More confusing parts to the puzzle.

[captcorvette]

As some of you may remember I have been having VATs issues forever. So here is a quick update.

Wanted to let the cobwebs clear out so did not touch the car for the last month. It was sitting at my home parking. School year starting and my schedule at a constant Mach II so no time to worry over it. School work settled down, weather good enough to ride the scooters and patience level increased sufficiently to want the Z here at my hobby shop for me to continue being more puzzled.

Had my recovery driver go to my house and pick up the car to transport to my shop. As the car was rolling off the recovery i opened the diver door and the non working horn decided to go into its "theft" mode. This is the first time i have ever heard the horn so I shocked to say the least. Horn blaring so I inserted the key and turned the switch on. No change as the horn continued to aggravate me and everyone else in the shop.

For grins and giggles I take the key out of the ignition put it into the door and turn the key in the unlock direction. No resistance so that indicates to me that the door was indeed in the unlocked position and of course the recovery driver and i had both opened the door. Recycled the key to the lock then the unlocked position and the horn stops.

OK so I check the steering wheel buttons and the horn will not work on either button. Then the penny drops. I had been watching the "security" light flash as it had been doing all the times last month when I was trying to get the car to engage the starter but then the security light went off indicating that the system had recognized the pellet and the VATs was working properly. What the hey I decided to try and start the bloody car. Fired right up.

Starting correctly for the last two days. Horn still will not work from the steering wheel, headlights still will come on but not rotate to up position. Warning panel clear except for the "full power" when I turn the valet key it illuminates the full power light.

Needless to say I am more confused than ever. This car has Marc's chip and it has the "no vats" setting. Next bit of news? The Tech I just purchased will not power up in this car. The cigarette lighter plug that comes with it had a green light which does illuminate when inserted into the socket. However my Tech Scan 7000 does work with this car.

Think I ought to rename this car Christine? :eek:

Not sure if it is "possesed" but it sure does make ole Yogi here feel stupid.

[tomtom72]

I'm not 100 % sure about this but I think that the VATS and the intruder alert system are two different systems that are not tied to each other.....:o I think that is maybe not the best explanation, but they're not interconnected nor are they dependent upon each other.

I also would like to toss this out as a fwiw:o I had been chasing a random no start condition in my friend's 90ZR-1 and as best as I could tested all the individual components in the starting circuit and the VATS system. I found nothing. His random no start was a broken wire at the ignition lock key cylinder inside the steering column. In order to repair it the column had to removed from the car and then taken apart to get to actually see the broken wire on the lock cylinder/key switch. The mechanics of the issue of the broken wire inside the column is that the wire breaks at it's solder point and can't go very far away from the cylinder. This causes a no start to be random.

I don't know that this would be of any help in your diagnosing the no start condition in your car. I would just add that I learned from listening to camaro and firebird techs that the C4 column is the same as those cars, and that this broken wire/random no start is a known fault in those cars. These techs told me that it is a case of 10 lbs of stuff in a 5 lb bag, and that's why the wire breaks.

:cheers:
Tom

[mike100]

I do know that you can run the horn circuit with the Tech1 i/o diagnostics. Basically it activates the relay for the horn on a separate wire. Most likely your horn switch in the steering wheel is broken. Those are actually easy to fix, you just need to remove the airbag with the screws on the back of the wheel.

The lock cylinder isn't too much farther back. Once the wheel is removed, you can get the turn signal stuff out of the way and access the lock cyl and vats circuit connector. I have found the pictorials on the internet good enough to figure out how to do it. You do need a steering wheel puller tool- nothing else is very special. well...some patience with the bright light switch (and some really thick grease to hold it in place to defy gravity).

[captcorvette]

Thanks for the extra info and help. The only reason I thought they were tied together somehow is that the flashing "security" light and the no start always happen together. Not one without the other. I have had the steering column out once by a friend of mine. Might have to take it out again just to check it all out.

Now I am wondering if the driver's door lock might be dodgy?:confused:

Not sure if I messed up my Tech I. Will not get power now for some reason. However the Tech 7000 is reading the OBD socket but it is very limited on what it provides me as far as I can tell.

At least it is starting, running and has put the permigrin back!

[mike100]

check the fuse that should be in the 12v adapter for the tech1.

[captcorvette]

More confusion please. Got brave last night and drove the Z from my shop to the mall. No issues. Still have not figured out what happened to the headlight motors but no problem I just hand spun the knobs to get the headlights up and drove home. (24 kms) No issues. Parked the car inside the villa wall and shut her down. Was feeling sort of frisky about being able to drive the damn thing-----until this morning. Had not touched ANYTHING, had not locked the door since inside the 8 foot high walls. Tried to start it this morning? Yep you guessed it. Security light back on and no starter engagement. Didn't have time to mess with it at 5 in the morning so just left it at home and rode with The Boss (my lovely bride of 25 years). She didn't even rub it in about my favorite toy not working but less than a dozen times over the past couple of years. She has a good heart. Me? Took me most of the morning to stop thinking of ways to teach this car to swim.

