Starting to Learn on 95 G30 5.7 for Towing

**donf** · 08-24-2017

To try and isolate the problem I downloaded the last trial version of datamaster. It does almost exactly the same thing as TunerPro. So it's definitely not a software problem. The key on engine off data passed fine. Once the engine is started the data goes nuts and the program starts alternating ALDL connected and ALDL disconnected. It would pass the cable test with the engine off, but when the engine was on it would say the connection was fine, but the computer returned unrecognisable data. The ECM in it now is a swapout from another 95 in the wrecker a few days ago. Just to rule out a bad ECM. I have two now. Both run fine in the van. The sample rate is a slider in Datamaster, and sliding sample rate just slows or speeds up the errors and data, the ratio of good data to bad looks to be unchanged.

Today I ran temporary test leads to all major ground connections to double check myself. No changes in errors. I did notice that the DA connection rate engine off, key on is about 10 or 11hz. The rate once the engine starts varies between about 4 to under 1hz. Most of the time it's under 1hz. Not sure if this is a clue or the product of my symptoms. It may be hokey but just to see I started temporarily wrapping a few components in aluminum foil to see if that would reduce interference if there was any. No changes in the data. I did the coil and the large wiring harness where it crosses all four plug wires underneath the distributor. The harness and the plug wires are in factory locations.

**donf** · 08-24-2017

After looking at other things this afternoon. I reread this post http://www.gearhead-efi.com/Fuel-Inj...e-starts/page3 and looked closer at the wires on the van and they are not standard supression plug wires. They are some low resistance spiral wound wire made by Belden. Since the poster in the thread above was able to cure his interference problem by just going back to standard suppression wires I think that's the next step. It's a wild guess, but I checked most other things and they are fine.

**donf** · 08-26-2017

Unfortunately new supression core plug wires had no effect on the errors I have been getting in TunerPro RT. It was a guess, so not surprised, but I sure was hoping to have a stable connection.

**donf** · 08-26-2017

This morning I decided to go in a different direction. I will track down the communication problems later. The engine runs perfectly and is not getting any changes for a few months at least, what I do want to change is the shift points. Since Switching from a 3.23 to 4.10 the shift points seem to be off a little. I think the first step in that is reading the factory memcal. So I looked for a BJYR bin here and did not find a copy. The van is a 1995 G30 van 5.7 4l60e, originally 3.23 gears (GU5). If you look up BJYR on the BCC lookup spread sheet you will see the mistake. Its listed as a manual transmission. That looks to be impossible since chevrolet never offered a manual transmission in the 1995 G30 van as an option. https://www.gmheritagecenter.com/doc...olet-G-Van.pdf - third page direct from GM = 4l60e or 4l80e. It also has been shifting the 4l60e for 108,000 miles. So now I want to read and save my stock BJYR bin file. I think I got it but not sure if its done right?

Edit: I removed the bin because it may be messed up. I got way different specs off of the same memcal with two separate readings.

**donf** · 08-27-2017

I think I may have the bin, but I am not sure it's correct.

**donf** · 08-27-2017

Does anyone happen to know the math that is used to come up with the RPM/VSS Ratio? I have my stock bin downloaded. I compared it to a few other bin files here and most of the transmission settings were identical except for the NV ratio for the final drive differences. Billy, I tried to PM you but it says your inbox is over the storage limit.

Edit: I found a few different formulas for the N/V ratio, but this one seems to be the most relevant? Ratio = (Tire Rev's Mile x Gear Ratio)/60; http://www.gearhead-efi.com/Fuel-Inj...ht-programming