Hello i just bought a 1998 honda accord ex and i think i might bought a limmon it has alot problems trying to get figuared out. first thing the check engine light is on the codes where for knock sensor as the main one and cats problems. I looked under the car and it has 2 new one it has a brand new radaitor to. okay the other problems are there is a massive coolent leak cant find where it is going in 1 week time i have put in atleast a gallon of coolent. theres no coolent in the oil or white smoke no oil mixing with coolent in the rad. the temp gauge always stays in the normal postion doesnt move at all no matter how long the car sits and the last prob while looking under the passenger side dash i seen where someone has spliced one of the wires runing to the computer and attached a wire to it and it runs somewhere under the dash i havent tracked it down yet i do know they changed the computer out with a different one

 

Post the actual codes on here.

Not sure what you mean about the knock sensor with a main and cat? Do you mean O2 sensors?

For the radiator leak, you can get a loaner radiator pressure tester at most parts stores. When the engine is cold, remove the radiator cap and pressure the radiator to about 15 psi. The system should hold pressure. If you quickly lose pressure, you should be able to find the leak with cold coolant as it does not quickly evaporate.

 

they say the knock sensor for this year of car is located near the oil filter the code i get for the knock is P0325 Knock sensor (rear) circuit malfuction.
the other codes are p0420 catalyst efficiency below threshold (bank1)
and the last one is code p1399 misfire in any cylinder thats what i get from autozone when they run the codes from the computer and likey replace the knock sensor and it would fix the problems. they said the knock sensor could make the rest act werid the rad is brand new so i don't think it is the rad that's leaking and when i look under the car the catalyst look like brand new

 

I agree, the knock sensor circuit code would be the first to address. The problem can be the knock sensor, the wiring, or possibly the PCM. If the problem is with the wiring or PCM, blindly replacing the knock sensor won't fix your problem.

As for the radiator, pressurizing the radiator pressurizes the entire coolant system. This can help you find leaks in the entire system not just the radiator.

 

Update found the leaks it was both rad hoes and thermstat gasket leaking changing the knock sensor next weekend

 

I'd clear the codes and see which ones come back.

 

Knock sensor changed all good now no more leaks just have the cat code showing up and none working temp gauge changed out the sensor and gauge still stay in the middle all the time doesn't move at all . it has start haveing a werid new problem now once and awhile i go out to start the car and no start it don't have any fuel pressure and the check engine light is off. i open the fuse box in the under the hood and push on all the fuses and the check engine is back and the car has fuel pressure and it starts like nothing is wrong

 

I have a 1998 Honda Accord EX code p1381 comes up how can I fix it or what can it be