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So, after fixing all the things for the last couple of years on my FD, I finally got the engine bay put together enough to fire the motor up. Nothing exploded or failed catastrophically, so I'll take that as a win.
I did notice when I ran some premix oil through one of the manifold vacuum lines (to lubricate things a bit while my omp works the air out of the lines), that smoke came out of the exhaust (expected), but also from under the air intake pipes (not expected).
I wasn't able to pinpoint the exact area the smoke was coming from under the hood today, but it does seem to be from the turbo/downpipe heat shielded area. I am going to take the DP heat shield off when the engine cools down and see if the culprit becomes more obvious.
My reasoning currently is oil goes in engine, engine makes triangle fire, smoke comes out the exhaust. So if I am seeing smoke under the hood, it must be from the downpipe/turbo connection? Does that sound correct, or are there other points where the exhaust gases might be escaping?
I had thought maybe through one of the y-pipe connections, but I was able to take a pretty close look at those, and they didn't seem to be the source.
Attached picture shows the general area that the smoke was rising from (smoke only comes out when I run oil/cleaner through the motor, so I don't think its anything serious)
Also, if it matters I have a HKS downpipe + JDM heat shield. Put in a new OEM gasket, and used the copper exhaust nuts to reinstall.
Took the heat shield off the downpipe, and it really does not seem to be the source of the smoke either. I can't pinpoint an exact location, but it seems to be coming from under the turbocharger heat shield right below the stock 02 sensor location.
I can't think of anything I touched on the car that could funnel smoke through there, but I know there are some gaskets between the turbochargers and the engine, as well as the LIM gasket kinda in that area. Might be that there was always a small leak there that I did not catch before when I bought the car.
You could have an exhaust leak but you could maybe have bad turbos leaking oil onto the exhaust. Oil an oil leak somewhere else leaking onto the exhaust. I say this because i have an exhaust leak and you normally can hear it. Sounds like valves tapping lol. Do you see smoke from your rear muffler too? Could be just oil burning on the exhaust.
You could have an exhaust leak but you could maybe have bad turbos leaking oil onto the exhaust. Oil an oil leak somewhere else leaking onto the exhaust. I say this because i have an exhaust leak and you normally can hear it. Sounds like valves tapping lol. Do you see smoke from your rear muffler too? Could be just oil burning on the exhaust.
Yeah, there was smoke from the rear muffler. The typical manifold cleaner/oil smoke screen. The only thing I'm trying to track down is why some of that smoke was also blowing from somewhere in the engine bay.
Took a pretty good look at the downpipe/turbo connection and it didn't seem to be coming from there, I also don't hear any of the typical exhaust leak noise (I tried using a makeshift stethoscope to listen around for it). The furthest I could track the smoke was the turbo heatshield right by the o2 sensor, but it seems to be flowing there from somewhere else behind the heat shield (not from the o2 sensor or DP connection)
Could be the turbo manifold to engine gasket that’s leaking. Did you replace that gasket with a new gasket?
I don't think so. You'd have to pull the turbos to access that right? I never removed my turbos. I'm also leaning that direction since it doesn't seem to be coming from anywhere easily visible. Bummer.
I don't think so. You'd have to pull the turbos to access that right? I never removed my turbos. I'm also leaning that direction since it doesn't seem to be coming from anywhere easily visible. Bummer.
I had that issue with my factory twins and I just couldn’t find the leak. So when I finally upgraded to Bnr’s I replace just about every gasket including that mani to engine gasket (expensive by the way) and haven’t seen any smoke since then. Well I did replace those other expensive *** gaskets which are twins to manifold and they are even more expensive, so I believe it’s any of those expensive SOB’S.
i had that issue with my factory twins and I just couldn’t find the leak. So when I finally upgraded to Bnr’s I replace just about every gasket including that mani to engine gasket (expensive by the way) and haven’t seen any smoke since then. Well I did replace those other expensive *** gaskets which are twins to manifold and they are even more expensive, so I believe it’s any of those expensive SOB’S.
Makes sense. That sounds similar to what I am seeing.
I really struggled with whether or not to pull the engine and/or turbos while I had everything else out of the car, but I decided not to since the engine had good compression numbers, no shaft play on the turbos, and didn't show any serious issues while I drove the car home from across the state. I guess this leak was minor enough to be masked by all the other issues the car had on its sequential system.
Sounds like something to just keep an eye on, and wait until I can upgrade or the rest of the engine needs to be serviced. If this ends up being the only issue left on the car, I think I can live with that for now. It seems like once the engine gets warm it kind of closes off anyways for now.
