On Sat, 12 Feb 2005 01:43:38 GMT, aarcuda69062
> wrote:

>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.

That's a good idea ! ;0
I can just disconnect for example the EGR vacuum line or something
simple like that while the engine is running so I can see what will be
recorded at the moment the MIL is lighted.

Good Idea. Beats wondering what and how much information I would get
when a DTC pops up. What I mean by that, is I am currently monitoring
4 out of a possible 23 engine parameters. So when a DTC is thrown, I
don't know how much information of WHAT parameters will get logged to
the chip. This is the perfect way to find out.

Lg


>
>> >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.