I have a 98 QX4 that I was having starting issues with, would start sometimes and other times not. So I had the battery replaced. Still the problems persisted. Then I was driving in town, about 15 mph and the car just died. All the lights came on.

I took to my local Nissan dealer who ran the tests. Said that they would have to "start" by replacing the computer and possibly more. For them the QX4 still started intermittently, mostly not.

If anyone has thoughts please help!

Starting with a new ECU is really rare - because they rarely fail. Not sure what sent them in that direction though...

Do you have another dealership in your area?

Heath

Yes, I have only Nissan dealers in my area. I would have to go out of state for an Infiniti dealer.

I was thinking of possible issues: the starter, alternator or fuel line, fuel pump issue. It can't be the alternator because the alarm is blinking and the lights come on.

The nearest dealer said they went through the protocol to find issues and came up with nothing....

Define driving out of state in miles as there are 150+ Infiniti dealers in US..............since you FORGOT to list your city and state .

kb301 wrote:.....The nearest dealer said they went through the protocol to find issues and came up with nothing....

The stealership is grasping at straws if they couldn't diagnose a problem but want you to buy an ECU. You would think they would have a spare ECU on hand that could be swapped in for 2 minutes to verify their guess at the problem before they try and sell you the $1000+ part.

Was the CEL (check engine light) ever on while driving? If so there should be stored codes in the ECU. A lot of auto parts stores will read them for free or if you want to do it yourself you can follow the self-diagnosis on the EC (emissions) section of the FSM, or buy a code reader at any auto parts store for use on all your vehicles.

http://www.nicoclub.com/FSM/QX4/1998_QX4/

If you never saw the CEL light up and there are no stored ECU codes then I would guess that the intermittent problem could be with the fuel pump or the fuel pump control unit (FPCU). Has there been a noise like a swarm of bees coming from the fuel tank area lately? The stored codes tell you a lot so that should be the first step in your diagnosis. Good luck.

I will try to get a code reader tomorrow and look into this. Thanks!

I rented a code reader and the car passed, no codes. I then sprayed some starter fluid in the air filter area and after several sprays it started. Drove around, tried to start again, which it did. Then third try to start, would not start. So I am thinking it might be a fuel pressure issue. Thoughts?

10 year old fuel pumps are just waiting to fail [worn out].
Easy to view current waveform [amperes] to see condition of commutator and brushes.

kb301 wrote:I rented a code reader and the car passed, no codes. I then sprayed some starter fluid in the air filter area and after several sprays it started. Drove around, tried to start again, which it did. Then third try to start, would not start. So I am thinking it might be a fuel pressure issue. Thoughts?

With no stored codes in the ECU you've got to suspect the fuel system. The easiest way to verify a lack of fuel pressure is to hook up an inline pressure gauge and measure it when she's running well and when it won't start. Look for a place to tee in on the fuel line somewhere before it enters the fuel rail.

Looking at the fuel system in the FSM for your QX4 I see no mention of a fuel pump control unit (FPCU), only a relay and the pump. The relay is a standardized type and can be swapped with another relay of the same color for testing purposes. Yours is in the engine compartment fuse box.

See fuel system explanations starting on pages FE-4 and EC-439
See location of electrical units starting on page EL-229

http://www.nicoclub.com/FSM/QX4/1998_QX4/

In summary, I agree with Q45T*ch- It's probably the fuel pump.

Might want to check your fuel pump relay and the ecm relay..