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-   -   Cold blooded yj!!! (http://www.jeepforum.com/forum/f12/cold-blooded-yj-1769082/)

758879 11-07-2013 05:55 PM

Cold blooded yj!!!
 
hey, so my yj that i recently acquired in june has been running like sh*t! it has the 4.2 and i did the nutter reset the timing cleaned the carter carbeurater( has a manual choke) checked for vacuum line leaks and for some reason it runs like terrible when its cold, it will die wont idle and if it does its really rough. The funny thing is when its warmed up it idles super smooth and runs great! Is there anything i can do to make it not such a b*tch to start my thought was to put a motorcraft on but after doing research the carb seems so hit or miss and an expensive risk. someone suggested putting an hei distribueter on and maybe that would help. Im so lost on it so please help!

dancytron 11-07-2013 06:09 PM

Do the things that are on it stock to make it run better in the cold work, i.e. the manifold heater and the tube from air cleaner to the exhaust manifold with the flap door?

FWIW, mine is almost totally stock except nutter bypass and team rush and it starts and runs dependably no matter how cold it is. Figure out what is wrong with it, don't throw expensive parts at it.

I have a manual choke. It does take a lot longer to push the choke in the colder it gets.

Sparrows 11-07-2013 08:12 PM

Not to hijack, but...

Mine has been acting up in the cold too. Similar issue; barely idles when I first start it, "lopes" really bad, and I have to give it a little gas/rpm to keep it going for the first few seconds. After about 30 seconds of idling, the rpms jump a bit, and it sounds fine. Once it has idled a minute it runs fine like normal. If I try to start it and just drive off, it tries to stall out, especially between gears. Any thoughts?

Jeep 2.5L/Ax5.

Cheers

Old4X 11-08-2013 06:22 AM

Lose the manual choke and put the auto choke back on.

Make sure the heat stove, CTO, and vacuum system is properly connected and working. Check the entire motor and vacuum system for leaks, esp the EGR system and the intake manifold to head gasket area. Also check the carb baseplate for vacuum leaks.

Poor cold engine operation is always a lean mixture problem, find out why it is running lean.

Siva283 11-08-2013 06:55 AM

Quote:

Originally Posted by Sparrows (Post 17531698)
Not to hijack, but...

Mine has been acting up in the cold too. Similar issue; barely idles when I first start it, "lopes" really bad, and I have to give it a little gas/rpm to keep it going for the first few seconds. After about 30 seconds of idling, the rpms jump a bit, and it sounds fine. Once it has idled a minute it runs fine like normal. If I try to start it and just drive off, it tries to stall out, especially between gears. Any thoughts?

Jeep 2.5L/Ax5.

Cheers

Your MPFI like me. These guys ae carbs. Big Big difference. If I were you I would start with checking for codes.

Sparrows 11-08-2013 11:18 AM

Quote:

Originally Posted by Siva283 (Post 17539345)

Your MPFI like me. These guys ae carbs. Big Big difference. If I were you I would start with checking for codes.

No codes. Just a similar problem and I know its a big difference, just figured there was no reason to start a new thread. :)

Cheers

Siva283 11-08-2013 11:59 AM

Quote:

Originally Posted by Sparrows (Post 17545329)
No codes. Just a similar problem and I know its a big difference, just figured there was no reason to start a new thread. :)

Cheers

Have you checked for Vac leaks? I am trying to remember what Que taught me when he was helping me with an issue. When the engine is cold the air temp, coolant temp, and map sensor are what controls the air\fuel mix. I would check for vac leaks and then check those sensors to make sure they are clean. How does it run at WOT. It will again switch back to those sensors at WOT.

Sparrows 11-08-2013 12:20 PM

Quote:

Originally Posted by Siva283 (Post 17546401)
Have you checked for Vac leaks? I am trying to remember what Que taught me when he was helping me with an issue. When the engine is cold the air temp, coolant temp, and map sensor are what controls the air\fuel mix. I would check for vac leaks and then check those sensors to make sure they are clean. How does it run at WOT. It will again switch back to those sensors at WOT.

Haven't checked for Vac leaks yet. At WOT it runs fine. So I start it and it "stumbles" for about 30 seconds at what seems to be too low of an idle, after about 30-45 seconds, the rpms jump a bit and it idles fine. If I start it and mash the gas to WOT, it runs fine while the gas is on, but when it returns to idle it begins stumbling again until it's ran for a bit...

Cheers

Siva283 11-08-2013 12:25 PM

Have you checked fuel pressure? Particularly if the pressure stays above 20psi for 20 minutes with the engine off.

Sparrows 11-08-2013 01:20 PM

Quote:

Originally Posted by Siva283 (Post 17547105)
Have you checked fuel pressure? Particularly if the pressure stays above 20psi for 20 minutes with the engine off.

I must admit, I don't know how to check that. :) :shhh:

Cheers

Siva283 11-08-2013 01:49 PM

Quote:

Originally Posted by Sparrows (Post 17548417)
I must admit, I don't know how to check that. :) :shhh:

Cheers

You cant rent the gauge from autozone or advance. It hooks up to the Schrader valve on the fuel rail(looks like a valve stem from a tire) Start up the engine. You should be reading 31 psi. Pull the vac line of the Fuel Pressure regulater(other end of fuel rail) it should shoot up to 39 psi. Shut the engine off leave the gauge hooked up. It should stay above 20 psi for 20 minutes.

Sparrows 11-08-2013 02:15 PM

Quote:

Originally Posted by Siva283 (Post 17549089)
You cant rent the gauge from autozone or advance. It hooks up to the Schrader valve on the fuel rail(looks like a valve stem from a tire) Start up the engine. You should be reading 31 psi. Pull the vac line of the Fuel Pressure regulater(other end of fuel rail) it should shoot up to 39 psi. Shut the engine off leave the gauge hooked up. It should stay above 20 psi for 20 minutes.

Thanks.
I'll try that tomorrow. :)

Cheers

Old4X 11-08-2013 02:46 PM

None of the fuel pressure,sensor, fuel regulator, fuel rail, schrader valve, leakdown test, etc drivel has ANYTHING to do with the OP's problem.

If you want to troubleshoot fuel injection woes, please start your own thread. You are doing nothing but confusing newbies to the site here.


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