I have a 2000 SL2 and it's got a few problems. Picked it up a few years ago and other than changing the oil it's been trouble free.

Recently the car started idling a bit high upon cold starting, like 1200-1300 and won't kick down, at the same time the temperature gage won't move at all. I'll get down the road a mile or so, and the gage hasn't moved, and the idle is still high, and all at once the gage jumps to the first line and idle goes to normal, 700-800 rpm at the stop light. This will repeat itself two to three times before it finally stays normal.

I've also experienced some hard starting. Yesterday the engine wouldn't catch and hold any idle speed. This was leaving work yesterday afternoon, outside temps in the mid 90's. It finally started, went through the "high idle, no temp on gage" a few times and then got back to normal a few miles down the road.

The car has the Low Coolant light on, and the Check Engine light. I know the coolant level is right up there, but I see some kind of orange colored foam in the coolant recovery tank. The car is not overheating at all, and oil use is negligible, maybe 1/2 quart or less between changes.

I read somewhere that Saturn used the spice ginger in the cooling system when they made the car?? Is that BS? Is that what the orange muck is?

I'm thinking the coolant has never been changed, so that's on my list to do. As is changing the tranny fluid.

I want to buy a OBD II reader, something cheap but reliable. Can anyone suggest one under $50? I went to Autozone once for a free read, and they were willing but not very helpful. Rather do it myself.

 

In my experience, two main culprits of idle problems on a S car are the ECTS(engine coolant temp sensor) and the intake manifold gasket. If it is missing at idle, it is usually the gasket, if the idle is not steady, usually the ECTS. Get an AC Delco part that is made of brass, not a cheap plastic one. I replaced one last year and got it for 18 bucks at the stealership.


Edit, for the OBDII reader, search the forum, this was discussed a few weeks ago. I got an app for my phone for $5.99 and a wireless adapter for 18 bucks.

 

Thanks Rob, I appreciate your help. I'll check those out.

 

I did some minor maintenance today. Removed the coolant recovery tank and flushed out the orange muck inside. I got it as clean as possible, and noticed the float sensor inside had freed up and was moving. Installed the tank and filled up with coolant, the low level coolant light went out. Nice!

I took the car two miles to O'Reilly's and they read the OBDII codes to me. I believe a few will go away and not return when I replace the ECTS. I asked them to erase the codes and I have the list here. I'll search around the forum and see what they are.
P0118 ECTS high voltage
P0125 Insufficient coolant temp for closed loop control
P0440 Evap emission system
P0731 Gear 1 incorrect ratio
P1599 Engine stall or near stall
P1620 Low coolant circuit
P1624 Customer snapshot data available.

I hope P0118, P0125, and P1599 will go away when I replace the ECTS. I'll be calling GM dealers Monday to find a sensor.

I bet P1620 goes away from the cleaning and topping off of the tank.

Now I need to figure out P0440 and P0731

The P1624 "Customer snapshot data available" seems like a non issue as far as the car running properly. Does someone know?

Thanks,

Kent

 

interesting.

Replacement ECTS needs to be the brass one with 2 wires. Replace the connector too. It is more expensive than the sensor but is also dealer only and is prone to corrosion related issues which screw up the PCM's temp measurement. Trust me, it's worth it to know that issue is out of the system as a variable.

The idle jump high/idle jump low/high/low made me think of it jumping back and forth from open loop (at startup) to closed loop (once warmed up). I've never seen anyone post this flip flop behavior. The thing that kept me from posting was that I could not for the life of me figure out why the temp sensor reading on the dash was behaving as described. The answer must be you had an ECTS, possibly with an intermittent connection, that alternated between an actual reading and being open circuit (reads as equivalent of -40) -- hence not warm enough to run in closed loop mode. As soon as the connection reestablished with a reading, the car would switch to closed loop, idle would drop to normal, etc. Connection becomes open circuit, idle goes up bec temp reads -40.

It is most likely he ECTS's bizarre readings were confusing the PCM and after numerous tries to keep it in closed loop mode, it threw in the towel (after too many -40 readings)

Keep in mind that the intermittent connection may be at the connector -- but replace the ECTS and connector and be done w it.

ECTS High Voltage to me means there was no voltage drop across the ects circuit = open circuit. Older saturns NEVER threw this code for open ECTS circuits. Good to know they got it right just before killing the S car.

Take care of the ECTS and connector, clear the codes and we'll se what comes back.

Connector is a squeeze connector

 

Yup, your issue sounds like the ECTS... Replace it with the brass one(like suggested above), and get a new connector... The SL1 I had did the same thing for the two weeks that it went un-fixed... The temp gauge at one point moved in sync with the tachometer... Point being that it can do some funny things when sensor starts to fail...

 

Yes 19bonestock88 the tach and temp gage are moving in sync, when one goes down the other goes up. This is only happening in the first 10-15 minutes of driving, then it seems to behave normally.


I work in a small Oklahoma town and I called the Chevy dealer in town, he can get the parts from Ft. Worth this week. $19.94 for the sensor and $28.19 for the connector. He said they had a few dozen sensors and over 75 harness's. Not bad, eh?


It's really sucking down the gas. I haven't taken the MPG lately but used to get 31+. I'm roughly estimating it's getting about 20-23 mpg since the issues started. I can sometimes smell the fuel in the exhaust, very rich. I filled the tank today and will check the mileage this week, as I won't have the parts until Monday-Tuesday next week. I bet after repairs it does better than 31 mpg.

 

You are the right track, when those sensors fail they report -34f. The car goes full rich and blubbers and smokes. I have not seen the sweep with the tach thing but most of what I work on has a separate sender for the temp gauge.

 

well, I was close. Same outcome. Not sure why the temp gauge would move with the rpm with a defective ECTS---especially across different Saturn models (S series and Bones' ion.) Unless it was simply the rush of coolant going by the sensor, generating a reading.....

As for separate PCM feed and dash gauge sender, saturn eliminated this dual config for the s cars beginning in 1996.

 

Actually, I was remembering back to when I too drove an S series... Back when I first joined here...