
Hot Rod Farmer: Finding lost power in a gas engine.
October 21, 2020Podcast: Play in new window | Download (Duration: 1:14:11 — 101.9MB)
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Educating the agriculture community on every aspect of today’s complex farm machinery.
Podcast: Play in new window | Download (Duration: 1:14:11 — 101.9MB)
Subscribe: Apple Podcasts | Google Podcasts | iHeartRadio | Email | RSS
Good Morning Ray.
Thank You. Just listened to your show. Good info as always. Some additional info to fill in the blanks.
Yes, the truck does idle a lot. So carbon could be an issue? When I had the truck in my shop for a good going-through a couple of winters ago, I checked compression and had 150 across the board. The truck does not have a catalytic converter, but does have a knock sensor. This makes me ponder a bit, because I have been chasing an issue with this for a while. The check-engine light will occasionally come on during a long trip (hour +). And the truck has what I think they call OBD 1. Where I cross two terminals and watch for the number of blinks on the dash. And it says knock sensor, which I then replaced. But it has still come on since replacing the sensor. Otherwise I don’t get any other codes. And when I replaced the distributor, I did time the engine per instructions, which said to unplug the single wire in the cab, to disable the advance.
Also during that winter’s going-through, I put the lower bearings and oil pump in partly because I had no history for the engine, and partly because I had a low oil pressure reading issue, (the issue was the dash gauge). And the bearings were not real bad, but felt it was a good investment for the engine anyway.
So as time permits I will check fuel pressure. And will check the vacuum. And get the fuel cleaner (to start with). But not rule out a valve job.
Gross weight of truck is 18,000 lbs. And I’ve questioned whether the truck should be able to handle it? But also recognize many farm trucks have this setup with grain boxes on them. So guessing they might be heavier?
So given that I don’t need a lot of extra horsepower, it could certainly be just a reduced performance from some of your suggested areas.
Thanks Ray. Good Show.
Dale,
Thanks for listening and the additional information. Keep in mind that a trouble code is a circuit code not necessarily the sensor but the circuit. If the ECM thinks the engine is detonating (pinging) it will keep retarding the timing. There is an algorithm employed that after a defined amount of timing retard and the knock can’t be controlled, it sets the code. There could be something vibrating or noise on the wire going back to the ECM. I had a Buick once when I worked in the dealership while in college that had a lack of power with the A/C on. Everyone dismissed it since it was a V-6 in a Regal. I found that the A/C belt was just loose enough to create a harmonic that the knock sensor picked up. I tightened the belt and the car ran great with the A/C engaged. Let me know what you find. Ray