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-   -   New IAC. 5.9 still surges in park sometimes ? (http://www.jeepforum.com/forum/f13/new-iac-5-9-still-surges-park-sometimes-1547579/)

Candymancan 07-10-2013 10:14 PM

New IAC. 5.9 still surges in park sometimes ?
 
So ever since I got this 5.9 it would randomly not all the time maybe once every few weeks or so idle really high like 1500 rpm's or so once I drove around and then put it into park.. if I sit in drive itll go up and down from like 350-750 rpm..

When I fixed my intake plenum I noticed it started doing this once every day.. So I cleaned the IAC and then it stopped doing it every day but it still randomly did it like once a week or something.. So I decided to spend the $45 on a new IAC from advance auto. I noticed this one had a much shorter tip on it from the stock one but I put it in to try and when I started the Jeep the rpms shot way up to like 2500 but then slowely after like 30 seconds dropped down to 5-700rpm like its suppose too.. Well its been about a week now since I put the new one in and today when I parked the Jeep its idle was really high again.. Anytime it does this, I just shut the engine off and turn it back on and itll be fine.. ??

So what is the problem ? Why is my idle doing this ? I have a TPS from another 5.9 that didn't fix it, a new IAC apparently didn't fix it either. All my vacuum lines going to the intake manifold are new.. Hell everything bolted the engine is new just about..

So I don't get it..


This video is exactly how mine behaves with the needle moving up and down, except when I put it in park itll rev to 1500 rpm's.. If I turn the engine off and on it stops and acts like normal


Also I noticed its getting harder to start the Jeep... Itll crank fast like 10-15 times before starting, it does this if its been sitting for a few hours or over night, and sometimes when its been driven a lot and I park and go into the grocery store or something and turn it back on itll crank once then sorta stop and crank really slowely a second time and then fire right up.

Taz360ZJ 07-10-2013 10:16 PM

Check for vacuum leaks & intake warp. IAC might be faulty too.

Candymancan 07-10-2013 10:20 PM

Intake warp ?

I already tried checking for vacuum leaks around the manifold with carb cleaner all that did was set my engine on fire a month ago.. lol.. What I don't understand is if it were a vacuum leak wouldn't it be doing this all the time and not randomly ? I don't think my intake has any vacuum leaks when I sprayed the engine with water to put out my fire I noticed water pooled between the manifold gasket and the valve covers, and it sat there for 2 days and the levels didn't drop.. when I did use brake cleaner before it caught on fire I did manage to get both sides of the manifold sprayed down and my idle didn't change.. I sprayed carb cleaner around my manifold a year or 2 ago per someone's suggestion and the idle didn't change either... So I really doubt its the intake

It did this before I took my manifold off and AFTER I fixed my plenum leak.. So I doubt well im just saying anyway, I doubt the manifold could be leaking it has to be something else.

Taz360ZJ 07-10-2013 10:30 PM

You are supposed to use propane gas for checking for leaks. You have a spark leak somewhere off your ignition. Fix it before you turn in to Michael Jackson in 1984.

Candymancan 07-10-2013 10:35 PM

I already turned into him when my engine caught on fire.. You should see the melted heatwrap tubing on my wire harness.

I don't know what caused the stuff to ignite.. It could be the cheap advance auto spark plug wires I have.. They are probly almost 2 years old now. I suppose tomorrow ill get my propane torch and use that, but im just saying I don't think its a vacuum leak on the manifold. it did it before and after I took the manifold off.. what are the odds are the same leak with a new gasket ?

Taz360ZJ 07-10-2013 10:41 PM

Funny you say advanced. On my long armed '99 Classic I got screwed over twice by those adv wire sets. I had to be pulled backwards out of a car wash one winter by a f150 BC the set got wet. Returned the set and went with the premium wires, same problem. Got my $ back. Went to Napa & used their premium set. Zero problems. Never again will I use an adv auto wire set.

