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  #53  
Old February 12th 05, 02:43 AM
aarcuda69062
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In article >,
Lawrence Glickman > wrote:

> >If it is fuel starvation or over fueling, it will show up on the
> >O2 sensor voltage and/or the fuel trim numbers viewed on a scan
> >tool, I mentioned this to him in a post a while back at the
> >beginning. He procured a scan tool but went no further with it.
> >He could have posted the scan data here and myself and a number
> >of others could have given out opinions of what was there.

>
> OK. Myself, I've recorded what should be "normal" numbers for my own
> engine using a data logger and storing the file(s) on my hard drive
> for future reference.


Good idea. It's always better to know what normal looks like
then trying to figure it out once things go wrong.

> I've also used my Scantool to record what parameters that reveals:
> e.g.
> long term fuel trim bank 1 % = 5.5, 4.7, 1.6, 2.3
> short term fuel trim bank 1 %= 0.00, -2.3, 1.63, 3.9
>
> long term fuel trim bank 2 %= 3.1, 3.9, 7.0, 7.8, 7.0, 7.8, 3.9
> short term fuel trim bank 2 %= 2.3, 2.1, 0, -.08, -2.3, -3.1


Add the long term fuel and the short term fuel to determine the
total fuel correction at that instant, anything over 10-12
percent is cause for suspicion.

> and I am lead to believe, from my readings, that it is perfectly
> NORMAL on my engine for bank 1 to be quite different from bank 2,
> although I can't put my finger on the source of that information at
> this moment.


Yes, that is true.

> Now goody for me, I can program my data logger to record all of the
> above values in a continuous stream if so desired, so if I see any
> MARKED deviation from my baseline reading, I've got a "clue."
>
> There are many many other parameters I've recorded for baseline
> purposes, too many to list here. Point is, I would have reference
> values to consult. Maybe this is asking too much for anybody to do.


It becomes a question of whether it is possible.

> >He did mention in one post that his running fuel pressure dropped
> >to 50 psi, this is 4 psi below the absolute minimum required to
> >open the poppet nozzles in his CPI system ( pressure
> >differential)
> >
> >He'd be best off with a scan tool with recording capability, that
> >way he can trigger a recording on a test drive at the moment the
> >problem occurs, and then review the movie from the trigger point
> >for anything unusual.

>
> Wouldn't he get what's called Freeze Frame? IOW, my data logger has
> the ability to show all engine parameters it is capable of reading at
> the moment a malfunction occurs.


His is a 95 model year, not yet quite OBD2, his system may not
have the capability to record freeze frame data, I also believe
that he's posted that he's not getting any fault codes, so if no
fault is being detected, no freeze frame.

> I've never had the pleasure of
> seeing this happen, so I can't be more specific, IOW, I can't give you
> the parameters delivered because it hasn't happened to me =yet=. But
> if and when it does, I may post for General Information purposes.


Just booby-trap something.
Loose gas cap, disconnect the EGR, pop the purge flow sensor off,
etc.

> >It's also entirely possible that it isn't a fuel problem.

>
> Could be electrical. Intermittent loss of power to fuel pump, etc.
> But I'm wondering if that wouldn't throw a DTC. Again, I've never
> experienced ( on this car ) a malfunction so I can't be more specific.

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