Going to have to find a much better spark chaser than me or anyone else I have found at any of the agencies.

Oh yeah and the Tech I is fried. Looks like it has been opened more than a screen door in the summer with a house full of kids.

[Pete]

Check/try a couple of things.

Clutch switch? common problem in these, most bypass them.

Try another ignition key just in case the pallet in your key is worn out.

Check and see if you get voltage to the big fat purple wire when you try and start the engine wire is in the big wire loom near or under the ECM
look in the loom of wires for the fat purple wire

Check the above and get back to us.

Pete

[captcorvette]

Thanks Pete, I have a total of 4 ignition keys. 3 new ones and one original. All have been ohm checked to make sure they have the correct value. Problem same with all the keys. When the "security" light comes on none of the keys will work.

When I first started having the VATs problem I purchased all the clutch switch stock I could find. (4 units). Checked the switch in situ and after removing it with one of the new ones. Same problem so put the old working switch back. Remainder are sitting on my Z panic shelf.

Just in case I replaced all the door plunger switches also. If memory serves this is the same switch as the clutch switch but not sure as I might be having a "senior" moment regarding both switches being the same.

But just for grins and giggles as soon as I get home this evening (its now lunchtime thirty) will check the clutch, door plunger switches, cycle the door locks---again.

[scottfab]

Thanks Pete, I have a total of 4 ignition keys. 3 new ones and one original. All have been ohm checked to make sure they have the correct value. Problem same with all the keys. When the "security" light comes on none of the keys will work.


I'd stay focused on the flashing security light. Forget the clutch switch for now. It's not involved with the flashing light.
Even more sounds like the wire to the lock cylinder to me. Do you have the stock chip for the ECM? Getting things stock for troubleshooting may give us all a baseline position from which to troubleshoot.

[captcorvette]

I agree with you Scott. I have always like to work on the KISS principle.

HOWEVER I just got home after the car sitting all day. Put the same key in the switch and the bloody thing started right up. Car has not been touched as I made sure to tell the house boy to not touch the car at all. Key was right where I left it this morning on the panel next to the shifter where the ash tray is.

If it will start in the morning will drive it back to the shop so when I have time can tear into it again.

I think it is time to take a poll to see if this car should be named Christine eh?:rolleyes:

[scottfab]

I agree with you Scott. I have always like to work on the KISS principle.

HOWEVER I just got home after the car sitting all day. Put the same key in the switch and the bloody thing started right up. Car has not been touched as I made sure to tell the house boy to not touch the car at all. Key was right where I left it this morning on the panel next to the shifter where the ash tray is.

If it will start in the morning will drive it back to the shop so when I have time can tear into it again.

I think it is time to take a poll to see if this car should be named Christine eh?:rolleyes:
Have you noted what the ambient temp is when it starts and when it won't? Is it maybe cool out when it starts?

It is starting to sound like you'll need to "instrument" the thing.
I find doing so on things that are intermittent to be helpful.
What I mean is tap into various lines and bring them out for measuring. I'd start with the VATs sense lines and put an appropriate
resister there on a switch.
The idea would be to measure at the two wires what the resistance is after it starts (have to shut off to measure) and what the resistance is when it won't start. If the resistance is way high (in the 100k ohm range) you could throw the switch and see if she starts.
You'd need to also measure the resistance of each wire is to ground because if the no start is not that the key pellet resistance then maybe one of the wires is shorting to ground.

In any event some tactical plan needs to be in place to nail this thing.

[WVZR-1]

On the next "no start" when "hot" try a push start. 2nd gear should at a walking pace shoud do it! If it starts with a push it should be a reasonably simple fix.

You've never mentioned battery condition!

All of these are covered here:


http://www.zr1netregistry.com/ZR1_troubleshooting.htm#Start

[scottfab]

On the next "no start" when "hot" try a push start. 2nd gear should at a walking pace shoud do it! If it starts with a push it should be a reasonably simple fix.

You've never mentioned battery condition!

All of these are covered here:


http://www.zr1netregistry.com/ZR1_troubleshooting.htm#Start

He says the "Security" light is flashing. (edited later... I mean security light was "on" as stated in post #6)
Don't think a push will do much except cause sweat in the desert ;)

[WVZR-1]

He says the "Security" light is flashing.
Don't think a push will do much except cause sweat in the desert ;)


He mentions "many things" - column has been out recently, the mention of "flashing" isn't mentioned every time he mentions "security light". If the car starts and runs but when going back to attempt a start while still not "cooled" completely but it will push start it eliminates many things.

I believe if I had a "flashing security light" I might open window, close door, lock the door using door switch inside the car and then using the key unlock from outside. I believe that resets UTD on most.

Additionally the CCM codes could be accessed from the DIC module and I believe before an attempt to check the UTD system it mentions checking for CCM codes. He doesn't need a Tech1.

I believe his car to be a '90 and the DIC should work for codes.

This information may NOT be with out error but for the most part is a very useful tool:

http://tech.corvettecentral.com/2011/01/c4-diagnostic-trouble-codes/

[Pete]

Is light flashing or a constently on?
Does light shot off after turning ignition to on/start position?
You mention column was out did they plug the VATs back in?

