The famous Neon rough idle question... - Moparts Forums

Register Log In Moparts Forums Moparts Question and Answer The famous Neon rough idle question...

Print Thread

Page 2 of 3

1

2

3

Re: The famous Neon rough idle question... [Re: eightlitermopar] #1632669 06/14/14 02:36 PM 06/14/14 02:36 PM
Joined: Mar 2005 Posts: 1,630 North Central Florida E eightlitermopar OP top fuel
eightlitermopar OP top fuel E Joined: Mar 2005 Posts: 1,630 North Central Florida	So I took off the IAC, and it actually looks pretty clean. If I wanted to clean it out, do I just spray brake cleaner in the hole to the left? I don't want to ruin anything... 8176105-DSCN0348.JPG (463 downloads) Mopar or no car

Re: The famous Neon rough idle question... [Re: eightlitermopar] #1632670 06/14/14 02:39 PM 06/14/14 02:39 PM
Joined: Mar 2005 Posts: 1,630 North Central Florida E eightlitermopar OP top fuel
eightlitermopar OP top fuel E Joined: Mar 2005 Posts: 1,630 North Central Florida	Also, while I was poking around, I noticed the plug on one of the vacuum ports. You can see which port I am talking about in the picture. 8176107-DSCN0350.JPG (1059 downloads) Mopar or no car

Re: The famous Neon rough idle question... [Re: eightlitermopar] #1632671 06/14/14 02:40 PM 06/14/14 02:40 PM
Joined: Mar 2005 Posts: 1,630 North Central Florida E eightlitermopar OP top fuel
eightlitermopar OP top fuel E Joined: Mar 2005 Posts: 1,630 North Central Florida	Here is the plug that was covering it..... 8176110-DSCN0351.JPG (673 downloads) Mopar or no car

Re: The famous Neon rough idle question... [Re: eightlitermopar] #1632672 06/14/14 02:41 PM 06/14/14 02:41 PM
Joined: Mar 2005 Posts: 1,630 North Central Florida E eightlitermopar OP top fuel
eightlitermopar OP top fuel E Joined: Mar 2005 Posts: 1,630 North Central Florida	another view 8176111-DSCN0352.JPG (510 downloads) Mopar or no car

Re: The famous Neon rough idle question... [Re: eightlitermopar] #1632673 06/14/14 04:28 PM 06/14/14 04:28 PM
Joined: Feb 2006 Posts: 52 CO T Twisted member
Twisted member T Joined: Feb 2006 Posts: 52 CO	Just spray everything including the TB side. I have connected power to actuate the valve but it doesn't seem needed if it seems to be working, just spray both sides. Not sure on that cap. It could be a problem but I would think it would be more noticeable of a stumble if it had a vacuum leak. Thank you Aaron 69 Dodge Polara 4DHT 70 Plymouth Duster 03 Dodge Neon R/T 05 Dodge Grand Caravan SXT

Re: The famous Neon rough idle question... [Re: Twisted] #1632674 06/14/14 07:16 PM 06/14/14 07:16 PM
Joined: Mar 2005 Posts: 1,630 North Central Florida E eightlitermopar OP top fuel
eightlitermopar OP top fuel E Joined: Mar 2005 Posts: 1,630 North Central Florida	Quote: Just spray everything including the TB side. I have connected power to actuate the valve but it doesn't seem needed if it seems to be working, just spray both sides. Not sure on that cap. It could be a problem but I would think it would be more noticeable of a stumble if it had a vacuum leak. I haven't sprayed the throttle body or the IAC yet, I wanted to see what difference the new vacuum cap made. Before I was idling (in gear) at about 600 rpm (according to the dash tach). I put on a good plug and now I am idling about 800, so some of a difference there, but the rough idle "shudder" is still there. I will keep playing around and keep you guys posted. eightlitermopar Mopar or no car

