VancouverR34

Another little update - yesterday I wanted to install electronic fuel pressure gauge in the car so that we could see the fuel pressure while driving. Bad news - the moment the car was started - engine was shaking/jerking vs the last time when it was working totally fine even after driving it in the neighbourhood and only started showing shaking symptoms when taken to a highway. With that much jerking/shaking as was happening yesterday we didn't even try driving it. Though with the electronic fuel pressure gauge installed inside - it showed same 40PSI while idling and no change when accelerating on "Parked". Soon I'll get another original working MAF and will try swapping MAF to it to see if that will make any difference.

I have a little update after resting resistance and adding a fuel pressure gauge. The car has been sitting without starting for a while by now and this time things were different. I was so used to starting it on my driveway and within a couple of minutes feeling the engine shaking at times that I just knew I could replicate this issue at any given time. Well, surprise this time. First of all I checked resistance between the negative on the battery and bolts connected to the chassis and then to different spots on the engine - it was good - everywhere around 0.1. Then I added a fuel pressure gauge and started the car - pressure went up to 40PSI and was holding it while idling. Waited for the car to warm up and the engine to my surprise wasn't randomly shaking. It finally shook a couple of times but that was it. The car warmed up - fuel pressure showed around 35PSI while idling with transmission set on "parked". I asked my son to take it for a drive around some blocks and it wasn't shaking. After he did that a couple of times we decided to take it on a highway and do a short trip to the next exit and back. Right after getting onto the highway it started shaking and since that wasn't on my driveway this time I couldn't check the fuel pressure this time. The whole time before this I could replicate this on my driveway but not this time. So, having a fuel pressure gauge on a wiper and watching it while driving would be handy for sure. When getting home engine shaking could be felt at different times in city driving but not constant, when parked after getting home it wasn't shaking anymore. Tried to accelerate while parked and fuel pressure went down to about 32PSI. What is it supposed to be? Let me know who knows. Also, the whole time while driving it we had a reader connected to ECU and found that O2 sensor readings were going up and down all the time while steadily maintaining speed. O2 readings would fall to 0 and stay at 0 if you remove your foot off the gas pedal. That fluctuation of O2 readings while driving didn't seem right. Let me know if that could be the cause of my issues. I'll put a video of the readings for O2 from driving it here. WhatsApp Video 2023-05-31 at 07.54.07.mp4

ahh, ok, thought you were talking about fuel.

The difference in octane number between regular and premium gas here is only about 4 octanes. So it's more about 4% difference rather than 20% in gas type. I'll do the fuel pressure and resistance first before going down to removing a spark plug and examining cylinder walls. it's a pain to remove the intake to get to the coilpacks

Thanks, will buy a 0-100 psi guage and will report back once tested Connections on the coil packs and ECU are solid. Redid them while trying all the coils first having just two brand new coils and then reconnected them all when got four more coil packs. Also noticed a small plastic piece broken off on one of the connectors to one coil pack and to make sure that's not the cause - replaced wiring harness to the coil pack with a brand new one. Also to eliminate the issue of ECU (one of the sparkplug holes was filled with water and I thought if it shortned anything, maybe ECU got a fried resistor or chip) I bought a good working ECU from HR34 for a "hard not to buy" kind of price to test it out. So connections to the ECU are solid too. For the gauge to connect to windshield wiper - no need to do that as I don't need to drive the car to recreate this issue. Just idling on my driveway after a couple minutes of running i can see this. So I can perfectly monitor fuel pressure while the gauge is under the hood. Also just to add, son was buying premium gas for it but he said this started pretty much soon after he filled it up with regular gas. It was then refilled again with premium but that didn't fix it. Theory of bad internals of CAS - I don't think so as I tried a different working CAS. So I can reproduce the issue with the original and with another used but working CAS and I can reproroduce it without revving up as it happens while idling. Not sure what Haltech is, probably a scanner/monitor. I got a code reader NDS1 connected to consult port but it's not helping me much. I didn't want to go that far replacing all these parts but P1320 was obviously taking me to ingnition which is why I tried coil packs and spark plugs first. Then MAF and then after that it wasn't too much expensive to add CAS and after that not too much more to add AICC and some other sensors. It wasn't planned to buy all these parts right from the start. Just taking it to dealership or a shop in Canada where they never see Skylines would probably result in losing way much more money and most likely end up still not getting it fixed.

For the fuel pressure guage - Is there a good mount point or just have it hanging on the hose? I see fuel pressure guages for sale in 0-15PSI and also 0-100PSI, which one should I get?

