P1294 and some funny throttle issues

Rubirob

Rubirob

TJ Enthusiast
Joined
Nov 11, 2017
Messages
399
Location
Sacramento, CA, United States
Hey guys I thought I would share this to show off that scanner I got and too see if anyone might have suggestions for me about this error code..

So it all started about a month ago with a p0441 code.. my engine was starting but dying soon after.. turned out my purge valve was upside down, so I flipped it, cleaned my throttle body, idle air control valve, changed my oil, changed my air filter, and threw in a new set of champion iridium plugs.. the code left and the engine started up good and strong for about a week..

Then one morning I noticed a slight delay in my jeeps return to idle speed when I popped into neutral, it jumped up too like 2000 rpms and slowly came back down to about 1000.. it was on my way too work so I kinda just dismissed it.. next day I started it up and the idle dropped right away for a second but didn’t die and regained it self to idle speed.. then the throttle issues started.. as I would drive it would constantly have a hard time finding its idle in between my shifting or popping into neutral.. this seems to only happen when I’m moving.. if I stay parked and rev the engine it will return to idle fine..

It got worse this morning as I went to get some Carl’s Jr. As I drove I noticed even if I stayed in gear, say 4th and I let off the gas the Jeep still was giving throttle and pulling itself along for 4-5 seconds until it realized I was no longer giving it throttle .. then as I pulled into the drive thru It was just staying at 3000 rpms..kind of funny trying to talk when it’s roaring.. it slowly dropped back down to idle once I pulled up too pay.. they parked me and i sat there waiting for my food I revved it too see if it would return to idle and it did just fine.. then on my way home it seemed to return to idle after every shift.. so to an extent it is doing this intermittently

I am wondering if I killed my idle air control valve when I cleaned it? I feel like if I had a vacuum leak it would have this problem all the time. Maybe because it’s kinda intermediate it’s a sensor going bad but at times working properly? Could it be my throttle position sensor? Anyone with experience in this would be appreciated. My code reader says it could be my computer.. I sure hope not haha

today I am too busy to perform a smoke test on my intake but I am going to try to do it tomorrow. I will take some pictures of this diy smoke unit I bought for 150$ to show you if it works or not.. 150$ is a heck of a lot better than 2000$ Napa wanted to sell me one for haha

Here are the code stills from my phone
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You can also quickly check for vacuum leaks with a squirt bottle of water. Just spray it around the lines and see if the water gets sucked in and the engine starts to stall.
 
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A vacuum leak would indeed have constant symptoms. It could be your PCM, I’ve seen it happen more often these days as these vehicles get older. However, I wouldn’t start there. I would start with the IAC and the TPS sensor. If you replace them, only use Factory Mopar parts, otherwise you’ll open up another can of worms.
 
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How did you clean your IAC? And if you removed the IAC to clean it, did you also clean the orifice in the TB the IAC's plunger fits into? Crud in the orifice can make it hard for the IAC's plunger to seal properly which would cause a vacuum leak or even intermittent vacuum leaks.

Personally I prefer cleaning the IAC with it installed while the engine is running at idle rpms. When the engine is idling, the IAC is the sole source of air for the engine so as it draws in air, it would also draw TB cleaner in through itself cleaning both the IAC's plunger and the orifice. Raising the rpms will take the IAC out of operation so it won't draw cleaner in through itself so keep the engine at idle. When the engine dies from the cleaner flooding the IAC, that's no problem... just restart the engine. Not to mention that extra time the cleaner sits inside the IAC after the engine dies works to your benefit by giving it more time to work.

Generally speaking I try to get at least a third of a can of TB cleaner past the IAC to assure it and its orifice is clean.
 
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Chris said:
A vacuum leak would indeed have constant symptoms. It could be your PCM, I’ve seen it happen more often these days as these vehicles get older. However, I wouldn’t start there. I would start with the IAC and the TPS sensor. If you replace them, only use Factory Mopar parts, otherwise you’ll open up another can of worms.
Click to expand...

Yea this is the path I was thinking about taking. After I check for vacuum leaks I am going to replace those sensors.. probably one at at time.. maybe start with the idle air control?


