massimo buck 400 Fault Code Troubleshooting "How To"

[Joe Toup]

Sounds like you're on the right track.  With that loose connection to the starter, don't rule out the possibility you had corrosion wick itself up into the cable where you can't see it.  As weird as it sounds, cables to get resistance build up when the corrosion is sucked into the core of the cable.  As soon as you get one thing resolved, the next weak link will reveal itself.  But it does sound like you are very close.  Let me know what you discover.  Pics too if you find the smoking gun.  Connections and cables will cause all kind of stupid issues.  

[k-bo]

Update 1/29: New starter did the trick; all issues resolved. Combination of bad starter switch and weak battery (a little more than 3 years old) caused the starter motor to fry. Photos attached show the broken motor and the new switch, actually 2 switches. I added a push button for starting. Also, I now have a cable to interface an obd2 code reader to the Delphi ECM.

[Don W]

Buy these things can be a handful. But as I learned a while back with Joe and others helping out and a little mechanical ability, which you obviously have it will work out!!  A great forum, so glad I found it and joined!!

[Redneck Mech]

Okay, I could use some help over here. I'm helping my brother with a Massimo Alligator 700. We've replaced virtual everything and can't get it to run.

It all started back in November. I was making the rounds in my deer lease and after about half hour of running it cut out and died. It started back up, ran fine for several hundred yards, cut out and died again. This repeated all the way back to the truck.

Came back a few days later and started troubleshooting. I suspected water in the fuel because the machine had been stored outside for several weeks. Fuel was fine.

Symptom got steadily worse until it won't even idle.

I won't go into the incredibly long story of everything we've tried just yet but here's my immediate question. What could cause this thing to idle good, for as long as you want it to, but only with the new TPS unplugged?

The fuel pressure shows to be about 38 lbs, stable, coming from the new fuel pump to the new injector. If I restrict the return line to increase fuel pressure to 65lbs or more, all symptoms go away and it runs like banshee!

 

[k-bo]

Hi Mr Mech,

I'm wondering if your computer is shutting your motor down due to an abnormally high voltage. Are you getting a check engine light and/or code. You can find out how to get the code from this thread if there's a check engine light on. If your voltage regulator malfunctioned, you'd quite possibly get a high voltage condition.

Good luck on this with your Massimo. I find mine is daunting to troubleshoot.

k-bo

[Joe Toup]

Hey Mr. Mech -

What you described sounds a lot like a faulty TPS sensor or wires. Even if you change the TPS, you can get a bad TPS sensor out of the box. However, most often a bad wire to/from the ECU will do what you described. If you lose the TPS signal, the ECU will let the machine idle, but increasing the throttle the TPS won't tell the ECU to increase the fuel demand. If it runs better when you restrict the fuel return, this is another clue that the TPS portion of the system is out of whack, 

Did you ever get a fault code of P0122 or P0123?  Those are typical TPS codes.  The system is easy to check.  The TPS has a 3-wire connector.  While I have not worked on an Alligator 700, your machine should be very similar.  Pin 1 should be green with a black stripe.  That is your ground. It comes directly from the ECU. If you lose ground, you will have all sorts of problems.  Pin 2 is usually a blue wire with a red stripe.  That is your 5-volt source also from the ECU. Pin 3 should be yellow with a black stripe. This is the signal return wire that talks to the ECU.  

Test 1: Using a meter set on ohms, see if the signal changes between pins 2 & 3 when you move the throttle (machine off)

Test 2: Using a meter set on DC volts, see if you get the 5 volts coming from the ECU at pin 2 (machine on)

Test 3: Using a meter set on Ohms, see if you get the ground coming from the ECU at pin 1 (machine on)

If all of these are good, then I'd recommend you check your wires for a loose, corroded, disconnected wire.

Also, when you changed the TPS, did you do a hard reset on the ECU to clean out the memory? I'd need more info before I could suggest anything else. 

- JT

 

[Redneck Mech]

So far the only code we've seen is a 118. I did verify the 5 vdc supply and ground to all sensors. I also verified the .50-.60 vdc return from the TPS at closed throttle. This check was made at the ECU connector. The return rises smoothly with the actuation of the throttle, up to about 4.4vdc-4.6vdc. As far as the 118 code, it's a new ECT sensor and I've verified the return signal back to the ECU jack. This signal does vary with the engine coolant temp. We have not done a hard reset of the new ECU.

