1990 Olds Stalls/Bogs on acceleration

"HLS" > wrote in message news:zPAwk.25012
> The waveform is a square wave, approximately, of ca 12 volts. The
> amount of current drawn on the average is determined by the firing time
> and a function of the impedance of the injector.
> Just because you see a firing pulse at the injector does not mean that the
> injector is opening properly. But there WILL be a difference current
> between an injector that is opening versus one that is not.

One more thing, the noid lamp tells you only if the injector is receiving
firing
pulses. It tells nothing about current, etc., in its common embodiments.

Remember also that those pulses are coming from an ECM or PCM. If you
should do something ill advised with a voltmeter or common test light, like
shorting it to ground, you might sizzle some expensive electronics.

On Sep 6, 12:30 pm, "HLS" > wrote:
> "HLS" > wrote in message news:zPAwk.25012
> > The waveform is a square wave, approximately, of ca 12 volts. The
> > amount of current drawn on the average is determined by the firing time
> > and a function of the impedance of the injector.
> > Just because you see a firing pulse at the injector does not mean that the
> > injector is opening properly. But there WILL be a difference current
> > between an injector that is opening versus one that is not.
>
> One more thing, the noid lamp tells you only if the injector is receiving
> firing
> pulses. It tells nothing about current, etc., in its common embodiments.
>
> Remember also that those pulses are coming from an ECM or PCM. If you
> should do something ill advised with a voltmeter or common test light, like
> shorting it to ground, you might sizzle some expensive electronics.

I see thank you for the advice, i really am doing my best to fix this
car. hopefully i will get it done soon

On Sep 7, 9:55*pm, wrote:
> On Sep 6, 12:30 pm, "HLS" > wrote:
>
> > "HLS" > wrote in message news:zPAwk.25012
> > > The waveform is a square wave, approximately, of ca 12 volts. *The
> > > amount of current drawn on the average is determined by the firing time
> > > and a function of the impedance of the injector.
> > > Just because you see a firing pulse at the injector does not mean that the
> > > injector is opening properly. *But there WILL be a difference current
> > > between an injector that is opening versus one that is not.
>
> > One more thing, the noid lamp tells you only if the injector is receiving
> > firing
> > pulses. *It tells nothing about current, etc., in its common embodiments.
>
> > Remember also that those pulses are coming from an ECM or PCM. *If you
> > should do something ill advised with a voltmeter or common test light, like
> > shorting it to ground, you might sizzle some expensive electronics.
>
> I see thank you for the advice, i really am doing my best to fix this
> car. hopefully i will get it done soon

please come back and tell us what you have found...

Mark

On Sep 8, 6:34 am, Mark > wrote:
> On Sep 7, 9:55 pm, wrote:
>
>
>
> > On Sep 6, 12:30 pm, "HLS" > wrote:
>
> > > "HLS" > wrote in message news:zPAwk.25012
> > > > The waveform is a square wave, approximately, of ca 12 volts. The
> > > > amount of current drawn on the average is determined by the firing time
> > > > and a function of the impedance of the injector.
> > > > Just because you see a firing pulse at the injector does not mean that the
> > > > injector is opening properly. But there WILL be a difference current
> > > > between an injector that is opening versus one that is not.
>
> > > One more thing, the noid lamp tells you only if the injector is receiving
> > > firing
> > > pulses. It tells nothing about current, etc., in its common embodiments.
>
> > > Remember also that those pulses are coming from an ECM or PCM. If you
> > > should do something ill advised with a voltmeter or common test light, like
> > > shorting it to ground, you might sizzle some expensive electronics.
>
> > I see thank you for the advice, i really am doing my best to fix this
> > car. hopefully i will get it done soon
>
> please come back and tell us what you have found...
>
> Mark

Here is where I am at now, The whole time i had been working on the
car the fuel pressure gauge has been hooked up. Pressure always looked
perfect. During the bog the pressure showed no drops, it actually
would increase do to the regulator getting less vacuum as the motor
picked up. It always showed the exact specs it should. This is what
made me think it was not the pump or fuel lines, so i looked to the
sensors and wiring, every thing looked great electrically. I checked
the signals from the sensors right at the ecm and all looked good.
Then all the sudden the engine started idling bad for the first time
and the fuel pressure gauge needle started jumping. This is the only
time the car had ran odd other than bogging at acceleration, and also
the only time the fuel pressure did any thing odd! After this, i
started thinking that i bet that even though the pressure is good
99.9% of the time something is still not right between the tank and
the motor. So, I plan to inspect the fuel lines, filter, pump and tank
for debris or blockage. If there is none i have a good feeling the
pump is going. What do you think? And since this one incident the
pressure has been stable and the bogging continues....

On Wed, 3 Sep 2008 21:12:18 -0700 (PDT), wrote:

>This car is a 3.1 v6 it runs ok most of the time. But randomly out of
>nowhere it will bog and stall when you push the gas pedal. ...

