Ist post. If I doing something wrong feel free to tell me. Here is the problem: 2001 Xterra-3.3 V-6-4x4 (83,000 miles) (daughter-in-laws)-runs fine but every so often after cutting if off and running an errand it will not restart (cranks over). Let it set for awhile and it will start and run fine again. (have already change fuel pump and filter). Have not checked for spark yet as each time it does it that by the time I get there it will start. Dist. parts only shows cap, rotor, wires, and plugs besides a complete dist. (remanf. @ about $400) along with a crank trigger. Anyone with any ideas will greatly appreciated (sorry about the long post)

Howard Burkhart
Knoxville, Tenn.

Ist post. If I doing something wrong feel free to tell me. Here is the problem: 2001 Xterra-3.3 V-6-4x4 (83,000 miles) (daughter-in-laws)-runs fine but every so often after cutting if off and running an errand it will not restart (cranks over). Let it set for awhile and it will start and run fine again. (have already change fuel pump and filter). Have not checked for spark yet as each time it does it that by the time I get there it will start. Dist. parts only shows cap, rotor, wires, and plugs besides a complete dist. (remanf. @ about $400) along with a crank trigger. Anyone with any ideas will greatly appreciated (sorry about the long post)

Howard Burkhart
Knoxville, Tenn.

Hi Howard,

welcome to ClubX. In short, sounds like vapor lock to me.

Stole this from a website,

"If an intermittent starting or driveability problem only occurs when the engine is hot or cold, only during warm-up, only when the engine reaches normal operating temperature, or only when the ambient temperature is high or low, you know that temperature is affecting something. The question is what?

Temperature-related intermittents often mean a circuit is shorting out or opening up as a result of thermal expansion or contraction. Heat may be causing a loose or corroded connector or ground to break contact. Microscopic hairline cracks in circuit boards, soldered connections, wiring connectors and even integrated circuits may open up as operating temperatures rise. An injector solenoid or ignition coil that shows normal resistance at room temperature may short out or open up when it gets hot. The same goes for relay coils and contacts. Sometimes diodes and transistors can become flaky at high temperatures and/or voltage loads, too.

Temperature effects on electronic components can be simulated with a blow comb or hot air gun. By directing heat at suspicious connections, modules or other components, you can sometimes get the part to misbehave when it gets hot. If so, this would confirm the problem and complete your diagnosis. The next step would be to replace the faulty component.

Changes in operating temperature also affect the way the PCM controls spark timing, the fuel mixture and other emissions functions. If an intermittent problem only occurs after the vehicle has been driven several miles, it may be occurring when the PCM goes into closed loop. The underlying cause might be a bad oxygen sensor signal, airflow sensor signal or MAP sensor signal that is upsetting the air/fuel mixture.

If a problem seems to occur only when the engine is running in closed loop, that would tell you it’s probably a sensor or PCM-related issue. The strategy here would be to look at some of the key sensor inputs with your scan tool to see if readings are within normal limits. Some problems may occur too quickly for the normal data stream to detect a fault, so you may have to hook up a digital storage oscilloscope to detect a momentary glitch.

Temperature also can cause mechanical things to stick as a result of thermal expansion when a part gets hot. Valves and lifters can stick if an engine overheats. EGR valves can stick from heat or a buildup of accumulated carbon deposits. Relay contacts may be affected by changes in temperature, too.

One thing to check here is the operation of the cooling system. A low coolant level may prevent the thermostat from opening and closing normally. An inoperative electric fan or a clogged radiator also may allow unwanted fluctuations in engine temperature that affect the way it runs."

edit: to say, WELCOME TO CLUB XTERRA! :)

Thanks for the replys. Boof: already changed fuel pump (in tank) and filter and opened gas tank(to relieve a possible vapor lock). Anthony: No overheating (temp gauge stays steady). Going to take it to Autozone and see if it is showing any codes. (free)-he he. I am begining to suspect the crank trigger module. Thanks for your time.

Just had the codes checked at AZ. Will a knock sensor cause the above problem? (code PO325-knock sensor -1 circuit-Bank 1) Also showed the codes where I had the tank connections loose.

The fuel tank issue could have caused the knock sensor code... Have you noticed any knock or pinging??

