toyospearo

Stock carbed 22r with a Headman Header bored .60 over. Motor has less than 5000 miles and the carb was rebuilt about 5 months back. The rig sits on a slope with the nose down just a bit. It is outside. However, there is no rain getting in the engine bay that I can see.
For the third time after a heavy rain my 82 right at start up sounds off a loud "POW." For those of you who know guns it sounds more like a 300WSM than a 22LR.
It is right as I turn the key and the motor cranks for a milisecond.
It only happens after a few days of hard rain.
Anyone experience this or have any idea whats up?

83pingpong

Is that from the exhaust? Sounds like unburnt gases in the exhaust are getting ignited after accumulating. Hard on seals and possibly the muffler I suppose.

Have you checked the valve clearances and points/timing recently? I have the same 22R non-EFI with a different issue all together (stalling).

toyospearo

Unburnt gasses would evaporate over a short period of time I would think? This happens in the after a all night rain storm after it has been parked.
Everything is to spec. All new tune up components and a recent valve adjustment. the "POW" does come out the exhaust.

xxxtreme22r

I bet that incline is causing the float to open up and drain fuel into the cyls. Check to make sure the idle cut-off sol is closing. Or that the float level isn't too high where the incline is causing fuel to dump over the air horns. One easy way to check the cut-off is to pull it's power source while the engine is running. When removed the engine should shut off. Gonna assume this is an AISIN and not a Weber.

Wait.... what really throws this off is rain. Is it only on heavy rain? Like downpour rain? I wonder if water is somehow getting the exhaust? And when you pressurize the exhaust on startup it's blowing the water out all at once? Kinda like the banana in the tail pipe trick?

Try facing the vehicle UP instead of down and see what happens.

83pingpong

xxxtreme seems on the right track with fuel spilling in. Banana in the tailpipe idea can be solved if you are brave enough to stand behind it while someone else starts it after the big rain. Also water will spew at start up even after lighter rain if that's what's going on.

toyospearo

Thanks for the help. About to head out to check the float, cut off solenoid etc.
I'll post an update.

kawazx636

iTrader: (3)

Maybe your truck is trying to tell you to hunt more! Although a 300 win short mag might be a little extreme unless you're trying to blow a deer to pieces!

Park it on flat ground, sounds to me like the bowl is spilling into the cylinders like xtreme said. Try parking it facing up hill if you don't have flat ground to park it on. Although I'm not quite too sure how rain would fit into that picture unless the barometric pressure is just enough when it rains to force the fuel out of the bowl into the cylinder.

toyospearo

It is suppose to rain cats and dogs this week. I'll turn it around and park it up hill and see if it will explode.

Hey Kawazx what kind of mpg are you getting with your Weber 32/36 carb on your 83??

kawazx636

iTrader: (3)

I'm getting 18-22 mpg (corrected with 31x10.5's), my ignition needs to be replaced though-i'm getting poor spark

toyospearo

wow thats pretty good milage!

kawazx636

iTrader: (3)

Oh, it was BAAAAAAD before it got better! The PO had the truck all jacked up and running retardedly rich with the factory carb and retardedly retarded (literally, the timing was over 10* retarded!). I got a new Weber, fuel pump, fuel filters, fuel lines, distributor, plugs, wires, fuel pressure regulator, fuel pressure gauge, vacuum lines, PCV valve and breather valve. Luckily, he didn't completely burn up the rings with his rich mix, but I still have below par compression. It's good enough now to get me through the summer until I have time to rebuild the motor this fall. I get a good amount of blow by, coupled by a weak crack shaft seal so I'm losing a decent about of oil. It just goes to show that an idiot owner can screw up these motors all he wants and it will still run! I can't wait to see what it's like at full compression after it's rebuilt considering the torque and power that the little four banger still has now! I'm thinking that a new ignition should bump my up to 20-24 mpg since I can feel it miss fire and it idles slightly rough when it's not warmed up all the way (even on warmer days) but the spark plugs are not fouled and the gap is set properly. We'll see!

What kind of MPG are you getting on your 82?

PS...sorry for the thread hijacking rant...

toyospearo

Are you replacing the coil??

kawazx636

iTrader: (3)

Yeah, I'm going to just get the Crane Ignition kit from LC Engineering, it's only $300. It comes with the ignition and coil

xxxtreme22r

I'm getting 18-25 with mine city highway with 33's and 4.10's. Of course I cheat, fresh motor. I think I could get even better if/when I get an adjustable cam gear to correct my timing from my block shave. Truck weighs 3850lb.

How'd the testing with the cut-off sol go?

toyospearo

WOW that is great milage.
I haven't tested the FCS yet. I did adjust the timing out to 8 degrees before TDC and I adjusted the idle mix screw and set the idle a little higher.
I was under the impression if the fuel cut of solenoid is not functioning the rig will not idle? Is that right. Mine idles pretty well.

xxxtreme22r

I have an issue with mine not shutting on the Weber. And mine runs just fine with the exception of an occasional dieseling when turning off.

kawazx636

iTrader: (3)

I got rid of the electric choke and replaced it with a manual choke Weber-simplicity and I love it! So with the manual choke I don't have a FCS and I don't diesel or have other issues

xxxtreme22r

The choke has nothing to do with the dieseling down. Some people have had that problem some haven't. It all depends on how the engine has been built. My cam timing is off and might contribute to that. I can't run past 3 degrees timing (0 is factory on mine) while some people can get 8-10 out of this gen engine without issue. I'm 20 over with 10 thous taken out of the block with a brand new head and a 268 cam.
IMO Toyota put a cut-off solenoid on these engines for a reason and should be retained when using a Weber.

I have a feeling those that don't have the dieseling problem aren't running the recommended pressure regulator and have retained the fuel return line from the pump. I haven't. Mine is regulated and dead headed at the pump to 3.5psi.

toyospearo

I have the solenoid off and I have another one I pulled from a donor carb. What is a good method to clean these fuel cutoff solenoids?

xxxtreme22r

Hit it with carb cleaner and air I guess, not much more you can do with them. Be sure you use the original jet not the one from the donor. I don't know if they are different or not. I think there is a flaw in either the replacement jet I got or the sol itself that prevents the thing from shutting. Shouldn't need to replace it as long as the truck idles and turns off when pulling the power wire to it.