Had a very rough running Mazda 626 on LPG, engine code FP. After renewing the spark-plug cables, some vacuum hoses and cleaning the throttle valve, I installed the lot again and got it running. It ran at a very fast basic rpm speed. (Rpm was 2500) I tried to screw this down with the air screw under the throttle valve. That did not work.
All of a sudden after some trial runs of about 5o km (about a week in total) the basic rpm dropped to about the normal 650-700 rpm. Only at cold start up it still runs at 2500 rpm. New "feature" on this issue is that after warming up the rpm drops too slow to the basic rpm (700) which makes shifting gears a problem.
BTW all symptoms while running on petrol and on LPG. The engine seemed to like what I did. It runs very smooth and the power has come back to it. It just doesn't like the way I adjusted the basic rpm. I don't know however, what I did wrong.
Has anyone any clue as to what I did wrong when reassembling all these parts.
The parts that came loose were. Throttle valve, petrol pressure thingy that is located on top which regulates petrol pressure when accelerating, and the vacuum valves that are connected to it. I fastened the map sensor which had come loose for some unknown reason. All vacuum hoses are checked. The spark plug cables are renewed. I further disengaged the battery every time I got to work on the engine.
Thanks in advance for your answers.
Sunday, April 17th, 2011 AT 7:36 PM