Hi Marshall, > I apologize for taking so long to reply, but I was taken > aback by your statement about there not existing any TBTS ! > Please go to allpar.com to read Bohdan Bodnar's reply to > someone who had a fast idle. > There is in truth such a thing as a TBTS.
No there is not. There is not a singe reference in that article to the acronym TBTS. My reply to you was that on the throttle body there is a Throttle Position Sensor (TPS) and an Automatic Idle Speed motor (AIS, that some folks also call an IAC). In that article he refers to a CTS which is the Charge Temp Sensor which is located about foot away from the throttle body roughly on the top middle of the intake manifold. > Bohdan Bodnar's advice about cleaning the connector > to the TBTS is right on and has solved the CHECK_ENGINE > light on my car after the third unplugging&spraying with > tuner cleaner as he advised. Kudos. I am glad you were able to fix the problem, however as I stated before, there is no such thing as a TBTS. > Try http://www.allpar.com/fix/AISmotor.html and look for > Bohdan's truth there. Other good places are Donovan's Dodge > Garage and Russ Knize's Minimopar pages. And neither of those refer to a TBTS either. > I am not going to build a RESET for my car's computer > mind because after that last spraying of the CTS, or > TBTS(they're the same thing) connector, the gradually > speeding idle has not returned: neither have I felt the need > to RESET the computer again. If the connector you are spraying is connected to an apparatus on the throttle body, then it goes to either the Throttle Position Sensor (TPS) or the Idle Speed motor (AIS) and those connectors are near the power brake booster. If you cleaned the connector to the Charge Temp Sensor (CTS) then that connector is behind the valve cover along the intake manifold. > I don't understand the limp-in mode for code 24: my car > sets this code, turns on the light, and enters limp-in. What > if I shut off the engine and restart it and the code doesn't > light up? Am I in limp-in mode? I don't think so. That's the > reason for wanting the RESET key inside the cabin. If it remains > in limp-in, there would be no use for the RESET! It remains in limp in as long as the problem with the TPS is still there. Here are the two paragraphs describing fault code 24 from the "Instructors Guide" which was used to teach the dealer techs how to repair the sensors on these cars: >> The logic module monitors the TPS signal line every >> 11 milliseconds (91 times a second) anytime the >> ignition key is "on". The TPS signal voltage must not >> be below .16 volts or above 4.7 volts. If either of >> those limits are exceeded, the logic module will turn >> on the power loss/limited light. The system will now >> be in "limp-in". Fault code 24 will be stored in the >> logic module's memory. >> >> At this time the logic module will use the MAP sensor >> signal voltage as an indication of throttle position. >> If the MAP sensor signal voltage is less than 2 volts, >> the logic module will consider the throttle closed. >> If the MAP sensor signal voltage is above 2 volts, the >> logic module will "consider" the throttle wide open. >> The system will remain in "limp-in" until 2 things happen: >> 1. The problem is fixed. >> 2. The ignition key is turned "off" then back "on" again. If the car has a marginal trouble that comes and goes, then it is possible the stored code and limp-in mode will go away on the next start of the car, providing the fault has cleared since the ignition was last turned off. > What I know about code 33 is quoted from the Codes > listed in the Mini-Mopar page: See code 25. Fault Code 25 > will lead you to a code 33, but I have gotten a 25 too > due to a bad ground or confused computermind. That's a typo. On Russ's site, at the bottom of the page for fault code 25 description, it reads: "Fault code 33 is stored." That should read "Fault code 25 is stored." It is a simple typo, and that's all. My car is only getting 22 mpg. with AIS unplugged and 5-spd. I have removed most of the plastic shrouding that leads from the carburetor to the driver's side, leaving only the air cleaner. Will try to get a picture. Ideas? Thanks, Marshall Barry Goodall <[EMAIL PROTECTED]> wrote: Hi Marshall, There are a few inaccuracies in what you have posted, so let's start with clearing those up. First off, there is no temperature sensor on the throttle body (no such thing as a TPTS), only a Throttle Position Sensor (TPS) and the AIS motor referred to by some folks as an IAC. > I want to clarify that my car has been running well for > awhile now, but that it occasionally sets the CE- Check > Engine light while driving. My car's limp-in mode is > good, is there any way to get my CE code while in > motion without shutting off the engine because some > codes are not fatal codes, just advisory? For the discussion here, any code you are getting that causes the computer to go into limp-in mode will remain after the car is shut off. I am pretty sure this is a hard & fast rule, but I will check each code you list to tell you different if my documentation states so. The documentation I am using is the instructors guide that was used by the Chrysler training centers to train the dealer techs. > CE 15 is the speed/distance sensor, and once set it goes > back to normal because I can set the cruise control. My 5-speed > has cruise control, and its great for highways. The cruise control will only fail completely when the Speed/Distance sensor quits completely. The sensor may have a marginal fault that will cause occasional symptoms (for example, high idle when coasting to a stop) long before it goes bad completely. Fault Code 15 will not set limp in or turn on check engine lamp. > CE 24 is the TPS and the limp-in mode is to use the MAP > sensor which feels the throttle position according to the > vacuum and acts accordingly. This code will set the limp in status and the fault code will be stored in the logic module memory until the problem is fixed and the key is then cycled off then on again. The logic module monitors the signal line from the sensor many times a second. If it sees a value below .16v or above 4.7 volts it will set fault code 24. So if you are getting code 24, then the voltage the computer is seeing is outside of these limits at some point while the key is turned on. > For me, this is usually set by the ground in the TBTS > plug beside of the AIS that has been permanently unplugged, > by decision of the driver(me). > > I always get code 33, which doesn't mean "the AC I don't > have" but rather that the AIS isn't responding as expected > instead of saving gas as it does unplugged. I can live with > a CE 33. Sorry, but you have been misinformed on this. Code 33 is indeed a sensed open in the A/C cutout relay. Any car not equipped with A/C will always have this code set and it should be disregarded. But all the code means is that the logic module did not see a change of state when it checked the relay (usually when the ignition is first turned on and the computer does it's diagnostic checks). Code 25 is for the AIS motor, but it only detects problems with the AIS control inside the logic module. Having the AIS motor unplugged will not set a code. From the instructors guide "An open circuit in the harness or AIS motor will not set code 25." and "So an open outside the logic module is not detected." > Maybe if I could hook up to the RS-232 diagnostic connection > under the hood, if I knew the Chrysler pinout to what should be > an industry standard serial bus, with a simple PIC computer > circuit that would read and display CE codes as they develop, > on an LED display inside the cabin? Might be easier to buy or borrow a DRB or scan tool from someone local to you. They will work while you are driving and allow you to view virtually all the monitored engine parameters. > Or if there were a reset for the computer that would tell > it to check again, and to go back to closed loop. My limp-in > gets about 14 mpg or less, compared to the aging motor's > typical 22 mpg. Fixing the problem is really the best solution. > I think Russ Knize is right on about the grounds, and I wonder > if I could simply run silver wire from ground to ground > around the car and bring everything into good performance? > I will try that after I try adding ground wires in extra abundance > to these critical points on the fuel rail. I think I can get more > grounds from our local u-pull-it. Good grounding is a key to making these cars run right. Having all the factory grounds in place and making sure they are free of corrosion is really all that is needed. Best of luck with your efforts, keep us posted. Barry Goodall Shelby Dodge Auto Club -----------------------REMOVE-FOOTER-WHEN-REPLYING---------------------------- Questions? Visit http://www.sdml.org/ To be removed, visit http://www.sdml.org/pages/leave.html