The fuel tank issue could have caused the knock sensor code... Have you noticed any knock or pinging??
No on the pinging. I found the problem (I hope). It would not start again yesterday at the Post Office. By the time I got there to pick them up I tried it again and it started. Got back online and did some looking and found a recall on the Xterra. Turns out that the fuel sending unit (where the lines enter to run the pump has a defect causing the connections to corrode). Went back out and check to see if it would start-it did so I took the pump plug off and put it back on again-no start! Removed again and took mirror so I could see inside the sending unit plug-in--lo and behold one blade was loose-it had corroded into and would make contact when cold then when it got hot enough not. (that explains why it would restart after colling off-I HOPE). Checked with dealer and her VIN is on the recall. The only problem is that no dealer in the area has one (dealer item only) so they have to order it. If they will let me I am going to install it myself as it is easy to get to. (already had it out once to change the pump (the one I probably did not need). Acess to it is under the pass. side rear seat. Sorry for the long post but it might help someone with the same problem.
Thanks,
Howard Burkhart
Knoxville, Tenn.

Damn - missed this one.

:D

Most people who have that fuel pump connector under the back seat corrode, just lose all power at once, and the X just dies...like while on the hwy at 60 mph, etc.

The "starting only" aspect of your situ was atypical for that problem....especially as driving would cause it to reach the same temperatures under there as parking with the engine off, etc...and driving would tend to create more vibrations, etc, as well.

- So expansion related loss of connection would be more likely to occur when the X was running at high speed than parked with the engine off.

It is possible that the exact tautness and orientation of your individual wiring is such that the recall will solve the problem. (You might get lucky)

:D

But - I would NOT be shocked if it didn't fix it...or it did.

Lets just all hope it DOES fix it though, as a free repair is always worth at least trying.

:D

Glad you got the problem solved. For anyone else interested, here's Nissan's narrative on this issue:

" Nissan has determined that some 1999-2003 model year Nissan Frontier vehicles, equipped with the 6 cylinder engine and 2000-2003 model year Nissan Xterra vehicles, equipped with the 4 and 6 cylinder engine may have a defect which relates to motor vehiclesafety. There is a possibility that the fuel pump terminal on the fuel-sending unit may develop a crack in its plastic molding which could cause the terminal strip to corrode under some environmental conditions. If corrosion occurs, the terminal strip could eventually break. This will cause the fuel pump to stop operating and will result in not being able to start the engine or cause the engine to stop running without warning during vehicle operation, which could result in a crash. To prevent this condition from occurring, Nissan is conducting a Voluntary Safety Recall Campaign to replace or repair the fuel-sending unit."

Anthony - good info - but it does talk about the connector breaking...pretty much a one time event, after which, it won't run.

We have a situ where it WILL run again, after cooling apparently.

So what we are now hoping for is perhaps a PARTIAL break, like a greenstick fracture or something.

:D

It may be broken but making contact when cold, and separates when hot.

Actually this goes back to my original reply...

Heat may be causing a loose or corroded connector or ground to break contact. Microscopic hairline cracks in circuit boards, soldered connections, wiring connectors and even integrated circuits may open up as operating temperatures rise.

Right, so if heat is breaking the contact...then maximum heat (Driving at speed) should give maximum failure correlation.

IE: It would be MORE likely to fail at speed than during parking.

But hey, there are ghosts in every machine...so lets hope that this one is exorcized by the recall repair.

:D

Update!! Checked with a dealer to have it fixed . Said it would be next week at the best. Asked if he had to order the part. No they keep them in stock. Asked if they would give me the part to install. Yes. Went by and picked it up-complete unit with new o-ring and hose clips. (daughter-in-law fixed me a steak supper tonight she was so happy) Will get some pictures to show the affected part.

Awesome !!

Here is what you need to look for: Picture 1 is the whole unit.

When you click on thumbnails, inlarge again by clicking again in lower right corner. (I ain't a PC whiz-but you can tell that-lol). Everyone that has a Xterra from '99 up should call their dealer and give them your VIN # to see if yours is listed and take it in to have it checked as it could stall at any time.
Have hers fixed now. Thanks for all the help.

So they have to give you a whole new unit, excellent, I will be sure to check my vin #'s

So they have to give you a whole new unit, excellent, I will be sure to check my vin #'s
Yes but they will install if you wish. (some may insist they do it.)

Yeah, i'm actually surprised they let you do the install yourself, considering it's a TSB.