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Friday, October 30, 2020

Troubleshooting + New stuff


The 350is runs on a Cobra (X3Z) ECU. While it "runs" and "drives", there is a huge hesitation starting around ~3200ish rpm under WOT. It only revs cleaning to the limited under light throttle application. With a Cobra MAF and 24lb injectors, there shouldn't be too many issues using this ECU . . . supposedly. To avoid shotgunning parts, I checked all the usual stuff  (no codes other than the missing emissions equipment) and came up with some possible issues:

  • Questionable grounds
  • Vacuum Leaks
  • Dirty MAF
  • Fuel
    • Old fuel
    • Old ass fuel pump
  •  Ignition
    • Spark Plug Gap
    • Distributor issues
    • Suspect Coil
  • Suspect O2 sensors
  • Suspect ECU

There are some free and near free (both labor and $$$$) items. The basic stuff like checking grounds, cleaning the MAF, spark plug gap would be a great place to start. If those do not resolve the issue, I'll move on to replacing part that I currently have on the shelf. An example is the fuel pump and strainer are factory original 1993 items. I'll replace this due to its age. If that fails, then I'll move onto other parts.

New Stuff 

The EEC-IV is capable of running a lightly modified 5.0L. Unfortunately, all these ECUs are old, used units that are highly suspect. They may have solder issues or have been incorrectly modified. A fragged ECU was one of the initial problems that plagued this build.
A canned tune cost $250 with the price rapidly increasing for true dyno tune. The equipment to self tune an EEC-IV is $300-650, but I would still be stuck with the EEC-IV. If the current X3Z is fragged, I would have to find a decent replacement to use. Those replacements vary from $30-500. So what to do? Enter MicroSquirt!!

I picked up this little box and adapter for cheap. As usual, it is from an abandoned project. Even with adding in the cost of wideband (needed for any type of tuning) and a fully unlocked suite of tuning tools, it is about the same as decent tune.

Before I install this, I'll make sure the car is mechanically sound and running as best as it can with the Cobra ECU.