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another mystery no start issue

Old 11-18-2011, 02:55 AM
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Default another mystery no start issue

99 z28 camaro. Everything was fine until out of the blue, no start when key is turned... and i have been chasing this problem for days.


with the key turned to the "on" position, all gauges work, fuel pump primes, stereo comes on, headlights work, everything as normal, but it refuses to turn over when i key it for start up. if i leave the key "on" and jump the starter relay manually (take the cap off the starter relay, and force the connection pins together) it fires right up, and the starter sounds fine, and the car will continue to run till i shut it off.


i installed an entirely different steering column (due to a series of mechanical issues with the prev one) and it still does this problem, the kicker is, i didnt change keys either, the car will run just fine with the new column AND the key that came with it, when i jump the starter relay. my tuner told me he disabled VATS, and i believe it (due to my car still running with another column and key)


i have cleaned every fuse, checked all wires, and just cant figure this out. im confident it is not VATS, but im no expert in this regard, any ideas??? Im totally lost, and have read through almost every thread on here that pertains to "no start BS".
Old 11-18-2011, 10:34 AM
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When you ground the starter solenoid it fires right up, and stays running? Doesn't die right? No click or anything when you turn the key? The VATS has been disabled otherwise it would not have cranked with the new key and column...so you can at least rule that out.
Old 11-18-2011, 12:18 PM
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No click when i key it for start up, but EVERYTHING else is as normal.

With key in "on position" I can ground the starter relay, and it fires up as it normally would, and stays running, with no issues, and this is with a whole different steering column AND key, same problem with te original column too.


I have replaced every relay, cleaned every fuse, and checked battery cables pretty damn thoroughly. Cant be a starter issue, because it works fine when I jump the relay, I dont have to mess with the actual starter area to fire the car. Cant be VATS, cause the car stays running even with new key and column. New column was in PERFECT shape too, so im doubting its the ignition switch. I am straight up lost. This is retarded too, as the car will need to run normally asap, as it will be in and out of the paint booth and such very very soon.
Old 11-18-2011, 01:01 PM
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have you checked the neutral safety switch at the shifter or clutch pedal? I'm chasing down the same gremlin right now but mine is a very intermittent problem.
Old 11-18-2011, 07:20 PM
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I closed the loop and bypassed (put the wires together) the safety switch all together, still, no start with the key.


Im officially getting super mad now, because the security light comes on when I key it now... BUT IT WILL STILL RUN AND DRIVE if i ground the relay to kick the starter, then as its idling, the security light goes away, and its business as usual and will keep on running untill i shut her down

. if the problem was VATS this thing wouldnt stay running, right???? so what the hell? I dont mean to alarm every one, but I am beginning to understand why people buy shot guns, and go on rampages now. Any suggestions? what do I check next?
Old 11-18-2011, 08:22 PM
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i hear ya about the shotgun. rifle works better actually, better penetration

i have the service manual for my 2002 and looking at the starting/charging electrical diagram:

ignition key start - fuse block underhood 15A (h10-h11) - branches two ways below

branch A to PCM starter relay coil supply voltage. Connector id C1=80 BLU, C2=80 CLR. It also mentions V6 L36 on this branch so i don't know if that means does not apply to LS1. wire color i think is PPL/WHT = purple white stripe. this branch ends here at PCM.

branch B branches out twice. first is to Instrument Panel cluster (logic) starter relay coil supply voltage, and ends there. The relevant part is to clutch pedal start switch for manual trans or park/neutral switch for automatic and is PPL/WHT wire. After this safety switch, Dark Green wire to fuse block underhood starter relay.
here's where it gets fun.
heavy current side of relay that powers starter, gets power from main bus. output is purple wire to starter solenoid. you are most likely jumping this part of the circuit and engine is starting.
On low current coil side of relay, the input is coming from the neutral safety switch that dark green wire. Output from relay coil side has to go to ground for it to function! And it goes to the body control module, which is described as starter enable relay control and looks like it's a yellow/black wire. The BCM then grounds the circuit provided the VATS system is working or properly disabled, and whatever else.

