1995 nissan quest... code 34

[hellah fresh]

I have a 95 Nissan Quest and it is giving me problems! When i start the car it runs for a few and then it dies if i dont keep my feet on the accelerator. So i scanned it and it comes up with the code: 34 and i read somewhere that the 34 code is the Knock Sensor. We already changed out the distributor cap + rotor and also some spark plugs. Check out the MAF and it seems to be ok. We had swapped out a MAF from a friend van and it still didnt help. We cleaned out the valve throttle body and it seem to help for a bit. But other then that the car still starts up and runs for a few minutes and dies again. So the code 34... is there anything else that can cause this? Im just trying to see if i can save $135 for a new knock sensor. Please help!

[tempfixit]

DO NOT replace the knock sensor, they rarely fail. (Save your money on knock sensor) The code is set because something is causing a vibration to set the code. Deal with the original issue and code should clear.

Do you have to step on the accelerator to start it???

Try checking and cleaning the IAC/FIC and port opening for carbon build up (they are not easy to get to but doable)

Also take off the cap and rotor again and also remove plate to check the optical sensor for any grayish/brown dust on it. If dust is present this is a indication that the distributor shaft bearing is getting bad and the distributor will need to be replaced.

Have you checked the fuel pressure???

Also check the Throttle Position Sensor.

You could also try disconnecting the oxygen sensor to see if that helps any.

There is a thread I believe titled Factory Online Service manual, check it out I believe it will be a lot of help to you.

[hellah fresh]

I checked so far:

Fuel pressure OK
Vacuum leaks OK - Didnt see anything
Cleaned out Throttle Valve Body - Ran fine for 1 day then slugish again
my dad checked the distributor cap and rotor.. seems to be ok but we are going to double check again.


We have not try to disconnect the o2 yet be we are going try it today. As for starting up we just start it up normally no need to hold the gas. My dad says when the engine is cold it starts and runs fine but once the engine warms up.. thats when it is acting up. It acting like it is misfiring but doesnt throw any misfire codes. And after it starts to run sluggish the van just dies out. We can start it and it will run for about 5-10sec before it dies agian. We cleaned out the throttle body 2 times and still nothing. So what do ya think?

[hellah fresh]

BTW not it threw out a code 51 i looked it up and says something about the injectors going out when the engine is hot.

[tempfixit]

Go to the Free Online Factory Service Manual thread, go to section EC page 130, it gives you a testing procedure for code 51.

Hoope this helps and keep us posted.

[hellah fresh]

ok so code 51 is gone and now it only shoes the 34 code. We tested the control mod with another one and still dies after 40 mins. Unhooked the o2 still dies. So im guessing we are going to try the knock sensor? or no?

[tempfixit]

What do you mean by testiung control mod??? Do you mean you installled a differernt ecu??

In my opinion replacing the knock sensor will be a waste of time and money. You need to find the problem that is setting the knock sensor code.

Did you do the step by step testing for code 51 from the factory service manual????

How many miles on the engine? When was the timing belt replaced and timing checked???

[hellah fresh]

Problem SOLVED! After testing EVERYTHING we can think of out... it turns out that the Knock Sensor was the cause after all! As you see in the picture it was cracked open. But like you guys and everyone else we didn't want to change out the knock sensor just yet because the past week we had a 97 Pathfinder and also another 97 Infinity qx4 and both car was running the same and the scanned showed up knock sensor. On those 2 car we replaced the Knock Sensor and the car ran like shit still so thats why on the Van i took your advice and double check everything else before doing the knock sensor. On the Pathy it turned out to be the main Relay and on the QX4 it turned out to be a dirty distributor cap & Rotor. So yes the quest is up and running finally! Thanks for all the help! Hope everyone sees this.

[tempfixit]

Thanks for telling us the fix.

That is the first knock sensor that I have heard of that failed on a villager/quest.
Where there any other symptoms you may have forgotten to mention for reference purposes??

Also could you put the pic of sensor on a website like photobucket, etc. I sure would like to see what it lloked like??

[villagerguy]

I have never seen a knock sensor cause a driveability problem either. The only thing they do is retard the timing in increments to prevent spark knock. I would love to see a picture of this sensor.
Also, Villager & Quest owners can go to this site for expert help. The group has techs and factory service engineers who worked on Villager/Quest for years.


http://autos.groups.yahoo.com/group/villagerquest/

[tempfixit]

You can disconnect the knock sensor and the engine will still run.

[hellah fresh]

Oh yeah the knock sensor was cracked. so yeah that was the root of my problem when i scanned it. If anyone here have the same problem and have the same code i suggest maybe you try and check out your knock sensor just to make sure there is no cracks. I know its a pain in the ass to get to but just a heads up to everyone.