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AR97Pathfinder

Hard/Rough Start

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I have previously had a rough hard start a few months ago that occurred after driving and then restarting the engine within a half hour to hour. The engine would hard start and rpms rise roughly for a few seconds then stabilize. No drivability issues at all. 

I added a can of bg44k and it went away. That was around March. 

Now I noticed the same issue arise occasionally again. And now the issue also shows up if you start the vehicle after not being driven a couple hours, shut it off and then restart again within a few minutes. 

I don’t have any codes and I’m running another can of bg44k in right now. 

I have a feeling the injectors are leaking down. But wanted to get any other ideas and what else I can do. The three outer injectors are easy to replace but the three under the plenum are the issue. Especially to get the egr off to get off the plenum and the bolts on the plenum itself tend to seize. 

Should I just try replacing the three outer injectors?

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I would check the air intake and coolant temp sensors.

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The next time it's hard to start, shut it off and check the plugs. If one's wet with gas, that points to the injector for that cylinder.

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Simple test for leaking injectors is to connect a pressure gauge at the fuel rail inlet. Observe the pressure rise when you turn the key to on without cranking the engine. It should go over 35 psi. Then  turn the ignition off and watch the gauge. It should hold pressure for a while. A drop of 5 psi or less in 5 min indicates it is ok and no leaks. A rapid drop in pressure indicates a leak somewhere. Could be the check valve in the pump assembly, the pressure regulator, or an injector. Plugging the return line will test if it is the regulator. Putting in a valve between the fuel supply line and the gauge will let you see if the pressure loss is the pump or injectors. When the system is pressurized you close the valve and watch for the pressure to drop. (my fuel pressure test kit has a 1/4" ball valve I got from a hardware store that I added so I could shut off the line and hold pressure in the injectors)

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Just occurred to me that your hard start and remote start issue might be related. It is possible you have a failing contact in the ignition switch. It is an inexpensive part that is easy to replace. If I recall correctly, it is pretty much the same as the ones Nissan had used for decades that I have had to replace in several of my old Datsuns, and the most recent was in my 93 Pathfinder last year. The thing almost fell apart in my hand when I removed it and the lock to install the keyless pushbutton ignition. 

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10 hours ago, Mr_Reverse said:

Just occurred to me that your hard start and remote start issue might be related. It is possible you have a failing contact in the ignition switch. It is an inexpensive part that is easy to replace. If I recall correctly, it is pretty much the same as the ones Nissan had used for decades that I have had to replace in several of my old Datsuns, and the most recent was in my 93 Pathfinder last year. The thing almost fell apart in my hand when I removed it and the lock to install the keyless pushbutton ignition. 


Should I purchase one directly from Nissan? Or are the ones from Rockauto okay such as the Standard Motor Products? 

 

I see it says must use scan tool to install due to anti-theft security. 

 

And the new keys probably won’t work on door right? 
 

 

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Standard Motor Products is a good brand. But some of the economy parts Rock Auto sells are garbage.

The comment about the scan tool is interesting. It leads me to believe that at least they think this car has a key immobilizer. If it does you'd need the Nissan equivalent scan tool, or you'll have to do it the manual way. I've never heard of a generic scan tool that can set manufacturer specific options.

I've seen both kinds of ignitions, where the key cylinder is separate to the switch and can be replaced without rekeying, and where they are one. If one and you want one key, you'd need to get a paired set or talk to a locksmith.

I'd look this stuff up if I had the 97 service manual, but I only have the 2001 one

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I suspect that's a generic warning, intended for newer rigs with chipped keys/immobilizers. I don't think Nissan started with the chipped keys until '00 or '01 (but don't quote me on that). Looks like the ignition switch (just the electrical component) is available pretty cheap and attaches with two screws. I replaced just the electrical part of the ignition switch in my '93 and it was a very easy job. Replacing the whole lock assembly would've required drilling out the screws that hold it in (the heads shear off when the part is installed so you can't just unbolt the cylinder to disable the steering lock).

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I going to change out the switch portion and see. Not the tumbler for key. 
 

I started up this afternoon and it stalled right away. I restarted again and hesitated for a second. 
 

