Seeing a lot of members here who complain about bad idle, engine shuddering on D (when at a standstill) and when the air con is switched on. These problems are more prone on the 1kr-fe engine's but the 1.3's are not spared either. I had the same issues with my vitz so I went ahead and replaced/cleaned a few things.
Note: Its been approx 5k km's since I did these DIY's. My odo was at 93k and its currently done 98k and the symptoms mentioned above have yet to return. So roll your sleeves, grab some tools and get to work.
1) Remove the air box completely. I cleaned the insides using some apc and a flexible cleaning brush gently. Let it dry for 30 minutes. Replaced the old air filter with a new Toyota one fore Rs450. Also, I cleaned the breather hose with a clean cloth. There was oil build up in there. You can remove the breather hose to clean it or do it while its connected to the air box.
I also cleaned the inside of the base air filter box with a damp cloth to remove all the stuck dirt.
2) Next up, the throttle body. These get mega clogged over time. The insides of the tb were jet black in my case. I un-clipped the plug connected to the tb and using pliers, un-clipped the top rubber inlet for the tb. You can let it be there. I did'nt wanna miss out on anything so I removed it before I removed the tb. There are two coolant hoses connected to the tb. Disconnect theses. You might see a little coolant come out, that's normal. Just put them to the side facing upwards but remember which was which. Finally, loosen the 4 bolts holding the tb in place. You don't need to remove them to get the tb out.
Here's how the tb looked after I was done cleaning it out using a tooth brush, some Carburetor spray and a clean cloth.
3) Here is the sensor that need's a lot of attention. Most of you might have skipped on this and you will be surprised how bad the MAP sensors condition is if its been neglected all this time. Its located right behind the TB and is held by 2x10mm bolts. Unclip the connector and gently remove it. It might need a slight wiggle to come out so don't panic if it dose not pop out once the bolts are removed.
When I removed mine, the sensor was a black oily mess. I didn't capture a before picture but here is how it looked exactly upon removal.
(Reference Picture of a BMW Map sensor)
Once I cleaned it up ( Carb spray can be used to clean a MAP sensor ) and let it dry, I had a sensor that was ready to do its job properly.
4) I removed the O2 sensors too. Cleaned them up and put them back in. I did not take any pictures in this case since it's been done here loads of times but I'll still update this post with how to remove them and see if they need replacement or a cleaning will do.
5) Finally, the plugs. Remove the electrical clips from the coils and unscrew the 10mm bolts to remove the coils. I put them in the order I removed them from the car. To remove the old plugs, you need a long reach bar along with a 16mm socket. I got both of them for Rs250 from a local store.
I loosened the plugs and then used a long reach needle nose pliers ( the one dentists use lol ) to take out the plugs. These were completely shot.
(PW wont allow more pics so I'll upload the rest in the next post).
So I went ahead and bought some new NGK iridium plugs. Here's a little trick to make sure you don't cross thread the plugs when you are installing them back in. Saw this on youtube. Buy a small rubber hose that fits on top of the spark plug terminal (1 meter costed me Rs40) and lower the plug into the chamber. The rubber hose allows you a better feel of the plug as you screw it in. If the plug goes in wrong, the rubber hose won't be able to turn the plug any further and damage the threads. Once the plug is securely in, pull out the hose and tighten it up using the socket and bar.
- Before you start with this DIY, disconnect the -ve terminal of the battery. Once done with everything, reconnect the battery, check if any tools are left inside the engine bay, remove those and turn the key to the on position. You might see the RPM do a few calibrations while the ignition is switched ON. Once the rpm needle settles, start the car up without pressing the throttle. Nissan mention not to press on the throttle when these DIYs are done to let the ECU calibrate for the X-trail and that's how I did it on my X-trail as-well as the vitz. I let the engine reach normal running temp before touching the throttle.
** I also replaced the the oil filter and poured Shell Helix Ultra when I did these DIY's. I will be switching back to HX7 when I replace the oil this time. The synthetic oil was used to clean out any build ups inside the engine since I had no idea what oil was used by the previous owner. I also use a 50/50 ratio of regular/HOBC fuel on every refill to counter the knocking issue.
I hope this helps out everyone. Cheers.