Zazz93

iTrader: (2)

I just buttoned everything up after pulling the block out to replace the bearings and pistons and rods. Upon the first startup the the motor came back to life quickly and fired up with a knock (guessing the vavle train's low oil) but quickly turned smoth and quiet. Then about 5-9 seconds after startup some happened and it began to misfire. I put a reader on the car and it read the following.

Diagnostic Trouble Code Information MIL DTC

P0300 Multiple Misfire Detected

P0300 Multiple Misfire Detected

P0021 Intake Camshaft Position Timing - Over-Advanced (Bank 2)


Short Term Fuel Trim - Bank 1 1.56 %
Long Term Fuel Trim - Bank 1 0.00 %
Short Term Fuel Trim - Bank 2 25.00 %
Long Term Fuel Trim - Bank 2 0.00 %
Engine RPM 1,337.50 rpm
Vehicle Speed Sensor 0.00 mph
Absolute Throttle Position 2.75 %


This suggests to me that the chain is no longer where I set it. This makes sense because I thought the tensioner was a little too loose.

If you think this is the cause what suggestions do you have when I go back in to set the timing again?

Zazz93

iTrader: (2)

After try #2, I've got rid of the P0021 but I still think there is a timing issue. It idles Ok (just barely) and there is still hesitation when I get on the throttle (even unloaded). I also noticed that one cat is burning a lot of fuel (getting glowing hot). So now, after trying to correct the timing, its still out (or that's my assuption) and I've probably burned up a cat (if not both). As a last ditch effort I'm going to check to plugs and see if one or two cylnders show the richness and trade them out and check the packs.

If you have any suggestions fee free to chime in.

Zazz93

iTrader: (2)

Ok guys I need help here.

After three weeks of playing with it, one trip to an independant Nissan service shop, a read from Consul and code scanner, and three looks into the front cover I'm not finding a problem. The service shop said nothing came up on Consul beside the P0300 and Bank 2 fuel trims +25%. I've checked the compression twice and they all measure from 210-215 psi. I've narrowed it down to two cylinders giving me a problem (Bank 2, cylinders 4 and 6). They are recieving +25% fuel trim adjustments for the bank. The injectors are very wet with fuel when I remove them and these are the only two that are wet. All the other come out dry. I've tested the coils in different cylinders and the problem persists. I've move the fuel injectors around as well but the same two cylinders show the problem. The two cylinders with the issue are dumping fuel passed the plugs (which come out the motor completely wet as well) and into the cat. The timing is not showing a problem now and Consul testing shows 15/14 degrees, and the cam positions and crank position match up with the proper placement.

I'm guessing that this has to be in the harness. BTW, I've also tested the coils on each of the bank's connectors and they all firing at the desired range (per service manual) of 13-17mm. It almost seems as though I crossed the fuel injectors with each other but I can't see them fitting in any other way. The only sensor I have not replaced is the AF sensor in the bad bank. I will be doing that shortly but currently I'm open to any suggestions...

rcdash

iTrader: (18)

Coil pack mix up?

Zazz93

iTrader: (2)

Not sure I get you... Do you mean its possible they have been mixed up with a different model? This would be highly unlikely because the car has run with them. If you mean to suggest that each coil has a specified location this would be new to me. I've been told they are identical.

Z_ology

iTrader: (44)

It sounds like you are on the right track with everything that you have checked...but this seems like a timing issue to me. Your short term fuel trim is very high. So something is telling the ecu that bank 2 is lean and the ecu is attempting to compensate. When you double checked your timing marks, did you check all of the cams?

Zazz93

iTrader: (2)

I only checked from the Cam position sensors, I used the JWT service aid for their Flywheels. I guess they have a couple of flywheels that can be put on in the wrong position and advance or retard the timing substanially. Luckily mine is not one of those that can't be put on incorrectly, within reason of course.

http://www.jimwolftechnology.com/wol...tion_check.pdf

Zazz93

iTrader: (2)

I'm going to be pulling the motor out for the second time. I'll check the timing once again. BTW do you have any tips on timing it? I can't say its hard to do but if it is out of whack its tough to double check because of the lack of fixed points.

