By A P
I have a 2022 hisun sector eps 550. 30amp fuse is blown for eps. Checked the motor and it’s fine. Opened up the controller and found a bad diode. Dealer wanted 500$ for the controller. Just posting this in case it helps someone. I couldn’t read numbers from the old one so just took a guess and replaced it with a 100v 3amp diode.
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?
Since I've seen some questions on this I took some pictures and will provide instructions on a valve adjustment for the UT400. This should be the same for the 550's and other various Coleman/Hisun single cylinder models with the cylinder slanted aft.
I have seen several people ask of it is really necessary, and read several reports of valves being out of adjustment from the factory. My valves were .004" intake, and .010" exhaust with about 5 hrs on the machine. I've seen different numbers thrown around for factory spec, but I decided to go with 0.005".
This is called valve lash. What is is is a gap between the rocker arm and the valve then the camshaft isnt opening the valve. Why does it matter? If it's too large the valve doesn't open all the way, if it's too small the valve dosent close. This can cause valve damage (overheating) as well as loss of engine power (burned fuel is going out exhaust rather than pushing the piston dow).
Tools required : 5MM Allen wrench, 10MM box wrench, needle nose pliers, flat feeler gauge set, rags
First you need to remove the fan cover on the passenger side. There is a cooling vent hose on the back side, remove the hose clamp and slide it off. From there there are 4x 10mm bolts holding the cover. The forward ones can be accessed from under the seat.
Next remove the spark plug from the drivers side. Carefully wiggle the spark plug wire off. Grip it as low as possible and give it a little twisting motion as you pull it off to help free it. Its a tight fit for a socket, but there is a sheet metal wrench in the toolkit that fits it. Unscrew the plug and set it aside. This allows you to spin the motor over freely with no compression to fight. When you reassemble this is a good opportunity to switch to an NGK iridium plug for better performance/less fouling DR8EIX)
Next you need to remove the intake and exhaust valve covers. The intake us the forward one. There are 3x 5MM Allen screws to remove. The Exhaust is the rear with 2x 5MM Allen bolts. Both covers have O-Rings instead of gaskets and are reusable. When you remove the rear be careful and use your rags as there will be oil that drips out.
Next up we need to spin the motor over to top dead center. Grab each rocker arm and give em a little wiggle up and down. Spin the engine over by grabbing the fan with your other hand. Spin the engine over until both rockers have some wiggle and are loose.
Once both rockers are loose slide the feeler gauge in like shown above. Try different feelers as needed to determine your starting spec. You should feel some drag but still be able to move the feeler without too much force.
If you need to adjust, use the 10MM wrench to slightly loosen the locknut, then with the correct feeler gauge in place, tighten the top square nut while wiggling the feeler in and out. Once you have it right you need to tighten the 10mm lock nut without moving the square head bolt. Once the lock nut is tight recheck the clearance.
That's it, button everything back up and make sure you have it all reassembled before running it again.
If you find this helpful give me a thumbs up or comment. If you have any questions or need more help let me know. If there's interest maybe I'll do some more of these