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Jerry Bransford said:
How did you clean your IAC? And if you removed the IAC to clean it, did you also clean the orifice in the TB the IAC's plunger fits into? Crud in the orifice can make it hard for the IAC's plunger to seal properly which would cause a vacuum leak or even intermittent vacuum leaks.

Personally I prefer cleaning the IAC with it installed while the engine is running at idle rpms. When the engine is idling, the IAC is the sole source of air for the engine so as it draws in air, it would also draw TB cleaner in through itself cleaning both the IAC's plunger and the orifice. Raising the rpms will take the IAC out of operation so it won't draw cleaner in through itself so keep the engine at idle. When the engine dies from the cleaner flooding the IAC, that's no problem... just restart the engine. Not to mention that extra time the cleaner sits inside the IAC after the engine dies works to your benefit by giving it more time to work.

Generally speaking I try to get at least a third of a can of TB cleaner past the IAC to assure it and its orifice is clean.
Click to expand...

I pulled the whole throttle body, removed the sensor and cleaned it with throttle body cleaner, and a nylon brush. It wasn’t that dirty, I also pulled back the valve and sprayed in there.. idk if that was a good idea [emoji15]. I also cleaned the channel it sits in on the throttle body and the throttle body plate.. honestly all of these were pretty clean.. but I did it anyway because of the p0441 code I had at the time.


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Chris said:
A vacuum leak would indeed have constant symptoms. It could be your PCM, I’ve seen it happen more often these days as these vehicles get older. However, I wouldn’t start there. I would start with the IAC and the TPS sensor. If you replace them, only use Factory Mopar parts, otherwise you’ll open up another can of worms.
Click to expand...

If it ends up being the pcm is there a reliable source to use for a replacement? I have heard about how difficult it is to fine a quality rebuilt one..


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Rubirob said:
If it ends up being the pcm is there a reliable source to use for a replacement? I have heard about how difficult it is to fine a quality rebuilt one..


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Click to expand...

I’m going to summon @StG58 to answer that one. There’s a ton of places that rebuild them, but being as though he recently replaced his, I want to see who he went with.
 
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So I did a smoke test today, with this new little gadget I got online. Turns out my throttle body didn’t get sealed good, and I have a hose line nipple in the intake manifold that has no hose connected too it and I have no idea where it leads too haha
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No. It connects to a small hard plastic line that runs along side the firewall and into the cab by the heater hoses. Pic in a second.
 
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CodaMan said:
No. It connects to a small hard plastic line that runs along side the firewall and into the cab by the heater hoses. Pic in a second.
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Sweet, I appreciate it!! I was scratching my head thinking there’s no way there going to design this to be open bringing in unfiltered air without measuring that air lol


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Thanks @CodaMan for the help with the locating of that missing line. No more leak there but even after the second throttle body gasket, there is still a leaks from the throttle body where it meets the air intake.. i torqued it too 90 inch lbs on all 4 bolts.. so idk why it’s leaking.. is that somewhat normal lol ‍♂️


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Rubirob said:
... even after the second throttle body gasket, there is still a leaks from the throttle body where it meets the air intake.. i torqued it too 90 inch lbs on all 4 bolts.. so idk why it’s leaking.. is that somewhat normal lol ‍♂️
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No a leak is not normal from there. If yours is leaking after having installed two different gaskets I'd have someone else install the next gasket. Or look for what is causing the leak between the gasket and its seating surfaces... debris? A small piece of the old gasket? Gasket seating surfaces must be absolutely smooth and clean.
 
Jerry Bransford said:
No a leak is not normal from there. If yours is leaking after having installed two different gaskets I'd have someone else install the next gasket. Or look for what is causing the leak between the gasket and its seating surfaces... debris? A small piece of the old gasket? Gasket seating surfaces must be absolutely smooth and clean.
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Yea both sides are completely clean, smooth with no gouges. I’m thinking of putting some ultra grey on both sides of the gasket and re torquing it.. and checking it tomorrow.. if all else fails I will have someone else give it a shot..


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