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still a bit of a rough idle with A/C on. Asking for help with diagnosis

 
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  • 1 Post By _PTGT03
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  • 2 Post By ptprice

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Old 12 Sep 2016, 05:58 am
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Default still a bit of a rough idle with A/C on. Asking for help with diagnosis

I realize the subjects been bantered to abstraction but I'm stumped with this and haven't find a directed answer popping up.

My son Pricie's 05 Pt, Turbo, Auto, 70000 miles, Vert had a rough idle with A/C on. Last weekend he and his brother Steve dug into it. It threw a few codes but after replacing the old battery the roughness was really reduced. From then on,there were no more codes. Pricie decided to live with it and asked his Uncle Scott, my brother, to tinker with it when Pricie drove up to Sugarloaf, Pa on planed trip of eight hours, to visit him.

Pricie called called me last week, reported the results, and I suggested the old dollar bill flutter trick. The bill fluttered out when held over the open oil filler hole at low idle with A/C on. This to me always indicated positive crankcase pressure, pointing to a bad PCV valve. He did and that dollar bill fluttered out.

Pricie and Steve got together again this weekend and changed the PVC valve. The report back from Steve was, "We put in a new PCV valve, STILL A SLIGHTLY ROUGH IDLE WITH A/C ON. Is that a valid test or is it bull crap, the dollar bill still flutters out!. I did the same dollar bill test thing on my PT and it fluttered out too. My PT's runnin' good!"

Aside from a helpful diagnosis, please answer a now family generational dispute. Is this a valid test for crankcase pressure? Dollar bill flutters out, positive crankcase pressure, flutter in negative? I've been using it for 50 years for rudimentary crankcase pressure diagnosis!

Essentially, I'm hoping for advice I can pass on, as to what else could be causing an un-coded slightly rough idle with the A/C on. All suggestions accepted with appreciation! I figger it's some mystery un-coded fluke in the emission control crap!

Thank's to all the knowledgeable PTers who've help with diagnosing in the past. You always make me look like a hero!

This'n got me stumped and I don't want Pricie to shell out big bucks at the Chrysler garage foe a hunt and peck search.

Thank you.

Happy PTin, ptprice
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SOOO BIG 2005 PT CRUISER, LIMITED EDITION, SIGNATURE SERIES
Cool Vanilla White, 3 Coats. 2.4 DOHC 16V SMPI Eng. Vanity Cover, 4 Spd. Auto Trans. 2.6 Overall Top Gear, Lock-up Torque Converter. PT Chrome Clad 16" X 6" Wheels, P205/55 R16 Cooper Starfire/Solarus tires, Touring Suspension. Chrome Package; Side Spears, Grills, Fuel Filler Door, Door Locks, Handles, PRND3-1 Bezel, Silver/Chrome Shift Ball/Knob, Bright Spoke Leather Tilt Steering Wheel. Chrome Tail Lights, 3/8" Belt Trim. Cruise Control, Power Mirrors, A/C, Deep Tinted Sun Screen Glass, Power Moon Roof, Fog and Back-Up Lights, Rear Spoiler, Variable Front Wipers W/Washers, Rear Wiper/Washer, Key less Entry, Replacement 2001 Dark Taupe Grey Suede/Leather Trim Seats, Dual Under Seat Storage Drawers, Drivers Side Power Seat Height Adjust. Full Length Console, Locking Glove Box, Overhead Temperature/Compass Console, Rear Shelf Panel, AM/FM CD GPS Navigation Radio, 6 Premium Speakers, Back up Camera/ 7" Monitor.
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Old 12 Sep 2016, 06:44 am
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Default Re: still a bit of a rough idle with A/C on. Asking for help with diagnosis