Candymancan 07-10-2013 10:48 PM

I don't remember what brand they were.. I just got the cheapest I could find.. because my distributor, rotor, ignition coil and wires were all original... You shoulda seen my cap and rotor... the rotor was black and charred and the cap the metal points were extremely corroded.. one was about to break off.. So I got a new brass rotor and distributor new coil and new wires, but the wires were the cheap ones.. Guess Ill get new ones when I get some money..

But back to the manifold... What are the odds of it being the manifold before, and after I took it off.. It did get worse when I took it off and fixed my plenum.. but cleaning the IAC made it go back to what it used to do.. so it really seems more electrical or something I dunno... If it were a vacuum leak wouldn't it be doing it all the time ? I'll try my torch tomorrow but I hope it isn't the manifold.. I do not wanna take that stuff apart again lol. I'll swap my new IAC for another one.. When I noticed the tip was shorter then the original I brought it into the store and showed them and the guy on the desk started to twist the tip and pull on it and I told him to not do that.. Maybe he messed it up ?

PolkaPower 07-10-2013 11:41 PM

Get multimeter+ohm plug wires= profit

Candymancan 07-11-2013 10:33 AM

Ok so I got my propane torch out and turned it on lightly and held it around the intake manifold from back to back side to side. I held it right next to the vacuum lines going to the manifold and I held it against the intake gasket where the injectors are.. and I didn't notice any rpm's change.. So I turned it up a little and still no change.. only thing I noticed was the engine bay smelling of propane.. Worried about my last engine fire I turned the propane off and turned the engine off.. i don't want some spark igniting the propane in the air lol... Pretty sure if there was a leak it deff would have changed rpms.. I really don't think its a vacuum leak around the manifold.

I didn't have a helper to watch my rpm's in the dash but I didn't notice the engine shaking or any increase in rpm by sound or how it was reacting.. So yea..

What should I do next ? I guess i'll return this IAC and get another and see if that does anything.. but what if it doesn't ? then what ?

AaronButler 07-11-2013 10:51 AM

when you cleaned the IAC and TB, did you clean the housing where the IAC goes into? Ive been guilty of not getting in there very well

dellis 07-11-2013 11:46 AM

Quote:

Originally Posted by Candymancan (Post 15664510)
So what is the problem ? Why is my idle doing this ?

Also I noticed its getting harder to start the Jeep...

Your symptoms of 2000 RPM at idle and hard starting are symptoms of a failing Camshaft Position Sensor (or, more correctly, loss of a CmPS signal).* You may also have a bunch of gunk down in your distributor that is messing with the CmPS signal to your PCM, so you might want to get in there and make sure it is clean with no metal interfering with your CmPS magnet.

If you put an OBDII scanner on your car and check codes, there's a good chance you'll see a fault code for the CmPS. But, before replacing the CmPS, make sure you test it to ensure it is the problem ... if it is, then Mopar is your friend.



*Disclaimer - This is what I've read, but have no personal experience with this problem.

Candymancan 07-12-2013 06:42 AM

Quote:

Originally Posted by dellis (Post 15666070)
Your symptoms of 2000 RPM at idle and hard starting are symptoms of a failing Camshaft Position Sensor (or, more correctly, loss of a CmPS signal).* You may also have a bunch of gunk down in your distributor that is messing with the CmPS signal to your PCM, so you might want to get in there and make sure it is clean with no metal interfering with your CmPS magnet.

If you put an OBDII scanner on your car and check codes, there's a good chance you'll see a fault code for the CmPS. But, before replacing the CmPS, make sure you test it to ensure it is the problem ... if it is, then Mopar is your friend.



*Disclaimer - This is what I've read, but have no personal experience with this problem.


checked codes with my scanner I have none.. But the cmp I could look into i haven't replaced that sensor yet on this Jeep. Are you talking about the Crankshaft position sensor ? Do our Jeeps even have a camshaft sensor ? where is it and what does it look like ?

