[img]smileys/smiley19.gif[/img]


My 97 SL1 RPM increases from 850 to over 1500 at I start to roll in neutral. After wheel motion stops and speedometer settles to zero...takes 1-5 seconds for RPM to settle to idle. Seems to be worse now that colder weather 40-50 F is here. All gauges normal. NO check engine lights.


I read in manual that a sensor feeds speed info to computer. Can I simply disconnect this input to see if problem is in "that" circuit ?


gpers

if you disconnect the WSS, it may alter your braking system, should you have ABS...when was the last time that the car was tuned up?

P,


Purchased used w 67 k...Now has 104 k . New plugs and wires so far. Engine coolant sensor bypassed with 500 ohm fixed resistor. Found connections all corroded and green. Was NOT sure of sensor op sincecould not pry off cover w/o damage to sensor contacts.Makes for a harder start right now when cold.


Intend to clean and reconnect. However, I have had this RPM increase since purchase, figured it was normal. Part of original trouble was high resistance cause by poor connection to coolant sensor. Computer thought coolant was still warming long after engine was to op temp. Resistor still connected for time being. RPM performance improved greatly after resistor test. However, has gotten worse now with colder weather. Always drops to 850 idle after speedometer drops to zero...2-5 seconds later rpm to idle.


RPM surges to 2000 between shifts sometimes. I know mileage is suffering. Should I get computer reader or start looking at throttle position sensor, or other Air sensors ?


Is there perhaps an engineering order by Saturn out there ? Can I find of list of recalls or OE's on the web. I'd like to resolve this on my own as much as possible w/o spending days at dealer and 100's of bucks. All that repair cost offsets fuel savings.


TNX agn P,


Gpers

i think that if you all a stealership, and ask them if there are any common issues with your particular vehicle, like recalls or TSBs, they may help you out.

Replace Engine Coolant temp sensor and connector.



$20 (get brass tipped one from Saturn Parts dept) and 20 min.



You'll be amazed at how many other things suddenly behave properly once
the car's computer gets the right info about the engine's coolant
temperature......



Also, try cleaning the throttle body.

Thanks derf,


Appreciate the input. Making time for furthur repairs. Enjoying the 41 mpg 97 SL1.


gpers

excellent info. thanks derf.

I had an RPM problem on a 93 SL. I changed out the PVC and the fuel filter. The car idles fine now.

fuel injectors may need cleaning

Yeah, i dumped in a can of slick 50 high milage engine cleaner as well... I changed a few things all at once, and one of them fixed it!