No change in timing and AFR

flowbench · Post by **flowbench** » Fri Jun 24, 2016 4:20 am

Good morning, I have steup my freshly rebuilt 350 sbc with an HEI 8 pin ignition system and run into some problems:

The timing does not change : I did "fix the timing" in tunerstudio to 10 BTDC and had the distributor adjusted so to get 10 deg on the damper
with my timing light.
Trigger wizard is set to 0 degrees.
Correct so far ? After that I put the timing on "use table" and burned it to the ECU. With the timinglight I still do have 10 Deg BTDC
indicated all the time on the damper even during rev up.
. The only change is a small retard, about 2 Degrees.

2016-06-24_13.10.08.msq

Any ideas on this ?

Next problem is that the car runs way to rich and EGO control doesnt seem to work at all. It indicates about 12.2 to 1 on the "dashborad". So I
put the EGO control to "disabled" and played with the injection timing to lean it out. It still stays around 12.2 indicated.
Next I had the EGO-control set up for "Single Wide Band" but observed
the same problem: no movement, no change in AFR.
any ideas here ?
I did add an log (right after cranking, not driving, just playing in idle)and it looks, that changes in timing are there, but not being "done".

2016-06-24_12.19.48.msl

Thanks a lot !!!

Matt Cramer · Post by **Matt Cramer** » Fri Jun 24, 2016 5:38 am

First, please confirm you have 5V on the bypass pin on the HEI module with the engine running.

flowbench · Post by **flowbench** » Mon Jun 27, 2016 3:19 pm

Matt, since the trouble from lastyear (read my last post) I did run the car with pin 6 disconnected ! When I connect the wire on pin 6 to the ECU, it wont start, I dont get an rpm -signal. When the engine runs I can connect pin 6 and it'll keep running but will still have no change in spark advance or fuel control. This must have something to do with finding the right polarity on the input- circuit, which kept me busy last season.Attaching pin 6 to the ecu will kill the signal from the distributor on the ECU board. Anyway,- after modifying the input circuit ( bridging the two diodes and removing the C30 Capacitor) we have a crystal clear signal coming from the distributor (HEI 8 pin), going through the optocoupler into the processor.When pin 6 is connected, it'll kill all the signal while cranking.Again, once the engine runs and out of the cranking-mode I can hook up pin 6: this willl stabilize idle rpm a little, but thats all. Engine runs super, super rich, and wont accept leaning the fuel map. Thanks for any help on this !!!

turbo conversion · Post by **turbo conversion** » Mon Jun 27, 2016 4:10 pm

If I am understanding this correctly you are saying the timing at the crank is 10 deg. no matter what.

Looking at the data log this is not the case, timing-mapdot and rpm are all over the place with steady tps.

No idea what is causing this but I have never seen such an unstable data log, anyone?

David

billr · Post by **billr** » Mon Jun 27, 2016 4:42 pm

Yeah, and both MAP and TP are staying constant.

flowbench · Post by **flowbench** » Mon Jun 27, 2016 10:12 pm

Yes, the timing stays more or less stable at 10 Degrees but will retard slightly at higher rpms. When I switch to "fixed timing" and will use for instance "20 Degrees" there it'll show that figure on the dashboard on the "ignition advance gauge", but timing measurd on the damper is still 10 degrees. I dare to play around with the settings since this engine is a brandnew rebuilt that has not been broken in yet... I already did flood it yesterday and I am concerned about the piston rings if this happens a few times more...
I feel the issue with the input circutrie might be something to focus on first ? By the way,- using the stimulator gives perfect results.
Thanks for any help !!!

billr · Post by **billr** » Tue Jun 28, 2016 8:38 am

Is the engine rpm actually varying that wildly? Or is that an indication of bogus data?

flowbench · Post by **flowbench** » Wed Jun 29, 2016 2:04 pm

Here is a simplified compilation on that issue. My ECU got modified as described here:
http://www.megamanual.com/ms2/inputHEI.htm

I only do get an rpm signal while cranking with wire on pin 6 disconnected (override crank) , see photo. Car will start with backfire, no nice idle at all but smoothes out when I reconnect wire into pin 6. See log, in the middle part where the rpm straightens out is the part with pin 6 reconnected. To the end it gets wild again with pin 6 disconnected again. Timing stays around 12 degrees,(as seen on the damper with my timing light) but retardes to about 2 deg BtDc at about 3000 RPM. I have severe backfire at that point. I can switch the ignition-setting from "rising edge / going high" to "rising edge / going low" with no differences.Also, with ignition "on" the LED D 14 on the ECU will light up. When I connect wire to pin 6 light will go out with a slight "click"-noise from the engine compartment. WHAT is going on here ???? I have the feeling if this issue here will someday be solved my AFR-problems might be gone as well...
THANKS for any help !!

turbo conversion · Post by **turbo conversion** » Wed Jun 29, 2016 3:27 pm

Have you tried Falling Edge/Going High?

