'86 no-start...VATS?
 

Hi,
I took my '86 coupe to get inspected today. Car ran great. Started fine (4 times). After passing inspection, I got in, turned the key and nothing. No fuel pump noise, no starter clicking. Interior and instrument panel lights came on just fine. After twenty minutes of waiting, trying again, jumping the battery, waiting some more, trying again, still nothing. I called AAA to get it towed home. In the meantime, I myself got a ride, went to work. The wrecker driver calls me up once he had picked up the car and dropped it off at my house, and he tells me the car is starting just fine. He tried it twice and it started both times.
So here's what I know:
-the previous owner had installed the VATS bypass gizmo that Eckler's sells.
-battery voltage showed 11.3V when it was in no-start mode. Jumping the car didn't help.
-the car had idled for a long time while they were inspecting it. The coolant temp was 205F (don't know oil temp)...not overheated.

So, here are my thoughts:
-maybe the VATS bypass gizmo is a POS and needs to be replaced. I honestly don't know much about the VATS other than it designed to not allow the car to start in the event an incorrect key is used...
-11.3V was too low. But then why did jumping not work?
-Motor (specifically the starter and solenoid) were too warm to start the car. But then again I didn't hear the fuel pump buzzing when I tried to start it.

At first I was embarrased about the car not starting, now I'm frustrated. Not only that, but I felt like a dork when the wrecker driver tellls me it started just fine a half hour after I had given up. I realize that the VATS is troublesome and has been discussed many times before, but I wanted to present my specific situation (coolant temp, batt voltage).

Any ideas, suggestions? If it's the VATS, is there any way to take the darn thing out altogether?

Thanks,
Ed
Houston, TX

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RE: '86 no-start...VATS?
 

There's definitely a VATS bypass under the dash.

I'm guessing the way those things work is that they trick the computer to think that a key with the correct resistance is in the ignition. I assume thatthe previous ownergot the correct VATS bypass since you have to match it with the key's resistance.
vatssucks.com talks about, in addition to the VATS bypass, to eliminate the 'starter-enable relay'. I think I might try that next. Because, the way I understand it, since the VATS bypass makes the computer think the right key is being used, a signal is sent via the relay to activate the starter. Maybe the relay isworn out after 21 years of use....

Any thoughts if I'm headed in the right direction? What with this process of trial and error, the only way I'll find out if it works is if I don't get stranded.

Ed

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RE: '86 no-start...VATS?
 

Hmmm. No I did not try that. Good info, thanks!

Which leads me to start wondering how exactly the VATS system works. What I understand so far is: The correct key resistance will complete the circuit telling VATS that it's OK to start. (The VATS bypass gizmo tricks the VATS module into thinking that the correct key is being used.) The VATS then tells the ECU to allow the starter to engage and the fuel injection to come alive. This may be a basic (non-technical)version, but how far off am I?
So, now I am wondering what other inputs is the VATS looking for in order for it to allow the ECU to start the car? So now I understand that the door locks are part of this. Any other inputs?

Ed

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RE: '86 no-start...VATS?
 

Last night I bypassed the starter-enable relay, as per the instructions on vatssucks.com. Since I'm still not sure what the exact problem of the intermittent no-start situation is, I guess I have to wait and see. If the relay was worn, then this will solve the problem.
However, if the situation is still vats related, then the next time the Vats module decides to go into another no-start mode, I guess the engine will turn over but the fuel injectors will be disabled per the Vats.

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