Temp sensor and fuel pump
Temp sensor and fuel pump
Nistech.......does the temp sensor control fuel circulation in any way? how do u know when a fuel pump is going bad? and when do change the fuel pump in the I30(1996) do u clean the tank? if so, how?
Re: Temp sensor and fuel pump
qmccall wrote:Nistech.......does the temp sensor control fuel circulation in any way? how do u know when a fuel pump is going bad? and when do change the fuel pump in the I30(1996) do u clean the tank? if so, how?
The Coolant temp does not have any control over the fuel pump/pressure. The fuel pump is active anytime the car is running or when the key is cycled from off to on it runs for about 5 secs. The only way fuel pressure is controled is b the fuel pressure regulator which is controled by intake vaccum. less vaccum in the intake manifold means higher fuel pressure. This is done by restricting the fuel from returning to the tank at the fuel pressure regulator. This is the only device in the entire fuel system that has any effect on fuel pressure. Pump speed is never varied or cycled on your car.
The coolant temp sensor has an effect on injector open time when its cold. It sends a signal to the ECM and that determines if the vehicle needs additional fuel to keep the car running when cold. Once the car warms up the coolant temp sensor is out of the loop and O2 is used primarily by the ecm to determine injector open time. Note though these are not the only sensors that determine open time but are a couple of the primary ones, Mass airflow sensor is the most important one on the car.
To determine if the pump is goin south use a fuel gauge and see if the readings are with in spec. should be around 36psi at idle and when the fuel pressure reg vaccum hose is pulled off it should jump to about 43 psi.
Claening the tank is really not neccesary unless you have heavy sediment in it then yes. But that is not usualy the case unless you are buying crappy fuel.
the code your seeing is fuel system rich or lean. Usually in the coolant temp sensor case it is rich. This simply means you are burning to much fuel which could be any number of things but coolant temp sensor is one of them. your fuel pump could be the source of the hiss but the best way to tell if you have a pump problem is to use a fuel gauge.
ok thank you nistech as always. i am getting bad gas mileage.........and I am trying to solve it. I also got a knock code and rear oxygen sensor code............I guess the oxygen sensor is the problem also...........for the rich fuel? is that hard to replace? where is it? I dont have a gauge to test the pump..........
qmccall wrote:ok thank you nistech as always. i am getting bad gas mileage.........and I am trying to solve it. I also got a knock code and rear oxygen sensor code............I guess the oxygen sensor is the problem also...........for the rich fuel? is that hard to replace? where is it? I dont have a gauge to test the pump..........
Usually when you throw a knock sensor CEL you will also get another code with it that I like to call a buddy code. I've seen the knock sensor code be accompanied by the rear o2 sensor code lots of times and 9 times out of 10 the replacement of the knock sensor will result in solving the other problem code. The rear heated o2 sensor(on the cat in 95/96 and right before the cat on 97-99) DOES NOT affect the fuel map, but the rear bank o2 does. The front and rear bank o2 sensors will affect air/fuel during closed loop operation of the ECU. Closed loop is part throttle and the ECU relies on sensors mainly to adjust the timing and air/fuel. When in open loop(wide open throttle) the ECU relies on standard programmed maps of air/fuel and timing.
qmccall wrote:ok.......well why does.....something about fuel comes up on the code machine when u have a bad temp sensor? I am getting some hestitation.......at times......and I hear a hissing sound.....under the car near the rear........sounds like the fuel pump..........please help
Are you sure it's not the intake air temperature sensor code?
also according to nistech the knock sensor will never make the engine light come on thats why u get other codes with it. because the other codes caused the light to come on.....,but hey i dont know. i am not trained. just trying to learn........guess i will replace the knock and the temp sensor and see what happens
Yes i know the knock sensor code is a ghost code, you still "throw a code", it just does not trigger the CEL. I'm just trying to save you some money. I'd replace the knock sensor, and then just take it from there.qmccall wrote:also according to nistech the knock sensor will never make the engine light come on thats why u get other codes with it. because the other codes caused the light to come on.....,but hey i dont know. i am not trained. just trying to learn........guess i will replace the knock and the temp sensor and see what happens