Re: The famous Neon rough idle question... [Re: eightlitermopar] #1632675 06/15/14 06:57 AM 06/15/14 06:57 AM
Joined: Jun 2008 Posts: 10,958 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,958 Oakdale CT	Quote: Could you actually see rust particles in the injector? Or were they just to small and wedged down there? One way to tell is the spray pattern on the injectors. "I think its got a hemi"

Re: The famous Neon rough idle question... [Re: eightlitermopar] #1632676 06/15/14 01:22 PM 06/15/14 01:22 PM
Joined: Jan 2003 Posts: 13,031 Benton, IL. D DaveRS23 Master of nothing...
DaveRS23 Master of nothing... D Joined: Jan 2003 Posts: 13,031 Benton, IL.	In my experience, when the IAC is dirty the idle is slow to respond or unresponsive. As in idles too high or the engine dies at idle because it is too low. The IAC is just a tapered plunger that plugs and unplugs a by-pass hole in the throttle body that allows more or less air into the engine. It doesn't usually cause a rough running idle condition, unless it causes an extremely low idle that causes the engine to shake. I usually spray carb cleaner in it and let it soak for awhile and then spray it again. Be sure to remove the gasket/seal first. Master, again and still

Re: The famous Neon rough idle question... [Re: DaveRS23] #1632677 06/15/14 01:32 PM 06/15/14 01:32 PM
Joined: Feb 2010 Posts: 1,377 Ohio Todd pro stock
Todd pro stock Joined: Feb 2010 Posts: 1,377 Ohio	Where I work we have BG induction service. It has an injector that sprays cleaner in the t-body with the engine running. Works very well. Cleans the entire t-body,IAC circuts and intake. I had a neon I did that to and the inside of the intake looked like new. I clean all my vehicles every 30k with it.

Re: The famous Neon rough idle question... [Re: Todd] #1632678 06/15/14 05:10 PM 06/15/14 05:10 PM
Joined: Dec 2010 Posts: 1,035 Missouri U.S.A. 7 71yelladustr super stock
71yelladustr super stock 7 Joined: Dec 2010 Posts: 1,035 Missouri U.S.A.	You might check to see if you have plenty of clearance between the core support and the engine and trans. I have seen alot of neons that have bottomed out at some time or another and pushed the core support back into the engine of trans. Especially the second gen cars. The The PCM and rad fans like to come in contact with the trans causing the issue you describe. One other thing, Have you ever done a compression test on your engine? Later 2.0s had horrible valve jobs and are common for the valves not to seat well and cause miss or shake without setting a MIL. 392 gen III hemi on E-85 727 trans Dana 60 10.02@134

Re: The famous Neon rough idle question... [Re: 71yelladustr] #1632679 06/15/14 08:22 PM 06/15/14 08:22 PM
Joined: Mar 2005 Posts: 1,630 North Central Florida E eightlitermopar OP top fuel
eightlitermopar OP top fuel E Joined: Mar 2005 Posts: 1,630 North Central Florida	Quote: You might check to see if you have plenty of clearance between the core support and the engine and trans. I have seen alot of neons that have bottomed out at some time or another and pushed the core support back into the engine of trans. Especially the second gen cars. The The PCM and rad fans like to come in contact with the trans causing the issue you describe. One other thing, Have you ever done a compression test on your engine? Later 2.0s had horrible valve jobs and are common for the valves not to seat well and cause miss or shake without setting a MIL. I have not checked the compression yet, mostly because I am afraid I am going to find a low cylinder. I have heard that about these cars as well. Also, the car drives great (other than the idle, which isn't horrible) and it gets great mileage, so even if I have a dead cylinder....I probably wouldn't do anything about it anyway Mopar or no car