My best guess is your BCM is preventing the ignition key start from working.
you can bypass it by going under the fuse block under the hood for the starter relay, finding the grounding wire to the starter relay and putting it directly to ground instead of the BCM. I believe this would be a better way to disable VATS rather than ******* around under the steering column with resistors. By running the starter relay coil actually to ground the starter should work, otherwise you have a problem somewhere in the circuit between ignition key and starter relay, or the power feed to the relay is bad.
Whether the PCM talks to the BCM about security and starting I don't know, if it does then it would then prevent the engine from running but you seemed to already prove that this isn't the case. hope this helps.

regarding vats, i'm pretty sure it's only a engine start preventing thing and it looks that way according to the electrical schematics and descriptions.

Last edited by 1 FMF; 11-18-2011 at 08:29 PM.
Old 11-18-2011, 09:00 PM
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i found the theft deterrent schematic, looks like the whole VATS thing is part of the body control module (BCM). and I think when the VATS is activated, it not only prevents the starter solenoid from getting power, it prevents grounding of the fuel enable control going to the PCM which is dark blue wire and either D8, C3, or 229 at the BCM connector. At the PCM I think it's #30 for LS1 and #70 for L36. So from the looks of it if you had a BCM problem you would want to ground this wire also that goes into the BCM, because the BCM isn't grounding it thinking there's a security issue. So really it's two wires you manually ground to disable vats, the starter enable relay control which i mentioned above, and also the fuel enable control which is a wire coming from the PCM.
Try only what I mentioned above first, and if you still have problems let me know so i can double check before you go cutting and grounding wires. Hardest part is finding the correct schematics in the book.
Old 11-18-2011, 11:19 PM
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i had no idea that the saftey switch wire goes directly to the damn relay, thats crazy. it does paint a pretty clean picture of what might need to be done, i cant thank you enough for seriously putting time into finding that **** and trying to help me with this damn problem.

is there by chance a picture or diagram of said wires? finding number 30 on the pcm is pretty straight forward, but under the fuse block looks like a different story.
Old 11-18-2011, 11:32 PM
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now, if the fuel ground wire is needed to be grounded, then he car would show symptoms of not even running due to no fuel, right? thats obviously not my case, as the damn car will run fine after i jump it. What are your thoughts on

Originally Posted by 1 FMF
or the power feed to the relay is bad.

what if its something as simple as that? and if so, where would i start, wouldnt that be from starter fuse-to neutral safety-and back on to the starter relay? i hope im not confused.... getting a rifle becomes more appealing by the minute, lol.
Old 11-19-2011, 12:33 AM
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*update*


I dont have any power at all, at the "starter" fuse in engine bay, coincidentally, I dont have power (key on or off) at the neutral safety switch wires.
Old 11-19-2011, 09:55 AM
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you are correct about the fuel relay ground wire. if that was not happening, engine would not run because fuel pump would not run.


if you have no power going to the 15amp fuse that is the starting circuit, then that's a problem. Ignition switch gets power from 50A ignition fuse, which is why things work when key is in run position. 15amp start fuse is between the ignition switch start side and everything else downstream i mentioned above. Because of the steering column replacement, I'd guess you likely have a problem with the ignition switch or the wire somewhere between the start side of it and the fuse box underhood.
The wire is yellow according to the book that comes from the start side of the ignition switch going to 15 amp fuse underhood, put power to this wire and starter should engage- provided neutral safety switch then works and BCM vats circuit does not prevent it, and starter relay is good.
Old 11-19-2011, 12:50 PM
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Originally Posted by 1 FMF
you are correct about the fuel relay ground wire. if that was not happening, engine would not run because fuel pump would not run.


if you have no power going to the 15amp fuse that is the starting circuit, then that's a problem. Ignition switch gets power from 50A ignition fuse, which is why things work when key is in run position. 15amp start fuse is between the ignition switch start side and everything else downstream i mentioned above. Because of the steering column replacement, I'd guess you likely have a problem with the ignition switch or the wire somewhere between the start side of it and the fuse box underhood.
The wire is yellow according to the book that comes from the start side of the ignition switch going to 15 amp fuse underhood, put power to this wire and starter should engage- provided neutral safety switch then works and BCM vats circuit does not prevent it, and starter relay is good.


Cant be in the steering column itself, due to the fact that it was doing the same problem with the other column, and this one is like new. lol, so power goes from the 50A fuse, to the column, then from column to 15A starter fuse, then to the neutral safety, then back to the friggen starter relay? Forgive me if I have it all wrong, im just trying to put together a map in my head on the route everything travels.