Kevinyj95 07-12-2013 07:23 AM

Don't mean to pick on you but get a mopar IAC. Ive been through three of the cheap IACs on warranty in a month before buying a mopar.

dellis 07-12-2013 07:45 AM

Quote:

Originally Posted by Candymancan (Post 15668628)
checked codes with my scanner I have none.. But the cmp I could look into i haven't replaced that sensor yet on this Jeep. Are you talking about the Crankshaft position sensor ? Do our Jeeps even have a camshaft sensor ? where is it and what does it look like ?

Inside your distributor just below your rotor, it is a black disc with wires coming out from it. The camshaft position sensor (CMPS) works with the crankshaft position sensor (CKPS) to determine timing during start-up, but the CKPS is what is used by the PCM during operation. These two sensors are also used to determine synchronization between the cam and crank, but can only be adjusted with one of the advanced computers (not a cheap OBDII scanner).

A failed camshaft sensor will mean that the car starts smoothly half the time, and half the time it will have trouble starting. A Chrysler automotive trainer also wrote once that it will cause the RPMs at idle to be in the 2000 range. However, if it is failed, I would have expected a code because the CMPS and the CKPS are used to diagnose faults with one another ... hmmm ... so, I am less confident of this as your problem. Regardless, here are the tests:

Checking for junk:
(1) Remove your distributor cap and rotor.
(2) Pull up the black disk and check the area below the disk for anything that might be interfering with its operation.

Checking for operation:
Here's how to diagnose whether or not the sensor is working:

(a) With the electrical connector disconnected and key in the "on" position, verify voltage to the cam sensor from the PCM. It should be 5.0 volts for 1996 to 1998 vehicles (8.0 volts for 93-95). Test between the white/black (voltage) and the black/light blue (ground) wires. If it is not 5.0 volts, then you need to investigate the circuit and/or the PCM.

(b) Next check for damage to the cam sensor ... place an ohmmeter across terminals B and C of the cam sensor connector. The meter reading should be open (infinite resistance, which shows up as "OL" or "1." on your digital multimeter). If you notice measurable resistance, then the sensor is bad.

http://www.orangehound.com/misc/ckps...0connector.jpg

(c) Reconnect the sensor. The signal produced from the camshaft position sensor is a regular square wave, so the RMS (AC) voltage on a digital meter that you should see would be half of the 5 V supply, or 2.5 volts. With everything connected, have your meter backprobed* into the connector's gray/black wire with the other end grounded. Then crank the engine to observe the RMS (AC) voltage. If you are using an analog meter, you should see the meter fluctuating between 0 and 5 volts. If you measure nothing, the sensor is bad and needs replacing.

*I usually put a sewing needle in though the back of the connector, and attach my multimeter lead to the needle.

dusterdude 07-12-2013 05:51 PM

Quote:

Originally Posted by Candymancan
I don't remember what brand they were.. I just got the cheapest I could find.. because my distributor, rotor, ignition coil and wires were all original... You shoulda seen my cap and rotor... the rotor was black and charred and the cap the metal points were extremely corroded.. one was about to break off.. So I got a new brass rotor and distributor new coil and new wires, but the wires were the cheap ones.. Guess Ill get new ones when I get some money..

But back to the manifold... What are the odds of it being the manifold before, and after I took it off.. It did get worse when I took it off and fixed my plenum.. but cleaning the IAC made it go back to what it used to do.. so it really seems more electrical or something I dunno... If it were a vacuum leak wouldn't it be doing it all the time ? I'll try my torch tomorrow but I hope it isn't the manifold.. I do not wanna take that stuff apart again lol. I'll swap my new IAC for another one.. When I noticed the tip was shorter then the original I brought it into the store and showed them and the guy on the desk started to twist the tip and pull on it and I told him to not do that.. Maybe he messed it up ?

If you bought xact wires,you got what you deserve,i dont feel sorry for you


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