Z_ology

iTrader: (44)

Take a look through the EM section of the service manual in the timing chain area. It has several detailed pics that will tell you exactly where all the timing marks go. The timing is straight forward. And there are plenty of marks on every part.

Zazz93

iTrader: (2)

Yeah I get the service manual's explaination and it seems easy in my mind. But the lack of fixed points such a mark on the head or timing chain case seems to be where I'm left wanting. Each time I've done the timing it has seemed just fine, where the gear's marks line up with the painted links, and gold links but it continues to run like its mis-timed. If it really is mis-timed how does one cylnder fire on that bank where the two others don't even come close to clearing out the combustion chamber correctly? #2 fires but 4 & 6 stay wet. If the whole bank were missing it would make more sense to me.

Z_ology

iTrader: (44)

It is possible to have a cam miss timed by a tooth or two and have missfires on some or all of the cylinders for that cam. It just depends on the valve timing and cam lobe orientation. If you want to tell for sure before tearing the motor down, do a cylinder leak down test. With each cylinder at TDC #4 and 6 should show leakdown that may not show on the compression test.

Zazz93

iTrader: (2)

Thanks,

I haven't tried a leak down test yet. I'll give it a shot.

Zazz93

iTrader: (2)

Gotta pick up a Leak Down Tester, but I noticed last night that the two cylnders that I'm getting a problem from don't hold all of their compression at TDC. Very small, but noticable when I literally blow through the spark plug tubes. When I get some real pressure through the cylinders I'll know for sure though.

Zazz93

iTrader: (2)

Hey Z ology,

The Leak down test yielded some weird results... the two problem cylinders have leaks. One in the intake and the other in the exhuast. That's not the odd part, the leaks occur when the cams are not touching the followers and if I retard the cam shaft alittle it seals up. I'm guessing theres a bent valve in each cylinder but its odd it can produce high compression figures and leak at TDC at the same time.

Z_ology

iTrader: (44)

Well good news you are close to finding your problem...bad news you have to take stuff back apart to find the problem. My guess is that your cam timing (the small chain) is off on bank 2. I would guess that you are a tooth or two off. That is most likely not enough to bend a valve. If you were off several teeth, the motor would likely not run and your compression test would be off.

So double check your timing first before you take a head back off!

Zazz93

iTrader: (2)

I took the head of the offending cylinders off today and found no faults. I put them back on and did a quick leak test (cold) and didn't hear the air escaping through the intake and exhaust. However, before removing all of the front case's components I noticed the timing was yet again off. I'm having a problem with slack offsetting the secondary from the primary.

binder

iTrader: (8)

do you mean when the tensioner is engaged the chain tightens and then moves the timing? I battle that quite often on the race bike motors. What i do is set one cam where i know it's dead on then set the other as close as possible. put the tensioner on then recheck everything to see if it's moved. If it has i take the tensioner off and adjust the cam that has moved 1 tooth at a time on the chain and then recheck. It sucks doing it this way but it works.

rrmedicx

iTrader: (54)

Just putting in my .02 to make sure you are 100% on point. You said you checked the timing marks. Not to get ridiculous but did you align the circle marks on the pass side cam gear head faces and the oval marks on the driver side cam gear heads? Is it possible you aligned the circles on both banks because that would be your timing error. It has been done before. I don't want to assume anything. You seem to have timing related issues so I thought I would throw that in. Good Luck with your repair.

Zazz93

iTrader: (2)

Thanks for the heads up rrmedicx, I think I've got the circles and ovals in the right places. My issue is with the number 1 bank moving off the cam lobe and offsetting things. If you remember the right side of te engine rests on the lobe causing the cam to want to move one way or the other. The main chain is where it should be but the secodaries are a little retarded. This leads me to believe I'm missing some movement on the secondary gears and chain. It kinda sucks there are no real line up marks on the head or case becase its hard to eyeball the marks after you spin it around and get the slack out. I think I'll mark up the case where I think it should be and make sure it all stays in place.

rrmedicx

iTrader: (54)

Oh Yeah. You will probably just need another set of hands to hold the cams from spinning with an adjustable wrench (or equivalent) while you set the individual cam chains. Not exactly a 1 man job. I know what you're talking about. Then you can line up the markings to the full timing chain. Once everything is lubed up its all slippery and difficult to keep aligned. Gotcha!
Good Luck.