I bought a 650J a year ago, ran it 5 hours noticed a fuel return fitting leaking, parked it and the next day crank no start. Long story short RDO did a ecm (not the issue) I pinned the motor, made sure I could pin the pump, sent it in in for a rebuild, put new injectors in, new filters and it fired up as soon as the air was out of the lines. It idled great but after revving it up it sounds like it’s hitting a rev limiter. F497 code came on so I got new pins and did an overlay from ecm to injection pump. No more F497 but now I have a F486 and can not find anything on that. Could I have been off a couple degrees on my timing? Crank position sensor? Thank you for any help! T0650JX113106
Welcome to HEF Mtrancher ! The F486 should actually be F48B. The last letter is shown in lower case, not upper case. F486B is an issue with the Crank Position circuit. IIRC, it is for excessive noise. Check the sensors resistance (I don't have the spec handy at the moment). Look at the sensor tip to make sure there is not any debris stuck to it. While the sensor is out, make sure the tone wheel is tight on the crank. Turn engine over by hand to make sure there are no missing teeth. While it could be a wiring issue, the sensor is cheap. Try a new one if all the checks are OK.
Thank you, I found 2500-3500 on a previous post about similar issues to mine. He never posted final findings so here I am still beating my head against the wall.
The spec is 2700-3300 ohms.
2,850 it is
Finally got a video uploaded.
Does the engine rpm read in the monitor?
Yes it does, fluctuating 10 rpm with stutter.
Did you check the items I mentioned in post #2?
Yes, tip was perfect, tone wheel tight, and couldn’t see any missing teeth. I didn’t stand on my head to look but I did use a mirror.
If the F48b is active and still displaying, then you need someone with diagnostic software to look at the crank position sensor readings. Did you put a new sensor in? I have seen the ohms reading good and still have a bad sensor. If not, it acts like it is starving for fuel when listening to the video. You sure you have a good fuel supply still?
I agree with mg2361 on the crank position sensor ohms reading being in range but still have a bad sensor. Inspect the sensor connector for any damage,corroision spread terminals etc. If you have a temp gun with cold engine start up at idle check temp at each cylinder at base of exhaust manifold to see if one stays colder than others. Pay close attention to 1 and 4 temp. 2 and 3 will run a little hotter next to turbo but not a lot. Run unit until stutter is bad shut off and remove timing pin plug at injection pump and check for air bubbles or foamy fuel. Fuel should be solid to bottom of plug hole. Stroke the lever on fuel transfer pump with plug removed there should be a solid stream of fuel coming out of injection pump housing. Please report your results. Did you torque the gear to injection pump shaft retaining nut to spec which is 140-foot lbs going by memory on this mg2361 may have the spec also did you make sure there was no oil on shaft or gear taper learned this the hard way.
No code after cleaning connection at crank sensor. I’ll get a new sensor ordered and installed.
I believe I torqued it to 144. Hard to remember it’s been a year since it made me mad and I left it. I’ll test temps and check for bubbles. I know from memory the fuel will flow freely from the timing pin hole because I did that when installing the pump to be sure it had fuel. It also had fuel coming out of the fuel return port after installing the new pump.
ok thanks, i noticed that RDO replaced the ecu did they tell you what was wrong with old one, could not connect or certain codes or problems. I would go back and double check the connector at the ecu they are easy to get cocked in housing and not get seated good. Look at terminals for corrosion or damage might spray them with some good contact cleaner to. Is this an open ROPS or cab unit. I saw where you installed new nozzles where they by any chance tested before you installed them.
Yes new computer because they said they go bad all the time . I just had the ecm connector off the other day to run an overlay hot wire from ecm to injection pump. I believe it is in good shape from what I saw all pins were clean and tight. This is a rops unit, yes I installed new nozzles. I didn’t have them tested, I suppose I could pull them and send them in with the pump!
Put a new pump on today and it ran like a top. Now I have to pull heater hoses off and flush the core out.
Thanks for posting the solution to your problem, I am sure it will help someone in the future especially the video.