1995 Saturn SL2 1995 Saturn SL2 (my mechanic is stumped by

Tiny
843CHRIS
  • MEMBER
  • 1995 SATURN SL2
  • 4 CYL
  • 2WD
  • MANUAL
  • 160,000 MILES
Just bought a used vehicle last week and I have had several mechanics try to figure out what's causing a problem and haven't yet found out the reason for this issue I am having.


1995 Saturn SL2 Twin Cam (Original Motor)
4cyl
5spd

When idling everything seems to be ok and the rpm guage reads right over 1000. The second I press the gas(slow), instead of the rpm's rising they drop down below 1000 for a split second before actually raising to 2000. When this happens it literally sounds like the car engine is trying to die out. Sometimes when manually pressing the throttle switch from under the hood it doesn't do it. Only sometimes and usually tries to die out when pressing the throttle slow. I have even stalled out several times because of this prob on the highway. One mechanic said he thought it was the map sensor but I changed it and that didn't help. Another mechanic said he thought the carbon had built up in the air intake unit therefor was effecting the throttle which I don't know if he's right or wrong? Does anyone know what in the heck is causing this issue? Any advice would be greatly appreciated.
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Tuesday, March 23rd, 2010 AT 10:33 PM

3 Replies

Tiny
SATURNTECH9
  • EXPERT
First of all thanks for ur donation it really helps to keep this site going so we can answer everyones questions. Ok do u have any codes?If u don't know anyway u could have them read?I think what's happening here is u have a bad coolant temp sensor it's screwed into ur head below where the upper hose goes on. It has two wires going to it a yellow one and a black one going to it. Check the connector if it's corroded u will have to replace it. Make sure u get a brass tipped one the plastic tipped ones crack. Make sure u replace the bottom one with the two wires going to it with the colors I told u. There under 20 for the sensor it's ur best bet for what u described. Let me know what u find and how it runs.
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Wednesday, March 24th, 2010 AT 12:37 PM
Tiny
843CHRIS
  • MEMBER
The check engine like DOES NOT show, so we never did try to get a code. The little code thing up under the dash is messed up anyhow, so I don't know a way to get a code. As far as the coolant sensor. I am having trouble locating it and I don't see anything with a yellow and black wire. Just out of curiosity, how would a coolant sensor have anything to do with the throttle anyhow? Another mechanic today said that the throttle sensor needed to be replaced. I don't really know what to believe. Any more advice would be greatly appreciated.
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Wednesday, March 24th, 2010 AT 7:13 PM
Tiny
SATURNTECH9
  • EXPERT


http://www.2carpros.com/forum/automotive_pictures/416332_coolant_temp_sensor_1.jpg


here is a pic of where ur coolant temp sensor is located.i have worked for saturn dealers repairing cars over 16yrs i have only replaced a handfull of map sensors and throttle postion sensors in that time on the s model saturns they dont go bad often thats one of the last things i ever look at on those cars.the coolant temp sensors i have replaced over 100 thats probably a very low number saying over 100 i have know idea how many at this point they had problems with them from the begining on that model from 1991 till in the 2000 or 2001 when they changed it to a brass tipped.funny thing is when they were using a seperate gauge sensor till 1995 they were brass tipped and i hardly ever replaced those.but the plastic tipped coolant temp sensors cracked got coolant in them shorted out and will cause high idle overheating no starts car dieing while driving and then not starting surging bucking while driving idle thats searching not stable.power loss when opening the throttle bogging or delay in throttle reponse.a very over looked sensor that alot people just dont think about that it could cause so many problems.its job is to tell the computer what temp the engine is so it can run richer or leaner depending on the temp of the engine.lets say the sensor says 50 degrees but the engine is realy 200 degrees the car is going to run like crap because its getting way to much fuel.also if it says 200 degrees but is really 65 degrees then it will be starving for fuel.i suggest the coolant temp sensor because its under 20 and they go bad all the time and could cause the symptom u have.the other thing i would check on ur car is ur fuel pressure but unless u have a fuel pressure gauge then thats harder to test.also when u get alot of carbon in those engines it causes the valves to stick when u go from cruising to a stop light they will stumble and die out sometimes.not when excellerating that i have seen.anyways check it out and let me know what u find also dont forget to check the connector they get corroding from coolant and if its corroded replace it.also u want the bottom sensor with the two wires going to it.
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Thursday, March 25th, 2010 AT 3:33 PM

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