Engine Trouble

[DreamRacer]

greetings!! well in our 00 civic with CVT and d16 motor, the car is throwing and manufacturing air/fuel metering code when the car runs over 4500 rpm, the car stalls and wont rev past 4500 anymore, ??
code p1259

[superbluecivicsi]

DO you have a vtec controller or vfac? a problem with the vtec soleniod valve circuit or vtec pressure switch circuit are likely causes of turning on the CEL.

Disconnect the electrical connector from the pressure switch. Connect an ohmmeter between the terminals of the switch. If there is no continuity, then replace the switch.

Connect a voltmeter between the body ground and the blue/black wire terminal (should be the same color in all vtec applications) in the harness side of the connector. Turn the ignition key to ON, but not with the engine running. there should be about 12volts reading. If there isnt, look for a break in the blue/black wire that is between the connector and its terminal at the PCM.

When you get the correct voltage at the blue/black terminal in the connector, connect the voltmeter between both the blue/black and black of the terminals in the harness side of the connector. with the kay on there should be a 12volt reading. if there isnt, check for breaks or bad connections between the body ground and the connector.

with the ignition off and disconnecting the single pin connector from the vtec solenoid, connect an ohmmeter to between the body ground and the pin in the solenoid. The ohmmeter should read 14-30 ohms. If it doesnt, replace it.

theres a bolt on the solenoid (its a 10mm or 12mm, i forgot), remove it and then attach a mechanicle oil pressure gauge with the adaptor. Warm up the engine and let it run at 1000, 3000, and then 5000. dont forget to write dwn the oil pressure reading at each speed and dont let it run for more than a minute is a rule of thumb. The oil pressure should be less than 7 psi. if its not, then check out the vtec solenoid.

to check out the vtec solenoid, connect a piece of wire from the batterys positive terminal to the terminal of the vtec solenoid. run the engine at 5000 rpms for no more than a minute. the oil pressure reading should read 56 psi or more. if it doesnt read at that pressure, then remove the solenoid valve assembly from the cylinder head then check out the vtec solenoid valve filter. Check the filter o-ring for any clogs. Clean it out and replace with a brand new o-ring. change out the filter and engine oil if it was clogged. this should keep it from clogging again. Also, unbolt the solenoid from the solenoid valve assembly and give a push on the solenoid plunger and check it for any free movement. Reinstall the solenoid with a new o-ring.

My vtec problems were always with a break in the connection. hope that is enough details for you

[DreamRacer]

thanks for the detail, the vtec now works, engine has been running fine, however the check engine light still comes on with same code.

p1259

[BennyBakwood007]

You may just need to reset your computer to get the engine light to go off.