matt4irish

Strange scenario-95 Maxima SE

Occasional/erratic start when COLD (it's winter). Car cranks fine and will either start right up or will crank and crank until I lightly depress and hold accelerator 1/4 down. Then will start, but runs rough for a couple seconds. When it does this, it will occasionally light the CEL with codes 0325 and 0130.

It also hates to restart once run (warmed) and then parked for an hour or two. I have to hold the accelerator down about 1/4 for it to start.

In either case, once started it runs perfectly fine.

This one's driving me nuts because the car was running perfect until I had a fuel injector problem. Replaced one of the ones under the intake manifold. Also replaced the intake gasket. Car seemed to have the intermittent starting issue after this repair, but like I said, it happens sporadically.

Any ideas are welcomed.

Thanks!

matt4irish

Any ideas would be greatly appreciated!

tigersharkdude

iTrader: (20)

Welcome to the ORG. Whenever you find yourself with a CEL and have access to the codes, the fastest way to figure out what said codes mean is to check the.

The problem you are experiencing though sounds to me like a dirty/clogged Idle Air Control Valve (this is fairly easy to clean)

http://forums.maxima.org/4th-generat...ere-first.html

P0325 - DTC=0304
Diagnostic Trouble Code 0304 points to a problem with the Knock Sensor. The KS is attached to the cylinder block. It senses engine knocking using a piezoelectric element. A knocking vibration from the cylinder block is senses as vibrational pressure. This pressure is converted into a voltage signal and sent to the Engine Control Module (The computer).

This malfunction is detected when an excessively high or low voltage from the KS is entered to the ECM. Possible causes include...
- the harness or connector (The KS circuit is open or shorted).
- the KS

The KS may be checked with an ohmmeter.

1) Raise the hood. View the engine from the driver's fender. Look into
the deep valley between the cylinder banks and below the intake manifold.
Identify the KS as a black item fastened to the block by a single vertical
bolt. A wire harness wrapped in black leads toward you, out of the valley.
That is the KS sub-harness.

2) Follow the KS sub-harness to it's nearest connector. This is connector F121.
It is located near the upper right-hand corner of the valve cover of the forward cylinder bank, as viewed from the front of the car.

3) Disconnect F121. You have to do a "press the latch and wiggle and
pull" to disconnect it. F121 has only two pins; if you see more than two
pins, you have the wrong connector. Use a digital ohmmeter capable of
measuring more than 10 Megohms. You want to measure the pins of F121, not
the sockets of the matching connector. Measure the resistance between a
good ground (such as the battery negative terminal) and pin #2 of connector
F121. On my car this is the highest of the two pins, the one closest to
the front of the car. The factory spec is 500 - 620 Kohms.

The manual says you have to remove the intake manifold to replace the KS. However, I think that a person with good dexterity and a 12mm ratcheting box wrench could replace the KS without disturbing the manifold.

Important note: the dealer can do a more thorough test with his CONSULT electronic tester. The resistance test described here is a useful but limited test. A Knock Sensor which fails this test is definitely bad. However, a KS which passes this test is not guaranteed to be good.

P0130 = DTC 0503

0503
Diagnostic Trouble Code 0503 indicates a problem with the front Oxygen Sensor on the right cylinder bank. The right bank is also called the rear bank. It is cylinders 1,3,5. A normal signal sweeps back and forth between 0.2 volts and 0.8 volts. This malfunction was detected when the Engine Control Module received a signal from the sensor which was a constant value of approximately 0.3 volts.

Possible causes include ...
- Harness or connectors (the sensor circuit is open or shorted).
- Defective Oxygen Sensor
- a defective Front Heated Oxygen Sensor heater.

matt4irish

Thanks. I had left out the EGR gasket when replacing the fuel injector under the intake plenum. Not certain as to whether this could have caused enough vacuum leak to throw off air/fuel mix, ISC, etc. So, tonight, I put it back in. Will drive a couple days and see if there is any difference.

It seems odd that that the Knock Sensor and 02 sensor would be in play so quickly as once the engine starts, it runs fine. Could these be unrelated codes just caused by the troubled start?

I'll wait to see if EGR gasket insertion relieves the issue and then take a look at the knock sensor. I know exactly where it is and will do the ohm test first.

I'm less confident as to where the 02 sensor in question is and how to test. Any thoughts?

Thanks again!