I have been helping my buddie today with his 91 3rd gen we swapped a 94 lt1 in. Well heres the problem When we turn the key to crank it the starter isnt getting any voltage from the ign. We used a colt meter on it and it was getting between 1 and 2 volts. We used my data cable and tuner cats to dissable vatts in the lt1 pcm and still it wouldnt send the voltage to the starter solenoide.
Is there anywires on his vats module that i should ground or is there a reason ign switch isnt sending the power to the starter solenoide? Im completely lost on this one. Thanks for any help in advance guys.

 

You probably need to bypass the Theft Deterrent Relay (TDR). It's wired between the ign switch and the starter. You can find some schematics on my website for the 4th gen to get an idea.

 

Thanks rob i found it in the 91 schematics i have. Ill go try it out and see what happens and come back with an update

 

Just a suggestion.... when you want help from a specific person or persons, please use a PM or e-mail. Its comes across as disrespectful of the other knowledgable people here on the board, when they could help you just as well. In fact, I haven't the slightest idea what the problem could be. Many others have more knowledge in this area.

 

sorry to dig up an older thread and one that is directed at only two people to begin with, but i need to locate my TDR...and im absolutely TERRIBLE when it comes to wiring schematics...can someone please tell me where to look??? i dont even know where to start

 

It's to the right of the glove box, pinned to the lower metal of the dash. You just about have to stand on your head and look toward the rear to see it. The hatch release relay is next to it and looks similar.

 

thanks i just pulled both now i have no idea which is which lol...one has three thick wires...purple black, and yellow and one thin wire....the other relay has 4 thin wires...which goes to TDR???? i also tested both with a tool i have...its like a screwdriver shape on one end that u touch to the object ur testing, and the other end is a clamp that u connect to a solid ground...the screwdriver end will light up if the object ur testing is receiving power and functioning properly...when i tested the relay with the 4 skinny wires...it lit up, however when i tested the relay with the 3 thick wires and 1 thin wire (one of which is a thick purple one that i believe connects to the starter), there was no light...what does that mean...that the TDR is bad, or that a connection leading up to it has gone bad??? (its a new bcm...)

 

Use this schematic from my website. The one with the thicker wires is the TDR as it carries more juice to the starter. The relay has to be operated before the purple wire will have power. The BCM sends a ground to the relay to do this (only when the key is in START).

 

i had the key in the START position with all lights on dash on...and then i tested for power to the relay and it doesnt seem to be getting any, however, i have a spare blank key (one with no resistor) because i was going to bypass VATS before, and when i use the spare blank key, the security light flashes, so that means the BCM is still good right?? and ive taken a look at that schematic several times but barely know how to figure one out...if im right...the ignition switch is wired before the TDR with the yellow wire connecting the two and would have to be working to give power to the TDR....i found a picture of the ignition switch on your website but have no idea how to get to it...

 

ttt

 

One of the yellows from the ignition switch goes to the TDR and the other to the clutch switch or transmission range switch. The BCM sends a ground to the TDR to allow it to operate when the switch is turned to START. The brown wire coming from the clutch switch or transmission range switch must also have 12v for the relay to operate.

There is a whole guide on my site about ignition switch replacement, so you should be able to find out where it is (if you need to).

 

i used ur guide, amazing i might add, and replaced the ignition switch with a brand new one...still i have no start...this problem is gettin ridiculous i dont even know where to look now...
i have no power gettin the the pigtail for the TDR, yet i have a brand new ignition switch, brand new ICM, and brand new starter....where do i look now??? im so frustrated and confused at this point...

 

Use the schematic and check the continuity of the wires.

 

Im kinda in the same boat as you. Did you have the dash out recently? Or did this just happen suddenly?
Right now I have to Bypass my relay to get it started.

 

im not gettin any power to the relay..kinda confusing bc when i turn the key i have power to the dash and bcm, but no power is getting to clutch switch, TDR, or starter so now im lost bc i have a new ignition switch, ICM, starter, and fairly new BCM...no idea wut to look for now...gonna let my friend's dad take a look at it...hes a certified master tech...ill let ya know wut we find out...