Unless a 1990 model year is different then a 1991-1995.

They all flesh till you turn ignition key on/start position.
If security light is consistently on and not flashing then it's a VATS issue.
If light still fleshing after turning ignition on then you have cylinder issue (not reading the key pellet) or VATs not pluged under the dash then check and fix or just put a resistor to the VAT plug under the dash same as your key pellet resistance.,till you change cylinder/fix issue.

If the light goes off when you turn ignition on it's not VATS issue or any of the above.

If above is working properly check for power to the starter if you get power to the starter then it's starter or relay.

No need to push start just put power (+) to the purple wire.

Pete

[WVZR-1]

He mentions it runs intermittently and understanding how most use the steering wheel for exit it would seem more likely that there's a problem with the wire to the cylinder.

I mentioned a "push start" if it was a situation with hot starts and it "push starts" NOT VATS.

He's mentioned so many things related to the "theft system" door switches etc it's hard to tell.

A week ago it was suggested the problem is in the cylinder wires and he's not responded to that. If he's got a "no start" and it's VATS then the DIC can be used to confirm that!

[scottfab]

He mentions "many things" - column has been out recently, the mention of "flashing" isn't mentioned every time he mentions "security light". If the car starts and runs but when going back to attempt a start while still not "cooled" completely but it will push start it eliminates many things.

... snip..
/ (http://tech.corvettecentral.com/2011/01/c4-diagnostic-trouble-codes/)

I miss stated that. It's not flashing. It's "on" as stated in #6.
which is a VATs issue.
There is no mention of attempting to start when hot.
But yah, if that's it and security light is off then were looking elsewhere.

[WVZR-1]

I miss stated that. It's not flashing. It's "on" as stated in #6.
which is a VATs issue.
There is no mention of attempting to start when hot.
But yah, if that's it and security light is off then were looking elsewhere.

Pete's comments are "right on" regarding flash/no flash and since it's intermittent he can use the DIC to confirm it's VATS and then decide to check the connection at column base and when that's confirmed probably buy a cylinder and install it or just do a resistor to the mating connector of the correct value.

DIC will confirm VATS or NOT there's No need for a Tech1.

OP needs to familiarize himself with the procedure to read codes using DIC and check them. Attempt a start and when he gets a "no crank" check the codes again. I haven't used the DIC for many years and I don't recall if it distinguishes between H-history or not. I've check a car using both the DIC and a Tech1 one after the other and they were identical in diagnostics.

http://tech.corvettecentral.com/2011/01/c4-diagnostic-trouble-codes/

[Pete]

http://tech.corvettecentral.com/2011/01/c4-diagnostic-trouble-codes/


Very nice sight.:thumbsup:
Saved it in my favorites

This is all he needs to figure it out.
Lets us know what you find.

Pete

[captcorvette]

Will do as suggested as soon as the problem occurs again. This morning cranked up straight away. Drove the 24kms to the shop without issue but am very suspecious now as to an intermentiant grounding as radio (aftermarket installed by original owner) dimming and then shutting off followed by coming back on quickly.

Will wait until the next occurance and check what is being set or not set. There are no codes and have been no codes.

Will hook the headlight motors back up and check them also. Horn still not working so will look at that also.

But as long as it is starting I am a happy camper.:-D

[scottfab]

... snip...
Will wait until the next occurance and check what is being set or not set. There are no codes and have been no codes.
..snip..

If the Security light comes on and stays on during a "no start" then I'm really confused. There would have to be a code set. But then if you're car has a modified chip...... all bets are off. Who know what "improvement"
have been done in the chip.
Diagnosis becomes problematic.
Sure hope the car doesn't leave you stranded.

[captcorvette]

The chip in the car is from Marc. The car has left me stranded so many times I don't even think about it anymore. Don't take the car out unless I am following or leading someone like to work and back or to dinner with my other half in her car.

I like a puzzle but this one is waaay beyond my talents in the spark chasing department. Will drive it as long as it will start but will keep my recovery and driver on the standby.

Did notice tonight that the radio came on and off with the headlights? Also the a/c took its sweet time to respond to input but she drove all the way home and I will try to take it back to the shop in the morning. I know my Boss is getting tired of following me back and forth but has got into the habit since the truck ran over my '86 pace car with me in it about 4 years back.

9 P.M. which is my Cinderella time.

[WVZR-1]

If the interest is first to make the car "crank and start" on every request then that needs to be what is discussed ONLY! I posted a link to how to do CCM faults from the DIC and after those are checked it's very easy to move on. The CCM codes should eliminate all of the "security" light discussion and likely might hint to whatever else is failing. Get past that and move on with the rest of the diagnostics. The OP mentions no codes but I'm guessing since there's no CEL he assumes there's NOT.



OP - Get familiar with the information in the link. It's very straight forward and it will help you! I'd suggest a 10G solid core jumper peened if needed on the ends a bit. It will stay in the terminal much better than stranded wire or a paper clip.