Mechanics

NISSAN SENTRA ENGINE PROBLEM

1999 Nissan Sentra • 124,000 miles

Engine starts good. Idles good at 1000 to 1500 RPM. At 1500 starts missing. After 30 seconds runs OK at 1500. Raise to 2000 RPM. Starts missing. After 30 -45 seconds runs good. Raise to 2500 RPM. Starts missing. After 30-45 seconds runs good. Raise to 3000. Starts missing. Sometimes after 4-5 minutes starts running good, sometimes don't. Turn off engine. Started again after overnight. Same sequence. Started again after 4 hours, ran good immediatly. Started again after 2 hours. Missing as in initial sequence.
Started 30 minutes later. Running good at all RPM's. New plugs set at.040. New coil/distributor cap. Timing set at 8 deg. BTDC. Plug wires OHM'd at 6.5K to 11.2K.
No hose leaks found. Originally no engine codes. After unpluging MAF while engine running, now have codes PO100, PO3400, P1320. Can't get codes to erase with my code scanner so I can recheck for new codes. I'm baffeled. Help.
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Tommyrosson
December 19, 2012.



P0100 is the MAF problem but the others are not.
P0340 - Camshaft Position Sensor.
P1320 - Ignition signal.

You are not able to erase all codes or only some codes?

KHLow2008
Dec 19, 2012.
No. Left battery cables unhooked all night. Didn't erase any of the codes. Scanner read codes but when I try to erase all, it says improper connection. Using Actron CP9145 scanner. Started car this morning. Idled good at 1100 RPM. Push on gas pedal, RPM moves up to about 1400 RPM, starts missing then immediately drops back down to 1100 RPM while missing continueosly. Release gas pedal, RPM stays at 1100 RPM, stops missing.

Tiny
Tommyrosson
Dec 19, 2012.
Started car again a few minutes ago. Ran good up to 3500 RPM this time. Then started missing. RPM wouldn't go over 3500 RPM without missing. This time. Outside air temp. About 60 deg.
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Tiny
Tommyrosson
Dec 19, 2012.
Started car again about 45 minutes later. Runnig good at all RPM's. If I wait a few hours or overnight, it all begins again. Missing.

Tiny
Tommyrosson
Dec 19, 2012.
Try clearing the codes with a different scan tool.

KHLow2008
Dec 20, 2012.
After disconnecting battery, did you check the codes before starting engine?

KHLow2008
Dec 20, 2012.
Finally got codes cleared. Check engine light is off. Started car again. Read codes. P301, # 1 cylinder misfire. Check engine light still not on. Still missing until engine is thoroughly warm, then smoothes out. In addition to coil/distributor and new plugs, also put new plug wires on. Didn't help. Same problem.

Tiny
Tommyrosson
Dec 23, 2012.
Started car one more time. Check engine light came back on. Code P0301, cylinder # 1 misfire. Engine missing. Let engine idle until it came up to operating temp, then engine smothes out at any RPM.

Tiny
Tommyrosson
Dec 23, 2012.
Some code requires two trips to trigger the MIL therefore the first start did not show the MIL.

Now that only one problem is indicated clearly, it would be much easier to work on.

Misfiring on cylinder # 1, possible causes : 1. Spark plug. Recheck plug and swap with another cylinder.
2. Plug wires. Ensure connections are tight and secure. If this is not OEM, check the wires carefully. The terminals at plug side tends to be pushed back into the cover and not allowing it to be seated well onto the spark plug.
3. Fuel injector. Ensure the connector is clean and tight.
4. Valve clearance. Check and see if any are out of specs.

KHLow2008
Dec 23, 2012.
Well the mystery continues. I swaped fuel injectors between no. 1 cylinder and next one to it. Cleared codes. Started car. Missing initally. Read codes. PO300, random misfire. Let engine idle until it reached operating temperture. Stopped missing. Cleared codes again. Ran car for 5 miles. Ran great. No check engine light. Started again 2 days later. Missing again but still no check engine light. Read codes. Now reads crankshaft position sensor even though check engine light didn't come on. Some oil leaking on floor right below sensor.? I guess I could put in new sensor and O-ring to stop oil leak. But. What baffles me is car runs great after reaching operating temperture. About 5+ minutes of idling.

Tiny
Tommyrosson
Jan 4, 2013.
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