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-   -   Help with surge please. (http://www.jeepforum.com/forum/f13/help-surge-please-1551165/)

funforfree 07-19-2013 08:01 PM

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.

Siva283 07-19-2013 08:04 PM

Quote:

Originally Posted by funforfree (Post 15697013)
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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funforfree 07-19-2013 08:06 PM

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.

Siva283 07-19-2013 08:12 PM

Quote:

Originally Posted by funforfree (Post 15697028)

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?

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funforfree 07-19-2013 08:56 PM

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?

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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.

ZeeJay1997 07-19-2013 09:03 PM

Is it surging or missing?

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

IAC only affects idle

funforfree 07-19-2013 09:26 PM

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.

ZeeJay1997 07-19-2013 10:28 PM

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?

ozzy_2_me 07-19-2013 11:16 PM

just out of curiosity in what condition are the plug wires and spark plugs? oh and check out the egr.

JS97ZJ 07-20-2013 06:10 AM

Clogged cat.

Siva283 07-20-2013 07:16 AM

Quote:

Originally Posted by JS97ZJ (Post 15697768)
Clogged cat.

He jusr replaced the cat.

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Rich93ZJ 07-20-2013 07:21 AM

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.

funforfree 07-20-2013 08:52 AM

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?

Siva283 07-20-2013 03:42 PM

Quote:

Originally Posted by funforfree (Post 15698109)

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

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Rich93ZJ 07-20-2013 04:38 PM

Quote:

Originally Posted by Siva283 (Post 15699065)
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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