Ill check for yellow wire between the starter switch at the column and see what the dealio is with the damn thing. I suppose ill try putting power to it and keying it over. I swear, **** like this makes me want to sell my f body and purchase a car that IS NOT put together like, and with the quality of a damn Lego Toy.
Old 11-19-2011, 02:18 PM
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I only read the first few posts and you didnt mention it but.... did you try a new starter relay? You already confirmed the high amperage side of the circuit works (by grounding the pins at the relay) so its rather a bad relay or the control side of the circuit. Do you have a wiring diagram? A VATS issue will not always inhibit starting. Sometimes it'll allow a start but the security light will be on. Its kinda dumb sounding I know but it depends on what the code is that causes the light to come on.
Old 11-19-2011, 05:42 PM
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Originally Posted by FiredUpZ28
I only read the first few posts and you didnt mention it but.... did you try a new starter relay? You already confirmed the high amperage side of the circuit works (by grounding the pins at the relay) so its rather a bad relay or the control side of the circuit. Do you have a wiring diagram? A VATS issue will not always inhibit starting. Sometimes it'll allow a start but the security light will be on. Its kinda dumb sounding I know but it depends on what the code is that causes the light to come on.



Yes, I replaced it right away with one of the 5 extra new ones I have laying around, to no avail. I know it has something to do with the control side, but where the problem is, is what is literally making me go insane, I simply just cant find the issue/ground/break in the system.
Old 11-19-2011, 06:51 PM
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*update 2.0*



Checked for voltage at the big yellow wire under the fuse block and it had no power, then at the same big yellow wire at the actual ignition switch and no power there either.... I am begining to think that I have not one, but TWO bad ignition switches in my possession now. Could the BCM still have an effect on power at the outgoing section of the ignition switch at the base of the steering column?
Old 11-19-2011, 08:38 PM
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Originally Posted by whitedevil
so power goes from the 50A fuse, to the column, then from column to 15A starter fuse, then to the neutral safety, then back to the friggen starter relay? Forgive me if I have it all wrong, im just trying to put together a map in my head on the route everything travels.

correct. with the ignition key in start position is sends power back along a yellow wire to the 15 amp STRTR fuse, pin marked H11, in the underhood fuse block. With key in start position and you don't see +12v at either pin in the fuse block, then that points to a bad key switch or a problem somewhere between ignition switch and fuse block. Look under the fuse block and make sure it's just not a bad connector there.

Could the BCM still have an effect on power at the outgoing section of the ignition switch at the base of the steering column?
no. in the start circuit the only function of the BCM is to provide ground to the low current (coil side) of the starter relay. When VATS is triggered, the BCM does not provide a ground to the starter relay and this is how it prevents you from starting the engine.
Old 11-20-2011, 02:47 AM
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Bought a brand new ignition switch, Ill be installing it tomorrow when it isnt nuclear winter outside, and will keep you all posted Here is hoping this fixes the issue.... or I'm lighting this car on fire, and watching it burn with hopes and dreams that it takes the rest of the neighborhood with it, and some how triggers a Zombie Apocalypse for everyone to take part in.


Again, thanks for the help fellas, your the best!
Old 11-20-2011, 06:24 PM
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*update 3.0*


PROBLEM SOLVED!!!


Diagnosis:


Car would clearly run when i jumped the starter relay, because VATS is disabled in my tune, clearly... However, the BCM still controls the Starter ground, no matter what, tuned out, or not. REALY grounding myself to the body of the car while i was testing for power at the starter fuse and ignition switch showed that i did infact, have juice running when keyed to start.


I then fixed the issue by grounding the yellow with black wire in position C12 of the 32-pin blue connector at the BCM behind the glove box, fired right up.



Why the VATS went haywire on me, even with my old steering wheel and key in the first place is beyond me, and i have no idea why, perhaps soldering in the BCM itself... Either way, it is now running again, and to any one else that nearly committed murder-suicide at a local post office because of their cars retard ism, just ground the damn starter relay like I did, and bypass it all together.




Thanks 1 FMF for helping me track this issue down, I really appreciate it bud!
Old 11-20-2011, 08:01 PM
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your welcome.

if i get around to it this winter, i'll post up a proper way for a do-it-yourself VATS disable.
Doing the resistor thing is a half-*** fix, and from the schematics it looks like all you need to do is put a couple wires from the bcm or from the underhood fuse box directly to ground.
Old 02-05-2012, 03:50 PM
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bump i think i have this same problem

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