Vats bypass module
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 6,470
Likes: 2
From: levittown pa. usa Even a bad day with my `Vette, is better than a good day at work
St. Jude Donor '10
Vats bypass module
Went to take the `87 to work this morning since it was such A nice day. Put the key in, turned it, everything lit up, heard the fuel pump, then NOTHING---Damned Vats 
. Waited ten mins. tried again---same result. Lucky it was in my driveway, since I had it out all day yesterday. This same thing happened a year ago right after I bought the car, & we had new keys made with new resistors. I do not want this to happen again, so I ordered one of those bypass modules from MAD for $24.99. My question is, does anyone use one & do they work. Oh yeah; after I got home from work, I went to start the car, & naturaly it fired right up. If the bypass works, I`m still going to hook it up when it comes, because getting stranded in some parking lot somewhere is total 
. Waited ten mins. tried again---same result. Lucky it was in my driveway, since I had it out all day yesterday. This same thing happened a year ago right after I bought the car, & we had new keys made with new resistors. I do not want this to happen again, so I ordered one of those bypass modules from MAD for $24.99. My question is, does anyone use one & do they work. Oh yeah; after I got home from work, I went to start the car, & naturaly it fired right up. If the bypass works, I`m still going to hook it up when it comes, because getting stranded in some parking lot somewhere is total
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Most likely the contacts in the ignition tumbler that make with the pellet are worn. You can prove this when it happens next time by removing the hush panel above the drivers feet and find the two white wires from the steering column that go to a connector. Unplug the connector and with the ign key inserted, measure the resistance across the wires from the steering column. It should be the same as the pellet. If over 13k ohms, you need a new ign tumbler which has new contacts. Also, you don't need to spend $24 to bypass your VATS. You can bypass VATS temporarily until you can schedule a repair by buying a 1/4 w 5% resistor from Radio Shack the same value as your pellet and clipping it across the connector that goes into the wiring harness (VATS module). Don't permanently bypass VATS because 99% of thefts are done by bashing the column and jumping the ignition. Also, you might have a defective clutch safety switch (gear selector sw if auto). You can bypass this switch next time it won't crank and try to crank again.
Drifting
Joined: Sep 2004
Posts: 1,638
Likes: 3
Common Fix
A fairly common (somewhat Bubba) Fix is to get a new ignition switch with a VATS key - and wire it in to the system - then they just leave that key in the switch - so it's reading the new ignition switch resistance. In the meantime - now you can use any cut key to start the car at the column - no resistor chip needed - and you can disable the car by turing off the second key under the dash.
I haven't done this - but after I bought my 86 - I discovered the second ignition switch and key under the dash- and eventually was able to figure out what was going on!
Carl Johansson
I haven't done this - but after I bought my 86 - I discovered the second ignition switch and key under the dash- and eventually was able to figure out what was going on!
Carl Johansson
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Originally Posted by Carl Johansson
A fairly common (somewhat Bubba) Fix is to get a new ignition switch with a VATS key - and wire it in to the system - then they just leave that key in the switch - so it's reading the new ignition switch resistance. In the meantime - now you can use any cut key to start the car at the column - no resistor chip needed - and you can disable the car by turing off the second key under the dash.
I haven't done this - but after I bought my 86 - I discovered the second ignition switch and key under the dash- and eventually was able to figure out what was going on!
Carl Johansson
I haven't done this - but after I bought my 86 - I discovered the second ignition switch and key under the dash- and eventually was able to figure out what was going on!
Carl Johansson
Burning Brakes
Joined: Feb 2001
Posts: 769
Likes: 0
From: Granbury TX
Originally Posted by stevec4
Where can we buy replacement keys for the vette?
Do we measure the pellet resistance and then just order them or are there 'special places' that do it?
Do we measure the pellet resistance and then just order them or are there 'special places' that do it?
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Drifting
Joined: Sep 2004
Posts: 1,638
Likes: 3
Originally Posted by jfb
If one of your headlights burns out do you epoxy a flashlight onto your hood? When mine burn out I replace the headlight!
The VATs system is slightly more complex that a burned out headlight -
I/m betting that The module you are buying from MAM is going to be a simple resistor switch and some circuitry- about 2.38 at Radio Shack. But you would know better than me!
I already said I didn't do this - I'm just telling you what many have done. The fact is the VATS system causes lots of electrical gremlins - and lots of people have solved them in lots of ways.
Of course you are an Electrical Engineer so of course this bothers you. So if your tire goes flat - do you develop an electronic tire pressure sensor - linked to an autojackup system? Not me - I just change the tire - whatever works!
Last edited by Carl Johansson; May 10, 2005 at 08:31 PM. Reason: Add info
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Sorry for jumping on your case since you didn't install the second ignition switch. About 10 years ago my 87 vette left me stranded at church and I figured out what was wrong and installed a fixed resistor so I could drive the car until I could schedule a replacement of the ignition tumbler. I have had no trouble since with the exception of the clutch safety switch failing which I jumped because it is impossible for me to replace it (too tight a space). What I am not able to understand is that forum members complain about their unreliable starting and even after they have determined it is the VATS and they never get it repaired and just continue to crab about getting stuck somewhere. Then other members start in with paying $24 for a bypass kit or putting toggle switches behind the dash and probably your cars previous owner recommending another outboard ignition switch. Get it repaired and get on with your life!!!!!!!!!!!!!!!!!!! sheeeeeesh
