motor problems

[grade_A_specs]

ive got my stock d15z1 motor in my civic right now and im saving up money for a swap but i want to fix this motor so i can drive it normally and get the gas mileage i should be gettin.

PROBLEM: the car hesitates under 3000 rpms in every gear and only does it when the engine is warmed up.

i would like to know if anyone would know what is up. i replaced the pcv valve, cleaned the throttle body changed the oil, changed the fuel filter, plugs and wires.

let me know if u need anymore info or if you know what the problem might be thanks!

[420sx]

Any codes? CEL?

[grade_A_specs]

CEL isnt on no codes

[420sx]

Does it smoke? Will it stall out under 3k? Does it run 100% normal when its cold?

[grade_A_specs]

doesnt smoke, doesnt stall, runs 100% when its cold, when it hesitates thos i have to press the gas down harder in order to stop it

[420sx]

Coolant temp sensor maybe?

[grade_A_specs]

the CEL would come on for that i think though but its a good option ill definitely try it

[420sx]

http://www.honda-tech.com/showthread.php?t=2553141

Not too much useful info there, but its a start. Ill do some more digging and get back to you.

[420sx]

http://www.honda-tech.com/showthread...esitation+3000

[grade_A_specs]

yeah i ll definitely have to try that as well thanks a lot for your help and if you find anything else let me know

[Ridachu]

...maybe thermostat....lol, try it
ecu....
fuel injectors...
...kinda weird actually
never really heard of it

IMO either it has to do with a temperature sensor and/or compression sensor



or your intake is connected to the end of your exhaust

[grade_A_specs]

After I sold the car the kid told me it was the o2 sensor.........figures

[Keeper1343]

Well thats not what it was but ok. You can run your car without a o2 sensor without it idling like that. Atleast mine didnt. It just made the mix soooo rich.

[cvcrcr99]

lol, you obviously dont know what you are talking about buddy. I was the one who bought the car from him. And it runs 100% at this time, except for the clutch master cylinder dying out recently.

It is a 5 wire o2 sensor, a factory wideband. In the VX and HX world, it is known to cause problems shortly after 100K without throwing a CEL. The vehicle was attempting to go into lean burn mode, which relies heavily on that o2 sensor. It was not working properly, thus the bucking and back firing. If you slam on the gas, it would back fire, go into vtec/open loon and run perfectly fine. The ECU prevents the motor from going into lean burn in first gear, thus the reason there was never a problem with 1st, but a problem with everything else. This was only a problem when the car was warm because the car does not use the o2 sensor until it has been warmed up etc. $180 later and everything runs great. Hitting 40ish mpg right now with a horrid alignment. Once that is dealt with, I am sure to be looking at 42-45 mpgs.

http://www.hondacivicforum.com/forum...-thread-89280/

[daewoo]

ignition?

[cvcrcr99]

Ummm wtf? The problem has been solved. Again, it was the o2 sensor. The runs 100% at this time.