NAHRPerfomance

whats up guys. i've had this problem for a while now and no ones been able to help me , so i signed up and am askin you to help.. i have a 85 s10 1.9L 2bar carb. well when ever it rains,moist, or what ever the whether is when it happens. if its a dry day this will not happen...... i let the truck warm up, and usaully i can tell right off the bat if it's going to happen, i will leave to go where ever it is that i'm going i have like a complete power loss, not right away but slowly start to lose power (motor wise). to me it seems like the second barrel is sticking. i can be at a dead stop, try to rev the motor to high rpm but it won't, it just reaches a certain point and does not max out. i will be driving down the road, cruisin at like 55 and notice that my speed is decreasing, while my foot has not moved. i will go to down shift into 3rd to try to get my power back up (i've got a 4spd), BUT it just makes it worse, i lose even more power and it does not build back up. if/when i pull over, shut off the motor, and let sit (cool down) for like 5-10mins, start it back up, i'm good to go. but it'll only run about the same amount of time. if any of you guys can help please do so. thanx much

OverBoardProject

It must be partly blocked.

Getting a good mechanic to pull it apart, soak it in carb cleaning acid, and re-assemble it with a new carb kit will probably fix the problem for about $50 - $75.00.

Then your problem should be over

NAHRPerfomance

well here's the thing.... this is a brand new remanufactured carb, i've gone through three others so far thinking it was them. any ideas that being said

sector95

I'll just run some thoughts across the table here.....

The '85 models had old style emissions controls (I have an '85 w/2.8l) which were vacuum operated. Many of the systems are timed to operate based on engine temp using a device called a Thermal Vacuum Switch which is usually screwed in to the block and senses coolant temps; in looking at my Chiltons for your engine, (1.9L Federal, lo-altitude, MT) the emissions diagram shows only the EGR valve is tempurature sensitive (it typically doesn't work until the engine warms).

What conditon are the emissions controls on your truck? Are they still connected or have they been gutted?

If they are still connected, then you could have a bad EGR valve. Even if the emissions controls are not operational, the EGR valve could still be causing problems.

But you say it happens when it's moist out....

...carb icing comes to mind......

This is physics 101: when air moves through the narrow venturi of your carb, it's velocity is increased and it's tempurature and pressure decease; when that happens the air is cooled and any moisture will condense out. The metal in the venturi area is cooled below freezing and ice forms.... giving the condition you describe as "the secondary sticking". As more and more ice builds, you are essentially choking off or closing down the venturi area which would explain your loss of speed (power) when at a constant cruise. And when you stop the heat of the engine melts the ice and everything is hunky dory until the ice builds up again. Okay, science class is over.....

I believe the 1.9L was a crossflow engine; the intake manifold on one side, the exhaust manifold on the other?...so you don't have the heat generated by the exhuast manifold heating the intake and carb. Do you have the original air filter housing installed *with the preheat stove connected* (which would be the small accordian tube that runs from the end of the snorkel down to a shroud on the exhaust manifold)? If not, you need to reinstall it. Also, you need to ensure the temp sensor mounted inside the housing and the vacuum motor which operates the preheat flap in the end of the snorkel are connected and working. There is also a "hot idle compensator" in the air cleaner housing for better idle when the engine is hot. These items *must* be operational on your engine to prevent intake icing...and intake icing can occur even on relatively warm days. The sensors are probably okay but check the vacuum hoses for cracks and deterioration; best to replace them all. The vacuum motor in the snorkel must work; vacuum is applied to open the flapper valve and bring in hot air off the heat riser on the exhaust manifold. Connect a rubber hose to the vacuum motor and suck on it. Does the flapper move up? Will the vac motor diaphragm hold a vacuum or is it leaky (like you continually have to suck to keep it in the open position)? If the vac motor is inop or leaky you need a new one (probably have to get it from a dealer...but check on line, you might get lucky).

The system schematic is pretty straight forward: a line runs from the intake manifold to the temp senor in the filter housing, then from the temp sensor to the snorkel vac motor. Tee-d into the line prior to the temp sensor is the line to the hot idle compensator.....The whole idea of the system is to keep the intake air at a constant tempurature to allow quicker warm-ups at cold start, maintain an even fuel density/mixture under varying outside air temps (an emissions function) and to prevent intake or carb icing.

Sorry this turned into a diatribe but I think you'll find once getting your "Thermal Air Intake" system working properly, you shouldn't have any more problems..... Another suggestion: if your emissions gear is still connected, I would go through and replace all the hoses and the EGR valve; you might be surprised to find the little wheezer will actually run better :-)

Good luck

mike

Cam1959

Often if rain or fog or just high humidity upsets engine, it's the spark plug wires and possibly the cap and rotor, that need repacing or atleast good spray of "dry&go" moisture remover/barrier.

Mine was doing that last fall. New wires fixed it.

__________________
1983 S10 4WD carbed 2.8L automatic w A/C

Biigpuker

put some dielectric grease on your spark plug and coil wires wires, I`ll bet it will clear right up. had that problem.