Hi Barry,
I apologise 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.
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.
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.
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.
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!
This is low-priority now Thanks to Bohdan.
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.
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 diffferent 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
'88 Plymouth Sundance 2.2l
Used-to-drive: Chrysler Simca 1204
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