Running with choke

[77ToyFJ40]

I'm trying to get my fj40 to run without using the choke. Adjusting the idle air mixture doesn't seem to help. I found a leak on the pcv hose on the manifold side. I replaced the hose clamp but the engine still revs up when I spray it with starting fluid. If I restrict the air flow to the carburetor with my hand it runs better when I have the choke halfway out. Am I having this problem because I'm running it without the filter on it considering that the filter would restrict air flow to a point?

 

[Mark Jennings]

What shape is the PCV valve in, I had one stick open once….same symptoms as you describe.

 

[mattressking]

You have a misfire, poor vacuum, or issues within the carburetor....or all three. By choking to run you are effectively reducing the amount of air into the motor to somewhat balance air/fuel mixture. Without any information, you likely just have vacuum leaks, which are unmetered leaks that affect your A/F.

Since a carburetor is mechanical, it doesn't have a computer to read the post-MAF/AFM and O2 sensors to compensate for leaks so you have to find the failure.

1. Fix all vacuum leaks and get vacuum to read 16inHg or more at sea level. Subtract 1inHg per 1k feet of elevation.

a. If you don't understand vacuum, any hose that terminates at intake manifold is considered vacuum. Confirm each is not leaking visually. Last is manifold gasket which is always an issue with a minimally serviced motor.​

2. Verify fuel cut solenoid is clicking when key is on.
3. Verify fuel stays within the middle-ish of sight glass.
4. Verify all 6 spark plugs are sparking by performing a visual test OR removing a lead at a time while idling and confirm idle change. If no idle change, that cylinder is not sparking or is a very weak spark.

 

[77ToyFJ40]

What shape is the PCV valve in, I had one stick open once….same symptoms as you describe.

It's not in the best shape as it is the original, but it's not leaking at the pcv valve it's leaking on the intake side.

 

[Pighead]

How about a pic or two of where you think it's leaking, and it's surroundings?

 

[fyton2v]

Follow Nate's advice. Find and fix your vacuum leaks first, then worry about idle mixture. If this is a new problem, perhaps you just have the one leak. If you're just digging into this truck ... there's probably more than one leak.

 

[77ToyFJ40]

How about a pic or two of where you think it's leaking, and it's surroundings?

I couldn't get a picture of mine because it's dark here but I found one on Google, but this is where its leaking at. Whenever I spray that hose with starting fluid the engine revs up

 

[Grayscale]

1. Fix all vacuum leaks and get vacuum to read 16inHg or more at sea level. Subtract 1inHg per 1k feet of elevation.

​

Mine pulls 14-in Hg + at 6,800' ?

 

[fyton2v]

Mine pulls 14-in Hg + at 6,800' ?

View attachment 3745912

 

[MatthewMcD]

Mine had a vacuum leak between the brake booster and the manifold. Fixed the leak and solved two problems.

 

[mattressking]

Mine pulls 14-in Hg + at 6,800' ?

View attachment 3745912

Yep, that means your motor is tight and you’d see about 20.5inHg or so, as one would expect at sea level. At sea level I’d usually see 20.5-21.5 on a stock motor.