Cant get Tunerpro RT to connect once engine starts

[EagleMark]

I could spot an issue fairly quick if you had some pictures? Osiliscope can find anything is how I learned to spot them. Coil seems a likely suspect but probably not ground, should be isolated in bracket. More like voltage EMI/RFI from coil or coil wire to body... and not sure that is the issue, just a hunch. You had all the clues, happened many of times.

What kind of altenator do you have? Voltage when running? Grounds from body to block, block to frame. Should have been 2 main grounds off harness to engine? Nothing from EFI grounded to body? Check the data wire from ALDL port to ECM? Ha! Runs right behind the firewall where coil is to ECM right?

I'm really at a loss why data would stop when engine starts? Maybe some ECM but I do that all the time with 1227747. Can you connect after running?

[Fastmax32168]

Looking at the plug wires I used on the car, I do not see them marked as resistor anywhere. Is it possible that nothing is actually hooked up wrong and the plug wires themselves, even though they are not closer than 3 or 4 inches to any ECM wiring are creating a signal that is causing this problem?
Roy

[PJG1173]

Ha! Runs right behind the firewall where coil is to ECM right?

The TBI conversion in my toyota I have the coil mounted to the firewall on a piece of angle iron. No issues with the 7427.

have you tried dataloging with an eval copy of datamaster?

[Fastmax32168]

I dont think Datamaster is available for a 7747. Those wires from the ALDL connector run along the front of the dash. There has to be at least a foot between them and the coil.
Roy

[PJG1173]

I dont think Datamaster is available for a 7747. Those wires from the ALDL connector run along the front of the dash. There has to be at least a foot between them and the coil.
Roy

I wasn't sure that DM was available or not. I also have low resistance spiral core wires on both my engine's and there doesn't appear to be any interference. you got a weird issue going on I don't know a whole lot about the 7747. while the vehicle is running with your autoxray can you see DTC's? I wonder if when engine is started something isn't putting it into limp mode. does your CEL work?

[EagleMark]

We've kind of ruled out everything... except! Chip.

Does CEL come on and blink, stay on till engine starts? Goes off? What I'm getting at is a bad chip burn...

[Fastmax32168]

The car runs reasonably well with no trouble codes. My Autoxray seems to work the same as it does on any other cars I have used it on. I can read codes, I can put it into monitor mode and see all the values changing while the car is running and driving. When I disconnect the timing wire I get an ESC code as would be expected and the check engine light comes on. Plug it back in, the light goes out and i can clear that code.
Roy

[Fastmax32168]

I can certainly try burning another chip, that is easy enough.
Roy

[EagleMark]

It does not sound like a chip issue... I'm really at a loss? Have you tried the latest ADX file? What file are you using?

[Fastmax32168]

Mark, Not sure exactly which ADX file I have. I know it was one I had to convert from an ADS file. Where would I locate the latest ADX file? Is it possible to email me a copy? If so send it to Fastermax@att.net
Thanks
Roy

[phonedawgz]

Disconnect the alternator and see if the problem goes away.

[Six_Shooter]

Disconnect the alternator and see if the problem goes away.

I just read through the thread and this was going to be my first suggestion as well.

If you have another ECM to swap in, that could also help eliminate some possible areas of issue.

[EagleMark]

What kind of altenator do you have? Voltage when running?

I should have added try and disconnect after checking charging...

[Fastmax32168]

I think I have this fixed. I Changed out the plug wires this morning for a set of Mallory suppression core wires and it stays connected now when I start it. I will try some datalogging later today.
Roy

[EagleMark]

Did the noise in radio go away too?