Ive been looking this up but not seeing a direct answer anywere, so figured Id ask it. Ok so i know i need the 15 individual resistors to find the correct on for my car, i found the list of different ones, but is that list the ones that gm uses for its cars or the list of different sizes of resistors to try, for example the first is like 402, so is that the size of resistor, or is that the size that gm used? and whats the variation on that, if i found one that was 500 would that work? I dont know if this is coming out clearly enough or not, but basically im saying whats the closest size resistor i can use to match up for that 402 resistor gm used, or am I wrong in this and 402 is the size of resistor i buy and thats closest to what gm used? I know my car is probably not the 402 listed in the list just using that as an example. please help guys, I plan to work on the car very soon and need to make sure I'm doing this correctly because i got other stuff to do to the car and want to get this done first then i can drive it and get everything else done to it. Slo does anyone know a place online I can buy individual resistors? only day off from work I have is sundays, and radioshack here is closed that day, it would be easier to find some online, but all I can seem to fid is pack of different resistors.

 

The resistance has to be pretty close to right on or the car won't start. If you get pocket lint on your key the car won't start. You can "build" a resistor pack by adding more then one resistor to reach the proper resistence, but if you can find an aftermarket company that offers the 15 individual resistors with the proper values it can save a lot of time and effort. Look at companies that offer remote starts and such and you can usually find a company offering a set of VATS resistors.

 

Easiest way would be to get a variable pot and temp wire that in
Turn until engine starts then read the resistance value with a DVM and compare to closest VAT resistance in chart in link below

Note there quiet a spread between accepted min and max values for each resistance; you don't have to be spot on

https://www.thirdgen.org/vats_passkey_system

 

Are you trying to bypass your vats system? Did you lose your original key, or did the ign cylinder just take a crap? if you have the original key, use a multimeter to measure the resistance of the pellet in the key and wire in a resistor of the same value in line with the wires going to the cylinder. I'm a GM technician and I have a 500 pack of resistors in my toolbox I got from radio shack for doing just this. cost somewhere from 5-10 bucks and has many different resistor values in it. I find the right one I need every time.

 

pretty much trying to bypass. I bought the car from a kid who bought it form a guy, who replaced the steering colum. the kid said everything was fine for a while but then it stopped wanting to start, (and the security light comes on when turning the key all the way)so he bypassed by running some wires under the hood and it starts from those wires from under the hood, but takes about 30 seconds to start like its not getting fuel for a while, then it starts, and runs fine then starts right back up if the engines warm, but cold takes forever to start, I read part of a post on vats, and someone said they bypassed for a remote start button under the hood an it took awhile to start cold, soi Im thinking thats the same thing I got going on also, Also on a side note here, I checked the colum and there are 2 resistors wired togehter in place of the vats connection, so I'm thinkin the resistors took a crap, or maybe he used the wrong ones. Hoping anyways, I'd love to be able to start the car with the key. I have gotten some good posts on a previous post I made on this, just have more info now to hopefully someone can help out a bit more on it.

 

You hit in on the head.
If you had a VATS problem it would not fire at all ,even with the starter relay bypassed because VATS takes out the injectors as well.
Start looking elsewhere ;you have a cold start fuel delivery problem.
Does the fuel pump prime for 2 sec when key turned on?
does the fuel rail remain pressurized?
Does this sound familar?
https://www.thirdgen.org/forums/tech...es-up-but.html

 

then why wont it crank over with the key then, and the security light lights up?

and once it fires up with the wires that are bypassed to under the hood, the car runs great and has no fuel problems at all. I had been thinking its a vats problem but maybe a bad fuel relay or something.