Re: The famous Neon rough idle question... [Re: DaveRS23] #1632680 06/16/14 02:58 AM 06/16/14 02:58 AM
Joined: Jan 2003 Posts: 27,421 Balt. Md 3 383man Too Many Posts
383man Too Many Posts 3 Joined: Jan 2003 Posts: 27,421 Balt. Md	Quote: In my experience, when the IAC is dirty the idle is slow to respond or unresponsive. As in idles too high or the engine dies at idle because it is too low. The IAC is just a tapered plunger that plugs and unplugs a by-pass hole in the throttle body that allows more or less air into the engine. It doesn't usually cause a rough running idle condition, unless it causes an extremely low idle that causes the engine to shake. I usually spray carb cleaner in it and let it soak for awhile and then spray it again. Be sure to remove the gasket/seal first. I agree as a dirty IAC wont cause a rough idle just a slow or fast idle. My question is does it feel like a dead miss or more like a vibration but still hitting on all 4 cylinders ? Ron Last edited by 383man; 06/16/14 02:59 AM.

Re: The famous Neon rough idle question... [Re: eightlitermopar] #1632681 06/16/14 12:43 PM 06/16/14 12:43 PM
Joined: Aug 2005 Posts: 6,050 Salem Grizzly Moparts Proctologist
Grizzly Moparts Proctologist Joined: Aug 2005 Posts: 6,050 Salem	I feel your pain, Eightliter, I am pulling my hair out with the same problem for the last 2 months. And, just like you, I found a lot of suggestions but no real solution with Google. One, that will be a last resort, is a fellow drilled a 5/32nd hole in his throttle plate. I just had a Dealer re-flash done on the car as per a TSB for "rough idle, P0300 random misfire" issues. It didn't help, but the misfire codes don't show up as much. Still getting P0300 and P0301. Have swapped wires, plugs, tested the coil, checked wiring harness to coil, changed the IAC, and just last night I took all the injectors out and cleaned them off the car (pretty neat method I found online ). Unhooked the battery, cleared the codes, and fired it back up. Ran smooth and figured I got it. Drove it a few minutes, stopped in Drive, and the miss/low idle is back. This little issue has really soured my high praise for Chrysler. The thing has low miles, well-cared for, drives/handles, just generally does everything better than any brand-x vehicle otherwise. I did the timing belt, crank seal, and cam seal and was very careful on getting the timing marks correct. The car ran perfect for a few thousand miles and then the misfire codes came up. Some great suggestions on here too, thanks Guys, I'll give them a try. I guess I gotta find some time this week and dig into it again. Mo' Farts Moderated by "tbagger".

Re: The famous Neon rough idle question... [Re: eightlitermopar] #1632682 06/16/14 12:56 PM 06/16/14 12:56 PM
Joined: Jan 2003 Posts: 21,129 Niles , Ohio T therocks oh wait.but hey.lets see.oh yeah.
therocks oh wait.but hey.lets see.oh yeah. T Joined: Jan 2003 Posts: 21,129 Niles , Ohio	What pluigs and wires did you use?I had one at work that I used Champions in that were direct replacement.It would run great but had rough idle at times.Changed them and wires twice.Finally I had the manager get Champions from the dealer.Installed them and no more roughness.Weird I know as they were the same plug and number.Wires will cause a rough idle and sometimes a miss also.The wifes PT went thru it.New Autolite wires 2 sets.New plugs 3 sets.Id pull number 1 and it would have a track on the porcelian.It wasnt much.I finally used Advanced wires 2 years ago.No more rough idle or occasional miss.Rocky Chrysler Firepower

Re: The famous Neon rough idle question... [Re: Grizzly] #1632683 06/16/14 01:09 PM 06/16/14 01:09 PM
Joined: Jun 2008 Posts: 10,958 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,958 Oakdale CT	Quote: I did the timing belt, crank seal, and cam seal and was very careful on getting the timing marks correct. The car ran perfect for a few thousand miles and then the misfire codes came up. We did coil packs like popcorn too, it was such a noted issue that I still have a test coilpack that was in my toolbox for down and dirty testing. "I think its got a hemi"