see if you can't fit an obd reader on there with live data to see how the rpm behaves once the ac is enabled.
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2003 GT M/T in Onyx Green Pearl on Michelin Pilot Sport AS 3 Plus Tires 205/50ZR17. Dark Slate Gray Interior. OEM cargo net, parcel shelf, slush mats and trunk protector, mud flaps, mopar subwoofer. Platinum edition pedals, Neon SX 2.0 steering wheel with black+grey wrapped leather cover. Generic lowering springs, KYB gas shocks, Valeo solid flywheel conversion and clutch kit. Urethane insert engine mounts. Energy suspension full body urethane bushing kit. Chrysler premium front speakers, Jenson 6x9 rears. Boston Audio 4x55W amp. Panasonic head unit with xtenzi bluetooth. 300W AC power inverter. Escort 360max and Escort Shifter ZR4, dual front+rear dash camera. stage 1 blow off valve and syked tune computer . Boost and oil pressure gauges with Turbo-Timer. Needswings 3" exhaust elbow, Electric valve actuated Y-pipe with catalytic converter. To do: coilovers, 2step controller, quaife diff, Air-Fuel Meter
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Old 12 Sep 2016, 08:46 am
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Default Re: still a bit of a rough idle with A/C on. Asking for help with diagnosis

I would suggest checking the radiator fan. There are two speeds and one of speeds might not be working putting stress on the A/C. With the engine cold turn on the A/C and the high speed on the radiator fan should be coming on.
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Old 12 Sep 2016, 12:43 pm
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Default Re: still a bit of a rough idle with A/C on. Asking for help with diagnosis

WOWSER! Really good input. I've texted Steve of your suggestions. We'll wait and see and keep you posted. Please keep the suggestions streamin' in. There's nothin' worse than a sick PT.

My gosh your both a lot smarter than you look!

Thanks.

Happy Ptin', ptprice
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SOOO BIG 2005 PT CRUISER, LIMITED EDITION, SIGNATURE SERIES
Cool Vanilla White, 3 Coats. 2.4 DOHC 16V SMPI Eng. Vanity Cover, 4 Spd. Auto Trans. 2.6 Overall Top Gear, Lock-up Torque Converter. PT Chrome Clad 16" X 6" Wheels, P205/55 R16 Cooper Starfire/Solarus tires, Touring Suspension. Chrome Package; Side Spears, Grills, Fuel Filler Door, Door Locks, Handles, PRND3-1 Bezel, Silver/Chrome Shift Ball/Knob, Bright Spoke Leather Tilt Steering Wheel. Chrome Tail Lights, 3/8" Belt Trim. Cruise Control, Power Mirrors, A/C, Deep Tinted Sun Screen Glass, Power Moon Roof, Fog and Back-Up Lights, Rear Spoiler, Variable Front Wipers W/Washers, Rear Wiper/Washer, Key less Entry, Replacement 2001 Dark Taupe Grey Suede/Leather Trim Seats, Dual Under Seat Storage Drawers, Drivers Side Power Seat Height Adjust. Full Length Console, Locking Glove Box, Overhead Temperature/Compass Console, Rear Shelf Panel, AM/FM CD GPS Navigation Radio, 6 Premium Speakers, Back up Camera/ 7" Monitor.
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Old 13 Sep 2016, 07:06 am
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Default Re: still a bit of a rough idle with A/C on. Asking for help with diagnosis

not only that but your PCM increases your idle air controller opening the instant A/C is enabled to compensate for engine load without a change in rpm/ so for me that's an important issue to get isolated as a cause
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2003 GT M/T in Onyx Green Pearl on Michelin Pilot Sport AS 3 Plus Tires 205/50ZR17. Dark Slate Gray Interior. OEM cargo net, parcel shelf, slush mats and trunk protector, mud flaps, mopar subwoofer. Platinum edition pedals, Neon SX 2.0 steering wheel with black+grey wrapped leather cover. Generic lowering springs, KYB gas shocks, Valeo solid flywheel conversion and clutch kit. Urethane insert engine mounts. Energy suspension full body urethane bushing kit. Chrysler premium front speakers, Jenson 6x9 rears. Boston Audio 4x55W amp. Panasonic head unit with xtenzi bluetooth. 300W AC power inverter. Escort 360max and Escort Shifter ZR4, dual front+rear dash camera. stage 1 blow off valve and syked tune computer . Boost and oil pressure gauges with Turbo-Timer. Needswings 3" exhaust elbow, Electric valve actuated Y-pipe with catalytic converter. To do: coilovers, 2step controller, quaife diff, Air-Fuel Meter
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Old 15 Sep 2016, 02:39 pm
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Default Re: still a bit of a rough idle with A/C on. Asking for help with diagnosis

