Vh swap with optional knock installed--HELP PLEASE

[rotorimp]

Well this was supposed to be a straight swap. JDM VH swapped into a 90 Q45. Started up the motor--ran great, ran smooth, no codes. changed the oil (clean no chunks of anything) put in 10/30 synthetic. Took it for a test drive. This car had been setting for about TWO years so while on the test drive I put about 10 gallons of fresh gas--(car had about 1/2 tank of varnish) About the time I arrived back home two problems have developed. I have a miss on three of the even cylinders 4,6 and 8 (I found this by using the E-bay conzult/power balance test) also the biggest problem is I have what sounds like ROD KNOCK.. If I let the motor cool down and fire it up the knock is not there--about the time it gets warm and goes into closed loop is when the knock starts. if I rev the motor it goes away--could this be a chain tensioner? and will bad gas foul the plugs that quick???? and cause my miss? the knock is coming from the right bank (odd cylinders) around number one. any help would ba appreciated--the injectors were all just cleaned and serviced.

[elwesso]

Jason I sent you an email to your profile email account, Greg gave me your digits and i'll probably be hitting you up tomorrow.

[T45]

Did you check the plugs when you had the engine out? My right bank's plug cavaties were full of water so I think that's what was causing the miss in my engine.

[rotorimp]

I had all the plugs out--I have a bore light that I inspected all the bores. I bead blasted all the plugs/ gapped them before I put them (NGK's)back in. It ran great for about 3+ hours. the miss only started happening after the test drive--I leaning towards bad gas fouling the plugs at this point. I will take the plugs back out today after work. The mystery ping/knock is still there--only after it runs for a while and it is very intermittent--almost sounds like a solenoid actuating.

[SSDwellah]

Could this be a problem with the VVT? I know on some other Nissans of this era with VVT (e.g. Maxima SE with VE30DE, 300ZX with VG30DE) it sounds like a tapping that might be confused with detonation. Also what about the chain guides, did you replace them? This is potentially a very serious defect.

[T45]

I know this may sound stupid but do you have 93 octane in that tank?

[rotorimp]

This poor car sat neglected for 2+ years so the gas smells/is pretty much like varnish. I did put about 10 gallons of 89 in when i went for the test drive. I'm fairly sure that the gas fouled the plugs--i'll know today.

Since the VVT is pretty much a solenoid I unplugged it to see if it would stop--which it didn't and unless one of the springs was broken letting the gear slide back and forth I have ruled it out--unless I'm missing something?

The owner did not want to spring for new chain guides--so that is a definite possibility. I'm going to drain the oil and look for chunks of chain guide. If I was to try and describe exactly where the knock was coming from it would be right under the VVT solenoid or on top of the number 1 cylinder in the cam region.

[SSDwellah]

I have a 240SX and I remember when I heard a terrible horrible rattling and tapping once. The early KA24DE's had an extra chain guard (not really a guide) at the top of the motor that was not only completely unnecessary, but would often break off causing a chain grinding or rattling sound that was really noticeable. I replaced my valve cover gasket around the same time I heard that noise only to see the guard dangerously just resting on the chain. Those chains can apparently take a beating but damn are they noise when things go wrong.

Everything is fine now, hopefully your problem is as easily remedied but the VH has problems with the actual chain guides and tensioner so that is more serious and can cause big problems. If its possible to keep the car off the road, then take a look at those chain guides.

[rotorimp]

I changed the oil and no chunks of any black material came out.

On a good note--I was looking into my missing cylinder problem and as it turns out the number 6 injector decided to go tits up-no Ohm's completely open--crap--so I pulled the plenum off and replaced the injector (under 2 hours--a new personal best!! ) not that I'm trying to get good at it or any thing. fired it up and smoooth as a baby's @ss. while doing this swap I had sent the injectors to be cleaned and balanced JUST to avoid a problem like this At any rate the motor is running great!! and the knock has not returned????????? I do not think that the injector could have made this noise--so I am a little worried that the knock will come back.

[SSDwellah]

Sticking injectors make a kind of clicking noise too. Louder than usual

[T45]

Any type of misfire can cause a knocking sound. It's detonating. Be sure to run premium fuel as these engines are high compression and if you run 89 you risk more detonation, which could lead to another engine swap. 89 isn't good enough for a 10:1+ CR.

[rotorimp]

89 is the all they had at the gas station when I went--91 is premium here in AZ. Since I changed the injector it runs great (I'm not sure how because there is a bunch of crappy gas in the tank) I did add some fuel stabilizer. I will be sure to let the owner know about the fuel. the Q45 is one of the more difficult swaps I have done. The last Q45 I took it out the top of the engine bay and this one I dropped out the bottom while still attached to the cross member---WOW So much easier probably saved 10+ hours doing it that way mostly because I left the ALT,AC comp and power steering pump still attached. I'm going for another test drive today and then hopefully close the book on this one--chock it up to a bad injector?

[rotorimp]

Sure did not sound like detonation--very mechanical. the bad injector was #6 and the knock was distinctly over #1???

[Raxephon]

I changed the oil and no chunks of any black material came out.

Thats because the pieces of chain guide are stuck in the oil pick up tube and in the baffles of the oil pan if the guide has gone bad.

Sure did not sound like detonation--very mechanical. the bad injector was #6 and the knock was distinctly over #1???

Are you sure the left bank chain tensioner wasn't bottoming out?

[T45]

True, the misfiring could have been causing chain slap. If it runs and sounds good then it's probably good. Roll with it.

[rotorimp]

Since the new injector--No--sound has returned. I took a brand new clear plastic pan and drained the oil into it--it was perfectly clean--nothing shiny or chain guide in nature, I have had it running/driving for about an hour since the injector replacement--just listening for the noise. I am afraid to get on it or rev it too much with the crappy gas. I can not really correlate the sound and the injector but--that has to be it??