Dies when I take off and gas in the engine - JeepForum.com
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Unread 08-20-2005, 04:47 PM   #1
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Join Date: Nov 2003
Location: Indianapolis (near the bars of Broad Ripple)
Posts: 230
Dies when I take off and gas in the engine

I recently swapped in a freshly rebuilt engine. I am still having the problems I had with the previous engine. I am still getting gas showing up in the oil. I have gone through three fuel pumps thinking maybe that was the problem, but no dice.

When I bought the Jeep, the person before had torn out most of the extra emissions vacuum lines. He basically left the ignition advance and all the vacuum lines going directly to the carb. He took off the stock air filter and replaced it with an aftermarket set up. Even without all this stuff it ran great for about a year.

I started running into problems with it dying under load at low rpms when starting from cold or medium engine warmth. In Nuetral or park it runs pretty well, but put it in drive and let you foot off the brake and it dies. I had heard of the Carter giving these symptoms, so I replaced it with a Weber. It ran better, but still most of the same problems persisted.

Someone I thought knew what he was talking about said I may be getting excessive blow-by in the cylinders and it may be time for a rebuild. Ok, bought a fairly identical engine and took it to a very good machine shop an had it machined and remanufactuered.

After a month of figuring out some small gremlins I got it back from my mechanic. Now I am at about 500 miles and I notice I am getting gas in my oil again and it still has not been working well at idle.

Finally I replaced all of the remaining vacuum lines thinking maybe I have a leak somewhere. Nope.

The only thing I have not replaced in the fuel system that could have some type of effect is the vapor cannister.

I am stumped. I am thinking these gas in the oil and the dying when I start are somehow connected. Has anyone else had this problem and how did you fix it?

89 w/1975 258. TF999 Automatic. Weber K551 38. BDS 2" lift. 15 in RockCrawlers w/31" Bridgestone Dueler REVO's. Smittybilt stereo security console. Alpine mp3 cd player. BMW steering wheel. 4.0 head conversion. Heavy duty bumpers. Deka Intimidator battery.

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Unread 08-20-2005, 06:41 PM   #2
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Join Date: Jun 2005
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Your problems definitely sound carburetor related. Before changing fuel pumps you should do a fuel pressure check and make sure you are getting around 7 psi of pressure. A vacuum/fuel pressure gauge costs less than a fuel pump, and is a necessary tool for adjusting carburetors and fine tuning carbureted engines.

If you are getting over 7 psi, that is too much, you can get a pressure regulator from most auto parts stores that will adjust your pressure down at the turn of a knob.

Is oxygenated fuel (gasoline with methanol) used in your area? Alcahol mixed in gasoline can affect the seals in carburetors, especially the needle and seat o ring that regulates float bowl gas level. If it's leaking, or if your float level is too high for other reasons, you'll end up with gas leaking into your intake.
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Unread 08-20-2005, 07:00 PM   #3
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Join Date: Jun 2005
Posts: 28
If your carb is letting fuel into the motor after you shut it off, you will experience hard start conditions because the motor is trying to burn liquid fuel instead of vaporized fuel. Not sure how to check that, maybe someone else will know.

As for it stalling out when put into gear to me would indicate a possible vaccume hose not hooked up. Another possibility is if you have an aftermarket intake, some require a spacer plate for the carb to sit on to crate proper conditions for automatic transmissions.
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