Wonder if I might ask a question about engine timing?
An older Olds; still with an adjustable distributor.
Fender label says disable the computer, warm it up,
and set the timing to 15 btdc.
Just watching it sit there, the timing "changes itself"
by about 5 degrees randomly and almost constantly.
So would the distributor be rotated so that the
recommend 15 is the most before it gets, or the
Thanks to all who can offer advice.
A wandering timing mark is not an acceptable condition when setting
initial timing. Either the EST was *not* disabled, or there is a
mechanical problem (timing chain sloppy). While the ECM can be placed in
field service mode to disable EST, the fool-proof manner is to disconnect
the EST wire in the engine compartment. Refer to the appropriate service
manual for exact wire color and connector location, but they are usually
a single inline connecter in a brown wire.
On Tue, 01 Jun 2004 13:56:51 -0600, Ken Weitzel wrote:
Thanks for replying...
I just double checked by putting a timing light on
it again. With the code reader plugged in, check light
on, I find the mark walking all over, but "surrounding"
Then pulled out the code reader. Instantly the timing
mark rotates almost out of site (more "before") way off
scale, and stays there. (but continues with its wandering.
Is that good enough evidence that the ecm was disabled?
If so, guess I'm stuck with the timing chain, and looking
at Haynes I'm kinda thinking I'm a bit too long in the
tooth to do it :(
Thanks, and take care.
Thanks Ian. I don't want to (probably couldn't) do it,
and I doubt it's worth paying a pro to fix it.
It's an old car; still looks good. But it's only
purpose in life is to stay at the cabin, gets used
during the summer to put the boats into and out of the
water, to move a guest trailer around once in a while,
and take down the gravel roads to the store in town on
The only problems it shows is a bit rough idle,
the check light comes on if we let it idle for
more than a few minutes, (reader sets lean mixture
code), and mileage seems terrible. The mileage is
probably related to how it's used. :)
Appreciate the advice.
If fuel injected;
To access the set timing mode, you want zero resistance between
pins "A" and "B" of the ALDL.
You have no way of knowing whether your Walmart code reader
actually puts zero resistance between pins "A" and "B".
Maybe spend the bucks on a paper clip?
Disconnect the four wire connector going into the distributor
The connector under the dash that you plug your Walmart code
Try a paper clip, if the timing is still jumpy, it could be a
warning that the ignition module is about to fail, a intermittent
short or open in the ignition coil, a faulty (cracked) pole piece
in the distributor or any of a few other things I'm not thinking
Saved up; bought a paper clip :)
Now the problem is that we can't find any label
or markings on the connector.
My eyes are getting a little old; my just turned
teen grand daughters are perfect. But neither of
us can find markings.
Can A and B be desribed by their location?
Thanks, and take care.
Try here, it's a pretty good picture of the ALDL and the pin-outs:
Pay attention to the little keyway tab shown at the top and it's
orientation to pins "A" and "B".
Fastastic! Unfortunately shows that my little tester
dead shorts those pins (actually both "pins" are one
piece of metal)
But something learned is great...
And that site is great; all kinds of information! :)
Thanks again, and take care.
Someone help me out here............I have documentation somewhere that
tells me to place a particular resistor ( I think 1000 ohm) in between two
pins to enter the computer into field service mode where the timing and RPM
are held at a constant. There is also another resistance that will test the
TCC on different pins...anyone know what I am talking about and can refresh
Hi Eightupman... (shouldn't that be seven up man? :)
I'm an old retired electrical engineer, so I know
pretty much which pedal to push to go and which to
stop; not too much more...
But if it helps, this little 19 canadian dollar walmart
code reader does that.
The timing isn't (for sure) controlled by the computer,
and the engine rpm stays constant. Well, constant.
When normally you start it it goes reasonably fast,
then within a few seconds slows down quite a bit.
With this device plugged in it doesn't slow.
Hope this helps.
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