 

Because you have two seperate problems
One to do with cold start fueling and one to do with the starter operation
If the car has VATS and will start by directly hot wiring the starter under the hood as you do it is not a VATS problem.
VATS takes out fuel injectors and starter

 

ok, so I think the fuel prob may be a bad fuel pump realy, according to others that have had that problem, the fuel pump dont prime up when the key is turned on, dont even hear it at all, so I already thought of that as a possible problem. So lets assume thats the fuel problem, and move on to the starting problem then, any ideas, do you think it could be the ingition switch? not the key switch but the actual switch bolted onto the steering colum under the dash. I really kind of need some ideas on this, I will probably buy a new fuel pump relay tomarrow to see if thats that problem or not, theyre cheap anyways. but i do need to figure out the staring problem, so as mentioned there is resistors already in the vats sytem, so about all i can think of would be the ing. switch, all fuses are prefectly fine, but i dont know if theres some fusible links in the start sytem under the hood or something to check, does you know weres a good starting point to check out?

 

We are assuming here that the wires you play with under the hood are putting power direct to the starter solenoid bypassing the starter circuit from ign switch completely?
Ideal way would be to follow the starter circuit through with a volt meter.
See if you have
12V on the starter wire at ign switch when in start position ,
12V both sides of start enable relay ,
12V both sides starter inhibitor switch
Can jump purple and green wires together at enable relay to bypass it .
Like wise can jump wires on starter inhibitor switch to bypass ( make sure out of gear 1st )
Typical GM starter circuit shown ( w/ VATS) below

 

There's no reason you need to buy a fuel pump relay to test if it fixes the long start issue... Just borrow the high speed relay from the vent fan.

I wouldn't be surprised if the VATS problem is preventing the computer from activating the fuel pump relay. As soon as the engine generates oil pressure, it bypasses the relay, and it doesn't matter.

 

see, now thats what i was originally thinking, making me think its is a vats issue, I thought that since it wont crank and the security light comes on when i hold the key in start position that it probably wasnt turning the fuel pump relay on to fire up the car. I get alot of mixed messages with this vats thing, some people say its somewhat working because it will let the injectors work, others say its a starting problem, others say its a fuel problem. unfortunatly I havent run into anyone who has had this same problem. Another thing that doesnt help is that the car is in rough condition and other than a new alternator nothing has ever been replaced on it and w/164k miles on it, just about anything could be shot, so it could be a number of things rolled into one issue here maybe, I dont want to replace everything if I find in the end all i needed was a new vats resistor.

 

Ok i checked out the car a little today, and heres another thing I found out. it was warm enough today to go out to the car, so I checked my codes and the computer threw a code 54 at me, which my book says is either a defective fuel pump, bad fuel pump relay, or bad ecm. So I am guess this fuel problem is definatly the fuel pump relay. I got one more question for right now, were is the fuel pump relay at, and another relay I could swap out to test it. one guy said to swap the high speed vent fan relay, weres that at, I want to try one I can easily get to. Also thanx for that starting sytem diagram, and I should also mention the computer did not throw a vats system code, so I guess its not vats related anymore just 2 different issues that look like one big issue

 

VATS does not take out the fuel pump , it disables the injectors. You can hot wire 12V direct to the pump to make it run but if the VATS is operational you will get no injector pulse.

https://www.thirdgen.org/vats_passkey_system

"System Operation
When the system is operating in normal mode, the VATS decoder reads the correct resistance during cranking. The module grounds the Start Enable Relay coil. When the start enable relay contacts close, voltage is allowed to the "S" terminal of the starter. The VATS module also sends an enable signal to the ECM. This signal allows the ECM to operate the fuel injectors during cranking."

The fact that his engine runs fine ( after the fuel pump comes online from the OP switch) shows VATS is not a problem

 

ok, I made a new thread on this with more recent info, butI'll ad the most recent info here as well. I replaced the fuel pump relay, and it didnt solve anything at all. Im a guessing that since the fuel pump works fine once its started thefuel pump must be fine, do you think it could be ecm related since both problems seem to be tied together?

 

Possibly.
Have you got 12V at the pump relay full time?
If you jumper the two thick wires ( red / orange ? ) on the relay plug with the relay disconnected, does the pump run?