I’m sorry if you covered this already but do you have wide band O2 sensors installed? Can you log data to a laptop? It’s tough to compare a newer car to yours but with my newer Challenger and its tuner I can log data to a laptop while driving. If you have that ability you can maybe see the problem as it happens. There might be someone with a dyno in your area that can help also.
I have the single 02 sensor installed that came with the EFI unit. I think it is working properly, as it seems to track changes in AFR quickly, as it is displayed on the hand unit. No, this unit does not have data logging, that's one of the questions I asked the tech when I called MSD yesterday. The hand controller has a USB port, but he said it is a dead port and has no function. I would guess it was used to install firmware at the factory, as I hooked my laptop to it, and it didn't recognize the connection. It did, however, disable the hand unit, so that no data was being shown and the joystick control didn't work. Being able to log data to see just what is happening would be a great tool, but it just isn't possible on this system.
As far as dyno tuning it, with the few parameters that are available to modify, I don't think that would be helpful.
The one thing that he felt was a major problem was that I have a hard line running most of the way from the tank the the EFI unit. It does state in the installation manual that you should only run a soft line, like was supplied with the kit from the pump to the EFI unit. He said that the pulsations from the pump that is powered by a PWM driver in the EFI unit could be what is causing the erratic behavior of the system. That could be so, but my question was that it had run just fine up to this point with the hard line, so why is it suddenly a problem now, after running it for over 400 miles? He had no explanation for that.
When I installed a FiTech system on a friends Charger, I ran SS braided line from the tank to the EFI unit, and he has had no problems with that at all, and he is using the same in-tank system that I'm running. I don't have enough rubber line to run it all the way, but I do have plenty of the SS hose, so I'm thinking of running that from the tank to the EFI unit and see if that changes anything. And if I didn't mention it before, the pump is in my tank, not externally mounted.
I've decided that if I can't get it straightened out, this winter I'm going to switch to a different EFI setup, either a FiTech or Holley. I just want it to run correctly and not have to fuss with it all the time.
I have it jacked up on jack stands and today I'm going to pull the had lines off and start running the SS hose. That's going to be fun, but hopefully it'll solve the problem.
Stay tuned.
