post #1 of Old 07-19-2013, 08:01 PM Thread Starter
funforfree
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Help with surge please.

Hi all. I have a 95 grand Cherokee it has a v8 in it. When I hit the gas past 2k rpm it surges. If I mash it to the floor it really surges and bucks hard. After a little drive it will loose all power and will only idle sounds like a bad miss. As soon as I turn it off and back on its fine again for another mile or two then same process. When I hit it hard it's like it hits a rev limiter trans shifts smooth ect. Tried new plugs, wires, cap, rotor, crank position sensor, and cat converter. Am very stumped. Check engine never comes on.

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post #2 of Old 07-19-2013, 08:04 PM
Siva283
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Quote:
Originally Posted by funforfree View Post
Hi all. I have a 95 grand Cherokee it has a v8 in it. When I hit the gas past 2k rpm it surges. If I mash it to the floor it really surges and bucks hard. After a little drive it will loose all power and will only idle sounds like a bad miss. As soon as I turn it off and back on its fine again for another mile or two then same process. When I hit it hard it's like it hits a rev limiter trans shifts smooth ect. Tried new plugs, wires, cap, rotor, crank position sensor, and cat converter. Am very stumped. Check engine never comes on.
Iac map or o2. There are ways to test the sensors with a meter but I don't know the readings for your year. Also did you reset tge ecm after any of these changes

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1995 YJ. 2 inch BDS Spring lift. 1 inch shackle lift. 1.25 inch JKS Body Lift 33x12.5x15's. Engo 10,000 pound winch.

Quote:
Originally Posted by Magnum View Post
I gave the Jeep the required offering of $$, sweat, and blood, and everything works fine now. -- Jim
Quote:
Originally Posted by ldso View Post
. It started with a $200 axle, and a few thousand dollars later I was done :)
Quote:
Originally Posted by Luuca View Post
diagnose the real issue before you start going all Obama on it - spending mad cash you'll need for other important things.

Ask me how I know...
Quote:
Originally Posted by Overhead View Post
this is also my second set of RC springs this year. I'd rather spend the money again and get something that will last.
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post #3 of Old 07-19-2013, 08:06 PM Thread Starter
funforfree
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Quote:
Originally Posted by Siva283

Iac map or o2. There are ways to test the sensors with a meter but I don't know the readings for your year. Also did you reset tge ecm after any of these changes

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Yes after I did the crank sensor I did.
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post #4 of Old 07-19-2013, 08:12 PM
Siva283
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Quote:
Originally Posted by funforfree View Post

Yes after I did the crank sensor I did.
How about fuel filter sounds like it is starving for gas. What's the condition of the distributor and shafts. If there is any real play when you tey to turn the rotor with engine off it can cause thw timing to be off. The higher the rpm the worse it could be off. Does it do this when the engine is cold and at operating temp?

Sent from my SPH-L300 using JeepForum

1995 YJ. 2 inch BDS Spring lift. 1 inch shackle lift. 1.25 inch JKS Body Lift 33x12.5x15's. Engo 10,000 pound winch.

Quote:
Originally Posted by Magnum View Post
I gave the Jeep the required offering of $$, sweat, and blood, and everything works fine now. -- Jim
Quote:
Originally Posted by ldso View Post
. It started with a $200 axle, and a few thousand dollars later I was done :)
Quote:
Originally Posted by Luuca View Post
diagnose the real issue before you start going all Obama on it - spending mad cash you'll need for other important things.

Ask me how I know...
Quote:
Originally Posted by Overhead View Post
this is also my second set of RC springs this year. I'd rather spend the money again and get something that will last.
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post #5 of Old 07-19-2013, 08:56 PM Thread Starter
funforfree
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Quote:
Originally Posted by Siva283

How about fuel filter sounds like it is starving for gas. What's the condition of the distributor and shafts. If there is any real play when you tey to turn the rotor with engine off it can cause thw timing to be off. The higher the rpm the worse it could be off. Does it do this when the engine is cold and at operating temp?

