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Power is lost. Turbo engine, Need help


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To start off I would first like to say my engine (l28et in 280z) runs pretty well. It starts up perfectly everyday, Idles perfectly, drives great for Normal driving. I trust it to start and run more than my daily driver. But my car just does not have the power it should, It is just as fast as a NA 280z, no faster. I cant figure out why my car isnt pulling like it used to on my previous turbo swap.

 

Im running the 300zxt ecu

 

If I rev my engine in neutral to high rpm's, a bunch of smoke will come out of the exhaust, it smells burnt. I cant say if its running rich or burning oil. and honestly the smoke isnt black or blue, ITS WHITE as hell! but I am %100 positive its not coolant, and it doesn't smell sweet. When looking at my plugs I also cant tell if it is carbon/unburnt fuel on them or oil. If I were to guess, I would say unburnt fuel but when i take my spark-plugs out, the threads on the cylinder head have like a puddle of dark fluid in them and the threads on the plugs also are wet with what looks like oil( The valve cover gasket is NOT leaking at all). But the tips of the plugs are tan and show no signs of oil on them.

 

Also Another reason I believe it could be burning oil is my oil levels drop rather quickly, but its hard to say because my oil pan does leaks pretty bad(have another one im going to be putting in). I have done a PROPER compression test on the motor and my numbers were 147 EVEN! across all 6. The Head was rebuilt( valve job, resurfaced, and valve seals replaced) no more than 1,000 miles ago. My short block had a supposed 80,000 miles on it and it looked to be in great shape, walls were perfect, no metal shavings in the pan. I have literally checked everything I can think of and am out of ideas

 

I have looked at everything and cant find any problems anywhere. Things Ive done/checked

All new NGK's

Plug Wires

cap and rotor

new CHTS

new o2

Tried a few different ecu's

tried several Maf's

new pvc

all injectors are clicking fine

checked fuel pressure

went overkill on all grounds

new alternator

switched out fusible links with fuse box

checked everywhere for vacuum leaks/boost leaks relighted nuts and bolts everywhere

boost gauge reads 7 psi

tried three different coils/power transistors

timing is set to 24

using 91 octane

This is all I can think of right now but im sure theres more.

 

So what could be causing my car to not have all the power it should on boost, Its hitting 7psi but the power just inst there.

I would like to figure out what the problem is before I pull my engine out to change the clutch and oil pan.

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Woah woah woah, are you sayin gyou're going to pull the whole engine out to change the oil pan and clutch?

 

If so, I've changed my oil pan gasket three times and I've done the clutch and completely removed the front crossmember and suspension all while the engine was in the car. I wouldn't recommend removing it.

 

As for the power, check your turbo piping and make sure there are no boost leaks. Also, check all vacuum ports and obvious things like that. Its a very good sign that your plugs are golden brown.

 

Oil level isn't going to effect your performance, it may seize your engine to not have enough oil/none at all, but wouldn't dog your engine.

 

Also, check to make sure your waste gate isn't stuck open, I wouldn't be surprised if that was the case.

 

Good luck!

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Woah woah woah, are you sayin gyou're going to pull the whole engine out to change the oil pan and clutch?

 

If so, I've changed my oil pan gasket three times and I've done the clutch and completely removed the front crossmember and suspension all while the engine was in the car. I wouldn't recommend removing it.

 

As for the power, check your turbo piping and make sure there are no boost leaks. Also, check all vacuum ports and obvious things like that. Its a very good sign that your plugs are golden brown.

 

Oil level isn't going to effect your performance, it may seize your engine to not have enough oil/none at all, but wouldn't dog your engine.

 

Also, check to make sure your waste gate isn't stuck open, I wouldn't be surprised if that was the case.

 

Good luck!

 

I to have changed the oil pan and the clutch with the engine in the car(did A clutch a couple weeks ago under a car), but i prefer to just take the engine out. It takes me about the same amount of time, and I hate being underneath the car doing both of those tasks. You mentioned removing the cross member, Did you remove it to change the oil pan?

