Cant get Tunerpro RT to connect once engine starts

Hi All, I am trying to tune a new application for myself. It is a TBI 350, I am using a 7747 ECM and $42 mask code. The car runs fairly well and shows no codes.
Using my Antique Auto x Ray I can connect and monitor the car. However when trying to connect using Tunerpro RT it will only work before I start the car.
I can get it to connect with the key in the on position and I can look at the the items list and see things such as the TPS changing when I depress the pedal, but as soon as I fire it up it begins connecting and disconnecting every few seconds. I have tried some of the normal fixes without having any luck. Suggestions?
Thanks
Roy

The more I mess with it the less I understand exactly what is happening here. If I go into preferences and set to com 3, then test for a cable, tunerpro says the cable is found and functional. Unfortunately I cannot get it to connect to the ECM at all in this configuration.
However if I go into preferences, set it to com 1, then test for a cable, I get the message that no cable is found. However in this configuration I can connect and read the ECM until I start the car, then it goes back to connecting and disconnecting.
This stuff is sometimes so frustrating.
Roy

You wouldn't be the first.

Plug cable in and on PC go to Devices and look for what Com port it is on.

Mark, I tried doing that. It does not show up on there at all. I cannot figure out how to get it to show up on there. When I go into advanced settings I can look at the different coms, and com3 says used, but you cannot see it under devices. I thought that might be part of the problem but cannot figure out how to make it show.
That said using the same laptop Tunerpro works fine on my other car using $A1.
Roy

Also, I have this same problem with the programmable ECM you just sent me, and the stock ECM so I can pretty much rule out a problem with the car. I just cant figure out why it connects fine until I start the car. I restarted the computer with the cable plugged into it and now it will connect on either com1 or com3. Until I start it up.
Roy

I downloaded TTS 's ALDL interface tester and used it to test Com1 and Com3 and both passed.

What are you using for an ALDL cable? I had some similar weirdness at one point.

I am using a Y style cable that Andrew from AKM made for me a few years back.
Roy

I had an epiphany this morning. I noticed I have a little ignition static coming through the speakers when the radio is off. I am thinking this could be creating interference and causing my problem. I am currently using a serial port connection. If I went to USB is it possible it would take care of this issue?
Roy

I haven't used serial cables in so long I forget how to check them. With USB if you plug in even a pass through cable (not device) it will show under Printers and devices in windows 7.

Since it is when running and you found electrical noise... Is this a conversion? Look at EFI harness. Is it anywhere near spark plug wires, coil or distributor cap? Or a arc from ignition somewhere? I think you found the issue. 40,000 volts near an EFI 5 volt signal does cause interrference.

I am having extreme frustration with this issue. My car has been together for over a month and I cannot datalog it so I can tune it. I have checked all of my grounds and made sure nothing is running parallel to ECM wires, arcing, etc. I have purchased a new usb cable and gotten rid of the serial port setup. I have even purchased a new laptop as my other one was long overdue for upgrade. I still have the exact same problem with the new laptop and usb as I had with the old laptop and serial port cable. Tunerpro works fine on my other car tuning $A1. It will connect and monitor this car using $42 until I start the car. As soon as I start the car Tunerpro begins connecting and disconnecting about every second or so. I am up for any and all suggestions at this point.
Thanks
Roy

Quote:

---

Originally Posted by Fastmax32168

I had an epiphany this morning. I noticed I have a little ignition static coming through the speakers when the radio is off. I am thinking this could be creating interference and causing my problem. I am currently using a serial port connection. If I went to USB is it possible it would take care of this issue?
Roy

---

Quote:

---

Originally Posted by EagleMark

Since it is when running and you found electrical noise... Is this a conversion? Look at EFI harness. Is it anywhere near spark plug wires, coil or distributor cap? Or a arc from ignition somewhere? I think you found the issue. 40,000 volts near an EFI 5 volt signal does cause interrference.

---

Sounds like you found the issue earlier! Since you have data, key on engine off, the data wire must be correct.

Yes but I cannot find any source for the noise and do not know where else to look. I made certain everything was clear of the plug wires and double checked all of the grounds. All of my wiring is neat and organized, So much so that I dont know what to re-do to try to fix the problem. The car is a Malibu wagon running a TBI out of an 89 C1500. I used the original ignition wiring to power the ignition, and the original ECM wiring to power the ECM. Any suggestion on what wires to start with?
Tonight I downloaded winaldl to see if I could datalog with it and I cannot. It acts the same as tunerpro. However my old Autoxray scanner will connect and stay hooked up no problem. I just cannot datalog with it so it is pretty useless other than to see generally rich or lean.

Mark, One thing I could look at is that I had to move the coil off of the motor and on to the firewall for clearance purposes. Does the coil ground through its bracket to whatever it is mounted on? If so I could rubber mount it and run a ground wire back to the motor so it was not grounding on the firewall but other than that I am having trouble finding something to look at. If the coil does not ground through its bracket then this idea probably holds no promise.
Roy

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?

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

Quote:

---

Originally Posted by EagleMark

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?

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

Quote:

---

Originally Posted by 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

---

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?

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...

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

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

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?

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

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...

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)

Disconnect the alternator and see if the problem goes away.

Quote:

---

Originally Posted by phonedawgz

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.

Quote:

---

Originally Posted by EagleMark

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

---

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

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

Did the noise in radio go away too?

Actually, the noise did not go away, but I can confirm that datalogging works properly now.
Roy

Strange that the radio noise was what sent us this direction. Glad you got er done!

So what were the spark plug wires that caused the issue? Make, model specifics of construction. Only ones I've had trouble with are on older conversion vehicles that had solid core wires.

They are Engine works Megafire 250 8.5 wires. Here is a description of them
"Engine Works 8.5mm Megafire Performance ignition cables are a true high performance spiral wound design with a very low impedance rating. The wires offer a Super low 250 ohm per foot resistance, pure silicone heavy duty boots, 100% Silicone outer jacket that is heat rated to 575° F, a Kevlar center core for strength, fiberglass braided reinforcement, HEI and socket style terminals."
Nice wires, I will just reuse them on my old school Chevy Monza.
Roy

A bit more FYI, I moved the coil off of the firewall and the feedback through the speakers went away.
Roy