Dmity Kiev

Hello , i send messages private messages to few 3gen members , but if you dont mind i will start new tread, maby some people will have any ideas.

Fireibrd 91 originally 3.1 LH0 i swap caprice 350 L05 in it.

ECM is 6965

Shes have only 8 deg of timing advance , and dont want to work by SA tables that i edit in tunerpro , even i zero or put to maximum values SA table shes work identical.

I have friend with Caprises L03 motors and take parts from they worked cars
I try 3 coils , 3 EST , 3 ESC modules , 2 knock sensors , 2 ECMs with stock or my prom. always the same problem only 8deg advance.

NO ERROR CODES , NO SES LIGHT

Versions of problem is BYPASS problems or KnockTest passing by ECM

All harness under hood is absolutely new , EST module is recieve signal from ECM . ESC ricieve signal from knock sensor and send it to EST.

by AllData wiring diagrams everything seems ok , and all signals os ok, unless interesting thing with BYPASS . we found that on this wire is 0 volt when engine running but wire is good without Short circuit , as we understant when shes goes to bypass mode on EST at connector B must be 5Volt (like this sheme https://www.thirdgen.org/forums/atta...ng-diagram.pdf)
but even whe BYPASS is on she stiil advance timing from 4 to 12 degrees. and at leg B EST in 0volt , when we put 5V to EST manually she goes to bypass and stop advancing timing. Question is WHY It is irresponsive to plug or unplug bypass connector, Questionw two is if she was in bypass always why she advance timing and dont send 5V to EST


Sorry for bad english. Dmitry . Kiev Ukraine

RBob

iTrader: (1)

When the BYPASS connector is open, there will still be some advance. This is for limp mode operation. So if you open the BYAPSS and check the timing at low RPM (idle) it should be at 0 BTDC.

Then as the engine is rev'd up (increase the RPM), there will be a sudden jump in timing. The ignition module will add in the range of 12 to 16 degrees of timing. This is normal.

After the BYPASS connector is closed (re-connected), the ignition needs to be turned off for at least 10 seconds. Then when the engine is re-started the timing should be about 15 - 20 degrees BTDC.

RBob.

Dmity Kiev

in my case when we open bypass at idle timing is stiil 4 , not 0 BTDC . when i add rpm max additional timing that i have is 8deg. next as Rbob said we key off ignition and then start engine and at idlle we still have 4 BTDC.

RFmaster

Dima

Take pictures (photos) of your distributor, rotor, EST module and pickup coil. It all should work, but I am guessing here being 6300mi (10,150km) from Kiev. So, since we are not going to visit Kiev this weekend let us see what you have mounted on top of that good looking intake!

Your dizzy should look like this:
https://www.thirdgen.org/forums/atta...-new-dizzy.jpg
https://www.thirdgen.org/forums/atta...o-211-crop.jpg
https://www.thirdgen.org/forums/atta...w-img_0001.jpg


I am also adding a basic ignition check list from a factory service manual (FSM)

and a picture of an original GM made EST module - please record ( or take a photo) and post numbers that you see on top of your module.

//RF

RBob

iTrader: (1)

If the timing is at 4 BTDC with the BYPASS open, then the distributor base timing is not set correctly.

Having the module add 8 degrees when the RPM is increased is a little on the low side. However, it may be an after market module which is why it doesn't advance enough.

As for still having the base timing once the BYPASS is closed and the engine re-started, it may be a calibration issue. Since you have changed out the distributor/module multiple times, may be the real issue is how the calibration is set up.


Question: when the BYPASS is open, does the SES light turn on and the ECM set code 42?

RBob.

Dmity Kiev

I check today all wires by schemes , all is OK but whtn BYPASS is opes i dont have SES light with 42 error code

RBob

iTrader: (1)

Does the SES light turn on when the key is on, and the engine is off?

If the SES is on during key-on, engine-off, and the wiring is OK, then either the ECM or the ignition module is bad.

Opening the BYPASS with the engine running should always turn on the SES and set a code 42.

RBob.

Dmity Kiev

if key on engine off SES light is on , when engine started SES is of , SES light work becouse i can get rich,lean,51,map high etc errors. i swap two difference ECM , one of that was stock L05 Caprice. can be 3 ignition modules from works cars be bad ? it seems like gremlin lives in my car

RFmaster

Dima

In my experience EST module failure has been an infrequent, but pain in the back occurrence. The problem is prevalent to aftermarket, non GM modules. Most aftermarket companies - Wells, Standard, Niehof, to name a few, make or have their parts made in Chinese factories. Quality control and adherence to specifications is questionable at best. So far, I have seen only one case of 7-pin GM EST module failure. IMHO, EST modules fail due to high heat especially when coupled with high current aftermarket ignition coil. A root failure cause can be traced to excessive use of dielectric grease or failure to remove old compound before installing new module. EST module acts as ignition coil's primary winding switch - in old days (before HEI) this task was performed ignition points. Ignition points had to be periodically inspected and replaced. The biggest enemy of EST modules is heat and ground path resistance as it's periodically pulls ignition coil negative terminal to ground - thus energizing primary winding, building a magentic field. When EST opens this circuit collapsing magnetic field induces current change in the secondary windings producing HV - spark.

Get another module (PM me), clean EST mounting pad inside distributor, make sure that there is a ground wire between dizzy and engine ground.

//RF

Dmity Kiev

I have 0 volts at bypass wire all time (and no SES 42 light), when it pluged or unpluged . i know that when engine is runnind ECM must send +5V from D5 by bypass to Ignition control module , after that recieve responce to D4 from module and then EST will work. but in my case when i put to D5 with bypass connected +5V timing dont move at all D4 voltage jumps are gone. when bypas connected or not with 0V on it timing move forward by 8 degrees. wire from D5 to module is good, D4 to Ign contrl module is good too, ECM is grouded . what should i check now ?