 

Like I said, My boost gauge Is reading 7psi and boost comes on just a little after 3,000 so I dont think its the waste-gate. Also, forgot to mention I have tried using a different turbo.

Edited by stravi757
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Just curious, what size is your exhaust? If your running a stock exhaust you might have issues with it running like it should. Try driving it with the exhaust unbolted from the down pipe and see if you feel a big difference. Its a shot in the dark but ya never know... B)

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Just curious, what size is your exhaust? If your running a stock exhaust you might have issues with it running like it should. Try driving it with the exhaust unbolted from the down pipe and see if you feel a big difference. Its a shot in the dark but ya never know... B)

 

lol, Sorry forgot to mention that , I took off my exhaust and just had the MSA down pipe on, no difference really.

Edited by stravi757
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The white smoke is probably due to bad seals in the turbo. Oil that burns in the exhaust will be white, not blue. Just because you can get 7psi of boost doesn't mean the turbo is in good shape.

 

Nigel

'73 240ZT

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The white smoke is probably due to bad seals in the turbo. Oil that burns in the exhaust will be white, not blue. Just because you can get 7psi of boost doesn't mean the turbo is in good shape.

 

Nigel

'73 240ZT

 

That makes sense. Although I did have this white smoke problem with my other turbo as well, but I guess I cant really vouch for either turbo. So I guess rebuild this turbo(wont hurt to do it either way), but Even if the seals are bad would this contribute to my major powerloss?

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Hey , you mentioned you had your head resurfaced and all that great stuff. Was this before or after you it was in the donor car? Cause one or two teeth off the chain you will get your valves opening a bit to early. Still giving you good compression but not optimal running. I had recently done a HG cause I blew mine from boost creep and thats what mine is doing.

Edited by softopz
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Hey , you mentioned you had your head resurfaced and all that great stuff. Was this before or after you it was in the donor car? Cause one or two teeth off the chain you will get your valves opening a bit to early. Still giving you good compression but not optimal running. I had recently done a HG cause I blew mine from boost creep and thats what mine is doing.

I had the head resurfaced before I put the block together. I am pretty sure I put the chain on correctly also. And I checked my brake fluid, its all there :)

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  • 4 weeks later...

Hey , you mentioned you had your head resurfaced and all that great stuff. Was this before or after you it was in the donor car? Cause one or two teeth off the chain you will get your valves opening a bit to early. Still giving you good compression but not optimal running. I had recently done a HG cause I blew mine from boost creep and thats what mine is doing.

 

So I finally got my valve cover off, turned out for whatever reason when I put my engine together I put the cam sprocket on #2 (shouldn't have since my chain kit is new) which advanced my cam timing 4 degrees. I put it back to number 1 on the sprocket and now my cam timing is good.

 

This would explain a powerless on boost, but would it be as a significant powerless as I describe? I took the car out for a really quick spin, but didn't really get to test it very much as my headlights are out and it was getting dark. but I did a couple short pulls and I did notice a power difference in boost but it still felt a little slow and had a miss around 4,700 rpm's. But I do need to change those plugs, they are pretty fouled.

 

What I would like to know is how big affect would the cam timing being advanced 4 degrees have on a turbo engine under boost? enough to describe the problem im having?

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  • 3 weeks later...

So I thought I would let everyone know I finally found out what the problem was with my major power loss.

 

I remembered that I had an extra actuator for the waste-gate, so I thought I would swap it out to see if it would fix anything. Upon removal of the actuator already attached to the turbo, I find that the vacuum line going to the actuator from the turbo was all cracked. When I took it off it broke into pieces..... I put a new line on and my car PULLS again. Such a STUPID problem. It was so simple and I couldn't find it this whole time. Im happy that the problem is fixed but pissed off at the same time.

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