Doosan (& Daewoo) G25P-5:
Backfiring

Serial # FGA08-1330-01493. 4389 Hours. It has the GM Vortec G424F engine. I have a forklift that tries to start but backfires loud through the throttle body and dies. It will restart for a couple seconds, then backfires and dies I've replaced the timing belt, gears, tensioner, crank sensor, cam sensor, Ign. coil, head gasket and had the valves ground. I bled the lifters off several times to make sure that the valves are not held open. I've had the head off of several machines with this engine and haven't had any problems. The original complaint was the backfiring, bad enough to destroy the inner air filter. Nothing that I've done has changed it. I found a service manual online for this forklift and got the procedure to find and clear the error codes. It shows no error codes. Is there a way to connect an OBD-II scanner to it? I have an adapter that works on some of the forklifts with the K21 engine. I can't locate a familiar connector. Thanks in advance for any suggestions.
  • Posted 6 Feb 2020 09:12
  • Discussion started by gw_e
  • Texas, United States
gw.ebbs@deepsouthequipmentdotcom
Showing items 1 - 4 of 4 results.
You will require Woodward software and dongle to connect a laptop. However most diagnoses can be accomplished without diagnostic software.
The symptom you describe sometimes result from PCV failure or incorrect PCV valve, Vacuum leaks and occasionally too lean adjustment of the idle mixture screw.
  • Posted 25 Jun 2024 08:15
  • Reply by tom_p
  • Alberta, Canada
have a problem with Daewoo forklift with engine GM G424FE.dual fuel.
Do you solve it?
  • Posted 25 Jun 2024 05:46
  • Reply by Afshin
  • Iran
Another possibility, coil connectors could be switched.
  • Posted 30 Mar 2020 11:40
  • Reply by tom_p
  • Alberta, Canada
Sounds like a lean backfire, possible vacuum leak? Check your FTV valves they should be closed with ignition off. If FTV valves stick open the engine will run too lean. PCV valve changed? It is odd no codes are displayed.
Additionally, Doosan recommends replacing all vacuum hoses including vapour line from regulator to mixer When experiencing fuel delivery issues. ( assuming you have a Woodward fuel system)
ODB scanner cannot be used.
Woodward software, dongle and cabling required to access SECM.
  • Posted 30 Mar 2020 11:08
  • Reply by tom_p
  • Alberta, Canada

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