ElMaq

Hi guys. ok?

Recently I noticed water temperature often working upper than middle, until in the city.
When I drive in a long climb (mountains), stays in 3/4 or more (never in red). Before I change the cap of the radiator, it aways stayed just a little upper than middle when in long climbing and aways a little lower than middle in other situations.

Now, everytime I drive in a long climb, temperature stay in 3/4 and check engine light comes. After this, motor goes on running fine, without bad symptoms, but check engine light ON.

I turn off the key, start engine again and check engine light works normal, but if I drive in a climb again, check engine light comes again.

If I drive with A/C working, temperature stay normal and check engine light doesn't comes if I climb a long road up.

Made jump, shows no code (check engine turn off after 2 seconds with jump wire)

TomCat39

To get the code you will have to wait until the CEL comes on, pull over, don't shut car off and then jump the service connector, the CEL should then begin to blink the code.

I think you may want to purge the cooling system of air just to be sure it's free from any air bubbles.

ElMaq

* I made the test after turn off the engine. I thought its error was stored in backup memory

** I checked it for two times. No leak... it seems ok for bubbles. I'm not sure about thermostat or tw sensor

mk378

With the jumper in the CEL should stay on steady if there are no codes. So, you don't have it properly jumped.

TomCat39

It is supposed to but sometimes that fails. So if you can't get codes normally but CEL comes on when driving, you can see the code by jumping the service connector prior to shutting engine off.

Also, you may want to read up on your ECT sensor:
https://honda-tech.com/how-tos/a/hon...sor-bad-377260

It might be a little bit of your issue and why I was hoping you could grab the code as it might indicate a sporadic ECT issue. Failing but not failed.

ElMaq

metal papelclip like an "U" connected to 2p plug above the ECU.

ElMaq

well guys... I'll try to drive and get the code with engine working.

ElMaq

I got the code: 43 Fuel Supply System

fragmare

Happens going up long hills? Fuel Supply DTC? It sounds like it's intermittently not getting enough fuel volume when it's running. Particularly going up long hills. Do a fuel pressure test and see if it's within spec. How many miles are on your fuel filter?

ElMaq

like I said above, I runned the engine in my garage at 3000rpm and CEL comes on. CODE 43 Fuel Supply System.

fragmare

Also, pull the little vacuum tube off the fuel pressure regulator and see if it's wet with fuel (if you haven't already) and inspect the tubing itself. If it is wet with fuel, your fuel pressure regulator is bad. If that checks out ok, then do the fuel pressure test. If the fuel pressure test fails, and your filter is under 1000 miles, I'd start looking at the fuel pump not providing enough flow when the car is running as the cause of the DTC 43

ElMaq

I'll inspect. But the car runs fine after CEL. There is NO poor performance.

ElMaq

Hi fragmare
Tested and all ok.
I read the service manual and it suggests that I should inspect/replace O2 Sensor when CEL shows code 43 BUT car driveability and engine runs fine

fragmare

Well, now you've eliminated the possibility of it being the pump, filter or fuel pressure regulator (assuming you tested the regulator per the service manual while you had the pressure gauge hooked up). It is very possible it's your O2 sensor, since the other things check out. I'm guessing you don't have access to a graphing mult-meter or scan tool? If you do, you could directly observe the O2 sensor during operation and see if it's behaving properly (switching from 0.1 to 0.9 v). If you have experience with a multi-meter, there's still a flowchart you can follow in the service manual that will get you the same results... that is to say, tell if you if the O2 sensor is bad or not. According to the chart, it's either got to be the sensor, the sensor wiring, or a bad ECU, at this point. There are all kinds of ways to diag a bad O2 sensor. Backprobing it while the car is running on a good multi-meter is good one. I've seen guys remove the sensor, put it in a vice, attach a multi-meter to it, and bench test it using a torch while looking at the multi-meter. Orrrrrr, you could just throw an O2 sensor in there and see what happens. Inspect the O2 sensor wires first, though... you never know, could be something as simple as an O2 wire rubbing on something.

ElMaq

I done now. Removed 02 sensor and probed wires (engine side) showed 0.05~0.04

fragmare

I'm not sure what wires you were probing or how you were testing it, but that sounds awfully low. I would expect to see the sensor ranging up towards .8 or .9v if it were functioning properly. Even if your multi-meter couldn't keep up with it switching, i'd expect to see anything from .1 to .9v

ElMaq

White and White/Green :-(

mk378

The test is with the sensor installed and connected, and the engine warmed up running at idle. The voltage from the output wire (usually white) to ground should vary between about 0.1 and 0.9 volts. A digital meter must be used. Old style meters with a mechanical dial pointer will overload the sensor.

ElMaq

I confess I tested with cold engine. In fact, I tested only with key turned on and disconnected o2 sensor

CandyRedRC46

Turning the A/C on, turns the radiator/condenser fan on. You may have a faulty radiator thermoswitch that is turning your radiator fan on too late or not at all, so turning the A/C on simply turns the radiator fan on, without relying on the radiator thermoswitch.
Is your radiator fan coming on at the proper temperature, with the A/C off?
Test your radiator thermoswitch.

ElMaq

sorry for delay. New Thermo valve installed, brand new o2 sensor installed the symptom still is there. CEL comes on when temperature is above to the middle and show code 43 when made jump wire. The car runs normal, without poor performance. :-(

ElMaq

Now changed the Thermoswitch. Temperature is ok now but CEL comes on when I drive for long hills. Code 43. I don't know what I do because the car continues running fine after this.

Check Engine light only comes on when I drive long hills.