle off (same way our dodge got broke into), got in and left.

Did he leave the keys in it? 2007.5-2013 GMT-900 trucks with PASSKey III (transponder in the key) are not easy to steal/hotwire without the correct transponder key...

2014/2015+ K2XX trucks/SUV's are incredibly hard to steal. Im not going to say impossible, but they have steering wheel locks (finally), the door handles are reinforced, and the doors themselves have metal plates in them and shielded lock push-rods to prevent punching out the lock cylinder or using a slim-jim. Even then if you were to break a window, the immobilizer system is very complex. Environment identifiers such as VIN coding, how long since the modules' last had power cut to them (ie, if the battery cable was cut or disconnected), and other information is stored in MANY different modules throughout the truck. The onstar module is really hard to get to, and has an internal battery backup.

GM doesnt even say which modules store environment identifiers and they dont even fully explain the details of the immobilizer system in the service manual, to make it harder for thieves to reverse-engineer the system. So basically, ECM/TCM/radio/instrument cluster, BCM (and more) modules all have to have matching VIN's, and have to have been powered up and plugged in for at least X minutes/hours before the ECM will pass anti-theft and allow the truck to start.

Not only that, even if you swap ECM's for one that has been tuned to delete VATS, the BCM will see that the ECM VATS is disabled (or rather, it will see that the ECM isnt doing the password challenge/response with the BCM) and then not send the "crank request" data message when the key is turned to "start". And if you replace/swap the BCM and ECM at the same time, you have to throw away all the keys and order new keys (they are side-cut like european cars) from GM....
 

duratothemax

<--- slippery roads
Aug 28, 2006
7,139
10
0
Wyoming
And the fuel pump relay is there for cab/chassis trucks. The duramax cab/chassis trucks have two fuel tanks, and an electric pump to transfer fuel between the two.
 

magnethead494

go fast crew chief
Dec 29, 2013
222
0
0
35
Fort Worth, Republic of Texas
Did he leave the keys in it? 2007.5-2013 GMT-900 trucks with PASSKey III (transponder in the key) are not easy to steal/hotwire without the correct transponder key...

2014/2015+ K2XX trucks/SUV's are incredibly hard to steal. Im not going to say impossible, but they have steering wheel locks (finally), the door handles are reinforced, and the doors themselves have metal plates in them and shielded lock push-rods to prevent punching out the lock cylinder or using a slim-jim. Even then if you were to break a window, the immobilizer system is very complex. Environment identifiers such as VIN coding, how long since the modules' last had power cut to them (ie, if the battery cable was cut or disconnected), and other information is stored in MANY different modules throughout the truck. The onstar module is really hard to get to, and has an internal battery backup.

GM doesnt even say which modules store environment identifiers and they dont even fully explain the details of the immobilizer system in the service manual, to make it harder for thieves to reverse-engineer the system. So basically, ECM/TCM/radio/instrument cluster, BCM (and more) modules all have to have matching VIN's, and have to have been powered up and plugged in for at least X minutes/hours before the ECM will pass anti-theft and allow the truck to start.

Not only that, even if you swap ECM's for one that has been tuned to delete VATS, the BCM will see that the ECM VATS is disabled (or rather, it will see that the ECM isnt doing the password challenge/response with the BCM) and then not send the "crank request" data message when the key is turned to "start". And if you replace/swap the BCM and ECM at the same time, you have to throw away all the keys and order new keys (they are side-cut like european cars) from GM....
He's not even sure how they did it. On star isn't even willing to help, either. They never popped the hood and weren't there but 15 minutes he said.

So the relay might as well be removed?
 

duratothemax

<--- slippery roads
Aug 28, 2006
7,139
10
0
Wyoming
Just donned on me that he had a turbo timer on the truck. I bet they watched it idle after he got out……

Yep....probably exactly what happened unfortunately. Its easy to break the brake/shifter interlock on these trucks. So they probably hopped in while it was still running, yanked the shifter out of park, and drove away normally (since there is no steering column lock on these trucks). :(
 

magnethead494

go fast crew chief
Dec 29, 2013
222
0
0
35
Fort Worth, Republic of Texas
Yep....probably exactly what happened unfortunately. Its easy to break the brake/shifter interlock on these trucks. So they probably hopped in while it was still running, yanked the shifter out of park, and drove away normally (since there is no steering column lock on these trucks). :(
tell me about it. I don't need the key or brake pedal to take my dakota out of park and be able to steer it- no whell lock and no shifter lock. Only reason it doesn't get stolen is that it looks like a beater and I have the MSD grounded out so it wont fire.

So back to kill switches. Where are some good points to find wires to interrupt?
 

bonomax

Member
Dec 27, 2011
223
1
18
Hermitage, PA
And the fuel pump relay is there for cab/chassis trucks. The duramax cab/chassis trucks have two fuel tanks, and an electric pump to transfer fuel between the two.

forgot about the duramax trucks with two tanks must have fuel pumps but none of single tank duramax have fuel pumps, right?
 

NC-smokinlmm

<<<Future tuna killer
May 29, 2011
5,187
354
83
At Da Beach
tell me about it. I don't need the key or brake pedal to take my dakota out of park and be able to steer it- no whell lock and no shifter lock. Only reason it doesn't get stolen is that it looks like a beater and I have the MSD grounded out so it wont fire.

So back to kill switches. Where are some good points to find wires to interrupt?

You could put a disconnect in front of the mega fuse, that would effectively kill the truck...
 

NC-smokinlmm

<<<Future tuna killer
May 29, 2011
5,187
354
83
At Da Beach
would also require resetting the radio. Would prefer a more discrete and easier option. Preferably multiple sources so it's kinda like an easter egg hunt- if they find 1, they still have to find a couple more.

Just pull the ECM or TCM if your that worried about it...