I have a yale glp060zg serial A875B35603C that has a tier 2 spectrum lp fuel system. The engine starts and runs normally, but the operator complains of the engine surging. i found while driving the forklift that when returning to an idle the engine would surge four to five times before idling smoothly. i have had similar issues with later spectrum systems when the trim injector goes bad, but have not had much experience with tier 2. it appears to have a trim valve on the mixer and one on the vaporizer. does anyone know if one of these valves can cause this issue or know of something else common on the tier two spectrum systems that causes engine surging? Thanks in advance.
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I have seen the Bosch throttle body cause this the two tps switches are built inside must replace the throttle body
Somewhere on this thread mentioned they had info on the spectrum first series trim valves I'm interested in there theory of operation. I have one surging and running rich. If I unplug the ptv on regulator idle smooths out but is still rich. Installed a new aftermarket part and machine surge was way worse. Mixer was changed 8 mo. Ago still good shape. Thanks for taking time
I have access to the ecom2 adapter and cables. I have installed the software, but have had no luck getting it to connect to the ecm. Today the problem has gotten worse to the point that it starts and idles high then shuts off. i get MIL flash code 638 throttle unable to close.
I have all the information you need on that system. Went to school for it in 2003.
Both valves you talk about are PTV and FTV Pressure trim valve is on the regulator and the fuel trim valve is on the throttle body. One is on 90% if the time the off 90% of the time. Do you have access to the GCP software and can buss ECOM? Check for 2-3 pounds pressure while running at the regulator. Turn the key on without staring and slowly accelerate the throttle. Listen to the electronic throttle or governor control for grinding noises like gears worn out. You'll need to hook up the scan tool once you fix it to reset the adaptive learn and clear the codes.
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