95 Neon RPM JUMPSwhen switching gearswith A/C on.
#1
11-14-2005, 09:48 PM
95 Neon RPM JUMPSwhen switching gearswith A/C on.
[:@] Here is the problem, I HAVE BEEN TO THE DEALER 6 TIMES SINCE 95 with this problem,WHen I shift the gears on a 2.0 SOHC 95 Neon sport (June 94)purchase, with the A/C on the RPMS jump in every gearkind of stick up on rpms then go down after shifting they do this on every gearwhen A/C is not on this does not happen . Dodge cant tell me whats wrong. Help!!!! I figure its a sensor or something.
Ryynnoo
Ryynnoo
#2
11-15-2005, 03:40 AM
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RE: 95 Neon RPM JUMPSwhen switching gearswith A/C on.
First, have the dealer check to see if your PCM falls into one of the recalls. They should have done this already.
Whenever the a/c (including defrost) is on, the PCM sends a signal to the IAC (Idle Air controller) to open a little more to compensate for the power draw. All neons tend to overcompensate a tad, but the very early '95 models were the worst. Usually replacing the PCM will help a ton. If the dealer won't replace it for free, don't worry about it now... The other problem is the IAC itself. The EGR system dumps nasty exhaust gases back into your intake manifold, building up a black goo all over the inside there... your intake manifold, intake ports, intake valves, throttlebody, and IAC are probably coated thick by now. The IAC is a moving part, so if it has that buildup, then the valve can't move as fast as it should. The PCM does check to make sure the valve is moving, and there is a time limit for it to move, and a code will be set if it isn't falling within those parameters. But a little bit can make a big difference... that split second of slow response is all it takes for the IAC to stay too far open during a shift, or too far closed when idling to a stop (has your idle been dipping low at lights? dying?). The fix for this is to take the TB off and clean the heck out of it with carb cleaner, some rags, and some q-tips for the smaller holes. You can remove the IAC, but be careful... they used loctite on the threads. I broke both bolts off and had the IAC tie-wrapped to the TB for 40k miles or so...
Antoher thing to consider, although less likely, is that your TB and/or TPS were superceded by another part. The original TPS didn't have a rubber o-ring seal, so moisture could get in there and start screwing with the readings, throwing off fuel trims and whatnot. I'd have to look up the part numbers, but I'm pretty sure it goes back as far as your car. Mine was a 12/04 build and was the old style (on an aluminum manifold, don't know if that has any relevance though...). Used TB's are pretty cheap. Think I paid $35 or less for each of mine shipped, with sensors. Your MTX TB, by the way, necks down to 49mm in the middle. If you can find an ATX TB, it's 52mm straight through. Not really all that much in the way of extra power, but typically enough to notice. And if you get one from a '96-'99 Neon, it's guaranteed to be the right style and will bolt right up.
If you do need a PCM replacement in the end, you can usually find stock ones for $35-50 if you look around, or Mopar ones for $150ish. It will have to be from a '95, no other year will work unless you have a love for cutting and splicing a bunch of wires...
Best of luck!
Whenever the a/c (including defrost) is on, the PCM sends a signal to the IAC (Idle Air controller) to open a little more to compensate for the power draw. All neons tend to overcompensate a tad, but the very early '95 models were the worst. Usually replacing the PCM will help a ton. If the dealer won't replace it for free, don't worry about it now... The other problem is the IAC itself. The EGR system dumps nasty exhaust gases back into your intake manifold, building up a black goo all over the inside there... your intake manifold, intake ports, intake valves, throttlebody, and IAC are probably coated thick by now. The IAC is a moving part, so if it has that buildup, then the valve can't move as fast as it should. The PCM does check to make sure the valve is moving, and there is a time limit for it to move, and a code will be set if it isn't falling within those parameters. But a little bit can make a big difference... that split second of slow response is all it takes for the IAC to stay too far open during a shift, or too far closed when idling to a stop (has your idle been dipping low at lights? dying?). The fix for this is to take the TB off and clean the heck out of it with carb cleaner, some rags, and some q-tips for the smaller holes. You can remove the IAC, but be careful... they used loctite on the threads. I broke both bolts off and had the IAC tie-wrapped to the TB for 40k miles or so...
Antoher thing to consider, although less likely, is that your TB and/or TPS were superceded by another part. The original TPS didn't have a rubber o-ring seal, so moisture could get in there and start screwing with the readings, throwing off fuel trims and whatnot. I'd have to look up the part numbers, but I'm pretty sure it goes back as far as your car. Mine was a 12/04 build and was the old style (on an aluminum manifold, don't know if that has any relevance though...). Used TB's are pretty cheap. Think I paid $35 or less for each of mine shipped, with sensors. Your MTX TB, by the way, necks down to 49mm in the middle. If you can find an ATX TB, it's 52mm straight through. Not really all that much in the way of extra power, but typically enough to notice. And if you get one from a '96-'99 Neon, it's guaranteed to be the right style and will bolt right up.
If you do need a PCM replacement in the end, you can usually find stock ones for $35-50 if you look around, or Mopar ones for $150ish. It will have to be from a '95, no other year will work unless you have a love for cutting and splicing a bunch of wires...
Best of luck!
#3
11-19-2005, 12:48 AM