For the fuel pressure guage - I can't think of a good place to have it permanently mount as fuel lines come up almost middle of the side of the engine bay with a hose going right from the fuel filter to the fuel line, so I guess that would be just a temp setup to test out the pressure, or is there a good spot to have it permanently mounted? Would be nice to have it there. For the resistance - would I be checking resistance between negative on the battery and on the engine? I myself have been wondering about possibility of the ground being the cause too. Very possible, I will have access to working parts from a 4wd skyline that runs in about three weeks, will swap one from out of there to test it out for sure if not solved by then. With parts availability in Canada this has been going over for some months by now. One package literally was held by customs for over a month. Only when I filed for refund with the supplier and they went to their UAE post and those contacted Canada post or Canada Customs - only after that it was processed the same day. For that order just took almost two months to get it. Those were actually the original coils that I was waiting for.

List of parts changed: Spark plugs Coil packs - Nissan 22448-AA000 - COIL ASSEMBLY, IGNITION Wiring harness to coil packs - Genuine Nissan (240795L300) MAF - original MAF was cleane and then was replaced with not genuine but replacement part for original part number - bought from rockauto.com AAC/IACV - Genuine Nissan (23781AA000) - used Angle cam sensor - used SENSOR ASSEMBLY, CAMSHAFT Genuine Nissan (23731AA010) - that weird rear sensor Fuel filter (pitworks) - Pitwork AY505NS001 - FILTER, FUEL Air filter - generic Oil filter (pitworks) - Pitwork AY100NS005 - FILTER, OIL PCV valve - Nissan 11812-41B00 - INSULATOR, PCV VALVE Also not related but replaced valve covers gasket due to leaking oil and did an oil change. Fuel injectors serviced/cleaned by a professional injector cleaning company n- gave them the whole fuel line with injectors Compression test done - 1 - 15, #2 - 13, #3 - 14, #4 - 14, #5 - 12.5, #6 - 12 Coolant pressure is holding, not loosing coolant Oil pressure is normal When engine vibration/jerking/stattering happens, gas consumption is higher than normal and I think I can smell unburnt gas through exhaust. Haven't reset Crank Angle sensor timing and haven't unplug the knock sensor. When putting another Crank Angle sensor I put it in the same position/angle as the previous sensor. I did plug in a phone (Android) connected to consult port and read codes using NDSI v1.53 app but don't know what to look for specifically at what sensors are doing. Error code that initially got detected (P1320) no longer reads, son is not driving the car since I figured out this is an engine and not a suspension/tires problem. I didn't want to risk harming it more so immediately he stopped using the car after we realized this is an engine related problem. Probably if we drive it now, it would give that error code (P1320) again. Hopefully this is easier to read than the original post.

Don't know what that is but went by how Nissan names it in its catalog - SENSOR ASSEMBLY, CAMSHAFT. It was only around $30 so I figured at that price it doesn't hurt to replace it too. Sure flywheel won't have missing teeth but the sensor might go bad and not read it. I thought it worked together with the front angle sensor. Either way - original one was pretty clean as actually everything including MAF and AAC/IACV and anything else I tried. Everything is super clean and didn't make a difference. I am going to get a hold of original known working MAF and try that and would be nice to check the pins if it's easy to do.

oh, one more thing I forgot to add - when I first checked codes after my son was driving it for several days with the engine vibrating, i got a code P1320. Which explains as to why I first replaced spark plugs and then the next thing I tried was replacing coil packs with real original brand new oem nissan coil packs. Also just to make sure I don't have problems from the wiring to the coil packs - I got a brand new wiring that goes to the coil packs from that connector to the main wiring. And once that didn't fix it, then I went to check the angle cam shaft sensor and the rear cam shaft sensor. And only after that did the injectors cleaning and testing.

ok, if you look right behind the driver's side wheel onto the transmission almost where it connects to the engine this is what I have there - that's rear camshaft sensor

ok, I'm now home and can post compression test results. Cylinders from 1 to 6 are the following - #1 - 15, #2 - 13, #3 - 14, #4 - 14, #5 - 12.5, #6 - 12. Oh, and I forgot to mention that I did clean MAF before buying a new one. Will take a picture of where the rear cam shaft sensor is and will post soon.

I did compression test, forgot to list it in the original post. Didn't do a leakdown test though. Cooling system is holding pressure.

It sounds totally fine but when it jerks - you can almost feel the sound changing just for the jerking moment. Otherwise sound didn't change. And yes, I did compression test, forgot to mention that. I think sixth cylinder was the worst but not that far out from all the other ones. I have test results at home, will update the post once I get back home from work.

MAF was purchased from an automotive store as a direct replacement to part number that Skyline uses. I think I paid about $100 for the MAF, can't remember now. For the coilpacks - i bought them OEM, came in OEM Nissan packaging and though I didn't spend $600, it ended up around $500 simply because I bought them from United Arab Emirates warehouse and not from Japan warehouse. Same OEM in Japan were almost twice the price. So those are real ones. Injectors were cleaned by a professional injector cleaning place - $450, filter in injectors was replaced to high flow and o-rings were replaced to new ones.