Notes on Pathfinder

Notes regarding Pathfinder,

It is a 1998 Nissan Pathfinder VIN JN8AR05S2WW263055

V6 3.3 Liter 3275cc Gas

Manual Transmission

It has 140000 miles on it

And I bought it in February 2011 from Auto Trade Center on El Camino.

I paid $3800 for it.

http://www.edmunds.com/nissan/pathfinder/1998/

The situation at the moment is that the car is having a lot of trouble starting – it takes 30 ~ 50 attempts to start. This only happens if the car is restarted quickly after stopping briefly, and it seems to be fine if left overnight. I’m thinking that it could be some kind of vacuum seal or thermally related gasket seal issue?

I’m debating buying a newer car but I hate ownership, and I hate wasting money. At the same time this is dangerous, not child safe, and not pleasant. So I’m trying to understand what the issue is before I make a decision.

The history of the car is that after a month or so of owning it I started to have similar stalling issues:

• It would falter and buck while driving in or out of gear – as if the engine was starting and stopping while driving. It felt as if the engine was starved of fuel; as if it was suddenly being choked.

• Sometimes the engine would simply stall while driving – even at high speeds – even with high RPM’s.

• Sometimes the car would stall while waiting at a light.

• Sometimes the car would have trouble starting.

• The battery and the starter motor appear to be in excellent condition in that they can handle sustained attempts to start the car and they deliver what sounds like a lot of revolutions to the engine.

I took the car into a local repair shop [ Kurt and Dorn’s Auto Service 930 Emerson St Palo Alto CA 94301 (650) 321-0461 ] and they also saw the same problem. They found that if they held the throttle open manually that the engine starts up and runs without any problems. They replaced a “thermal switch” and a “bracket control plate”. They noticed that the RPM’s were not changing “when adding a load” (whatever that means). So they “cleaned” the “throttle body” ( whatever that is ), replaced the thermal switch and unbent the bracket for $700. They also recommend replacing other parts.

Their repairs had a temporary effect but the car started to consistently fail later on in the same way.I brought the car in for inspection again a month later. They couldn’t find anything wrong and charged me $180 for the inspection. The car stopped failing for about a month and started to fail again consistently ( I believe they are adjusting something that is reducing failure for a while). I brought it in again and they inspected it for free and have now decided that the computer and the fuel injection system have to be replaced also. They said this was based on a recall advisory: http://www.motortrend.com/cars/1998/nissan/pathfinder/recalls/index.html … but I don’t see that specific advisory. Their total set of recommendations are:

• Clutch for $1093

• Radiator $549

• Valve Cover Gasket $493 [ http://www.ehow.com/how_4485029_replace-valve-cover-gasket-nissan.html ]

• Computer $1500

• Fuel Injectors $1200

My concern over the above repairs is that I am unsure if they will solve the issue or not. I want a better diagnosis. Here are the candidate things that could be wrong with it overall [ http://www.wikihow.com/Fix-a-Car-That-Stalls ]

• In general it is either electrical or fuel related. Either failing to spark or spark at the right time or failing to deliver fuel.

• The car used to idle low and stall at idle but now it is ok – I assume they adjusted the idle control valve a bit.

• The car does build a gas tank vacuum. I am testing to see if removing the gas cap helps the car start.

• Apparently replacing the distributor cap is fun http://www.partsgeek.com/mmparts/distributor/nissan/pathfinder.html ?

• The fuel filter can be clogged. This might show up if going up or down steep hills and seeing if the engine changes performance or stalls. I don’t see this behavior.

• The spark plugs are fine according to the repair dude.

• Low engine compression overall due to an old engine? Unknown. Apparently I can get a compression check?

• http://www.aa1car.com/library/2005/us80530.htm suggests that it could be an engine vacuum leak. The repair guy said that the engine pressure was fine. This article also suggests that it could be sensors [ airflow sensor, coolant sensor, air temperature sensor, manifold pressure sensor, crankshaft position sensor ].

• The air conditioning could be dragging on the system – I’ll make sure it is off.

• The battery could be dragging on the engine during recharging… ( I doubt it because this happens under high RPM ). Electrical systems overall could be turning off and on – stopping the spark plugs and the like. Apparently it is possible to hook the car up to a diagnosis machine that can trace out these kinds of things.

• Stalling while driving is apparently often ignition related – to the spark plugs. This could be a “crankshaft position sensor” or an ignition coil ( except the pathfinder has 6 of them ) http://wiki.answers.com/Q/How_do_you_replace_an_ignition_coil_on_nissan_pathfinder_2001 .

• Fuel Injection Relay? This would mean no fuel was being delivered. Apparently it makes a clicking sound when failing. Since I don’t hear this sound it probably is not this.

• Bad PCM ( engine computer relay ).? Bad ECM? http://www.rockauto.com/catalog/x,carcode,1316833,parttype,2896 http://qcwo.com/otherdeal/Car-Computers/Nissan-ECMs/1997-1998-Nissan-Pathfinder-ECm-ECU-MECM-W185 http://www.autopartsfair.com/nissan-usedparts/pathfinder-1998-engine_computer.html?fit_notes=68ec112cd4ec934732a8ef83254cea9d&seq_num=9

• Bad fuel pump.

• Bad seals in general – perhaps the whole set of rubber components connecting the head gasket to the body should be replaced.

Revisiting this topic in November – the car still behaves just as badly. There is no real clarity on what is going on – and thousands of dollars later it is still behaving exactly as badly as it always did. I’ve spent more money on trying to find the issue than the car is worth.

I just can’t believe that it is not fixable however – it is more of an academic puzzle at this point than anything I hope to get value out of…

I feel that of these issues it is not the ones that I have x’ed out (based on the following URL’s and playing around with the engine ).

http://www.2carpros.com/articles/engine-hesitates

http://zhome.com/ZCMnL/PICS/hesitation/hesitation.html

• It is definitely fuel blockage

• I don’t think it is lack of vacuum pressure

• It possibly could be a bad cap and rotor?

• x spark plugs

• x timing belt?

• x mass air flow sensor? → should report a trouble code

• x ignition coil? → should report a trouble code

• x plugged air filter? → removed it and inspected it

• x fuel filter? → removed it and looked at it

• x vacuum hoses in general → inspect

• x fuel pump bad? > tested it and tried cleaner

• ? fuel injectors

• ? fuel relay switch

• ? carborator

• ? IPDM / ECM computer stuff?

• ? distributer / distributer cap?

• ? rotor

• ? throttle body

• ? catalytic converter

• ? crankshaft position sensor? → bolted near starter motor → look.

• ? dirty wires? → this is a great possibility

One key insight is that it seems to do worse on bumpy roads. Also when I physically jiggle the fuel relay switch it sometimes turns off the car – as if there is a loose or corroded wire.

Anyway I will probably just buy a brand new one at this point.