Perlexing Persistent Computer Problem

**Scorp1us** · 10-27-2014

So I have a 16197427 setup on an IH 345 which has never really run right. I've always run into data errors in tuner pro. Sometimes it works without error. Usually it doesn't. TP report DATA ERROR while the issue is on-going.
None of the gauges work EXCEPT for MAP and Engine Temp. The rest are dead. maybe O2 works...

Recently (today) I started it up and it was working perfectly. I tuned my idle (APU1, emulation mode) (added a 262 cam recently and was trying to get it to idle better) and went for a data collection run. It ran great for a few minutes (after many many minutes being tuned at idle) The computer at some point developed data errors and it began running sloppy. (hard to idle). When this happens tuner pro shows the data in the 400 rpm section of the log. My realization today is that the data error issue might be related to it running poorly. I always thought the data was a separate issue. After all why would TP report data errors? And the computer doesn't fully "die" it just runs rough. But at the same time, the injectors are firing so it's getting a DRP.

I have two 16197427 PCMs, and I can swap them. The problem happens on both. I'm wondering if the ignition module is over heating?

**Scorp1us** · 10-28-2014

So I got a new ignition module. It wasn't it. However it just started working right. I did some more tuning, burned a chip and the chip wanted an idle of 1875, which isn't right. But I verified the chip.

I put the emulator back in and then no data. But it was running, well not right, but not terrible either.

I can't figure out what is going on.

**sturgillbd** · 10-28-2014

I had data errors when I first started playing with my 7427. One problem was the plug wires being too close to the harness from the pcm. The other problem was grounds. Make sure your grounds are making a good connection. Bad grounds wreak all kinds of havoc.

Brian

**Scorp1us** · 10-28-2014

How many grounds and ground points do you need? All my tan grounds go to a single point on the block. I've got some other non-tan grounds that aren't connected.

What do you mean the PCM was too close to the plug wires? My PCM is in the cabin. Thanks for the tips I just want to make sure I understand.

**steveo** · 10-28-2014

having the engine harness too close to the plug wires can cause all sorts of interference.

having all your engine grounds go to a clean point on the block is fine, as long as your block to chassis ground is nice and clean too.

billygraves · 10-28-2014

Originally Posted by Scorp1us

How many grounds and ground points do you need? All my tan grounds go to a single point on the block. I've got some other non-tan grounds that aren't connected.

What do you mean the PCM was too close to the plug wires? My PCM is in the cabin. Thanks for the tips I just want to make sure I understand.

Do yourself justice by making 100% SURE ALL GROUNDS are connected. If you connect them to the block use a couple of points. THEN TAKE A GROUND STRAP TO THE ECM GRD TO THE BATTERY GROUND. I have measured over 3 volts on grounds and by turning them 1/4 turn the grounds measured 0.1 volts. (How you do this is the grd probe to the Battery neg terminal and use the red volt probe to the Gronds AT THE ECM by back probing ALL of them WHILE it is running.)

Then after the engine runs for a while, (to get the ECM/PCM HOT) tap the ecm/pcm case with your hand to see IF the engine stumbles or changes. Changes, even by running better, then hit it again to see if it will change to run bad or some I've had stall. This most likely is a controller with loose solder joints and you need a reman. I've had 2 ECM's in a row that were bad, so don't count this out.

If your Engine is painted where the PCM/ECM grds are, wire wheel or file it until the metal is shinny and clean. I use a STAR washer or STAR WAHSER LOCK WASHER as GM DOES. IT really works.

SOLDER ALL CONNECTIONS TO ANY AND ALL OF YOUR CONNECTORS, even the crimp on too..

Like as mentioned, the HEI Secondary wires close to the PCM/ECM wiring can induce odd signals.

Try running a ground wire to where the module is connected. If you are using a pick-up coil, are these wires away from any Plug or Coil Wires?

**Scorp1us** · 10-31-2014

Thanks everyone!

I found that A1 was not grounded... But I went on and soldered all the crimped connections, and added a ground point for A1, which I tied to the MAP ground, then tied all the grounds together a little distance from the computer. It seems to be working now.

I accidentally started it without the emulator or a chip in it -- and I had been running on the memcal alone!!!

**Scorp1us** · 10-31-2014

Well it ran great for a while... now it won't even rough idle off the memcal.

It was purring along, I was changing some idle points and monitoring data and it just up and died without warning. Idling, stumble, dead. Swapped the computer with a fresh one, same result. I can only get it started if I hold the throttle down and keep it running. I unscrewed the IAC to let some air in, this worked to keep it running for a while.

Meanwhile the data was fine, but once it died the data went to crap. Tunerpro's gauges were twitchy, bouncing from basically 0 to reasonable and absurd values.

**Scorp1us** · 10-31-2014

UPDATE!

I still have problems but what I found was placing the original memcal and program back in (removing the G1 adapter) cleared the error. I have no idea why. Maybe my G1 adapter is bad?

**sturgillbd** · 11-01-2014

After you get an error that triggers limp home mode, you will have to take the battery loose from pcm or unplug the pcm to reset. Look at the solder joints on your adapter. It may have a cold or cracked connection. You have probably found your problem. Good luck

**Scorp1us** · 11-01-2014

I would have thought that switching PCMs would have provided the appropriate power cut? Unless limp home mode has something to do with the ignition control module?

**sturgillbd** · 11-01-2014

Switching PCMs would have reset. Limp home mode is a function of the PCM and memcal. If there is an error with the EPROM or data between the EPROM and PCM, it lets you "limp" the vehicle home.

**Scorp1us** · 11-01-2014

This stuff remains between switching PCMs. Only replacing the memcal without the adapter works.

I'm testing a proper EEPROM in the G1, and not the emulator in the G1. This will let me know if it is a emulator problem or something more hardware related.