Hey guys, every GPR I put in my truck seems to be bad for some reason, I've tried 3 now... I don't know what's going on to be honest...I can only start my truck when I jump the 2 lugs for 30 seconds with a screwdriver.... so I gotta have the woman start the truck while I'm under the hood holdin the screwdriver...it sucks! Any ideas what could be goin on?
I put a multimeter on it, the 2 small lugs are reading around 3.5-4 and the lug closest to the turbo is reading 12V give or take, when the key is off, the lug closest to the passenger side battery is reading nothing, when i turn the key, the lug closest to the passenger's side battery is reading 5V....Do I have the damn wires on backwards or is it just another bad relay? This is the THIRD one I've put in which didn't work...


Had a thought that the wires might be backwards... just went outside and changed the wires around, same exact thing...weird stuff, I have a Edge programmer and it doesn't have any codes either...any solution to this would be much appreciated. I have a Stancor relay in there right now, brand spankin new and the lug with the black wire/red stripe is 0 with key off, and only 5V with key on...the black wire with orange stripe is 12 with key on or off, and the 2 small lugs jump around 4.5ish


I'm really at a loss I need an expert!


Thanks in advance,
Larry

 

There should be power (12V) to one of the big lugs all the time, and power to one of the small wires all the time. The PCM grounds the other small wire to activate the relay and then you should have power at both large terminals.

What are these relays you're getting? They're not the wrong (starter) relay are they? Starter relays usually ground through the mounting plate, so if that's what you have, the relay would be on all the time until it burned itself up.

With the right relay in there it doesn't really matter how you wire it so long as you hook up the wight sized wires to the right sized terminals.

Also, as a work around, if you're sure the truck is in park or neutral, take 2 screwdrivers with you, jump the GPR with one and when you're ready to start the truck, use the other one (or just take it off the GPR) and jump the two big terminals on the starter relay on the passenger side fender. Just be careful...

 

Well, it's a Stancor GPR definitely, it doesn't mount perfectly on there but it mounts...(I was told it wouldn't fit perfectly before I bought it) -- I have been jumping the lugs with a screwdriver and having my wife start my truck, I was totally unaware I could start the beast from under the hood! Any chance you have a picture of the terminals for the starter on the passenger fender so I don't screw something up? I never knew about that... Also thanks for the quick reply!

 

This it right here?

 

That's it! Jump across those 2 big lugs and it will crank the engine.

With the Stancor, I sure wouldn't think you would be having trouble with the relay itself. That's a serious piece of gear. I have the same relay in my truck and it hasn't given me a lick of trouble. So what I guess I would measure is the voltage on all 4 terminals with the key on (when the GPR should be running the GP's.). Measure that and report back and we should be able to get you squared away.

Like I said though, one of those small wires should measure 0V to a ground when the PCM is calling for the GPR to be running. That's how the PCM turns the GPR on. Rather than switching on and off the positive leg of the circuit, the PCM switches the negative side. It's safer that way and better for the electronics. If you get voltage on all 4 terminals, something isn't right in the wiring between the GPR and the PCM.

 

black wire with red stripe (closest to passengers side battery) = 0V/Key off; 5V/Key on
black wire with orange stripe = 12V/key on or off
small lugs = 4.5ish - 5V constant, key off or on don't matter with these dudes

Any ideas?

I really hope someone knows how to solve this one...I'm at a loss definitely

 

Oh man I hope this problem didn't stump you :/

 

Sorry, I got busy last night and had to sign off.

The one wire on the GPR should be a Pink wire with an orange stripe, correct?

That wire goes it pin 101 on the PCM. That's the wire the PCM grounds out to activate the system. If you're reading constant voltage on that one, then the PCM isn't getting it to ground for some reason. It could be that the wire is broken, or it could be that the PCM is not taking it to ground because it thinks your EOT (Engine Oil Temperature) is warm enough that it isn't needed. Do you have a way of reading live data from the PCM (AE, Aeroforce Interceptor, Torque, etc)?

You can either unbolt the connector from the PCM and ohm that wire out from there to the GPR or you can come up with a scanner that will tel us what the PCM is seeing for an EOT.

You can also ohm out the EOT sensor to see if it out of spec
K Ohms__Volts____TempF___Temp C
826______4.75______-32______-36
785______4.75______-30______-34
575______4.73______-22______-30
525______4.72______-20______-29
365______4.68______-10______-23
300______4.65______-4_______-20
250______4.63______0________-18
192______4.6_______10_______-12
173______4.55______14_______-10
139______4.49______20_______-7
103______4.4_______30_______-1
98_______4.38______32_______0
64_______4.18______40_______4
59_______4.13______50_______10
43_______3.92______60_______16
37.3_____3.8_______68_______20
33.6_____3.73______70_______21
26.8_____3.53______80_______27
24.3_____3.44______86_______30
21.5_____3.32______90_______32
17.2_____3.08______100______38
16.1_____3.01______104______40
13.9_____2.84______110______43
11.2_____2.59______120______49
10.9_____2.56______122______50
9.34_____2.38______130______54
7.55_____2.11______140______60
6.28_____1.89______150______66
5.34_____1.72______158______70
5.32_____1.71______160______71
4.48_____1.52______170______77
3.84_____1.37______176______80
3.75_____1.35______180______82
3.17_____1.18______190______88
2.8______1.09______194______90
2.68_____1.04______200______93
2.2______0.88______210______99
2.08_____0.86______212______100
1.87_____0.78______220______104
1.56_____0.67______230______110
1.33_____0.59______240______116
1.19_____0.53______248______120
0.38_____0.17______CEL Below This

This won't necessarily tell us what the PCM is seeing, but it will tell us if the sensor is bad.

 

That sounds like your problem. The red/green small-terminal wire should have 12V at all times that the key is in the RUN position. Is your fuel filter heater still connected? Try disconnecting that red/green wire from the relay and turn the key to RUN and check the voltage right at the wire terminal.

Another trick you might try - run a jumper wire directly from the battery + to the terminal on the relay that takes the red/green wire. Then turn the key to RUN and listen for the relay to close. If it does, then you know the relay is good, and the PCM is properly completing the coil circuit. Leave it that way for 10-15 seconds and see if that helps with engine starting. If that all checks out, then there's something funky about the voltage supply to that red/green wire.

 

Yeah, good catch. I didn't catch the voltage there. That should be 12V not 5.