Quote:
Originally Posted by p00t
There is a lot going on here so I may have missed something...
Verified timing chain is on there correct? I know you took the head off but you have two chains to deal with. Low vac on stock cams is often because one of the chains is off a tooth.
Have you tried disconnecting the MAF just to see how it runs? You have to start it twice without cycling the key to off with the MAF unplugged. I am not sure if there are any tight bends in the piping before/after the MAF (which is going to F-you).
If all that checks out look at your tune. Specifically the balance between latency and K value. What are you using? For idle that is lean keep increasing the latency. I don't care that you think 1ms of latency or what you have is too much, if it is lean keep increasing!
Once that is idling in the neighborhood of 13-14AFR then work on your K value. and keep going back and forth until you are happy. You will likely have to deal with a richer idle so that you are good in cruise and boost. Stock injectors are very linear in how they behave, as you go bigger the low pulsewidth stuff is just shitty.
Also before you change anything else in the tune TURN OFF O2 FEEDBACK. It has never worked right for me with bigger injectors.
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Timing looks good to me but now im second guessing myself looking at other pictures. I made sure to lock up my lower timing when I sent out my head for new valves. When I got it back did upper timing and basic head stuff all over again and car ran the exact same way.
The low vac is gone after messing with tps/throttle plate/iacv it now idles with good vac at 20ish but super lean like before. I tried disconnecting the maf and it instantly richens up. Swapped in two good know z32 maf and my piping is solid. Ran perfect when I was stock motor for 3k miles daily driving.
Tune wise I've cracked latency to 1200ms and no change in idle afrs and when holding revs it leans out still. I tried messing with k value and gone higher than the stock value which in theory should be dumping 3x as much fuel with my 1000cc if the value is the same as the 270cc. Still lean on idle and holding revs, in the tune as well i've turned off o2 feedback as well so thats all good.
Going to try revist timing. To me it looks fine but could be off a tooth on the lower because other pictures the exhaust exhaust lobe thats pointed up in cylinder 3 sits straight up while mine is a smidge to the left. The yellow bottom link is at the lowest point while in mine its a little bit to the right of the sprocket.