Re: The famous Neon rough idle question... [Re: gdonovan] #1632684 06/16/14 01:41 PM 06/16/14 01:41 PM
Joined: Aug 2005 Posts: 6,050 Salem Grizzly Moparts Proctologist
Grizzly Moparts Proctologist Joined: Aug 2005 Posts: 6,050 Salem	Rocky, I went to an NGK. The gap on them has opened a bit but nothing too crazy. They have probably 15, 20,000 miles on them is all. I saved the old Champions and threw it back in #1 hole and it still has the miss. I have heard over the years the only thing a Dodge likes is Champions. I found that out too with 360 Magnum: tried NGK's and wound up going back to Champions. Swapped the 1 and 4 wire and still missfire on #1. I swapped the #1 and #2 injector last night, we'll see what happens after it gets some miles on it. Mo' Farts Moderated by "tbagger".

Re: The famous Neon rough idle question... [Re: Grizzly] #1632685 06/16/14 01:54 PM 06/16/14 01:54 PM
Joined: Jun 2008 Posts: 10,958 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,958 Oakdale CT	Quote: I have heard over the years the only thing a Dodge likes is Champions. I found that out too with 360 Magnum: tried NGK's and wound up going back to Champions. Normally I run nothing but Champions, but have Autolights from Wally-world in the neon 3 or 4 years ago and it didn't seem to care. Still running great. The coil pack on your car might have a carbon track on it, wasn't unusual at all. "I think its got a hemi"

Re: The famous Neon rough idle question... [Re: gdonovan] #1632686 06/16/14 03:16 PM 06/16/14 03:16 PM
Joined: Jan 2003 Posts: 21,129 Niles , Ohio T therocks oh wait.but hey.lets see.oh yeah.
therocks oh wait.but hey.lets see.oh yeah. T Joined: Jan 2003 Posts: 21,129 Niles , Ohio	We run NGKs in everything.I always ran Autolites.Then I went NGK in the 440 with 12.5 compression and street driven.It really likes them as does the other cars.Even the PT likes them.The 440s have been in about 4 years and still no problems.The Autolite race plugs always had a slight off sound.Rocky Chrysler Firepower

Re: The famous Neon rough idle question... [Re: therocks] #1632687 06/17/14 01:45 AM 06/17/14 01:45 AM
Joined: Mar 2005 Posts: 1,630 North Central Florida E eightlitermopar OP top fuel
eightlitermopar OP top fuel E Joined: Mar 2005 Posts: 1,630 North Central Florida	Sorry for the delayed update. It seems to run fine, just that "shudder" at idle. No codes are being thrown. Plugs and wires changed as stated. I replaced the plugs with original champions (from NAPA), and MOPAR wires from the dealership. It did not run any better or worse after the swap. I noticed it fired quicker with the new plugs, not as much cranking. I'll have to check my coil pack too, and I still have to check the resistance on my injectors. Last edited by eightlitermopar; 06/17/14 01:47 AM. Mopar or no car

Re: The famous Neon rough idle question... [Re: eightlitermopar] #1632688 06/17/14 09:41 AM 06/17/14 09:41 AM
Joined: Aug 2005 Posts: 6,050 Salem Grizzly Moparts Proctologist
Grizzly Moparts Proctologist Joined: Aug 2005 Posts: 6,050 Salem	Quote: ...........I'll have to check my coil pack too, and I still have to check the resistance on my injectors. I had 12.4 to 12.7 Ohm all the way across on mine. Injector Testing Also, in that troubleshooting series I used their method for testing the coil: Coil Test Had a nice, fat spark. I pulled all the plugs last night and tightened the gap to .30: run it again for awhile and see what happens. Good luck. I'm still thinking about drilling the hole in the throttle plate.... Mo' Farts Moderated by "tbagger".

Page 2 of 3

1

2

3

Moderated by Al_Alguire, Hotwheelsjr, moparts, not_a_charger, RangerDan440, tboomer

Hop To

Powered by UBB.threads™ PHP Forum Software 7.7.1