what is wrong -292?

[Shamil]

Hello guys, yesterday I decided to go fast with my truck (engine is stock 292) I am not a speed fan; so I hit the gas, throttle wide opened, after maybe 10-20 sec. the engine stop response but it did not shutdown I removed my leg of the pedal, slightly hit the gas again the engine respond but I had to drive normally. Fuel tank is almost full; I changed the fuel filter nothing changed. I asked my friend he is mechanics he told me it is normal it happened sometimes even with V8 engine, is there anything I can do or should I live with it.

[D13]

Let me see if I understand.
You pushed the pedal to the floor and held it there.
The engine accelerated for 10-20 seconds, then stopped accelerating but did not stop running.
You let off the pedal and then you could get the engine to accelerate normally.

If that is so, 3 things come to mind.
First and most likely, you probably ran out of fuel. The 292 is a big motor for the single barrel carb, which does not hold a lot of fuel, and has a fairly restrictive fue linlet. You probably got the fuel bowl drained. When you let off, the fuel needs dropped and the bowl refilled. You can get a bit more by raising the float slightly, and/or raising the fuel pressure via an electric pump and regulator (which will be overkill for the carb), but this will help only a little. The real cure for this is more carb with bigger fuel capacity and bigger inlet.
Second, you ran out of breathing. The 292 moves a lot of air, think of it as a 400 SBC with two holes missing. The head is not particularly good flowing, and the carb is restrictive. So when trying to move a box shaped truck thru the air, the engine is trying to breath a lot of air, and the carb and heads will, at some point, limit its performance.
Third, if it's an automatic, you may have gotten to the breathing limit in the engine without the trans shifting to the next gear, which would drop the RPM and let it work.

I highly recommend you get a copy of Leo Santucci's book on the inline six (the second edition just came out). It's more race oriented but there are some good sections about carburation. Also inliners has some good info on their site.

[Shamil]

Originally Posted by D13

Let me see if I understand.
You pushed the pedal to the floor and held it there.
The engine accelerated for 10-20 seconds, then stopped accelerating but did not stop running.
You let off the pedal and then you could get the engine to accelerate normally.

If that is so, 3 things come to mind.
First and most likely, you probably ran out of fuel. The 292 is a big motor for the single barrel carb, which does not hold a lot of fuel, and has a fairly restrictive fue linlet. You probably got the fuel bowl drained. When you let off, the fuel needs dropped and the bowl refilled. You can get a bit more by raising the float slightly, and/or raising the fuel pressure via an electric pump and regulator (which will be overkill for the carb), but this will help only a little. The real cure for this is more carb with bigger fuel capacity and bigger inlet.
Second, you ran out of breathing. The 292 moves a lot of air, think of it as a 400 SBC with two holes missing. The head is not particularly good flowing, and the carb is restrictive. So when trying to move a box shaped truck thru the air, the engine is trying to breath a lot of air, and the carb and heads will, at some point, limit its performance.
Third, if it's an automatic, you may have gotten to the breathing limit in the engine without the trans shifting to the next gear, which would drop the RPM and let it work.

I highly recommend you get a copy of Leo Santucci's book on the inline six (the second edition just came out). It's more race oriented but there are some good sections about carburation. Also inliners has some good info on their site.

yes while driving on normal speed i pushed the pedal to the floor, the engine is accelerating for 10-20 sec. then stopped accelerating but did not stop running.
i am sure i am not out of fuel because before trying to accelerate i went to the gas station and fill the tank.

i'll go back to Leo book (i have the first edition).
thanks for the info.

[78 Chevyrado]

What he means by saying you were out of fuel, isnt that your tank is empty, but that your carb is too small to physically supply enough fuel and Air to en engine that size.

When you accelerate hard, the engine needs "X" amount of fuel, and as the RPMS go up, it needs even More fuel. you may have enough fuel supply to run the engine at lower RPMS, but it isnt capable of supplying fuel to the engine at higher RPMS.

[Shamil]

Originally Posted by 78 Chevyrado

What he means by saying you were out of fuel, isnt that your tank is empty, but that your carb is too small to physically supply enough fuel and Air to en engine that size.

When you accelerate hard, the engine needs "X" amount of fuel, and as the RPMS go up, it needs even More fuel. you may have enough fuel supply to run the engine at lower RPMS, but it isnt capable of supplying fuel to the engine at higher RPMS.

that is the problem, how to solve it? a bigger carb would fix it

[Your41Plague12]

Yep, seems like you need a bigger carb. I'd go with a nice 500 CFM 4bbl carb of some sort, preferably with small primaries to help save gas during city driving.

[njlimbaugh]

Are you sure that there is not a governor on your engine? That's almost what it sounds like.

[1LowToy]

Or maybe a $3 fuel filter?

My truck had a wierd problem. Someone set up the auto trans kick down cable way too tight. I wasn't getting but half throttle out of the carb before the kick down cable ran out of rope.

[rwhit57]

It sounds like a weak fuel pump or restriction to me. If it is the factory carb it should handle it. It could be float adjustment. I think I would change the fuel pump and make sure the lines are clear first.
This can also occur due to improper jetting for the elevation in your region.

[67_SS396]

You have some good suggestions here. You replaced the filter, so one step down. Has the carb been apart ot sat for any length of time? Does it seem to run relatively smooth other than falling on it's face? The fuel pump could be weak as well. Run a temporary inline fuel pressure gauge and see what it does when it acts up. Compare to how it reads under normal driving. With a little patience, we'll help get you there.
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