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[new title] 77 280z w/ l28et regeneration


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Since you do have the full turbo engine and not just the P90a head on a non-turbo L28, you might not want to be putting in a higher lift  or longer duration cam. Bigger cams are not much of a help on forced induction engines. (at least not on this old L-series)

Go with more boost and other upgrades but leave the stock cam in there.

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The crank sprocket will have a dot stamped in it. Or it should, check the other side? Set engine to TDC and you can set the cam sprocket by counting the links up from the crank sprocket. I think it's 44 links. The L28 block is similar to the L20B block for height. The L20B came from the factory on the #2 hole. The missing V is a pain but you can start with #1 hole and by using a chain wedge to keep the tensioner in place, move the cam sprocket to the #2 hole and try it. Keep records of MPG and how well it performs. If there is any improvement run with it. 

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Guhhhhhh! just tried to put my head back on with fresh headbolts and one snapped during the second round of torquing.  What a fucking pain in the ass.  Guess I have to buy another overpriced bolt and pay for shipping again and try again.  I thought 2016 was over.

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Oh i've got turbo already.  Made myself a fuel rail today and just tried to avoid thinking about the bottom end for a day.  


Found out why my head torquing went haywire...my damn torque wrench seems to work fine a few times then refuses to 'click' at random and you have to reset it and then it will start working again.  Frustrating cause I thought it was a decent one.


I looked up at the crankshaft while turning it and can't figure out where that big hunk of metal came from.  My hopeful thinking is that its the result of a previous incident that was already addressed.  Can't spy any broken off bits while turning the crank and looking all over from the underside.  

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Okay, I got the car back together and running.  Dropped it off at a muffler shop today to have them sort out some new mounts.


I found that a PO had installed a wideband o2 sensor....but didn't actually wire it to anything.  Since the original wiring was still in there, I put in an OEM sensor and will hold onto the wideband in case I upgrade the ECU and stuff in the future.  The car seems to run much better with the o2 sensor actually sending some data.


Had to replace the alternator, it has an internal regulator so I thought I could take out the old reg that under the panel on the passenger side.  For some reason I couldn't get it to charge so I tried connecting those wires again and it seems to be charging correctly...but I thought this would mean two regulators in the system which is bad?  I thought the reg was a leftover bit from the pre-280zx motor swap but its still a struggle to figure out what bits of the wiring system are from the old vs new setup.


Also, now when I hit the throttle and then release it, the idle drops super low and sometimes recovers, other times it dies.  If it doesn't die it will come back up to a good idle.  I don't know if this is effected by the TPS setting, AFM settings or something about the edited vac system.  I am still try to research this area but I am also planning to drive it to a local mechanic who specializes in z cars for advice.

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now when I hit the throttle and then release it, the idle drops super low and sometimes recovers, other times it dies.  If it doesn't die it will come back up to a good idle.  I don't know if this is effected by the TPS setting, AFM settings or something about the edited vac system.  I am still try to research this area but I am also planning to drive it to a local mechanic who specializes in z cars for advice.

I wish I knew as well! Both my turbo swap and my stock OEM 280ZX turbo had that trouble.

Someone once told me that could be from low fuel pressure. Check for a small filter by the fuel pump... replace your pump... maybe put in new filters. Make sure they are injection type filters and not carb fuel filters.

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So did you just live with it Bleach?  Seems like if you're conscious of it its easy to blip the throttle a bit on the way down but it would be nice to have it working correctly.


I replaced the fuel filter but I don't know if its EFI specific.  I haven't tried watching the fuel pressure regulator as I rev and release, that might let me know if the pressure is really dropping.


If I get any good advice form the z car man, I will pass it along.

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Once I found the mystery debris in the oil pan, I really wanted to throw in the towel...and then later get an rb25det to swap in but I had already spent so much time and $ on parts for this motor that, I have to make it work for now.  Hoping this motor will be good for a while, at least until I can afford the $ for a different motor and the time to actually swap it.

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I put in one of the aeromotive FPRs with a vac line when i put in the fuel rail i made.  So I can see that the fuel pressure isn't dropping when I rev and release the throttle.


I am thinking it could have to do with the AFM adjustment, a vac leak somewhere or electrical connection.  The idle also sometimes hangs up at 2k when I release the throttle.  It will sit there for a second or two then drop.  When this happens I can see that the AFM arm sits at a spot before dropping down...Not sure if this causing the hang-up or just an effect.


 There are just a handful of janky areas from previous owners so its taking me a while to figure out what each component is supposed to looks like when adjusted correctly.

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I think the AFM arm is holding open due to the rpm of the engine. The air passing by is what keeps the AFM arm up. (that's its function)


My guess would be a vac line somewhere. I had modified some of the emissions lines on both turbo L28s, so I blamed myself.

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I made a possible breakthrough. I was trying to set the TPS again and was getting strange continuity readings so I took it off to take a look. The black plastic case was broken off a 1/4 of it so I could watch the mechanism inside.


Some of the plastic parts were worn so when the throttle opened, the pieces would only occasionally catch and move as they were supposed to. This led to it being stuck in one position or another, rather than responding to the throttle position.


Unfortunately these parts are hard to find in the z stores, had to cough up way too much $$ on the eBay. Hoping it's a leap forward though.

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Hey Cgraves, thanks, I think they are the same unit but the turbo only uses two wires rather than 3.  If i hadn't already bought the ebay one id throw you some $$ for yours!


Slowpoke, I still have the BOV, was going to remove it but wasn't sure what to plug it with yet.  Looks like a big hole, any idea what the threads are?

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Okay, got the new TPS in and it really helped with the idle.  Now the car doesn't turn off when rolling to a stop!  


The throttle response is still weird if you just stomp on the pedal.  Just bogs to nothing until you let off and let it slowly rev up.  Not sure if this is an AFM adjustment or what but at least its drivable.


I ordered some of the Konig rewind wheels.  I was trying to decide between 15 or 16" for a while but since i'm not going for a real performance oriented setup, I decided to go with 15" and will use a little taller tire to nicely fill the wheel well and provide a little more comfort.  I figure these old suspensions weren't designed for the real short sidewalls that are popular on modern cars.

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I would keep checking for vac leaks, I has about a hundred when i did my swap. Did the ol cigar smoke test, helped me find a couple of them. For the pop off valve, i just took it off and brought it with me to he hardware store. BTW the pop off vale and the blow off valve are different parts. L28et's have both. I think you have the correct part though. The pop off valve is located on top of the intake manifold toward the firewall.

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One spot that I had vacuum leaks on was at the injectors. Right around the holders themselves. Had to add gasket dressing to the rubber rings themselves to fix it.

I also was noticing boost leak and it was at the injectors of course. Took me forever to find that one!

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  • 2 months later...

hey its been a while, I have been away from home on a job for the last couple months.  Here is my 280z as it wis with its new wheels and louvers.  I also put in new lower rear control arms because I found that the driver side had soem crazy toe-in and the stock arms had no adjustment.


It looks like I am going to be off of work for about a month so I am going to go on a roadtrip in this thing.  Its definitely got some weakpoints but I will just see how far I get and what I can fix myself along the way.


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