I've searched on the internet and here and I am getting conflicting information. Some places/people say that the VATS can keep the fuel pump from coming on via the fuel pump relay and some places/people say that it is only keeping the injectors from coming on but the pump will prime... SO, which is it?

This morning my 91 3.1L Camaro would not start. When I turn the key, but not to start I do not hear the fuel pump come on, but when I try to start it I get nothing - no clicking, no cranking, nothing. Pretty sure the battery is fine - have buzzer, lights and idiot lights come on, although I did not check the voltage.

I don't think it is the fuel pump specifically or the car would crank... don't think it is the starter specifically or the fuel pump would come on. I'm pretty sure when an igntion module goes it will crank.

I have not checked the security light yet because I only just started to research the problem when I got to work.

 

 

Your battery can easily run the lights, radio, etc. and not have the juice to even click the starter solenoid. Fuel pump will not always prime at every turn of the key - if it primed and you turned key off and back on within a few seconds, it will not always prime again (ECM kinda knows when last prime was).

Here's a start troubleshooter - grab a meter and check it out: http://www.austinthirdgen.org/index.php?pid=38

And here's a fuel pump troubleshoot: http://www.austinthirdgen.org/index.php?pid=35

 

Conflicting information on the web.... No Way!

But seriously, with my own 91 RS when the wires for the VATS broke on the key cylinder I had no crank, no fuel pump prime and a security light came on.
Right out of a factory service manual it states
"The module has outputs to the starter enable relay, the fuel enable relay and the instrument panel security light connector".

Measure the resitance of the pelet in the key.
Then locate under the dash, coming out of the steering column, a small orange wire sleeve with two small wires inside. they could be yellow, black or white.
Disconnect their plug and with the key inserted into the ignition measure the resistance between those two small wires.
The resitsnace should be the same or very, very close. if not then you have some breaks in the wires near the key cylinder and you will have to replace it or bypass the key cylinder.

 

If the factory manual did not mention that there is also a pulsed wave signal sent to the ECM that disables injector firing, then it was also wrong there.

Maybe they just oversimplified the manual - I mean it does interrupt the fuel, but not the pump, just the injectors. If it was a simple matter of wiring up the starter and the fuel pump relay, none of us would have to replace the pellet in the key with an inline resistor to satisfy the VATS module - we could simply ground the starter enable relay and ground the fuel pump relay and go!

 

I am sure the factory manual is simplified. Its for the parts changing technition and not the guy that is going to dig into the ECM or pry open a relay or something like that. And enough engine cranking will engage the fuel pump through the oil pressure switch so there is not much secuirty there.

But given that the fuel pump relay is controled through the ECM as well, and also not long ago I had no crank and NO fuel pump prime and the fix for me was to bypass the ignition locks resitor wires, I would think its something the OP should check into.

 

BTW,
I had also seen a thread somewhere here that was going back and forth on bypassing the VATS decoder module. Sometime ago I ran across this,
http://www.summitracing.com/parts/PRF-64023/
There are a couple different ones. Maybe this would be helpful to others.

 

I've seen some have success with those bypass modules, and some not - seems like the wiring up of them is difficult. The resistor is easy, but not always an option if you don't know what resistance your looking for. Still amazes me that anyone would have an antitheft key and not make a copy of it before they even drove the car home. I towed my car 300 miles home, and I stopped and got a spare key made before I even left the town I was towing from.

 

At the very least, make a note of what the resistance is!
If not, buy a bunch of resitors (or a potentiometer) and some patience in changing the values and testing until you find the right one.
Seems like the only problem I have ever run across on a VATS system is the lock cylinder being the weak link. Having small wires tucked behind the key buzzer contacts on a cylinder that makes them moves seems like a bad idea.

 

If you have a GM shop manual for the car it will tell you what it drops the resistance to.

