Dear friends,

Some weeks ago I wrote here because, although my 88 Vette often starts perfectly, sometimes it does not: the engine cranks, but the cylinders do not explode. When this happens, no matter how many times you try, the car do not start; after few minutes, it starts perfectly. Due to these symptons, I assumed that this is a VATS related issue.

I had the chip on my ignition key (code #12) very worn, so the first thing that I did was to purchase new ignition keys to see if that could fix the problem. Unfortunately, I have received my new keys and they work exactly as the old one: the car starts 90% of the time, but few times it does not.

At this point, I am not sure of what must I do. I intend that the other VATS related parts are the ignition cylinder and the VATS control module. Please my friends, what do you recommend? I have read that it is possible to replace a resistor on the cylinder to see if the problem comes from this piece before purchasing a new one, but how can this be done? To replace the control module under dash is complicated? What do you thing about installing a VATS bypass switch, is this easy? Any help or suggestion will be very much appreciated.

 

I will start out by saying if the car is cranking chances are it is not a vats problem. It is rare to be a vats problem and the car still turninf over but not starting. I would check your fuel pressure and valum when it is not starting. I would also see if you have fire when it is not starting. My quess is you have a fuel pump or module that is crapping out

 

1st, STOP assuming !

that's the kiss of death in DIY diagnosing.

Apply FACT, not supposition.

The eng turns over. HIGHLY unlikely VATS is involved.

If the eng does turnover but fails to FIRE, not even a burp, then get a spark tester.
Same time use the fuel pressure test gauge to see what the fuel pressure is when the key is turned to ON and Start.

Key on should see 40 psi fuel pressure BEFORE the starter even engages.

Tell us what codes are stored.

No start with cranking is either fuel or fire. Spark is easy. The fuel is more complicated. You must have enough pressure first of all. next you must have a good signal to the injectors.
All these things are related, as the fuel pump only runs 2 seconds until the engine is firing and running without the starter helping. If the engine does not fire and run after 3 seconds cranking on the starter, let off, hesitate and turn the key again. This action will send another 2 second fuel pulse. You SHOULD be able to hear the pump run for 2 secs just prior to the starter engaging. If so, then you need to know the fuel pressure.

There are many things that can effect the cold starting. temp sensors, fuel pressure, spark, other sensor failures. The codes will help determine what needs attention, if anything.

 

Not VATS.

 

I just went through the wholes VATS issue when the driver lost the keys and key fob. I had a new key cut to factory records...Door worked but no go on the ignition....it had been changed out in the past. Key guy cut a new key to match the lock that had been changed...Cylinder turned but still Nothing, like a never dead battery.

With his whatchamacallit plugged into the computer and working through the codes we found out my VATS code was not a 6 but way off.

Cut new key with the correct code and it fired right up.

You might have a ground issue that needs cleaning or tightening but that is a very uneducated guess.

Karsten

 

I don't know if your issue is with VATS, but I got rid of mine and am much much happier. This involved:

- a jumper with a resistor at the base of the steering column that makes any key work. An eprom reprogramed and a cut wire behind the radio - result? No VATS and I walk a lot less

 

Well,

I guess that is one thing I like about the 85; no VATS; no third brake light; no Anti-lock brakes (yea, I know some of you like it as a safety concern); not a fan of the system myself........

although, having said that, you may not have a VATS problem with your issue; sounds more related to a spark or timing issue; maybe fuel delivery as well....checking spark is the easiest to figure out.

 

Check the error codes. A VATS problem will set error code 46.

 

Dear friends, thank you for all your messages.

Let me explain why I think that this is a VATS issue: as said, the car usually starts, but when it does not start, you MUST wait about 5 minutes, then it starts flawlessly. During the 5 minutes period, you can try to start many times, but the car will not start. Insted, if you simply wait 5 minutes, you try again and the car starts. I have even tryed to turn on and off the contact to let work the fuel pump more times, but nothing changes.

