This is topic No Acceleration?! 92 5.0L in forum Tech Talk at Northern California Ford Owners  .


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Posted by Cobra5.0JEEP (Member # 1482) on :
 
Symptoms: No aceleration, idles lower than normal, low vaccuum, no codes, no vacuum leaks, if you lightly give it gas the vehicle jerks and bangs the transmission, intermitten problem will only do it for a couple of seconds, acts like its missing while driving, Idle sounds really funny but if i let it sit for 2 minutes the idle smoothes out and goes back to normal RPM and normal Vacuum levels.

I have no idea what the problem is, i replaced the EGR, EGR sensor and wiring for the EGR(connector was broken) None of that did anything. I don't get any codes from the computer except the system pass code. Has anyone had this problem before? what did you change to fix it?
I BELIEVE the fuel filter was replaced maybe 2 years ago but i don't remember if i did change it or not. Spark plugs and wires were replaced maybe 10,000 miles ago, I'm just going by memory here i don't have all my written down information infront of me.
It runs fine when the engine is cold but does it while the engine is near running temp. Sometimes though when i start it and the engine is cold instead of keeping the rpms up in the beginning it just goes straight to idle. Sometimes doesn't idle good cold either.

Modifications: E303, Hooker headers, K&N, intake gap, MSD ignition, engine is in a highly modified CJ7 Jeep.
thanks in advance for your suggestions or comments,
Dana
 

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Posted by blind (Member # 3052) on :
 
catelytic converters are plugged, have you recently been hearing rattling from the exhaust that went away? A chunk of the cat's honeycomb might have broken apart and spun sideways blocking the exhaust flow.

my truck behaved the exact same way, computer scans (ODB-II) showed misfires while under acceleration, nothing else.

I took the Y pipe off and sure enough, peices of the cat fell out when I pulled it off the truck

oh well, a fireplace poker and a sledge hammer took out the rest of the honeycomb and get it back on the road and running better than ever
 

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Posted by Cobra5.0JEEP (Member # 1482) on :
 
I haven't heard any funny noise from the exhuast. Is there any way i can test that though?
 

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Posted by blind (Member # 3052) on :
 
any competent muffler shop should be able to flow test the cats.

one quick way to test though is take it off and drive it open headers to see if it runs any different
 

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Posted by Cobra5.0JEEP (Member # 1482) on :
 
A couple of nights ago it was doing the no acceleration thing and i floored it and heard a pop nosie from the passenger side of the engine. Then all of a sudden it basicly lost all power i didn't think i'd make it home but i did, it would only cruise at around 25 mph and thats with me giving it a lot of gas.
Yesterday i had my dad drive it cause i really thought something broke and it would do it for him and of course it didn't so i drove it to school and the gym and it never did it! I THINK coming home right when i got to the bottom of my hill i think it did it for a second but i am not sure. I have no idea what this is and its driving me nuts! I am going to drive it today and see if it does it.
 

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Posted by Cobra5.0JEEP (Member # 1482) on :
 
i drove it yesterday to my morning work and i think it did it when i turned on my electrical fan, once i turned it off it stopped
 

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Posted by Rickster (Member # 962) on :
 
Could be be bad O2 sensors?

When you get to Grass Valley look me up...

273 7021

[ February 17, 2005, 01:04 PM: Message edited by: Rickster ]
 

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Posted by Blue Oval (Member # 2548) on :
 
just curious what kind of condition is the timing chain in?stock?or replaced when cam was swaped?THAT COULD be the problem but its not very likely.
 

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Posted by BlueOvalRacing (Member # 1531) on :
 
just for kicks, borrow someone's MAF and see if it gets better
 

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Posted by Cobra5.0JEEP (Member # 1482) on :
 

quote:

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Originally posted by Blue Oval:
just curious what kind of condition is the timing chain in?stock?or replaced when cam was swaped?THAT COULD be the problem but its not very likely.

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quote:

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Originally posted by Fostang:
Could it be fan wash on the maf?

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i would think it would be the opposite if it was. When the fan is off the engine runs good, when the fan is on it runs crappy as hell.

[ February 17, 2005, 11:59 PM: Message edited by: Cobra5.0JEEP ]
 

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Posted by Fostang (Member # 3752) on :
 
no because when the fan is on it shoots colder air into the open element screwing with the maf that measures the temperatur of the incoming air.
 

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Posted by Cobra5.0JEEP (Member # 1482) on :
 
so wouldn't it still run better if that happened?
 

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Posted by Fostang (Member # 3752) on :
 
How well does it drive with the fan off?
 

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Posted by Cobra5.0JEEP (Member # 1482) on :
 
its drives like normal, might have a slight miss but i am not completely sure.
When idling with the fan on though it idles 300rpms lower and the vacuum is about 3lbs lower. When i turn the fan off everything goes back to normal range. The pop noise i heard a couple of days ago i wonder what that was cause ever since then it has driven really good nots of acceleration but when i turn the fan on it gets iffy and i don't think the fan made any difference a week ago.
 

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Posted by Cobra5.0JEEP (Member # 1482) on :
 
i wonder if that alternator was what made that pop noise
 

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Posted by Fostang (Member # 3752) on :
 
one of those things you have to be there to diagnose.

That popping noise could have been a cat clearing out that was damaged?
 

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Posted by Cobra5.0JEEP (Member # 1482) on :
 
no the popping noise came from the front of the Jeep on the passenger side so now i am positive it was the alternator that made the noise. I originally thought it could have been the air pump or some vacuum line on that side.

[ February 18, 2005, 12:19 AM: Message edited by: Cobra5.0JEEP ]
 

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