And the Reason

wrote:
> why I wont buy that 1990 Chevrolet RV van from a neighbor who lives in
> that house behind me is because I dont know anything about throttle body
> fuel injection,,,, I think I am too old to learn either.Carburetors,
> (simple one barell and two barrel carburetors, I know how to work on and
> get them going) It is a nice looking 1990 Chevrolet RV van, but not for
> me.
> cuhulin

I am about your age and I will never stop trying to learn new things.

In article > ,
"HLS" > wrote:

> "Pete C." > wrote in message news:YQjEj.5554
> >
> > I think FI is simpler than a carb. It's just a solenoid valve, power it
> > to spray fuel.
>
> Which brings up a question of mine....
> On some of the GM 3800 applications (in this case a 1990 Reatta), a waveform
> is generated by the ECM to fire the injectors under starting conditions.
> This will
> not happen if the quirky security system (key resistance reader) is feeling
> obstinant
> at the time.

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

> Once the car is started, the ECM takes over the function of the fuel
> injection system
> controlled by operating parameters.

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

> Not much is available, AFAIK, about the nature of that startup waveform, in
> case a person would like to bypass the security system totally. (The
> electronics in these cars
> is excessive and subject to multiple types of glitches)

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.

> Does anyone know if that waveform is a simple set of pulses, or is it more
> complicated?

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.

"aarcuda69062" > wrote in message
...
> In article > ,
> "HLS" > wrote:
>
>> "Pete C." > wrote in message news:YQjEj.5554
>> >
>> > I think FI is simpler than a carb. It's just a solenoid valve, power it
>> > to spray fuel.
>>
>> Which brings up a question of mine....
>> On some of the GM 3800 applications (in this case a 1990 Reatta), a
>> waveform
>> is generated by the ECM to fire the injectors under starting conditions.
>> This will
>> not happen if the quirky security system (key resistance reader) is
>> feeling
>> obstinant
>> at the time.
>
> The ECM doesn't generate waveforms. it merely processes inputs
> and toggles outputs.

**** 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.

>
>> Does anyone know if that waveform is a simple set of pulses, or is it
>> more
>> complicated?
>
> The key resistance is not a waveform, it is a simple voltage drop.

****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.


> 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.

***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.

AZ Nomad > wrote in article
>...
> On Thu, 20 Mar 2008 11:09:29 -0500, * > wrote:
>
>
> wrote in article
> >...
> >> why I wont buy that 1990 Chevrolet RV van from a neighbor who lives in
> >> that house behind me is because I dont know anything about throttle
body
> >> fuel injection,,,, I think I am too old to learn either.Carburetors,
> >> (simple one barell and two barrel carburetors, I know how to work on
and
> >> get them going) It is a nice looking 1990 Chevrolet RV van, but not
for
> >> me.
> >> cuhulin
> >>
> >>
>
>
> >Geez!
>
> >You say that as though you truly believe that there are more than a
couple
> >of people - if that - in this world whose lives simply will not go on
> >without your daily ramblings!
>
>
>
> Ditto for your bitching. Originally, I never saw his rambling because I
> filter out all webtv posts. Thanks for reposting his ramblings along
with your
> amazing insights. not.
>

Glad I could be helpful to you.

You might have missed the old guy's post otherwise.

On Thu, 20 Mar 2008 22:36:05 -0500, aarcuda69062 > wrote:
>In article > ,
> "HLS" > wrote:

>> "Pete C." > wrote in message news:YQjEj.5554
>> >
>> > I think FI is simpler than a carb. It's just a solenoid valve, power it
>> > to spray fuel.
>>
>> Which brings up a question of mine....
>> On some of the GM 3800 applications (in this case a 1990 Reatta), a waveform
>> is generated by the ECM to fire the injectors under starting conditions.
>> This will
>> not happen if the quirky security system (key resistance reader) is feeling
>> obstinant
>> at the time.