Due to these circumstances, I doubt that this is a fuel pressure problem. If so, it has no sense the 5 minutes of mandatory waiting period, don't you thing? Also, I am aware that there is a modification that bypass the starter relay, so you have still VATS, but the engine cranks. Maybe my car has this modification (it is second hand, so I do not know). Also please note that I replaced all my spark plugs few time ago.

I can buy and replace my fuel pump, but I doubt that this is the reason for all said. By the other way, of course I am not sure if this is a VATS problem, or something else. I would not to replace the cylinder or even the VATS module for nothing...

You are talking about the error codes, please can you explain how can I read them?

Hooked073, you talk about the fuel pump or the module: at what module do you refer?

Thanks!

 

http://www.corvettephotographs.com/c4vettes/codes.htm

Every time you turn the key on, the VATS timer resets to zero again if the correct resistance is not seen

 

So, let me insist: what should I do? Symptoms are already exposed.

If this is a VATS problem and the key is new, should I replace the cylinder with new keys, or also the VATS module under the dash?

Also, how can I replace one of the resistors of the cylinder? I have read that this can be done to avoid the purchase of a new one.

Or, must I just bypass the entire VATS and forget about it?

Thanks and sorry for my insistence.

 

http://www.joestradingpost.com/vats/index.html read this !!! good info on vats!!

 

corvette cental sells a bypass for the key, mine had one in it when i bought it, there is also a thread I read about bypassing the whole vats system, you have to take the center covers off the dash to get to it from the pictures I saw, it looke like a jumper wire.

 

When I had the problem when I first got my car, we finally got another lock cylinder and placed it under the dash with a key we didn't turn so the theft system would read that resistance and not the ignition switch key code. Never had a problem after that.

 

[QUOTE=mitcher;1585649838]So, let me insist: what should I do? Symptoms are already exposed.

what symptoms?
the list that indicates there is a serious fuel problem? either pressure of injectors? THAT symptom?
For the LAST time....YOU DO NOT HAVE A VATS PROBLEM.

Test the fuel pressure and look for bad filter/pump and or injectors. Ohms test inj hot and cold. Pressure leak down rate when off, Fuel pump REALY....You DO KNOW that IF your FPR has failed that you have to crank the starter for a long time to trigger the oil pressure switch that THEN gives power to the fuel pump? right?

Just because there are 60 minutes on the face of the clock, does NOT mean that VATS is involved. It generally takes about 5 minutes to go thru a drive thru. That is NOT VATS related. A good shower takes about 5 minutes. Mine runs out of hot water after 5 minutes,. VATS is not at fault. The guy standing there using the hot water IS. AGAIN, waiting a few minutes is NOT A SYMPTOM of a VATS problem !

What are the stored codes the ECM is displaying? You don't know...
I Forgot.

FWIW,
Just because you CAN start after a 5 minutes, in NO WAY indicates that VATS is involved ! Especially after the starter has been working ! damn !

Whats it gonna take?

You want to ask for help with this but refuse to accept what you are/have been told by everyone that's taken the time to respond !

If you already KNOW what the problem is, why are you asking anyone here?

I'd love the opportunity to help someone today, BUT this is starting to look like a troll-thread. You keep getting GOOD advice from knowledgeable people but reject it in favor of you GUESSING because you WANT it to be VATS or you just want to screw with people that genuinely wish to help you.
I wish you well in your quest for a VATS issue !

Like Mr Wonderful says.........
"I'm OUT !"

What should you do?
The 1st paragraph is a great place to start, IMO. Good Luck

 

Humm, maybe one of these will help.

http://www.ecklerscorvette.com/corve...1986-1996.html

Karsten

 

Which you can do yourself with 50c worth of resistors from Radioshack.
Refer link in post # 12 above

 

apparently he has a VATS problem; once fixed he can address the issue of why the car is cranking but not starting.

 

Until he pulls the codes we will never know.
VATS takes out the starter and the injectors so he could have either

a VATS problem.( key reading , module , etc)

or have a starter problem and a engine fire up problem at the same time.

 

Where are you located? Do you have a FSM? Those two questions I'd guess need answered and the rest shouldn't be an issue.