I have a 98 SL2 with 117K . I just replaced the fuel filter and the plugs and wires were replaced not too long ago . Well today it has just started bogging REALLY bad upon take off and in between gears (5 spd) . If i punch it it will bog a bit then take off like crazy . I dont know if the ECTS has ever been replaced but my temp reading on the dash is below the 1/4 mark when its cold outside . It also hardly EVER climbs above the 1/4 mark even on warm days . Please help ! Thanks in advance !

 

For one, the temperature must climb above the 1/4 mark for proper engine operation, though the engine should run fine even if it doesn''t. I had this same problem with my Saturn, and acceleration was still great. However, idle was always high, and city mileage sucked due to the engine always running in open loop (cold mode-richer). Take a meat thermometer and dip it into the water resivoir. It should read at or above 180 degrees, and the gauge should be somewhere between 1/4 and 1/2 after thorough warm-up (at least 15 minutes, if not more, preferrably after a hot fast run (45 mph or higher)). If the temperature is normal, but the gauge is low, then the sending unit is probably faulty. If the temperature is below 180 degrees and agrees with temp gauge (also low), then thermostat is bad. The thermostat has a rubber gasket on the moving part (valve) which breaks apart. The rubber is molded onto the valve and into holes that perforate the circumfrence of the valve. When the rubber breaks away, if the valve does seat, water still leaks through the holes, preventing the engine from warming up properly. In my personal experience both the sensor and the thermostat were bad. The gauge would take forever to come up, but read accurately once it didbad sensor, and the gauge always read at or below 1/4bad thermostat.


Regarding bogging, I''m not a Saturn or fuel injection expert, but I have done extensive work on various cars including fuel injected cars and my Saturn (not others), so I do have general experience with bogging issues. If the car is bogging, several things could be happening. Reading the computer codes helps. Otherwise check for proper fuel pressure. Should be in the 40s. Low pressure might cause bogging during acceleration. Check the throttle position sensor. If it doesn''t sense throttle movement, it can''t tell the injectors to inject more upon acceleration (like the accelerator pump in a carburetor). When the intake is opened rapidly, even with wonderful fuel injection, vacuum drops. Vaporized gasoline drops out of suspension and condenses on the intake walls, leaning out the mixture. Increasing fuel flow during acceleration compensates for this.


Also, the EGR valve could be sticking open, or the PCV valve could be sticking open (though this is not likely to affect acceleration much, especially since it opens a lot during acceleration anyway). Furthermore, there could be a problem with the fuel vapor recovery system, though that''s less likely.


Be sure that spark plugs are gapped properly. Conventional plugs are better than Bosch platinum plugs. They tend to malfunction. Check spark wire resistance. They shouldn''t be over 10,000 ohms. Also, if coils arc internally, they are more likely to do so when the cylinders are filled with a big charge than a small one, as it is more difficult for the plugs to spark under high compression than under low compression, though failing coils are likely to also show up as a rough idle and missing while cruising, though not definitely.

 

Sounds like the ECTS. If its reporting back to the PCM that the engine is always cold, it''ll dump fuel in an attempt to warm up the engine. And if the engine is actually at operating temperature already, there''s where your bogging comes from.

Luckily its a cheap part. You can get one at your local autoparts store, but if you have a Saturn dealer close by or cane order one from the various on-line Saturn parts departments, I''d go that route. Th OEM sensors from Saturn seem to play much better with the cars electronics.