95 G30 5.7 Van DA:Error Running Only

Discuss General Motors (GMC, Chevy, Pontiac, Hummer, Cadillac, etc) tuning topics here. Request definitions, discuss parameters, etc.

Moderators: robertisaar, dex

Post Reply
donf
Posts: 5
Joined: Tue Aug 22, 2017 5:05 pm

95 G30 5.7 Van DA:Error Running Only

Post by donf » Tue Aug 22, 2017 5:31 pm

Hello first post here, I am having a problem. I do think its not the software but something else in the van that is causing the problem. Here is a screen cast of me trying out another ADX that a nice person at Gearhead-efi gave me. It was the same as the original $0D adx that I had been trying. Here is a link. https://youtu.be/MlwmLdQSyC0 At first I am able to connect and the data looks fairly stable I open and close the throttle and scroll down. It looks OK, until I start the engine. Then things get crazy. The van runs well and was hooked to a Snapon Modis Scan Tool about a year ago with none of these connection problems.


I tested most of the grounds by doing a voltage drop test between the negative battery terminal and whatever the ground point is I am testing. Both ECM grounds were checked at the computer and a test wire was run directly from those wires to the negative battery terminal to see if that would improve anything, it did not. Other grounds removed and checked were all four grounds that bolt to the engine, buss bar ground under the dash and the chassis grounds at the front of the chassis.

The ALDL was tested for power and ground was voltage drop tested.

I checked A/C voltage at the battery to test alternator. It passed with .1v A/C. Removed the belt from alternator, no change in symptoms KOER.

ECM I swapped in another 427 ECM from a wrecking yard complete. No change in symptoms.

I rolled my desk top computer outside hooked the aldl cable to that and used that instead of the laptop to eliminate the possibility of the cheapo laptop having something to do with it. No change in symptoms. Laptop is battery power only, the only connection is the ALDL cable.

I have added the wait for silence to the macro, also adjusting the time from 20ms to 900ms. The longer wait time does slow down the errors, but it looks like everything is slowed down, good data and bad. I put the macro back to original.

I bumped the latency on the USB Cable port from 16 to 32, no change. Tried latency a 4 and 8 also. No changes.

KOEO o2 seems to vary at times not sure if if its a true reading or not. I unplugged the o2 just to see if that would affect the Tunerpro symptoms, no change in symptoms.

I do see Moates sells something called ferrite beads. http://www.moates.net/ferrite-bead-f...ble-p-203.html It describes the problem I am having with errors while running. Has anyone had these solve their data problem? I did find one of these on a old USB cable and unsnapped it and put it on the USB side of the ALDL Cable. I think it might be slightly better. Its still not working well at all though.

I am running out of ideas, but I did see on gearhead-efi where another member changed their plug wires and eliminated their KOER data errors in Tunerpro. My existing wires are fairly new, Napa lower line wires nothing special, but it's almost wild guess time now. Anyone have an idea?

donf
Posts: 5
Joined: Tue Aug 22, 2017 5:05 pm

Post by donf » Wed Aug 23, 2017 12:10 pm

To try and isolate the problem further, I downloaded the last trial version of datamaster. It does almost exactly the same thing as TunerPro RT. 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. 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. 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
Posts: 5
Joined: Tue Aug 22, 2017 5:05 pm

Post by donf » Fri Sep 08, 2017 10:50 am

After checking everything from grounds, to running additional grounds, to unplugging the sensors one at a time, to messing with com port latency, to putting delays in the macros, I was stuck and had no more ideas. As a longshot, I had John from 1320 electronics send me a bluetooth Aldl cable instead of my USB version. Just like that the data is rock solid. He said there is a difference in the way the bluetooth adapter is grounded, making it less likely to pick up noise. Anyway I thought I would post the ending of my problem here as I searched and searched threads and no one mentioned the hard cabled ALDL adapter as a possible source of the errors.

Post Reply