Mechanics

SL-1 ENGINE PROBLEMS

1999 Saturn SL1 • 4 cylinder 2WD Automatic •

I have a 1999 Satrun SL-1. Wenday when I came to work it was running fine. When I left the parking lot and got on the freeway it was okay. But when I got stopped in traffic the car started running hard and the RPM's would drop. I got almost all the way home and the car died. I had a friend take me to Checkers and they said my alternator and battery were bad. So I change them. Well I am still having the same problems. When the car first turns on the idle jumps straight over 2000 RPM's then goes back just under 1000 RPM's as soon as I put it into gear it drops even more and eventually dies before I can move it a few feet. What could be causing this?
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Justin Adair
January 7, 2011.




Did you make sure the car is charging now since you replaced the battery and alternator?Also go to the auto part's store and have them scan the car for code's and let me know the exact code number's you have. Now let's try this take off both of your battery cable's off your battery for at least 30 second's while there off make sure the cable's are clean if they aren't clean them with a battery brush and baking soda and water. Put them back on and let's see how they run. Let me know what you find.

Saturntech9
Jan 7, 2011.
Okay I will do this as soon as I get home tonight. My buddy is suppose to help me get my car to autozone so I can get a diagnostic. I will post after 5 PM MST Arizona time.

Tiny
Justin Adair
Jan 7, 2011.
Okay I got the vehicle diagnostics checked out. I have two codes but I forgot to bring them with me. But how ever I do remember 1 and know what they said. 1 code said TFT (Transmission Fluid Temperature Sensor) and a Misfire code. I changed the wire and spark plugs and I also discovered after taking the vehicle to my Uncles house that I had a blown head gasket. We are installing the new head gasket this coming weekend because we both work Monday through Friday. Now I am just wondering if anything else needs fixed.

P0300 - Random Misfire
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Tiny
Justin Adair
Jan 10, 2011.
With the random miss fire could have been the plug's and wire's causing that You will have to see how it run's after you replace the head gasket. Make sure you have the head checked for being warped crack's etc. AS far as your tft code it's most likely caused by a bad coolant temp sensor.I know it sound's funny but when the coolant temp sensor starting reading a great enough temp that is way lower then actual temp it will set a tft code. It's really common for them to go bad and could be the reason you blew the head gasket.I would also check the connector going to the sensor if it's corroded you need to replace the connector too. How do you know you have a bad head gasket?

Saturntech9
Jan 10, 2011.
My Uncle has been a mechanic for several years. When I took it to his house I showed him what I done and gave him the code list. We started looking and he decided to pull out the spark plugs and test the pressure. When we tried to crank it over there was about equal pressue coming from both at the same time. It never fluxuated back and forth. Be said somethings wrong with the head gasket or cylinders and we took off the headsand found a blown gasket. Now I called the auto parts store to ask about the TFT sensor and they can't seem to find one. I heard that the TFTbcan be changed out with a ECT (Engine Coolant Temperature Sensor)? Is this true or do I have to keep looking? I will check the connector first however but if its corroded I want to change them both out.

Tiny
Justin Adair
Jan 10, 2011.
In my last post to you I explained you probably have a bad coolant temp sensor not a bad tft.I have replaced very few of the tft's but have replace hundred's of the coolant temp sensor's and when they go bad they can set a tft code. As far as the coolant temp sensor connector goes I would only replace that if it was corroded. Also yes the tft is the same as the coolant temp sensor but I feel replacing the tft also would be wasting your money but that's up to you. The bad coolant temp sensor probably caused your engine to overheat because the fan didn't come causing that blown head gasket.

Saturntech9
Jan 10, 2011.
Yeah but normally when the cars fan isn't working properly (even due to a sensor) Wouldn't the car then overheat? My vehicle never overheated? I instantly checked the coolant and got under the hood when this all started happening. Thats what leades me to believe the sensor or sensors are just bad. I also discovered my motormount was no good. So I believe with the blown head gasket and a bad motor mount that could explain the reason why it ran itself down in gear and shut up and why it idled harder. I will take your advice though its just kind of weird. I have had a head gasket blow before in a previous car I had but it wasnt nothing like this. The car was given to us and we drove it from South Carolina to Arizona. I just need to get this working for a good 3 or 4 months for work and I will save for a new vehicle. No more trips to the lake or extra ciricular activites for awhile.

Tiny
Justin Adair
Jan 10, 2011.
The coolant temp sensor on that car run's both the temp gauge and tells the computer what temp the car is. So when they go bad they read colder then actual temp so you would never see it running hot on the gauge right?I have lot's of customer's ask that same question I liked it a lot more when on the 1991-1995 saturn's they had a temp sender for the gauge and one for the computer that way you could be tipped off that you had a problem by seeing the gauge running hot.I have replaced the one on my 1999 saturn twice since I have owned it for 5 year's now.

Saturntech9
Jan 10, 2011.
Yeah thats possible. The one thing that gets me about it is that I never seen it on the gauge and never seen it when I opened the coolant cap? I would think your hear it bubbling or something in the coolant container?

Tiny
Justin Adair
Jan 10, 2011.
You would never see it on the gauge the sensor that's probably bad run's the gauge also so if it's bad and reading a lower then it's supposed then your gauge would read at that lower incorrect temp.I have seen some of those sensor's go bad and read over 40 degree's cooler then actual coolant temp. You can't always hear it bubbling in the coolant tank keep this in mind depending on your coolant mixture which raise's the boil point of water it could have very well have been overheating without you knowing it.

Saturntech9
Jan 10, 2011.

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