Hey guys I'm having an issue with a JD 650J s/n X178103; it will start right up on first crank but when engine is shut off it is hard to start, or won't start, on restart. If it does start the RPM's are very low and throttle won't work. I have found that if I disconnect the suction control valve on the fuel pump the engine will start every time and throttle will work like it's supposed to. The engine will rattle at low idle but smooths out when throttled up above idle. When I reconnect the suction control valve engine runs fine. My question is does this sound like the SCV is bad? BTW the only code on dash is for water in fuel. The filters have been changed and the fuel is clean, checked and replace the fuel in water sensor at primary fuel filter.
Shouldn't have done that. That sends the HPCR pump to full pressure. Then it opens the rail relief. I may not be correct on this, but around the time those were built some of the rail reliefs were no good once they have been opened (one time relief). So I would remove the fuel drain line from the relief and cap the line and check for leakage from the rail relief valve. If all is good there, did you try to start it with the rail pressure sensor disconnected?
I haven't tried that yet I'll check that out when I get back to it.
The suction control valve on those engines are prone to get corrosion and stick when water has gone through it. Especially if it had water go through it and it has sat unused for a while.
Can I remove the valve and clean it?
Post a picture of it. If it is the short SCV (about 1-1/2" long) then you would want to upgrade it to the longer one. The short one was prone to sticking. The longer one is an improved design. However it will set someone back about $770.
Thanks for your reply. It is the short version of the solenoid and you’re right about price dealer here wants over 800 for one plus recalibration fee.
There is no calibration for a suction control valve. It is plug and play.
Thai's good to know I was lead to believe there was. That just shows how much I don't know and how much knowledge this forum has available.
That is on the Deere built engines. I know the Yanmars we use in some of our equipment does require a calibration for the SCV.
Just want to give update on this dozer I finally got the SCV replaced and after the engine ran a bit it smoothed out and had no problems with restarting. Thanks mg2361 for your help.