88 Buick VIN 3 stalling, ECM?

[peter paul fenske]

Hi Lynn

Well I have seen quite a few buick 3.0s and 3.8s
with the same symptoms. 

After replacing everything including the ecm et al
we came to the conclusion there is a air leak.

What are you MAF readings.

Some of the stuff we came up was worn valve guides and
vacum leaks. 

But to be honest idle was still not the best
As a clinch we cranked up the idle spd in the
ecm.

good luck:peter


>Some symptoms:
>
>_seems_ to be heat related
>No problems at freeway speeds
>No ECM trouble codes
>During the sensitive time in LA, parking lot speed bumps would cause
>static on the AM radio and make the CE light flicker on.
>Still idles like sh*t -- never hasn't. Not just 90 degree V6 rough,it
>also misses.
>
>Diagnostics:
>
>All cylinders 140-150 psi compression cold. Hot? You jest! Not on my
>skin!
>New plugs and wires. Needed anyway. No change.
>New PCV. Needed anyway. No Change.
>10" hg manifold pressure at idle. Is this normal? Reading taken from
>transmission vacuum line.
>
>
>Got a scanner hooked up today. Following readings are at idle.
>
>ECM PROM ID 1254 -- The ALLDATA CD shows a stall related TSB on this,
>but it isn't included in their (extra cost) TSB's. Sigh. ALLDATA is
>better than Chilton's, but watch out, some of their information is
>missing or flat out wrong (I got bit on a wiring diagram).
>
>Some readings:
>                  ALDL Mode     Diag. Mode    Backup Mode*
>RPM               1000-1100        650          675
>Coolant Temp.     196 F            206 F        217 F
>Intake Air Temp.  156 F (why?)     86 F         84 F
>TPS                0.4 V           0.4 V        0.4 V
>O2 sensor         400-600 Mv       473-549 Mv   920 Mv*
>Spark Advance      28.6 deg        0 Deg        0 Deg
>IAC Position       51              38           49
>Integrator         132             129          128
>Block Mult.        133             133          113
>EGR Duty Cycle     0 %             89%          79%
>EGR Switch         Off             Off          Off
>Closed Loop        On              On           Off
>Fuel Mix           Lean/Rich       Lean/Rich    Rich*
>Learn              On              On           Off
>
>*Sets O2 sensor rich error code.
>
>About all I can figure out right now is to try a new ECM and get the
>latest service release on the PROM. 
>
>Anybody got any other ideas?
>
>TIA,
>
>Lynn
>
>/*********************************************************/
>I may be stupid, but I ain't _that_ dumb.
>lre at xmission.com   www.xmission.com/~lre
>/*********************************************************/
>
>