chris03tl

Started our TL this morning. On the first start it stalled. On the second start it started but ran like poop. I gave it a few seconds to see if it would recover by itself but it did not. Turned it off then restarted it and it worked fine. CEL was lit.

Stopped and started it another 2 times while out and about and again it worked just fine.

By the time I got home the CEL had gone off, but I checked the logged fault codes and the only one there was P0118, which points at the coolant temp sensor.

I have no problem replacing the sensor, I was just wondering if it could lead to the symptoms I was seeing. A few references on the net indicated it could, but I figured Id ask the experts here first.

FWIW the EGR, intake and IACV were cleaned a few months ago along with a valve adjustment so Im guessing its not them.

Thanks.

-Chris

01tl4tl

I always suspect the last work done when things are not running smooth!!
Did the prob start right after the work?

a simple coolant temp sensor can fool the ecu- giving bad info on actual temp which causes ECU to adjust the fuel mixture

reviewing the basics:
Spark plugs are good- correct 8 dollar each ngk? air filter condition good and top of box on tight - no loose or over-tightened breakage to plastic, coils on tight etc
Ignition relay swapped?

Codes are USUALLY clues,,, not a direct diagnosis, but it can be straight up good info on occasion!

chris03tl

Its been a couple months since the most recent work was done, so I didnt think it would be that.

Car as 111K on it, plugs were replaced around 80K with genuine correct NGK plugs.

Air filter was replaced 2 months ago with the other work.

Main relay was replaced 6 months ago, car had trouble starting when in the sun with windows closed. Problem went away with main relay replacement.

I checked the freeze frame data from when the CEL lit up and it showed the coolant temp as -40C (it was chilly here, but not THAT cold ). But since then the readings have been normal. I will try and get another reading tomorrow morning after the car has sat outside overnight.

3.2TLc

Try cleaning the sensor's connector and check wiring. Then reset the PCM and see if the code comes back. Perhaps the sensor is bad or shorted ? Cheap and easy enough to try replacing it.

chris03tl

Will do. Took a look at the wiring today and it looks OK....connection was tight, etc.

Letting the car sit outside overnight, it should get cold enough to mimick this mornings conditions so Ill try to remember to check it first thing before even cranking it.

TLZINE99

P0118

Defective Engine Coolant Temperature Sensor
Rusty or corroded Engine Coolant
Faulty or corroded Engine Coolant Temperature wiring or connections

01tl4tl

well that would do the symptoms you have
Never heard that hot weather windows up one before!

We DO have an issue with the solder under the relay board- maybe still something there?

How old is the coolant- time between changes- was it ugly looking when changed?

01tl4tl

wire connection problems are found by pulling and wiggling the wire at the connector- it can be loose while looking ok and connector itself is tight
but the wire corroded inside! or loose enough to screw with system-- look beyond the casual for the really stupid!

chris03tl

Coolant is 30K miles old.....changed it, the tstat and the hoses a few years ago. Its still perfectly blue like the Acura coolant is when it comes out of the jug.

The windows up thing is pretty common, I thought. The interior gets so hot with no where for the heat to exit....really makes the solder issue show up (everything expands from the heat). Park the car in the shade or with the windows down for ventilation and it stays cool enough not to be a problem. When I took out the old relay I pulled the case off and sure enough there looks to be a small spot where a solder may have stress fractured.

This morning before cranking the car I checked the coolant temp sensor reading and it was correct (about 50 degrees....surely not -40). Battery voltage was 12.7 with the car off, 13.3 with it running. The off voltage seems OK, but Im not sure if 13.3 was correct with it running....Ive always been taught it should be 14+, no?

01tl4tl

how old is the battery, more than 3 years?
did it start and run good today?
I think the voltage is low on both readings, Parts stores will ck batt and alt for FREE!!!, don't have to remove anything just drive to them
Leave radio, lights and heater/ac OFF during drive, to preserve voltage and allow recharge after starting
15 min drive above 2000 rpm does it

01tl4tl

a weak battery (may have a bad cell) will really mess with the sensors and what info the ECU is getting
don't forget the need for clean ground connections

I live where its 100+ in summer, almost that hot this week in October!
Always leave sunroof open a bit or rear windows down a little to allow a chimney like effect of hot air rises- to escape- and with rears slightly open it may even pull in some outside air and out the roof vent,,like a house roof has lower intake vents that a top vent system pulls cooler air thru

chris03tl

Yeah, the battery is probably over 3 years old (closer to 4 I think)

And there was some corrosion on the original positive clamp. I cut it off and added a heav yduty "universal" clamp....now there is a little corrosion on the cables themselves but the clamp is clean. Probably time to try a new battery harness (or to replace the short lengths if I can), along with a new battery.

It did crank just fine today and even yesterday when it threw the CEL. Today it started as expected. I think Ill start looking at replacement cable(s) and a new battery....its probably something that should be done regardless

01tl4tl

ck out the diy on batt cables and the extra smaller ground wires for frame to engine/trans we have

the main batt cables get crud eating them inside- if you had to cut off the connector you can bet the cable was as bad inside~
Limiting its ability to transfer the electricity on its journey

Often when the batt starts outgassing, it forms that blue growth on terminals
That's the liquid inside the battery....leaving !
stop by a parts store for that free system test