Final report. We were all wrong, and it took Pricie my youngest son and least mechanically reclined, to do the diagnosis. He had the foresight to realize the rough idle was only with the A/C on. He realized the common denominator was the A/C. He put a long screwdriver to his ear all around the A/C system and finally to the compressor, only to hear the sound differential with the A/C on resisting engine rotation at low idle. Ergo a dying compressor bearing that might last two more days or two more years till the compressor implodes!

See us Youngmans aren't as dumb as we look!

I had SOOO BIG's compressor replaced earlier this year for well under $500.00 including a new approved, mail order compressor plus labor.

Thanks for all the input. In life and mechanics, it's often finding what it isn't that leads to what it is! At the Chrysler Garage that's called hunt and peck at $120.00 per hour! In the real world of PT land that's,goin' to the Forum, askin' questions, gettin' good answers and comin' up with the answer for a lot less money.

Thanks to one and all...........You solved it vicariously!

Happy Ptin', ptprice
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SOOO BIG 2005 PT CRUISER, LIMITED EDITION, SIGNATURE SERIES
Cool Vanilla White, 3 Coats. 2.4 DOHC 16V SMPI Eng. Vanity Cover, 4 Spd. Auto Trans. 2.6 Overall Top Gear, Lock-up Torque Converter. PT Chrome Clad 16" X 6" Wheels, P205/55 R16 Cooper Starfire/Solarus tires, Touring Suspension. Chrome Package; Side Spears, Grills, Fuel Filler Door, Door Locks, Handles, PRND3-1 Bezel, Silver/Chrome Shift Ball/Knob, Bright Spoke Leather Tilt Steering Wheel. Chrome Tail Lights, 3/8" Belt Trim. Cruise Control, Power Mirrors, A/C, Deep Tinted Sun Screen Glass, Power Moon Roof, Fog and Back-Up Lights, Rear Spoiler, Variable Front Wipers W/Washers, Rear Wiper/Washer, Key less Entry, Replacement 2001 Dark Taupe Grey Suede/Leather Trim Seats, Dual Under Seat Storage Drawers, Drivers Side Power Seat Height Adjust. Full Length Console, Locking Glove Box, Overhead Temperature/Compass Console, Rear Shelf Panel, AM/FM CD GPS Navigation Radio, 6 Premium Speakers, Back up Camera/ 7" Monitor.
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Old 17 Sep 2016, 12:16 am
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Default Re: still a bit of a rough idle with A/C on. Asking for help with diagnosis

Quote:
Originally Posted by ptprice View Post
A dying compressor bearing that might last two more days or two more years till the compressor implodes!

Could have been because of an improper amount of compressor oil or not enough pressure in the system or a leak over time ?
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2003 GT M/T in Onyx Green Pearl on Michelin Pilot Sport AS 3 Plus Tires 205/50ZR17. Dark Slate Gray Interior. OEM cargo net, parcel shelf, slush mats and trunk protector, mud flaps, mopar subwoofer. Platinum edition pedals, Neon SX 2.0 steering wheel with black+grey wrapped leather cover. Generic lowering springs, KYB gas shocks, Valeo solid flywheel conversion and clutch kit. Urethane insert engine mounts. Energy suspension full body urethane bushing kit. Chrysler premium front speakers, Jenson 6x9 rears. Boston Audio 4x55W amp. Panasonic head unit with xtenzi bluetooth. 300W AC power inverter. Escort 360max and Escort Shifter ZR4, dual front+rear dash camera. stage 1 blow off valve and syked tune computer . Boost and oil pressure gauges with Turbo-Timer. Needswings 3" exhaust elbow, Electric valve actuated Y-pipe with catalytic converter. To do: coilovers, 2step controller, quaife diff, Air-Fuel Meter
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