David

billr · Post by **billr** » Wed Jun 29, 2016 4:18 pm

I can't say this is your problem, but: abandon the Megamanual and start using the manuals linked-to above; check your ignition wiring against the current manual to be sure there isn't an error in the Megamanual that "gotcha".

flowbench · Post by **flowbench** » Thu Jun 30, 2016 1:46 am

Thanks so far !
I will try Falling Edge/going high tonight. Here is one question that came up: we did modify the input circuit for a hall-sensor, since I was told that that is the one I have in my distributor.
Some questioning on that subject revealed that I should have actually an VR-sensor. See picture attached, thats the kind of sensor I have.
If I get this right from the manuals, the difference between these two is actually that it requires a different setting in the ignition setup like going from rising edge to falling edge.
Is that correct ?
So, actually I do have an VR sensor ?
Could my new ignition wires have such an impact ?
Could my older ignition coil play a role ?
The new coil I have had gave up during these tests.
Thanks again !

slow_hemi6 · Post by **slow_hemi6** » Thu Jun 30, 2016 5:18 am

Sure that is a VR sensor in the distributor but the HEI7/8 modules contain a VR to Squarewave converter circuit and that comes out on the R pin. As best I remember that is an open collector output and probably requires a pull up to be a true squarewave input trigger. But in reality works like a ground switching hall sensor.

flowbench · Post by **flowbench** » Sat Jul 02, 2016 3:05 am

I did change the ignition setting to "Falling Edge/Going high" and got a good idle !!!
Also engine will now start with pin 6 connected but will still run slightly worse with 6 disconnected. See attached log. But the timing stays almost constant at the damper and will still retard (!) at about 8 degrees when reeved high.
Sorry for asking all this dump question and still bothering the community but I have no electrical engineer background and have been fighting with this problems almost a year, so please someone here give me a better understanding on this:
We figured out: I do have a VR-sensor, but my ECu is set up for a "Standard Hall-Input". If I interpret slow_hemi6 and the instructions correct it doesnt matter how the ECU is "mechanically setup" on the board, its a matter of how the ignition setup is configurated within the software. Correct ?
If answer is "yes" what part in the system is responsible for giving me this headache ? The ECu gets the timing signal from the VR-Sensor, takes the signal throught the processor, adds timing and puts the modified signal to the coil on the next firing sequence. Right ?
So,- could the processor be the culprit ?
Keep in mind that pin 6 always seems to play a major role here...
Also the stimulator works well on the system, at least looking at the numbers through tunerstudio.
Does anybody have any idea what else could cause all this ?
Thanks again ! Cheers Cornelius

slow_hemi6 · Post by **slow_hemi6** » Sat Jul 02, 2016 5:16 am

What hardware are you using? Is it a V3.0 board or a V2.2? Pin 6 on a V2.2 is connected to ground and would be a big problem if you were using one of those.

flowbench · Post by **flowbench** » Sat Jul 02, 2016 7:50 am

It's a 3.0 board. Any answers to my previous questions ?
Thanks a lot !

flowbench · Post by **flowbench** » Tue Jul 05, 2016 12:54 am

Still fighting ,have new results: we put an oscilloscope to the in- and output of the ignition circuit and good a strange looking pattern. On the bottom is the signal from the VR-sensor, on top is what is going out to the coil. We tried different configurations:
"Falling edge/ going high" and "rising edge/going high" gave as 6 amps (!) flowing through the coil at 0 rpm and ignition "on". So we skipped that.

"Rising edge/going low" and "falling edge/going" low gave as no current through the coil, so we concentrated on these two settings.
All four (!) settings gave us these strange patterns as you can see. With pin 6 connected at the ECU the signal to the coil smoothes out a little bit, but it always looks I do have somekind of a second signal going to the coil. Or what can that be ?
Did I install my distributor wrong ,wrong phasing ? I installed it as always: 10 degrees BTDC on the damper, and the reluctor tooth is aligned with the sensor and the finger is facing towards the nr 1 spark terminal.
Anybody here with an idea ?

Post by **jsmcortina** » Tue Jul 05, 2016 1:09 am

As things are still weird, it might help to go back to the mods stage and re-wire your board so you are using the standard MSEXTRA instructions from the MS2/V30 Hardware manual. Then you can use the supplied settings and know that they will work.

James

billr · Post by **billr** » Tue Jul 05, 2016 10:14 am

Have you tried a known-good HEI8 module? As pointed out before, that ch.1 trace is not that of a VR sensor; that is the square-wave that the HEI creates from its raw VR input, and presents to the MS. The shaping of the drive to the coil (ch.2) is pretty much up to the HEI. MS can control when, relative to crank angle, the drive pulses occur, but not the shape so much.

flowbench · Post by **flowbench** » Thu Jul 14, 2016 5:50 am

I changed the module and sensor and get a good signal now !! Still I get about 40 + deg timing at idle, so I will check polarity on the VR-sensor.
Initial timing is set to 8 deg BTDC, (reluctor tooth ligns up to sensor), trigger offset is set to 8 deg. At 23deg BTDC the rotor points at #1 terminal.
Any other ideas besides checking for polarity ?
Thanks...

flowbench · Post by **flowbench** » Thu Jul 14, 2016 9:49 am

Just did change the polarity on the VR sensor and changed the ignition input setting,- things got worse. Timing still way advanced, jumping around and backfiring....
Let me start a new post on this since the problems seem to shift....

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