My 91 80 has a running issue that had progressively got worse. It is a trail rig/truggy but drive line is 100%
so last year took it on a run on the last day was going up a trail and it started stumbling and losing power. Never had done this before and kinda assumed it was low on gas and brushed it off. Then I took it out at the beginning of the year and it randomly started stumbling every once in while and knew I had a problem at this point. Got back home did a basic tune up plugs, wires, cap, rotor, and fuel filter. It ran and idle much smoother. So loaded it back and went out again. It ran good for about 6 hours then stumbling and no power. This time though it stayed that way, it runs all the time, idles and starts great
so started digging into it first thoughtwas TPS sensor, ordered a new one. Put it on it is set at .9v at at idle. Still started and run great but has no power and still stumbles. Was suggested to check the cat out. It was clogged and bad. 600 degree difference from the front to rear of the cat. So I just took it out and re did the exhaust since there are no down stream o2s. Now it runs better smoother way way way more power until it starts getting a little warmed then back to stumbling and running bad. Next place I go is the coolant temp sensor, it’s broken. Put a new in it since I figured that’s it. Stumble is gone butttt it won’t rev well now. So check fuel pressure, like 54 at the fuel filter. But I check it behind the regulator and it still like 54. So the regulator is straight by passing and there is no real rail pressure. So put a new one of those on and it seemed to help it rev more. Ohmed and voltages check the AFM it shows perfect also
So where am at now. With the truck warm and in park if you give full throttle it revs very slowly. If you give like half throttle it revs like a top. If give just a touch supplement fuel while rev the motor (carb cleaner) for full throttle it rev up perfect like it should. So this tells me it’s a fuel delivery issue and it’s lean.
I’m really hoping someone can help because I don’t know what to check
sorry for the long lost just trying
To give and much info about the problem as I can. This is my first post but I have fixed and built mine reading this forum
so last year took it on a run on the last day was going up a trail and it started stumbling and losing power. Never had done this before and kinda assumed it was low on gas and brushed it off. Then I took it out at the beginning of the year and it randomly started stumbling every once in while and knew I had a problem at this point. Got back home did a basic tune up plugs, wires, cap, rotor, and fuel filter. It ran and idle much smoother. So loaded it back and went out again. It ran good for about 6 hours then stumbling and no power. This time though it stayed that way, it runs all the time, idles and starts great
so started digging into it first thoughtwas TPS sensor, ordered a new one. Put it on it is set at .9v at at idle. Still started and run great but has no power and still stumbles. Was suggested to check the cat out. It was clogged and bad. 600 degree difference from the front to rear of the cat. So I just took it out and re did the exhaust since there are no down stream o2s. Now it runs better smoother way way way more power until it starts getting a little warmed then back to stumbling and running bad. Next place I go is the coolant temp sensor, it’s broken. Put a new in it since I figured that’s it. Stumble is gone butttt it won’t rev well now. So check fuel pressure, like 54 at the fuel filter. But I check it behind the regulator and it still like 54. So the regulator is straight by passing and there is no real rail pressure. So put a new one of those on and it seemed to help it rev more. Ohmed and voltages check the AFM it shows perfect also
So where am at now. With the truck warm and in park if you give full throttle it revs very slowly. If you give like half throttle it revs like a top. If give just a touch supplement fuel while rev the motor (carb cleaner) for full throttle it rev up perfect like it should. So this tells me it’s a fuel delivery issue and it’s lean.
I’m really hoping someone can help because I don’t know what to check
sorry for the long lost just trying
To give and much info about the problem as I can. This is my first post but I have fixed and built mine reading this forum