And the Reason

The ECM doesn't generate waveforms. it merely processes inputs and toggles outputs.

Actually, this occurs as soon as the starter motor engages and turns the crankshaft.

In this context, by passing the VATS system is as simple as measuring the resistance of the key pellet with an ohm meter and substituting a resistor of that value at a convenient point in the VATS harness. IOWs, the standard work around if installing a wireless remote start.

The key resistance is not a waveform, it is a simple voltage drop.

I haven't studied this system in over 20 years but it is probably a situation where there is a matching resistor on whichever circuit board serves the VATS system, When the key is inserted in the ignition lock, that resistance is put in parallel with the one on the circuit board. If the voltage drop is correct, the fuel system is enabled.

**** According to the schematic I have, the system generates a series of pulses to fire the injectors during startup. Sort of jump starts the injection system. After the engine starts or engages, the FI is controlled separately. Maybe we are saying the same thing, maybe not. Havent looked at the schematic in a while. Maybe those pulses come from somewhere other than the ECM, but they are generated only if the resistance "code" is met. Otherwise, I could bypass the security system and activate the starter directly. If I try that as it sits, the car will not start because no fuel will be injected. ****Yep, correct. The VATS is nothing more than a code reader at this level. The resistance in the key is compared with that in the VATS system, and if it is within reasonable correspondence, the system should allow the starter to engage.And if the system is functional, the FI system will inject a starting charge at this point. ***This is a resistance comparator situation, as you suggest. I already bypassed the resistor in the key with a precision resistor, and this worked well for a while. Then it stopped working. I havent gone back in to see what is wrong with it, but it is probably just a simple connection problem.

This car has been plagued by another problem, intermittent battery discharge. Hard as hell to find in a normal car, and this car is far from normal with the electrical system being as complicated as it it. I put a battery cable switch on it, and use that to protect myself. Sometimes the battery will do fine for several days, and then suddenly will be discharged.

I think my wife may have spotted the solution. She woke up in the middle of the night and saw the taillights come on. I suspect this is the long sought intermittent.

I have just about lost interest in this car due to the problems. Not one of Buick's finest moments in engineering and construction, the car is still sharp looking and fun to drive, not so fun to push.

Maybe Ill just part it out.

Where did you get that insane notion? Do you even know what a waveform is?

You believe that the ECM generates waveforms?

Wave forms are an observed phenomena, the shape of which are influenced by inductance, reactance, resistance, reluctance, etc.

Lets suppose we're analyzing amperage waveforms of the injectors on HLS's Buick. He has one shorted injector and 5 properly functioning injectors. The shorted injector is easily identifiable when analyzing the waveform. Explain for me how this is the result of anything having to do with the ECM.

The ECM no more "generates" waveforms then the newspaper generates news.

The waveform I was referring to is a simple square wave, switching situation for the injectors during startup.

All irrelevent. A waveform is simply a plot of amplitude over time.

No shit sherlock. It is one reason you use an osciloscope instead of a voltmeter.

All the ECM does is provide a ground to the fuel injector for a programmed period of time. It DOES NOT generate a waveform !!!!

voltmeter.- Hide quoted text -

For all other reasons, I just use an *oscilloscope*, Watson... y'know, to see waveform(s) on the screen that represent voltage activity on the tested circuit(s).

Toyota MDT in MO

In providing a grounding function it serves as a switch, and certainly does provide the switching waveform.

A PWM signal *is* a waveform.

Yes it does. It generates a pulse train and controls the frequency and pulse width. Again, you demonstrate you ignorance.

Ignorance is bliscilloscope.

From Answers.com/Sci-Tech Encyclopedia (a general scientific reference to all types of waves that can be "formed")

Waveform

The pictorial representation of the form or shape of a wave, obtained by plotting the amplitude of the wave with respect to time. There are an infinite number of possible waveforms (see illustration). One such waveform is the square wave, in which a quantity such as voltage alternately assumes two discrete values during repeating periods of time. Other waveforms of particular interest in electronics are the sine wave and rectified sine wave, the sawtooth wave and triangular wave, and the arbitrary wave--a recurrent waveform which takes on an arbitrary shape over one complete cycle; this shape is then repeated in successive cycles.

Or more simply and specifically explained for the purpose of this discussion at InFocus:

Waveform

A display of a signal (on an oscilloscope) that shows the magnitude of current or voltage with respect to time. For example, by displaying the waveform of a signal on an oscilloscope, and measuring the time between cycles, its frequency can be calculated.

So again, the scope generates the waveform.

Toyota MDT in MO

That's right, and ECMs do not generate "plots."

That's right, I use an oscilloscope. What do you use?

Wanna wave your dick some more?

Yes they do. They set the output based on time and the result is a waveform.

No, it doesnt. It makes the waveform visible to the observer..

By fish's logic, there's no such thing as a electrical waveform. The best thing to do with the fool is put him into a killfile.

By your logic, if I take the lid off of an ECM, a bunch of waveforms are going to spill out.

You're absolutely insane.

Sorry I even asked. Too many people get hung up on the semantics, but I suspect (1) everyone knows what Im talking about, or (2) some have no clue about this system.

Let's drop the waveform word. I wanted to know how to fool the system into injecting fuel during startup if the security system was balky.

Apparently nobody knows.