coolant temp sensor... bad gas mileage... fuel smell.... related?

[sinhumane]

2000 ls, 3.9.

i had AZ pull codes for me, along with the misfire that is now cleared and fixed, i have a coolant temperature sensor error code. cant remember specifics, but something about it not reading sufficient temperature during startup enrichment.

i am also experiencing poor gas mileage (something like 14mpg mixed, thats terrible...) and a fuel smell before it gets to normal operating temp, and when i am being mean to the car.

thinking all of these are directly related... except the rich smell when i peg the throttle and it goes into closed loop.

the only thing that takes over there is the fuel pressure reg, yes? could this be an issue?

any of these a common issue on the gen1 ls? searched for answers on the fuel smell, and ect sensor, but only come up with fuel filter leaks (which are constant, not at startup) and CHT sensor faults (and from what i understand, that controls only the gauge.)

so i'm thinking the ect is futzed or really dirty, as looking at the connectors i didnt see any broken or frayed wires. (cant really see anything in there really, i'm oblivious as to how the car was actually assembled...)

am i on the right path here?

 

[FASTLLS]

Exact code numbers?

 

[FASTLLS]

Almost sounds like cats are starting to fail.. I don't think the two problems are related..

 

[oddball]

The code description you posted implies that the car is warming up slowly. Could be thermostat stuck open. Can be exacerbated by a fan that runs too fast.

Ensure cooling system is running OK, post the actual OBD code. Also try resetting the PCM (just unhook the battery for 5 mins) so it re-learns the fuel curve.

The PCM uses the CHT sensor to tune the fuel delivery. So a wacky CHT will cause plenty of problems. Try to verify temp readings by using a scanner to get the current temp. When using an infrared thermometer, a reading right next to the head on the inside - there's a water passage bump up near the front - is only a few degrees cooler than the actual temp.

 

[sinhumane]

thermostat was just recently changed, i'll have codes run again and get the exact one. its not a CHT sensor fault, but an ECT sensor fault.

i was under the impression that the ect worked to tune the fuel curve, not the cht. i'll go reset the pcm and see if anything improves.

 

[sinhumane]

i reset the pcm and still getting piss poor mileage. i dont get a rich smell as often, and dont have a CEL yet. but 13.7 is NOT what this thing should be getting. i replaced the air filter, and will try cleaning the MAF next.