After that it’s been starting good. 

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Yep, the switch is separate from the lock, so don't have to worry with the key. The 3.3L R50 didn't have a chipped key option, so no immobilizer issues anyway. The "security" system was pretty much a stand alone unit that wasn't much more than a starter inhibitor with a siren. Pretty safe going with a Standard brand for the switch, probably comes out of the same facility as the Nissan branded one which I believe is made by Niles. 

A friend of mine has an early 1999 model Pathfinder LE that I took the factory unit out and installed a DEI remote start in its place. It offered all the features of the original unit(remote lock and unlock, and starter kill) and added remote start and remote rear window release ( I had installed the release servo from a QX4 a couple years earlier, don't know why Nissan didn't offer the electric window release in the R50 Pathfinder, was almost standard in the WD21) so was something useful for him. Only problems I recall has been when the truck sat with a dead battery for a few months, had to reprogram the unit I think. 

 

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Oh, forgot to mention, with Nissans that have a chipped key or I-key, the only way to program a replacement key is with Consult. Also the immobilizer is built into the body control and engine control modules. That is an entirely different can of worms to mess with. Neat feature with the chipped key immobilizer, if the wrong(not programmed) key is used to try and start the engine 5 times in a row, you need Consult to unlock the system because it locks down and if the correct key is used it will still not start. Had several cars and trucks towed in because a lost key was found and the owner tried to use it. If a key is programmed, you have to do all keys at the same session, because it clears them all when you put it into learn more. Great fun and amazingly difficult to get the average owner to understand. 

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Turns out I had an ignition switch and key assembly in my garage from some steering wheel parts a friend gave me several years ago after he didn’t need. 
 

I swapped out the ignition switch. The old one look fine from appearance but who knows what’s wrong inside. 
 

Everything so far (crossing fingers) seems to be fine when using the remote start. I took several drives after changing it yesterday and no shut down yet. I’ll have to wait and see. 
 

Almost everyone I ask including remote start installers, the viper company, and mechanics say it is impossible for the viper system to override the key while driving and shut it down. 
 

Thanks for the help! 
 

Hope it solves my issue. 

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So the ignition switch may have solved the shutdown while driving, but the rough startup I'm still getting. 

 

It feels like the engine struggles slightly upon starting. I just warmed it up this evening to check the oil level. Then started it back up 2 hours later to run to the store and it happened again. 

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So, the issue with the rough, slow startup happened twice yesterday with the engine failing to start once. Check light came on. 


I got the code P0135 O2 Heater Circut Bank 1, Sensor 1. 

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You should get that fixed, but there's no way an o2 sensor should cause rough start. The ECU has a preprogrammed fuel map for starting and cool idle until the o2 sensor gets to temperature.

My 01 had starting trouble when the fuel filter got clogged, and when I got confused about using 60k spark plugs instead of 100k.

Besides that, I'd look for vacuum leaks, correct air and coolant temp readings, and the idle air control motor.

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Yeah I'm gonna get that fixed asap. 

 

Fuel trims cold and hot and pretty good and in range, so not sure about fuel issues. Fuel filter also has been change, maybe not even two years yet. 

 

I used NGK platinum plugs when I changed about 15k ago. 

 

In the meantime I'm changing the ECT sensor and the engine air temp sensor. 

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A MAF sensor can also cause poor running, especially at lower engine speeds. But they aren't a cheap throwaway part swap, so id run the diagnostic on it.

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Thats been changed with a Hitachi a year ago. Had a code and engine used to stall at idle and whenever you touched the harness plug. 

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The engine runs absolutely flawlessly when driving. Its literally on a startup sometimes only. 

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Is it possible the MAF sensor is going out after two years? I bought a Hitachi brand from advance auto. 

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Unlikely but possible. With cars, one discounts the possibility of something failing, especially if it has been recently replaced, at their own peril. But that is what service manuals were written to help with, and using scan tools that can read sensor outputs.

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So nothing is wrong with the maf sensor and O2 sensor (P0135) has been replaced. 
 

Should I get a professional fuel injection cleaning?

 

Or could there be fault with the IACV? 

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