Kalmar P50BXPS:
Surging at high idle

Guys,
I need some help. I have a customer with the Nissan K21L engine and above a certain RPM it begins to "surge" just like a velocity governor out of adjustment. I checked for air leaks at the carburator, drilled the rivets on the side of the electronic govenor and inspected, and played with the speed pot adjustment with no help. Still the up/ down on RPM's at the higher speeds. Any ideas??
  • Posted 15 Sep 2010 01:38
  • Discussion started by Forkliftt
  • Louisiana, United States
Showing items 1 - 5 of 5 results.
Same issue. Found an intermitten loss of crank sensor signal. Replaced crank and cam sensors, since they are close together. Machine would code and go into limp mode. Un hook battery cables off of battery, Then hook the 2 cables together for 2 or 3 min. Hook the battery back up and codes should be gone. Hope it helps.
  • Posted 22 Jun 2018 03:56
  • Reply by Shadetree5080
  • Nevada, United States
cat had a similar issue with surging over idle speeds and it was due to the charging system overcharging. The higher voltages were affecting the sensors and other related components and causing the system to fluctuate trying to compensate for the voltage irregularities therefore creating the surge.

check the alternator output and make sure it is between 13.8v and 14.9v. Anything over that and there is an issue that needs to be addressed.
First check chassis grounding points and make sure they are good clean contact points. A volt drop test should be done between the battery and the ground point on the frame, any drop exceeding 0.5v indicates a problem and should be repaired.
Also check the ground to engine block in the same manner.
The overcharging will not necessarily trigger any codes so there may be none showing on the display and the MIL light may not light up either.

If no issues are found with grounds then replace the alternator.

good luck!
  • Posted 6 Oct 2012 12:43
  • Modified 6 Oct 2012 12:44 by poster
  • Reply by swoop223
  • North Carolina, United States
You've been swooped!
swoop223@gmail.com
Might also want to check your fuel PSI,in the regulator at the time it surges and see if it is dropping pressure,could be a dirty screen in the LP Lockoff solenoid valve,or the regulator itself is gumming up with tar.
  • Posted 6 Oct 2012 02:14
  • Reply by kevin_t
  • Pennsylvania, United States
Possibly a dirty/ Faulty Mass air flow sensor.....
  • Posted 6 Oct 2012 02:11
  • Reply by kevin_t
  • Pennsylvania, United States
I had one doing this... with the key on and motor not running check to see if the check enging light is working. we had one and it really stumped us. found the check engine light was out...
just a thought
  • Posted 6 Oct 2012 01:36
  • Reply by DennisW
  • California, United States

Post your Reply

Forkliftaction.com accepts no responsibility for forum content and requires forum participants to adhere to the rules. Click here for more information.

Having trouble using the Discussion Forums? Contact us for help.

Toyota 4FD240
Yokohama, Japan
Used - Sale
UN Forklift FB25N1QZ1
HANGZHOU, Zhejiang, China
New - Sale

PREMIUM business

Tailift Material Handling Taiwan Co.,Ltd.
Focused simply for the new era.
Latest job alerts …
Johnston, IA, United States
La Vergne, Tennessee, United States
La Vergne, Tennessee, United States
Louisville, KY, United States