MSgpio.com read only forums (Jan.15,2018)

it seemed very steady. Still doesnt pick up speed below about 12mph though.

Mikey,

This is the compromise you have to make when filtering out noise, unfortunately. Squelching the noise means less sensitivity at lower speeds. For R59, you can try any value that works - it's hard to say in advance what will work and what won't.

The only way around the low speed filtering compromise is to eliminate the noise itself. That means twisted pairs, shielding, great grounds, etc., etc.

One common source of noise is the alternator. One thing people have tried (more with MegaSquirt than MegaShift) is removing the alternator belt (or unplugging the connector - but ONLY while not running) and seeing if it is any better. If it is, then the brushes and/or diodes in the alternator might be on their way out.

I didn't realize that the line pressure was cable controlled - that eliminates a possible source of noise.

Lance.

Test drove it last night. It shifted great with the exception of some "hunting" for gears at certain speeds and loads, which I know is just a setting I need to change. Broke the tires loose and it didnt bounce off the rev limiter like the stock trans controller did.

Having no speedo below about 15 isnt working for me. Im going to try to raise the value on R45 and also raise the value on R59 and try to get my low speed signal back. I will also install a diode inline with the VSS signal. Lance- you said a conventional diode- Any particular part number? I have a ton of different ones laying around i could try.

Mikey,

I'm glad you are beginning to get it sorted!

The most common part number for a conventional diode is 1N4001, but there are literally thousands of equivalent part numbers that will work. Most of these have similar forward voltage drops, and in this application were aren't worried about the wattage, etc. If I was you, I would just try any of the ones you have and see how it works. If you get it backwards, you will have no signal at all, so just turn it around.

Lance.

Progress! Changed out R45 to 220k and R59 to 150k and added a 1N4001 inline with the vss signal and it seems to be working great. Every once in awhile the speedo jumps up above 100 and real slowly settles back down. Not sure what causes that. I will ba driving it around this weekend and seeing how it will shift.

I do have one question though- Simple put- how do I get it to shift into 2nd at low speed low load? At low load, ! have the table setup to go into 2nd at 10 mph due to my 4.3 rear end ratio and the 3400 stall converter. Sitting in the garage, when I start accelerating, it shows the target gear is 2nd, but it stays in 1st till about 27mph, then it shifts to 2nd real quick, then right to 3rd. I have tried changing different settings and it still does the same thing.
Settings I have changed- shift speed hysteresis- 1 to 8 mph, shift load hysteresis- .5 to 10, hysteresis enable speed- 1 to 30. I set my idle tps threshold to 1% and the lower rev limit to 500. I changed these settings to all different values and it still does the same thing. Am I missing something?

Mikey,

It does sound like you are making good progress! I suspect the speedo jumps are residual noise.

For the second gear issue, there are a few things that will block a shift. One is rev limiting, hysteresis is another, but there are other factors too. The best bet for us to see what is going on is to post a datalog and MSQ.

Lance.

I will post a datalog tonight, possibly two. One from the car sitting in the air, and the other driving it. I figured with the lower shift rpm at 500 it would still shift.

Test drive went great. I found out that even after I changed the lower rev limit to 500, it never did take effect. I went back and looked at it and sure enough, it was at 1500. I lowered it to 500 and it seemed to solve the problem of not shifting out of first rigth away. I will include a datalog and msq for you to look at. I still have a gear hunting issue i need to figure out, and for some reason my rev limiter was at around 5500. I need to look into that later on. Overall Im very happy with how its going. I will get more time to mess with it tomorrow and saturday.

Mikey,

Cool, it sounds like you continue to make progress. I will have a look at the MSQ and datalog when I get a chance.

Lance.

Very interesting progress, especially using the diode to create a noise threshold. Clearly a lot of what you are doing should relate to the 8 speed so I'm trying to follow along.

Jim

Drove the car around alot today. Got the "rev limiter" figured out... the igniter didn't like a 3ms dwell time. Dropped it to 2ms and now it revs fine.

Car still hunts pretty bad in gear, and due to some noise still in the vss signal, it still shifts through all 4 gears when I take off (due to the speedo going to 175 for a sec or two), then when it smooths out, it seems to shift ok. I have several datalogs I can upload if needed. I just dropped R45 to 150k and I'm going to take it for a spin in a bit.