1982Stingray

Hey Guys,
I want to bypass the VATS, not just jump the resistor,
i will also bypass the VATS starter interrupt relay, and i know how to that.
But,
I also want to bypass the injection cutoff at the ECM, (i do not want a new PROM chip).
This should be possible by bypassing wires from the VATS 'black box' control module and/or car's ECM, i prefer at ECM so VATS module is out of equation.
I am thinking there should be a wire from the VATS module that interrupts and then completes the 'enable' circuit for the injector.

What i need to know is how-to, as in which wires, to do what, cut, splice, jump to what.

Thank you

Car is 1989 L98

Tunedport90

There are only two ways to get rid of the passkey module.
Have the ecm prom reprogrammed or a hz modulator.
The ecm expects to see a 30-50hz signal to enable the injectors.
http://www.bakerelectronix.com/products_vats/

1982Stingray

can't seem to upload pics here
so VATS module pinout is

A1 = ign sw input
A2 = crank fuel signal
A3 = starter enable relay
A4 = security lamp
A5 = blank
A6 = key resistor (hi)
A7 thru A8 = blank
B1 = ground
B2 = key resistor (lo)
B3 thru B7 = blank
B8 = batt power

Tunedport90

B6 of your 1227165 service number ecm is the hz signal. It’s a dark blue wire .

1982Stingray

No offense but, Are you technically knowledgeable about ECM circuitry?? or just posting a link to a product?
I admit I am not, so why asking for those with such actual expertise.

i find it hard to believe if the VATS module craps out that it cannot be jumped or bypassed to get running.

Tunedport90

Contact this guy to get it programmed out.
Yes I know how the passkey works your welcome.
https://www.thirdgen.org/forums/dfi-...ormance-3.html

1982Stingray

so on stock system what generates the 50hz signal??, the TDM (theft deterrent module) ?

milsurpman

[QUOTE=1982Stingray;1596311719]Hey Guys,
I want to bypass the VATS, not just jump the resistor,
i will also bypass the VATS starter interrupt relay, and i know how to that.
But,
I also want to bypass the injection cutoff at the ECM, (i do not want a new PROM chip).
This should be possible by bypassing wires from the VATS 'black box' control module and/or car's ECM, i prefer at ECM so VATS module is out of equation.
I am thinking there should be a wire from the VATS module that interrupts and then completes the 'enable' circuit for the injector.

What i need to know is how-to, as in which wires, to do what, cut, splice, jump to what.

The vats module controls 2 things the vats start relay and sending data to ecm to disable fuel. Tuner can take care of second. you have to disable both no way around it. jp

bosshog8

http://vatssucks.com/?reqp=1&reqr=

Tunedport90

The passkey module sends the hz signal to the ecm. With a vom if the passkey is working you will see 2.5-5v on this line. The passkey module also grounds the enable relay so cranking can occur. You can either ground the enable relay or splice the larger gauge wires together usually green and yellow.

1982Stingray

Yes, i plan to take the relay out of the equation, and likely wire a switch to use as a starter disable switch.

So on the TDM, can it be jumped to always provide the HZ signal?
and is that part of the TDM failure prone?

Thanks.

Tunedport90

​​​​​​if accessory power is changed to constant 12v and the appropriate resistor is installed for the key reader wiring the hz signal would be constant. This would also cause a small parasitic draw though.

Tunedport90

Sorry I misread your post. As long as you have a combined amp draw of the ecm and hz modulator is half a amp or less you will be ok. Any more than that the battery loose it’s charge faster.

1982Stingray

Cool, that Create SIM chip is close to the solution i was looking for. Thanks!

1982Stingray

Is the TDM output on a 1989 50hz or 30hz?
From what i've read so far, some earlier GM cars use 30hz, like camaros, but most others are 50hz.

WVZR-1

OP - unless you've a failed system I don't believe I'd be concerned with anything other than understanding how it functions. From what you've mentioned it's hard to say that you actually do.

If you don't dick with it when it comes time to actually sort it it's generally much easier. To do other than the accepted 'known to function' I'd say foolish as he!!.

Do I? For the cars I've had or have currently I'd say yes and NONE are currently bypassed. I bypassed the '90 for diagnostics with another CCM but returned it back to enabled.

Tunedport90

1982Stingray

The system currently functions fine, and i knew most about how VATS functions (i installed alarms in the mid 80's), except for the injector signal part, hence my question.

I just wanted to plan out the way i will bypass the TDM to keep injection function from ECM without eliminating VATS altogether by changing PROM chip.

I will set up something i can switch on/off, wired under the dash but so it is accessible, so if stuck a bad place will be quick & easy to bypass VATS and go..

The reason is simple. so i do not get stuck anywhere with a failed VATS and they do commonly fail, i've seen hundreds bad, but been lucky so far on the 89 with only the key cylinder failing at 36k miles.
With planned bypass options wired in i will not have to pull dash apart again. I'm currently doing upgrades to viper alarm & audio system, so dash is already apart, and removed/cleaned seats & carpets, and will put better insulation, i replaced the heater core too as preventive maintenance, so hopefully i won't need repeat such labor anytime soon.

The Only thing "foolish" are those who do not try to learn, do not step outside their comfort zone because they are Afraid to try to do things for themselves.., nothing ventured = nothing gained.

1982Stingray

Thanks. it seems no one knows for sure, so guess i will make a small hz unit with both 30 and 50, this way i can use it on other cars if needed.

JimLentz

Where are you located? If it is anywhere near me we could throw my pocket oscilloscope on it and know for certain.