This post will explain how to hook up your PC to the ECU of a Hisun/Coleman/Etc UTV to be able to read error codes & engine parameters for troubleshooting purposes.
This is applicable to all small engines using the Delphi MT-05 ECU. This should cover all fuel injected Hisun models, as well as various other Chinese FI engines, as the Delphi MT-05 ECU seems to be the favored ECU solution.
Even though we get actual engine error codes to display on the dash, sometimes we have “pending codes” (not yet confirmed by the ECU) or other intermittent issues that are hard to diagnose, for example a poorly connected sensor that may give intermittent false readings, or a sensor that’s putting out bad date, but not bad enough for the ECU to realize.
The setup requires 2 cables, which are available for around $25 combined, a PC with a USB port, and some charityware software called “HUD ECU Hacker”. This gives the same functionality as the $300 dealer code scanner for a fraction of the price.
In searching I found info about HUD ECU Hacker, but I have yet to see info anywhere about how to hook it up to a Hisun, so I took the leap and bought some cables, and made it work. I will show a step by step of how to do so in post two.
I will be breaking this down into 2 posts:
Delphi ECU Info & Overview (This post) System setup & use Delphi ECU Info (Skip ahead to the next post if your eyes glaze over technical details)
The Delphi MT-05 ECU was developed to allow small engines to use fuel injection. A fuel injection system requires feedback from various sensors to operate efficiently. This feedback allows the adjustment of ignition timing, fuel injection volume, etc to efficiently and cleanly produce the most power possible from a given engine.
The MT-05 ECU has a number of sensors that are required for proper functioning including; Coolant temp, crankshaft position, intake temp, intake pressure, exhaust O2, throttle position, as well as some other optional sensors that are used on more complex vehicles.
From the sensors the ECU adjusts: Fuel injector timing/pulse, Idle air control valve, and ignition coil
The Delphi MT-05 puts out diagnostic data, however it is not ODB2 like a modern car, where is where it gets tricky reading it. There are three options, there is an old 16 bit piece of software Delphi has that is not able to run on a modern computer, there is the motorscanner tool for dealers ($300), or there is freeware HUD ECU Hacker with the proper cables.
Getting my prowler to a running stage and can't figure out why it won't idle without throttle. Also see fuel spitting out air intake while running. High speed runs rough as well. I've done many things (that were needed) but it hasn't helped. New plug, rings (120 lbs compression luke warm), timing chain, valve job. Even tried a cheap new carb. Thinking I may be off a tooth on the timing but it looks pretty dang close. anyone see this issue before?
Bought it about a month ago and when I test drove it, it ran good. Loaded it up and took it home. Owner said it had been sitting for a long time, but was "just serviced". It only has 500 miles on it total. Drove it around and found out the charging system wasnt working...so had to charge the battery once every week and a half or so. One day my daughter was driving it and it died. I couldnt get it to start again and I noticed there was no fuel in the filter...I first checked pulse/vacuum line to make sure it was sucking and it was. So I replaced the fuel pump with one I found local...which is for a large riding lawn mower...and it worked. Engine started and ran, but struggled at low speed immediately following running it at higher speed. It would bog when decelerating. I have also noticed now that it will backfire some on decell and die.
In the meantime, I went ahead and installed new stator and trigger coil assembly to get the charging system working again (that was an issue because it would not start at all after that...but eventually found that the trigger coil was wired backwards in the plug from the factory). I have also set valves, but I set them to .005 (intake) and .007 (exhaust)...per the manual. But what is weird is the manual states its mainly for the 700 series, but "can" be used on other models. On the front it says 500/600/700. I have noticed that the most common setting seems to be .005.
Anyways it still has the issue to me that seems like its running lean. Not full power now, struggles immediately running it faster, and will die and pop some on deceleration.
My main problem now is that it wont get to higher rpms as fast as it did when I first bought it. It struggles on deceleration after running near top speed.
Things I have done:
changed fuel pump
replaced stator / pickup coil
thoroughly cleaned carb (twice)
set valves to .005 and .007 (is .007 too loose for exhaust?)
anyways it seems to have a lean problem, and wondering if you have any suggestions on what to check.
By Tim Barbero
I left my 2020 axis 500 UTV parked under the carport for about 6 months and when I went to start it recently a squirrel has built a nest under the throttle body and chewed through the efi harness. I stripped all the wires back and reconnected them with waterproof butt connectors. The problem I have is there is one blue wire with a red stripe coming from the main harness this wire has 5 volts dc showing on my multimeter but there are two blue wires with a red stripe coming from 2 different sensors on the throttle body. I looked through all of the bits and pieces of wiring left behind and there’s no indication that the three wires of the same color were all tied together. Any help with this issue would be greatly appreciated.