Does the smoke consistently happen? I when I rebuilt my engine and started it for the first time I also saw smoke rising from the turbo area, but it never happened again. Best I can figure is that oil worked it's way into the old turbos while they were sitting for 6+ months and it burned off when I started them up again
Does the smoke consistently happen? I when I rebuilt my engine and started it for the first time I also saw smoke rising from the turbo area, but it never happened again. Best I can figure is that oil worked it's way into the old turbos while they were sitting for 6+ months and it burned off when I started them up again
It doesn't happen during normal idle, just a puff on startup sometimes. It does happen consistently whenever something is added to the intake that would also cause smoke out of the muffler (oil, intake cleaner, etc). This is how I originally noticed it.
So I guess I can consistently make it happen, but it doesn't happen non stop all the time on its own (at least that I have seen so far)
I couldn't leave this alone, it kept bugging me. So I hooked up a boost leak tester and started trouble shooting the system. The first few minor leaks were easy, couplers needed tightening, the crossover gasket on the efini y pipe was no good, etc. Fixed all those up pretty easy.
The doozy is that the front y-pipe -> turbo inlet connection leaks like crazy at about 5 psi. Based on the proximity, I'm fairly confident this was the smoke source.
I haven't been able to solve this. I checked the torque on the two nuts, they were fine. Tried loosening the pipe and re-torquing, and it still leaked.
I don't have any new gaskets on hand, so I swapped one in from a non-leaking location and re-torqued the pipe. Still leaking, perhaps worse now.
I've ordered 4 new gaskets so I'll have some spares when I go at this again next weekend, but I'm really questioning if its a gasket issue. Has anyone had trouble sealing the front y pipe/turbo connection? I need to review the install/removal instructions that are already published, but I've read them before and I don't think there is any secret step I am missing in the process.
Any help is appreciated, otherwise I'll keep gnawing on it until I think of something else. Might have to completely remove the y pipe and check that mating surface with a level.
Was so close to having the engine put back together.
Fair enough, but I don't think the location is a coincidence. Maybe the air escaping from the leak was stirring up the smoke coming from another spot and blowing it around.
I think as I move through with the leak tester if it's an issue with any of the intake or exhaust gaskets it will show up as I tighten the system up.
I've been continuing to go through the system and repair minor leaks here and there. Once I was able to pressurize to ~8 psi I started hearing another leak from the turbo/downpipe area. First one was the O2 sensor not being torqued quite to spec, easy fix.
Second one appeared to be from the downpipe <-> turbo gasket at first based on soapy water bubbles. I pulled the downpipe off and inspected everything, everything looked fine.
Scratched my head and decided to plug the downpipe connection on the turbos with one of those inflatable test plugs, and repressurized the system. The air isn't coming from the downpipe hole, its come from all around it through the turbo assembly. Its a lot more obvious with the DP out of the way and the extra visibility behind the turbo heat shields.
This + knowing it was exhaust gas, I can only come to the same conclusion that existanzrx7did. Gotta be a problem with one of the exhaust manifold gaskets, or something internal to the turbos (if that's even possible).
Should have pulled the engine when I had the chance. Oh well, lesson learned. I'll address it whenever the motor the car came with kicks the can.
Pulled my turbos and exhaust manifold, and tested the system as best I could (need to find some smaller test plugs for the bare exhaust ports, mine don't seal perfectly).
System pressurizes much faster, but still topping off around 8 psi. Takes much longer to depressurize as well. Can't find any leaks besides from my ill fitted plugs, but did notice that the idle control valve starts buzzing above 7 psi (which is weird, since I have the battery disconnected, but whatever), so the 8PSI might just be the upper limit of what my tiny compressor can do.
I'll test again next weekend with better plugs, but it seems like the leak was definitely from either the twins themselves, or one of the exhaust manifold connections.
Interesting observation that almost all of the studs came out with the bolts, but extremely easily. 5/6 turbo stud-bolts were barely tighter than hand tight. I was taking them off with my little 1/4th ratchet.
Exhaust manifold stud-bolts were a little tighter, but not much. Seems like the previous install with these twins wasn't great.
I'll be replacing all the gaskets/studs/nuts, and putting in a different set of turbos (hoping to find a used 99 spec set, but might just bight the bullet and get BNRs). My twins have a fair amount of cracking, and I'm suspicious of their internal seals anyways.
04-07-19, 02:10 PM