[Redneck Mech]

K-bo, I've checked voltage supply to the ECU and it's 12vdc-12.38vdc. I also checked the 5vdc supply to the TPS sensor, ECT sensor, and manifold pressure/temperature sensor. They are all 5vdc-5.02vdc. I literally checked for opens, shorts, and grounds for all wires between all sensors and ECU connector and didn't find anything abnormal.

[Redneck Mech]

Bump

[Joe Toup]

Hey Mr. Mech -

I've had VIPs in town this week so I have not had time to do much other than entertain.

Sounds like you've checked all of the usual suspects.  I'm about fresh out of ideas on a 700 Alligator.  I'm looking for a manual to see if there is anything that might have been overlooked. 

The only thing left that might be a contributing factor would be the crank position sensor. But the symptoms don't make sense for a CPS.  I will tell you this.  One thing that has bitten me so many times I cannot even count is valve lash.  Believe it or not, if the lash gives up the ghost you can have hard starting, bad idle, and shutdowns once it gets warm.  Too tight or too loose can do either. I know it sounds implausible but I've survived the frustration of finding bad valve lash after I ran out of ideas.  

 Without seeing the machine in-person, hard to diagnose.  Even harder if you're not getting any fault codes. A valve lash won't throw codes directly.  But it can cause igniter codes and coolant temp sensor codes.  Don't ask me why.  You'd have to ask a mechanical engineer.  But I've seen it.

Can you walk me through the situation from a cold start?  What happens and when does it shut down?  Is it hard to start?  Crank forever or start right up?  Does it begin to shut down only after it gets warm, or is it all the time?  The more info you can provide, the better we can frame your problem. 

- JT 

 

 

[Justin jones]

I have 2018 hisun sector it’s not cranking I’m getting power to the starter I put a new starter new selanoid and checked all the fuses I’m lost for ideas it’s not turning over the starter 

[Joe Toup]

Based solely on what you described, I’d say it’s most likely one of two things…and these are easy to rule out without spending money  

bad battery

bad cables 

Check battery to see if it has a full charge. But…even with a full charge, a bad cell could cause a voltage drop when trying to crank. You can pull it and take it to advance auto.  They will check it for free and let you know if it has bad cells. 

Cables and/or their connections are also a notorious reason for not cranking when fuses and starter are deemed as good.  Corrosion where the cables connect can cause bad connections. Make sure connections are clean and cables are tight. If the cable itself is corroded internally from sitting too long outdoors in rain, etc., the corrosion can build too much resistance this not letting enough “juice” flow from the battery to the starter. 
 

I’d check those things first since they are easy. If those things don’t help, will need some more info to help peel the onion back more. I.e. Have you checked fault codes? 
 

- Joe

[Joe Toup]

One question I that I forgot to ask. Do you hear it trying to engage but it just doesn’t turn over?  Or is it simply dead in the water. Reason I am asking, if the solenoid is attempting to engage (you should hear it) but just doesn’t turn over the engine, you have a whole other issue. I don’t even want to dig that hole before we go over other stuff. 

Another thing to consider, the ignition switch.  A loose wire/bad switch could prevent starting even if you get some dash lights.  

Last question. Have you checked the brake switch (foot on brake to start engages switch)? If that switch is bad, even when you press the brake to start, it won’t let the circuit complete for the ECU to send the signal to the starter.  It would be worthwhile to check it. If you turn the key and your brake lights are on when you aren’t pressing the pedal…the switch could be faulty.  Or, with key on and pressing the brakes you get no brake lights, that would be another clue the switch is toast. One other thing I’ve seen with those switches, where they mount they can come loose enough not to make contact when you press the brake. Make sure it is securely mounted. Just quick things to check.  

Always check for loose or corroded connections, wires that may have come disconnected at switches, etc. This will probably be something  easy but not obvious at first without ruling out the simple stuff one thing at a time.  

Write down things you check as you go thru the machine investigating.  All the stuff I suggested to look at should only take a few minutes and does not cost anything to check. Let me know what you find.  

- Joe

[Joe Toup]

On 9/7/2023 at 8:33 PM, Justin jones said:

I have 2018 hisun sector it’s not cranking I’m getting power to the starter I put a new starter new selanoid and checked all the fuses I’m lost for ideas it’s not turning over the starter 

Did this ever get resolved? If so, can you provide what the fix was?  Thanks - JT