Is 500 rpm too low for idle? - Page 2 - JeepForum.com
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post #16 of 35 Old 01-25-2013, 09:39 AM
FAlfani81
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Quote:
Originally Posted by PolkaPower View Post
700-800 is normal.
Really? is it different for a 4.0 then the 5.2? I thought they idled about the same.

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post #17 of 35 Old 01-25-2013, 09:49 AM
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Quote:
Originally Posted by FAlfani81 View Post
Really? is it different for a 4.0 then the 5.2? I thought they idled about the same.
I think so too. Maybe 600-800 range for idle to give it more room but 700 being the sweet spot! 500 is on the low side.
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post #18 of 35 Old 01-25-2013, 09:53 AM
rcMikeS1990
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Quote:
Originally Posted by PolkaPower View Post

700-800 is normal. Possible bad IAC sensor.
For the 5.2 or 4.0?

1994 Grand Cherokee Limited 5.2L V8 318, Spectre cold air intake, Flowmaster Super44 muffler to 3.5" resonator tip, 30x9.5 BFG A/T's, Custom Tranny and TC shifter mod
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post #19 of 35 Old 01-25-2013, 10:01 AM
MTBlue
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Quote:
Originally Posted by PolkaPower View Post
700-800 is normal. Possible bad IAC sensor.
That's pretty much what I gleaned from this whole thread too. Try cleaning your IAC with brake cleaner (no carb cleaner. Too hard on sensors), and if it is still idling low, replace the sensor. Also, check your MAP sensor connection and any codes your Jeep might be throwing. My 4.0 idled rough to the point where my CEL came on. Threw the "bad MAP sensor" codes, so I replaced it. Purred like a kitten after the combo of clean IAC and new MAP. Never had to deal with engine mounts, so hopefully others will chime in on that portion.

Hope that helped,
-Evan

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post #20 of 35 Old 01-25-2013, 10:02 AM
PolkaPower
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Quote:
Originally Posted by rcMikeS1990 View Post
For the 5.2 or 4.0?
I am guessing for both. If you clean the IAC do not move the plunger in and out. If you buy a new one get a Mopar OEM replacement.
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post #21 of 35 Old 01-25-2013, 10:38 AM
bananaslug
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How are your motor mounts? Any changes to the engine?

When I got the 703 injectors they lowered my idle.
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post #22 of 35 Old 01-25-2013, 10:47 AM
B93
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I've had two 5.9s, both idle at 700 (one at like 730).

1998 Grand Cherokee 5.9 Limited. ~356,000 kms
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post #23 of 35 Old 01-25-2013, 11:06 AM
rcMikeS1990
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Quote:
Originally Posted by PolkaPower View Post

I am guessing for both. If you clean the IAC do not move the plunger in and out. If you buy a new one get a Mopar OEM replacement.
I have cleaned it properly, the reason mine appears to be so low is bc i forgot those pics were taken while I was stopped in drive, not true idle

forumrunner_20130125_120528.jpg

That's probably closer to how yours is I bet. Thats idle in park, others were idle in drive so there was a load

1994 Grand Cherokee Limited 5.2L V8 318, Spectre cold air intake, Flowmaster Super44 muffler to 3.5" resonator tip, 30x9.5 BFG A/T's, Custom Tranny and TC shifter mod
My Build Thread--not sure how to make that the link-http://www.jeepforum.com/forum/f13/my-build-thread-1568707/
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post #24 of 35 Old 01-25-2013, 11:09 AM
PolkaPower
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Quote:
Originally Posted by rcMikeS1990 View Post
I have cleaned it properly, the reason mine appears to be so low is bc i forgot those pics were taken while I was stopped in drive, not true idle

Attachment 550568

That's probably closer to how yours is I bet. Thats idle in park, others were idle in drive so there was a load
Yes.
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post #25 of 35 Old 01-25-2013, 07:33 PM
papitt
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SO What does the MAP sensor look like and where is it.
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post #26 of 35 Old 01-25-2013, 07:38 PM
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Originally Posted by papitt View Post
SO What does the MAP sensor look like and where is it.
It's a square plastic box that is mounted to the drivers side of the throttle body.
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post #27 of 35 Old 01-25-2013, 08:42 PM
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post #28 of 35 Old 01-26-2013, 08:27 AM Thread Starter
kb9mfd
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Can the MAP sensor be bad without throwing any error codes? Only the idle seems a little low, and after cleaning the IAC, the idle does not change when put under load (like the A/C pump or putting it in drive), but it use to. I cleaned the IAC its self but I did not know how to get into the hole it sits in to clean that. Could I take the body it sits in off the intake and clean that? Since its a '95 with 135k the chances are neither of them have ever been replaced. The previous owner is a friend of mime and I have all the service documents and they where never serviced, and he had it for 10+ years. - Jeremy
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post #29 of 35 Old 01-26-2013, 08:42 AM
ZeeJay1997
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Originally Posted by kb9mfd View Post
Could I take the body it sits in off the intake and clean that?
Yes. Get some carb cleaner and a new gasket. Take all the sensors off and soak and clean the throttle body.. You can use soft brush or Q-tip to clean IAC ports, just dont scrape the seat for the plunger. The TPS screws can be tough to get out, but i found that if you back them out until they get stiff, then spray penetrate, then run them back in. Keep repeating this until they are out. Also check the small port for the MAP tube for clog and be careful with the elbow.
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post #30 of 35 Old 01-26-2013, 09:41 PM
MTBlue
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Quote:
Originally Posted by ZeeJay1997 View Post
Yes. Get some carb cleaner and a new gasket. Take all the sensors off and soak and clean the throttle body.. You can use soft brush or Q-tip to clean IAC ports, just dont scrape the seat for the plunger. The TPS screws can be tough to get out, but i found that if you back them out until they get stiff, then spray penetrate, then run them back in. Keep repeating this until they are out. Also check the small port for the MAP tube for clog and be careful with the elbow.
Awesome advice. Had to use most of that when I redid my IAC and MAP sensors. The screws on my TPS WOULD NOT come out, and since I had to replace the whole thong anyway, I just broke the damn thing off completely.

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