Cant get Tunerpro RT to connect once engine starts

[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

[EagleMark]

5.1.xdf and 5.0ADX are the latest ones, you'll like them a bunch more then whatever you have.
http://www.gearhead-efi.com/Fuel-Inj...Information-42

But there's not much to go wrong with a 160 baud ADX file...

You got power wires to ECM hooked properly? One for constant 12 volt and one key on power that stays 12 volt to crank and back to key on? I've really never even heard of an issue like this and guessing at what could cause this? For conversions I usually use the power to old coil wire to turn on relay for this power. But if it runs good and still can't connect then it's not a power issue... wish I was there, I like challenges...

[shimniok]

Shortly after I had my problem I threw one of my scopes on it and it lead to ground issue. Actually I had to measure resistance to ground at a few spots with a DMM. When you checked ground is that how you did it?

EMI and ground problems can be rather tricky to track down. I'd give cash money to see the TTL serial waveform on a scope... if you feel like throwing more money at the problem you could get a pocket oscilloscope or an old used analog one like I have for not much. (lots less than a lot of other stuff one has to buy to do a TBI conversion)

[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