I may have missed it, but did you look at the MAF? I saw sort of the
same thing on an 80's Buick, though (IIRC) it happened more on hills.
(Loading, all the same.)

G

On Sep 9, 1:06 pm, George > wrote:
> On Wed, 3 Sep 2008 21:12:18 -0700 (PDT), wrote:
> >This car is a 3.1 v6 it runs ok most of the time. But randomly out of
> >nowhere it will bog and stall when you push the gas pedal. ...
>
> I may have missed it, but did you look at the MAF? I saw sort of the
> same thing on an 80's Buick, though (IIRC) it happened more on hills.
> (Loading, all the same.)
>
> G

Car has no MAF, but i did check the MAP sensor

On Sep 10, 9:06*pm, wrote:
> On Sep 9, 1:06 pm, George > wrote:
>
> > On Wed, 3 Sep 2008 21:12:18 -0700 (PDT), wrote:
> > >This car is a 3.1 v6 it runs ok most of the time. But randomly out of
> > >nowhere it will bog and stall when you push the gas pedal. ...
>
> > I may have missed it, but did you look at the MAF? *I saw sort of the
> > same thing on an 80's Buick, though (IIRC) it happened more on hills.
> > (Loading, all the same.)
>
> > G
>
> Car has no MAF, but i did check the MAP sensor

I think that to solve this, one way or another, you you are going to
have to monitor the pulses from the ECM to the injectors. It can be
done safely if you don't short any wires together or to ground.

Is this car multi-port injectors or single injector throttle body?

Mark

On Sep 11, 9:30 am, Mark > wrote:
> On Sep 10, 9:06 pm, wrote:
>
> > On Sep 9, 1:06 pm, George > wrote:
>
> > > On Wed, 3 Sep 2008 21:12:18 -0700 (PDT), wrote:
> > > >This car is a3.1v6 it runs ok most of the time. But randomly out of
> > > >nowhere it will bog and stall when you push the gas pedal. ...
>
> > > I may have missed it, but did you look at the MAF? I saw sort of the
> > > same thing on an 80's Buick, though (IIRC) it happened more on hills.
> > > (Loading, all the same.)
>
> > > G
>
> > Car has no MAF, but i did check the MAP sensor
>
> I think that to solve this, one way or another, you you are going to
> have to monitor the pulses from the ECM to the injectors. It can be
> done safely if you don't short any wires together or to ground.
>
> Is this car multi-port injectors or single injector throttle body?
>
> Mark

Ok, how do i go about checking the injectors exactly? I checked and
had 12v, to one wire but i don't understand how to find out how the
pulses are changing as you push the gas... It is multi-port injectors,
so they are really hard to check under the plenum. The only other way
i know to check them is to use a light and that will not show the
changes you speak of it will just show that it is firing the injector
right?

On Wed, 10 Sep 2008 18:06:00 -0700 (PDT), wrote:

>On Sep 9, 1:06 pm, George > wrote:
>> On Wed, 3 Sep 2008 21:12:18 -0700 (PDT), wrote:
>> >This car is a 3.1 v6 it runs ok most of the time. But randomly out of
>> >nowhere it will bog and stall when you push the gas pedal. ...
>>
>> ...

If you have a laptop, you can get an adapter to connect it to the car's
OBD output. The software that comes with the adapter (among other
things) lets you run a trace on the various sensor signals, as the
computer sees them. So, you could drive through one of the faults, and
see if it showed anything interesting. (The trace display would let you
examine the dump in a more lesurely setting.)

I bought mine at http://www.scantool.net a couple of years ago, and I'm
fairly happy with it. (My big problem is that my laptop has zero
battery life.)

George

George wrote:
> On Wed, 10 Sep 2008 18:06:00 -0700 (PDT), wrote:
>
>> On Sep 9, 1:06 pm, George > wrote:
>>> On Wed, 3 Sep 2008 21:12:18 -0700 (PDT), wrote:
>>>> This car is a 3.1 v6 it runs ok most of the time. But randomly out of
>>>> nowhere it will bog and stall when you push the gas pedal. ...
>>> ...
>
> If you have a laptop, you can get an adapter to connect it to the car's
> OBD output.


Will he be able to get at the computer that way when the car is that old
(1990)?


The software that comes with the adapter (among other
> things) lets you run a trace on the various sensor signals, as the
> computer sees them. So, you could drive through one of the faults, and
> see if it showed anything interesting. (The trace display would let you
> examine the dump in a more lesurely setting.)
>
> I bought mine at http://www.scantool.net a couple of years ago, and I'm
> fairly happy with it. (My big problem is that my laptop has zero
> battery life.)
>
> George


Look for a new battery on ebay or run the laptop from the car's
electricity using an inverter to convert to 110V AC.