Get a small little switch from radio shack. Have it so that when the switch is set to "off" (whatever way you choose that to be) the wire goes to nothing. Then on the wire that you want to have as "on" solder the resistor on and run the wire down to the vats. Then drill a small little hold in your lower dash cover and mount it under there so it is hidden.

If you do that, you can still have VATS security while still bypassing the key. Just flip the switch to off whenever you park it somewhere where you want VATS on and they won't be able to start the car. Just remember to flip the switch to on, because if it's not the car won't start.

 

Thanks for all the replys! I tried to get one here last night but my internet at home is horribly slow and I could never get past log-in.

I went home to check the security light and when I tried to start it - it was normal, came on for a few seconds and then went off and stayed off... but no fuel pump prime, no crank. However, that afternoon I had an electronic 'buzz' from the dash (that you typically hear when you turn the key but don't try to start), which I did not get that morn. So, I tried to start it again and it started up!

Now I tried to measure the resitance of the pellet in the key, but it was hard to get a good reading... I'm going to see if I can take it to a locksmith to read it and get another key made since I only have one. I assume that the pellet resitance never goes 'bad'?

 

That's what my car was doing until I did the resistor fix on the ignition.

This explains how to figure out the resistance and fix it. I can assure you that it isn't the key most likely.

 

Thanks, glad to know that it most likely the issue.

I got a reading on the resistance of the key pellet, so I'm going to try to do the bypass this weekend even though it is pretty cold out. Why do these things only happen when it is too cold out to work on something w/o gloves on??

 

It wouldn't be as fun that way :P

 

When my went out it was in a Wally Mart parking lot at 2:30am PDT (Prime Drunk Time) and Radio Shack which was less than a block away was not open.
The 2.5 mile walk home would not have been bad. Used to do that in about 20 minutes with a stop at a quik-e-mart in the middle. But with my heart failure now it took me about 2 hours!

 

So, the RadioCrack didn't have resistors. Where are you guys buying them?

 

I have a quick question, I have an 91 rs which Im planning on putting in an 87 5.7 tpi into it, I have everything from ecm and wiring harness to do the swap, is the current VATS going to be an issue?

 

No Resistors... what kinda joint are they running there!!!
Well if you have no other electronics store maybe look online and order. I have ordered from Electronics gold mine before. Or let your fingers do the walking through your areas phone book.

Gregs_
if you have the ECM and wiring you should have no issue with the VATS. It will be elliminated. 89 was when it came out in F-bodies.
I would suggest though either taking your large yellow power wire off the VATS' starter enable relay and running it to the neutral safety switch or gear selector (which ever you have) thus eliminating the relay. Or, you could use the VATS modules ground wire to the relay to a hidden switch for security.

 

Thanks Mad_ for the great info and idea on the "kill switch"

thanks again !

 

So, I finally got the resistors and I'll wire those up this weekend. However, I was thinking, since my problem is intermittant - sometime the car will start - won't I have a problem if it does read the key with the resistors in line, it won't start because then the resistance will be too high?

 

Don't wire it so it also reads the key. What I did, because I was not 100% it was the keys resistance, was just unplug the wire from the ignition lock at the bottom of the column where they come out at, folded the ends of the resistor and jambed them into the plug that goes into the harness as a temp fix until I knew that was the problem. When I was 100% I just got a new lock and key since my original was feeling loose and may have started not turning anyway.

What I have done for others is to just cut the plug and a lenght of wires off the ignition lock side of the harness so no to cut the cars harness, then solder the resistor ends to the two wires. It won't be reading the key resitor at all. Then if you ever decide you wanted to replace the lock, the cars harness is still intact.

The intermitent problem may be due to the wires at the lock not completely broke yet.

 

I see - that makes sense. I'll plan on doing that then...

I did buy a new key blank and had it cut and it seems to be starting fine. The pellet in my old key (the only one that came with the car) was worn way down compared to the new key and I wondered if that could have had an effect?

 

If the old key was not making correct contact with the terminals inside the lock then the VATS cant read the resistance; no start.