Sent from my SPH-L300 using JeepForum
Mostly at operating temp. When it starts to break up I pull over turn it off and restart it hit the gas a few times it smells like soot and runs fine again for a mile or so.
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post #6 of Old 07-19-2013, 09:03 PM
ZeeJay1997
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Is it surging or missing?

If it starts missing under load, suspect the cat is stopped up.

IAC only affects idle
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post #7 of Old 07-19-2013, 09:26 PM Thread Starter
funforfree
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Quote:
Originally Posted by ZeeJay1997
Is it surging or missing?

If it starts missing under load, suspect the cat is stopped up.

IAC only affects idle
It idles good. Sounds like a miss like it is choking out. Have to pump the gas fast to keep it going. But if I shut it off it runs fine again when I restart it.
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post #8 of Old 07-19-2013, 10:28 PM
ZeeJay1997
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A lot of times these type issues will be caused by low manifold vacuum due to leaks or excess back pressure that passes around valve seats under load.

Are you hearing the valves rattle before it starts missing?
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post #9 of Old 07-19-2013, 11:16 PM
ozzy_2_me
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just out of curiosity in what condition are the plug wires and spark plugs? oh and check out the egr.
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post #10 of Old 07-20-2013, 06:10 AM
JS97ZJ
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Clogged cat.
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post #11 of Old 07-20-2013, 07:16 AM
Siva283
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Quote:
Originally Posted by JS97ZJ View Post
Clogged cat.
He jusr replaced the cat.

Sent from my SPH-L300 using JeepForum

1995 YJ. 2 inch BDS Spring lift. 1 inch shackle lift. 1.25 inch JKS Body Lift 33x12.5x15's. Engo 10,000 pound winch.

Quote:
Originally Posted by Magnum View Post
I gave the Jeep the required offering of $$, sweat, and blood, and everything works fine now. -- Jim
Quote:
Originally Posted by ldso View Post
. It started with a $200 axle, and a few thousand dollars later I was done :)
Quote:
Originally Posted by Luuca View Post
diagnose the real issue before you start going all Obama on it - spending mad cash you'll need for other important things.

Ask me how I know...
Quote:
Originally Posted by Overhead View Post
this is also my second set of RC springs this year. I'd rather spend the money again and get something that will last.
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post #12 of Old 07-20-2013, 07:21 AM
Rich93ZJ
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Did you replace you crank sensor with a Mopar unit or one from the autoparts store? Mopar ONLY on the crank sensor. The cheap aftermarket junk will do weird stuff like you are describing.
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post #13 of Old 07-20-2013, 08:52 AM Thread Starter
funforfree
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Quote:
Originally Posted by Rich93ZJ
Did you replace you crank sensor with a Mopar unit or one from the autoparts store? Mopar ONLY on the crank sensor. The cheap aftermarket junk will do weird stuff like you are describing.
Yes I did get a mopar. I just noticed that the vacuum line to the map sensor has a rubber cap on it no line is this correct?
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post #14 of Old 07-20-2013, 03:42 PM
Siva283
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Quote:
Originally Posted by funforfree View Post

Yes I did get a mopar. I just noticed that the vacuum line to the map sensor has a rubber cap on it no line is this correct?
No the map should have a vac line going to it

Sent from my SPH-L300 using JeepForum

1995 YJ. 2 inch BDS Spring lift. 1 inch shackle lift. 1.25 inch JKS Body Lift 33x12.5x15's. Engo 10,000 pound winch.

Quote:
Originally Posted by Magnum View Post
I gave the Jeep the required offering of $$, sweat, and blood, and everything works fine now. -- Jim
Quote:
Originally Posted by ldso View Post
. It started with a $200 axle, and a few thousand dollars later I was done :)
Quote:
Originally Posted by Luuca View Post
diagnose the real issue before you start going all Obama on it - spending mad cash you'll need for other important things.

Ask me how I know...
Quote:
Originally Posted by Overhead View Post
this is also my second set of RC springs this year. I'd rather spend the money again and get something that will last.
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post #15 of Old 07-20-2013, 04:38 PM
Rich93ZJ
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Posts: 461
Quote:
Originally Posted by Siva283 View Post
No the map should have a vac line going to it

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^^This^^. Should also have a check valve in line with it
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