[Gmecm] EST on the 808/165

[Andrew Hopton]

The manual I have (referred to in an earlier post) states that EST is also
disabled if the ALDL test terminal is earthed, and RPM are below 2000..
Maybe your datalogger is pulling/loading this pin down enough to affect EST.
Also, the problem with the O2 makes me think you could have a dodgy earth
somewhere, which is contributing to both problems. Another area you could
look at is the pickup coil (I am assuming you are using a reluctor-style
dizzy) and it associated magnet ? if you have a digital voltmeter, measure
the AC generated ? I think it needs to be at least 1.5v to drive the usual
Bosch HEI (not 100% sure about that). (Note, the HEI module also needs to be
well-earthed thru its mounting holes).  Another thing you could check is the
resistance of the pickup coil- should be 500-1500 ohm and not earthed.

 

-----Original Message-----
From: gmecm-bounces at diy-efi.org [mailto:gmecm-bounces at diy-efi.org] On Behalf
Of Andrew Huxtable, IT Support, Lonsdale
Sent: Thursday, 7 April 2005 9:55 AM
To: gmecm at diy-efi.org
Subject: [Gmecm] EST on the 808/165

 

Guys,

            I?ve got a bit of a question.  I have an 808 based 4Cyl car and
for some reason it keeps misfiring at about 3K+.  It?s an intermittent fault
too.

 

I?ve replaced dizzy cap, rotor, plugs, leads and ignition module and the
problem remains.  The problem actually seemed to worsen when I replaced the
ignition module so I swapped it back. I?m not getting any ECM codes though.

 

I have now started to log the data from the ECM to look into this further
and have noticed a couple of things that do not seem right.

 

1)       Around (not at) the time that it tends to misfire, the O2 goes to 0
(single wire 02)

2)       The EST flag is constantly changing with engine running

 

Now, according to the doco that I have, if the engine is above 400rpm EST
should be enabled i.e it?s only in fixed mode when cranking. Does this mean
that I?ve found the problem?  What about the o2?

 

Any help appreciated.

 

Thanks,

            Andrew

 

 


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