16197427 Memcal vs 16196395 Memcal

[Six_Shooter]

I've recently discovered some interesting information regarding netres function which appears to be sourced from GM / Delco engineering documentation. It's been around for many years but I don't think too many people have spent time with it. Many of the references are to pages, figures, and diagrams which the author assumes are available to the reader but are not included with my copy so I'm going to try and spend time with it clearing up some of the references if possible.

That would be awesome.

IIRC the OP's trigger wheel angle ends up firing significantly ATDC when bypass mode is enabled making engine operation difficult if not impossible in LHM.

Then the ignition system is not set-up correctly and will cause global issues.

[corvairnut]

For curiousity's sake, please let us know how this works out.

Works like a charm. I clipped #56 chip side and installed a 1/8 watt 15k ohm between #53 and #56 pinout side. I then installed a 1/8 watt 7.5k ohm between #56 and #58 and all appears well.

Took her out for a drive today and monitored with Tunerpro. All appears normal except for the IAC counts.... they are high on start and settle down within a couple of minutes, but other than that, exactly the same. This was my original question and I knew there are too many smart people on this forum and my question would be answered.

Thanks again.

Ted

[1project2many]

Excellent!!! Thank you. The only advice I offer is to consider temperature stable resistors. Typical carbon resistors can change resistance considerably if it gets cold out. I tried to replace laser cut resistors in a speedometer once to recalibrate it. Everything was great form temps of about 60 deg and up but at 35-40 deg the speedo read 20mph too fast. I'd hate for someone to start a car in winter just to make sure it's run only to have issues.

I knew there are too many smart people on this forum

That's funny. You, sir, earned quite a bit of respect from me for working out your DIS system by trial and error. Not an easy thing to do. Many people with much education have failed at the task.

[corvairnut]

Now that we know what pins 53, 56 and 58 do and how we can affect them, what does the rest of the netres pins do? Be cool the map them, but I dont even know where to start and what differences they would make if I did. Do anyone have a clue? Be cool if you could move timing and number degrees by inserting a certain ohm resistor (important on DIS). Just thinking out loud.

Ted

[Six_Shooter]

AFAIK, the NETRES has ZERO effect on timing, since it's really only used for LHM, besides the hardware side of the cylinder select.

LHM timing is controlled by the ignition control module alone.

[RobertISaar]

right, the NETRES is really only fuel control when in LHM. when the ICM doesn't have the bypass line driven by the ECM, the module uses something like 10* BTDC at all times. i've seen some references where the timing is suggested to increase slightly with RPM.

[Six_Shooter]

There is a timing curve built into the ICM that will cause some advance to happen, even without ECM control. There are some calibrations that have latency tables that should be adjusted when swapping between certain ICMs, or too much or not enough advance can happen. Applies mostly to V8 dizzy applications.

[1project2many]

The documentation I've found mentions how some of the fuel curve corrections are applied by the netres. If we can get that worked out then anyone should be able to adjust a memcal so it works with their particular engine.

[corvairnut]

It appears that it also affects IAC counts. My IAC counts opened to max and pretty much stayed there until in park, idle... then they went down to about 30. This was enough for me to pull it and start mapping them out. Im leaving for the keys for a few days and might carry one with me to play with while im gone.

[corvairnut]

It appears that it also affects IAC counts. My IAC counts opened to max and pretty much stayed there until in park, idle... then they went down to about 30. This was enough for me to pull it and start mapping them out. Im leaving for the keys for a few days and might carry one with me to play with while im gone.

Wanted to update this post... Ive been busy, but that is no excuse. The reason for the high IAC counts was the romulator (I have to power cycle it to make everything just like a chip). Dont know why, but thats the way it is and Im cool with it.

The chip is fine with the resistors soldered in place and works perfectly. Just wanted to update the post with the correct information.

[1project2many]

Thanks for the update. Now if I can find the time to get back to the netres stuff we'll be doing great.