95 nissan maxima cold start problem

[nfnd]

My 95 nissan maxima has a hard time starting in the cold.
It has a 3.0 L V6 24V.

Its been like that ever since I got the car and I get both a knock sensor and an upstream O2 sensor trouble code. I am thinking it is the O2 sensor but I really am not sure. The car runs fine, just hard to start in the cold and does also knock sometimes.

the check engine light had been on ever since I got the car.

The trouble code for the oxygen sensor is 0901 which reads as
"Upsteam oxygen sensor heater fault (right bank)"

The trouble code for the knock sensor is 0304 which reads as
"Knock sensor or circuit fault"

[rick_6]

Wish I had an answer, but I have the same problem. During the warmer months, the car starts no problem. During the colder months, I have to press on the accelerator to start it. Tried putting dry gas or equivalent in the tank. Tune up during summer. Not sure if its fule related. Seems to turn over fine, I think it may be a fuel issue but know too little.

Aside - Co-worker says pressing the gas shouldn't make a difference in start up because EFI. I told him tell the car that. Does the pressing on the accelator make a difference duing the start; swear the car won't start in cold weather without.

[Nahkapohjola]

Originally Posted by rick_6

...but I have the same problem. ...

U friend is partly right... = only IF TPS is ok. Pedal movement makes changes in contact or moves dirt in the potentiometer...

TPS
- Search this forum for TPS. Awesome serch engine here!

- Costs about 90$, easy to DIY change. Located on Throttle Body TB. VGE TPS here: http://www.cardomain.com/ride/748507/6

- is used ONLY as cold engine input to ECU & A/T. After warmup, its used only for A/T, O2 sensor will be used from this point onwards. Try and find detail info for your car via http://www.cardomain.com/id/pohjola#links

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nfnd

Take batt out for 30min to clear codes & light. See if returns. Measure the O2 sensor & its output with multimeter... You may try jumpering the O2 sensor inputs at ECU, after disconnecting the faulty one.

Replace/clean TPS. see link above

KS can be reliably tested by a OBD tester. Buy tester smwhere (or rent from autozone.) Also for tst purposes it may be bypassed with resistor. I have bypassed it alltogether (caution), see http://www.cardomain.com/ride/748507/9

Take out your plugs -replace-, compare the oldies to what http://www.ngk.com/sparkplug411.asp?...gnition&mfid=1 -site plug problems troubleshoot chart... Maybe its time to clean your engine?

Note: std plugs last 5-8kmiles. Platinum etc 10x...

worst case...

.