I bought a 95 fixer upper. Have done extensive wiring work on the engine and am at the point where I would like to get the motor crank.

I had to have a key made off the VIN so the VATS resistance is a crap shoot. The counter guy guessed #3 so WTF I gotta start somewhere. The key works the ignition switch, but will not crank the engine.

Should the engine crank even with an incorrect VATS key? Or does the key disable the crank ability?

 

Your best bet at this point is to use the search feature, especially in the C4 tech forum. There is a ton of information out there on VAT's, no starts and all the issues you've got.

 

Thanks I was hoping for a simple answer to the question. I'd like to start there rather than spend the next hour sorting through all the posted info on the VATS system.

Anybody?

 

If the PASS key pellet is incorrect it will not crank.

 

Thank You toptech.

Now I will determine the correct value following steps I have found on the site.

Apparently #3 is not it.

 

That's the first place to start. making sure you have the correct key. The counter guy should not be guessing. He knows better or at least should.

 

He told me that the VATS records do not go back that far.

He also cut the first set wrong. I had a set cut. Took them home and neither one worked. I had to return the next day for an ordered part. So I removed the luggage compartment lock, took it with me. He cut a second key and it worked. Yeah! Then cut a second ignition key. He told me that he may have gotten the numbers crossed. I was very happy when I tried the ignition key and it worked.

So I did not have to change the door keys, or the console or compartment locks. Or the ignition switch. Could have been an expensive PITA because he did not do his job correctly. I did have to pay 20.00 for the code and 15.00 VATS key 2.00 door key to begin with. Not bad if I can figure out the VATS.

 

The car is not going to start without the proper resistance key. I was going to say to get a bypass kit, but for that you also need to know the resistance properties. Damn....I'm clueless.

 

As posted it will not crank. I normally would suggest you order a VATS bypass cable until you can get it sorted out but since you dont have a key that wont work. Since you dont have that its cut 12 Keys until you find the right one or find somebody outthere with a VATS interrigator machine. Another possibility is to take your VIN and title to GM and see if they can tell you (For a fee of course)

 

Correct pellet code allows the car to crank. Any key with the correct cut profile can unlock the column and get the dash lights on just not crank.

Keys from the dealer are a toss up. For one unless you're the original owner you don't know if the ignition switch has every been replaced. If it has the key won't work plus they are non-refundable.

Dealer still had my records but key didn't work cause my ignition switch was not original. Wasted about $45.

I hired a local locksmith with VATS devices. The guy I hired after a failed dealer key had a device which plugs into the ignition switch that tests each resistance code one at a time with the turn of a ****. Once we found which resistance code cranked the car he cut the key profile into a blank VATS key of that resistance.

 

You can try each resistance yourself one at a time by buying a variable resistor and using an accurate ohmeter to set the variable resistor to each resistance (must be within 4% to work) and trying them one at a time. Modern electrical test meters are digital and their ohmeters are very accurate. You can even buy one from Harbor Freight for $8, less when they are on sale to find your correct resistance. VATS won't allow another trial when wrong for 6 minutes unless you want to reset VATS by disconnecting the battery momentarily. On earlier C4's there is a wire near the battery with a connector that powers the ECM that you can unplug and replug back in so you don't have to wait 6 minutes. 95's might have the same wire.

 

This is interesting and educational for me. So does the VATs system disable the starter or the ignition / fuel system?

When I hear "crank" that makes me think the starter is not engaging.

 

Yes it disables both the ignition and also the starter.

 

I figured it out yesterday. I followed some very helpful posts.

redrose posted this,


"get a 1k and a 10k cermet pot (potentiometer) from raddyshack for under $6 total...wire the two pots in series for coarse/fine adjustment...unhook the vats connector at the base of the steering wheel...using the 'key chart' and a DVOM, set first key value into pot pile , jumper onto car vats connector and turn key to start...if no response, turn key off, unhook pots, set pots to second 'key' value', wait for remainder of vats time-out of total 4 min, retry...and then next key value, until ya get lucky...WORST case is needing to try all 15 key values, = an hour

once the correct key value is in the pots, put a tiny dab of paint (or typewriter 'white-out') on each pot adjuster to lock in, make perm connect of the pots/jumpers to the car and live free, or use the info to go other ways."

And socalman posted this link,

https://www.corvetteforum.com/techti...=153&TopicID=2


By following the advice given I was able to try different resistance values until I got to #13 and my starter engaged. I was starting to wonder once I went past 10 and 11 if it was working. Then at 13 it worked.

Thanks guys for the guidance.

 

I will ad that the Radio Shack Cermet Potentiometers I used for the test circuit are RS part numbers,

RS 271-0343 and RS 271-0342

Here is how I wired them,

Line 1- Pot #1 pin 1, pin #2 jumper to Pot #2-pin 1, pin #2-Line 2

This allowed me to adjust from value number 1 up to 14. I would have had to reconfigure the circuit to test 15. I did not bother after I found that 13 worked.

May be helpful for someone.