guys i am working on a special project.. the engine has a ccw rotation distributor .... the standard gm has cw rotation ...

i had a custom distrobutor machined to use the GM factory distributor module ...

I am having trouble tuning ... i think it has to do with TIMING .. the module wants to advance timing but my scanner program shows the timing retards and goes negative....

Am i CRAZY .... if i set all the timing tables to zero the vehicle runs much better than adding advanced in the charts ...


HELP anyway i can make the module act in reverse via programing .. a NEGATIve timing table ????

 

If your scanner program is showing the timing retarding, then there is an ECM problem. The ECM acts on it's own when calculating the SA value. The only thing the distributor provides is a DRP to the ECM hardware.

What does a timing light show on the crank compared to what the ECM is telling the distributor the timing should be. And what ECM are you using??

RBob.

RBob.

 

Rob,
The ecm I am using is a 94 16196395 tuning with E6
NO knock sensor

does CCW rotation have anything to do with the negative value
if the computer adds timing " for the standard CW rotation" that would subtract timing for the CCW ... does that make any sense

... what weird is that if i take out all the time in the CL/OP throttle the car begins to run better ...than if i add timing to the tables ...


FYI unable to get to timing mark's english engine timing off the flywheel...

 

The ignition module only sends a stream of pulses (DRP's). Each pulse is for each cylinder in turn. The ECM counts the pulse rate (frequency) and from that calculates the RPM.

The ECM hardware handles the EST signals (again pulses) to the distributor. The EST pulses set the dwell and fires the plug when required.

Other then the RPM calculation the ECM doesn't use the DRP's for the SA value. If you had said that the "at-crank" timing was off and retarding, then there could be an issue in the distributor.

Does the RPM reading on the scanner program match what the engine is really at?

You mention no knock sensor. . . Are the knock retard tables zero'd out?

RBob.

 

it appears that the running e6 on a OD computer does not work well ..

I set it up with 93 TBi truck ecm E6 code and started to tune..

the engine is a siemized runner intake 4 cylinder
the intake has cylinder 1&2 tied together 1 injector 3&4 tied together with 1 injector.

fires 1342.... it acts just like a car with no timing advance if you slowly give it the throttle it will start to run smooth and the higher rpm max rpm might be 2500 rpm...
i started added timing in the main table closed and open throttle tables ... still stumbles off idle ..engine take 16degree max timing!

at idle it starts to stumble after running for 30-45 seconds... it does not seem to be overly rich ....

i am wondering if the intake manifold design is causing problem !


Thanks ROB