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

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

In article
>,
AZ Nomad > wrote:

> On Thu, 20 Mar 2008 22:36:05 -0500, aarcuda69062 >
> wrote:
> >In article > ,
> > "HLS" > wrote:
>
> >> "Pete C." > wrote in message news:YQjEj.5554
> >> >
> >> > I think FI is simpler than a carb. It's just a solenoid valve, power it
> >> > to spray fuel.
> >>
> >> Which brings up a question of mine....
> >> On some of the GM 3800 applications (in this case a 1990 Reatta), a
> >> waveform
> >> is generated by the ECM to fire the injectors under starting conditions.
> >> This will
> >> not happen if the quirky security system (key resistance reader) is
> >> feeling
> >> obstinant
> >> at the time.
>
> >The ECM doesn't generate waveforms. it merely processes inputs
> >and toggles outputs.
>
> 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.

"aarcuda69062" > wrote in message
...
> In article
> >,
> AZ Nomad > wrote:
>
>> On Thu, 20 Mar 2008 22:36:05 -0500, aarcuda69062 >
>> wrote:
>> >In article > ,
>> > "HLS" > wrote:
>>
>> >> "Pete C." > wrote in message news:YQjEj.5554
>> >> >
>> >> > I think FI is simpler than a carb. It's just a solenoid valve, power
>> >> > it
>> >> > to spray fuel.
>> >>
>> >> Which brings up a question of mine....
>> >> On some of the GM 3800 applications (in this case a 1990 Reatta), a
>> >> waveform
>> >> is generated by the ECM to fire the injectors under starting
>> >> conditions.
>> >> This will
>> >> not happen if the quirky security system (key resistance reader) is
>> >> feeling
>> >> obstinant
>> >> at the time.
>>
>> >The ECM doesn't generate waveforms. it merely processes inputs
>> >and toggles outputs.
>>
>> 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.

On Fri, 21 Mar 2008 11:29:02 -0500, aarcuda69062 > wrote:
>In article
>,
> AZ Nomad > wrote:

>> On Thu, 20 Mar 2008 22:36:05 -0500, aarcuda69062 >
>> wrote:
>> >In article > ,
>> > "HLS" > wrote:
>>
>> >> "Pete C." > wrote in message news:YQjEj.5554
>> >> >
>> >> > I think FI is simpler than a carb. It's just a solenoid valve, power it
>> >> > to spray fuel.
>> >>
>> >> Which brings up a question of mine....
>> >> On some of the GM 3800 applications (in this case a 1990 Reatta), a
>> >> waveform
>> >> is generated by the ECM to fire the injectors under starting conditions.
>> >> This will
>> >> not happen if the quirky security system (key resistance reader) is
>> >> feeling
>> >> obstinant
>> >> at the time.
>>
>> >The ECM doesn't generate waveforms. it merely processes inputs
>> >and toggles outputs.
>>
>> 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.

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


>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.

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

"AZ Nomad" > wrote in message
...
> On Thu, 20 Mar 2008 22:36:05 -0500, aarcuda69062 >
> wrote:
>>In article > ,
>> "HLS" > wrote:
>
>>> "Pete C." > wrote in message news:YQjEj.5554
>>> >
>>> > I think FI is simpler than a carb. It's just a solenoid valve, power it
>>> > to spray fuel.
>>>
>>> Which brings up a question of mine....
>>> On some of the GM 3800 applications (in this case a 1990 Reatta), a
>>> waveform
>>> is generated by the ECM to fire the injectors under starting conditions.
>>> This will
>>> not happen if the quirky security system (key resistance reader) is
>>> feeling
>>> obstinant
>>> at the time.
>
>>The ECM doesn't generate waveforms. it merely processes inputs
>>and toggles outputs.
>
> Where did you get that insane notion? Do you even know what a waveform
> is?

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

On Mar 21, 11:58*am, AZ Nomad > wrote:
> On Fri, 21 Mar 2008 11:29:02 -0500, aarcuda69062 > wrote:

> >> >The ECM doesn't generate waveforms. *it merely processes inputs
> >> >and toggles outputs.
>
> >> 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.
>
> All irrelevent.
> A waveform is simply a plot of amplitude over time.
>
> >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.
>
> No **** sherlock. *It is one reason you use an osciloscope instead of a 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