On Thu, 17 Aug 2006 04:35:00 GMT, aarcuda69062
Use to check CO,NC and NOx emissions here bi-anually until last year
when they stopped doing it. That burb easily passed it every time and
well below limits.. Matter of fact, none of my cars ever failed.
It was simulated driving cycle on a dyno if that is what you are
looking for. It was about a 10 minute cycle but if vehicle was far
below max limits, the software would terminate test and pass vehicle
early. It would only go full cycel if it was close to limits and they
needed a bigger data spread to work with.
Did you disconnect the vacuum advance before you checked he
timing, was the idle speed all the way down to curb idle?
Did you take the cap and rotor off and check that the mechanical
advance isn't seized?
Ja, Ja, did the vacuum advance....its an older van...stationed here in
-40C Winnipeg, Canada....the battery been frozen over at least 4 times.
First time I started it in nearly 2 years. Still has that old gas from
two years ago....but I might need to adjust the Carb because there was
an issue about it before the tear down.
Ok... you got 12vdc...good.
When you installed the new coil, did you make sure the grounding strap
was connected between the frame of the coil and the middle leg of the
connector on the side of the cap? If not, it'll smoke your new module
in a hurry.
I asked in another response, but I'll ask again...does the module have
4 or 5 pins? If it's a 5-pin module, there's a GM service bulletin
that pertains to bypassing the basic ECM that connects to it.
When asking about the module....I assume the black horseshoe item
located beneath the rotor. If so...it is a five prong Module, three on
one side 2 on the other. So...does this mean I should still be able to
Go to where the missing box is under the drivers seat, jumper the
green wire to the black wire, this bypasses the ESC function.
(you'll no longer need the module under the seat, so don't run
out and waste any money on one)
A blue scotch-loc will work fine for his.
Better be ready to run timing at ATDC some because it will knock on 87
octane in warm weather big time if it is a ESC system and when you
retard spark you retard MPG too.
I know it is different as it was first generation (they are on third
gen now) but even the modern replacement parts for it are more
relaible than those parts made nearly 25 years ago.
Silly me. Spent the whole day working on a Nissan Maxima,
I guess I forgot my GM basics.
... no I didn't.
No, the newer -designs- are more reliable, not to mention that
your 89 has no mechanical fuel pump to contribute noise into the
knock sensor circuit and uses a serpentine belt instead of the
(vintage 85) vee belts which would get hot and stretch in the G
vans and contribute enough racket into the knock sensor to cause
power loss and poor fuel economy.
The term "couldn't pull cotton out of a Kotex" was frequently
used back in the mid 80s WRT 305 trucks and the way the ESC
You know I have been driving since late 60's and have been around and
dirven most of the vehicle discussed here or ones like them. I saw
some reliable ESC systems. Also the knock sensor has a quarts crystal
in it and it listens for a certain frequency that a knock produces and
it is a lot different than fuel pump noise in this regard. Van
generally were more prone to knock because they had higher underhood
temps which increase tendancy to knock on lower octane fuel and would
make them appear more troublesome at times. BTW, the reason they went
to a electronic pump is because TBI fuel injection needed a stead fuel
presure supply not because the pump was interfering with knock sensor.
I know all about those pumps because my dad rep'ed for a company that
did prototype work on the pump motor for GM in mid 80's and provided
them for a while too. I could tell you all about those motors. I used
to have one of the prototypes years ago but it is long gone now. It
was a bit of a challange at first to make them work and last but they
worked it out before production. My 89 still has original pump too.
(one of my "dad's" motors so to speak)
Indeed. Seems I recall Snoball making a claim to that effect...
Agreed. A classic example would be comparing a mechanical/vacuum
advance distributor with ESC in a 1985 van to a computer
controlled EST/ESC system in a 1989 Suburban (or S-10) and
expecting the second to behave the same as the first.
Without the ESC/ECM module connected, you probably will not be able to
The purpose of the ESC (electronic spark control) is to delay (retard)
spark timing based on input from a knock sensor. The 5-pin module you
have basically has an "in" and an "out", which are pins 1 & 3 on the
3-pin side of the ignition module.
Aarcuda69062 gave you the quick fix on how to bypass the ESC. If the
ESC is missing altogether, then this is also the solution to get up and
running with that 5-pin ignition module. Basically, if you traced them
back to the distibutor, the two wires he describes connect to those two
outer pins on the ignition module. You're just bypassing the computer
and letting it form a loop.
As I stated earlier, that early form of electronic spark control was
problematic enough to where GM issued a service bulletin detailing the
very simple process of bypassing the system. Once the two wires are
jumpered together, the ESC can be disconnected altoghether.
TIMING CHAIN GEARS Broken ( does the ignition rotor Turn when rolling
over the Engine?)
Distributor Gear pin SHEARED
Distributor MODULE ( NEVER CHECK for Spark by grounding an ignition
wire. Also Attach a good spark plug to that wire or U will Blow The
IGNITION module )
ignition fuse blown in the fuse box ( No 12 volts on the RED wire that
hooks to the ignition cap )
Jon R. Pickens wrote:
It Doesnot Take Brains To
Get A High Paying Job!
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