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Discussion Starter · #1 ·
I need help from the gurus here. My car is a 93 GS300 with Aristo automatic 2jzgte. About 5000 miles on a fresh rebuild.. bearings, rings, seals.. everything new. USDM 6 speed cams, stock JDM fuel injectors, 255 walbro. Twin K26 turbos, never been boosted past 16psi (no BCC yet). My car has a smoking problem, and the patch won't cure this one.

When I built the turbo system, my front turbo was already starting to go.. smoked on my last motor.. an sr20det. I built the turbo system with it anyway and endured the smoke.. knowing where it came from. It only recently starting to lag a bit more boosting and I scored another new rebuilt K26 for a great price and installed it 2 days ago. The car is still smoking..almost as bad as before. I thought it was maybe the turbos getting too much oil.. -3AN feed into each, with -12AN return (teed into one into the oil pan factory fitting) I made inline restrictors and put into the feed lines.. now they are maybe -1AN size on the inlet to the turbo fitting. Still smokes.

There is a lot of fuel smell to the smoke as well, but it is grayish blue. not black. So, I looked at the fuel system. Sard FPR, running 35psi rail pressure. Okay there, but then I thought of something. I have the stock fpr still on the rail, the return line off that goes to the Sard fpr input and my gauge is on the body of the Sard. I was wondering if maybe I was getting the stock pressure at the rail, in addition to the 35psi that the guage on the Sard is reading. the car is also hard to start in the morning or when the engine is cold. I have to press the gas pedal to the floor to get it to catch, and then the idle is lumpy for a good few minutes until the car warms up. Earlier today I eliminated the Sard fpr from the equasion and I'm running just the stock fpr now. Havent had the car cold enough to see if this helps the start at all yet. Still smoking though.

I have a greddy catch can on the valvecover breather, and one going to the intake, both -10AN. Not an excessive amount of blowby oil at all.

My EGT guage is mounted just after the exhaust housing on my back turbo right now.....maybe 2" from the outlet. Cruising around town I'm seeing MAYBE 500*F. At idle the gauge is bottomed out.. lowest it reads is just south of 400*F. This is also when I'm seeing a lot of smoke at stoplights. Idle is somewhat smooth at around 600rpm or less. It may sound like it has a miss, but it's hard to tell because I might have some sound cancellation on my custom made dual exhaust. The highest EGT I have seen is still less than 800*F.

That is all I can think of at the moment to give you clues. I'm open to any and all suggestions.. personal experiences..help of any kind. I'm desperate to get his smoking issue done and over with b/c i got a ticket a few weeks ago for it. I have til the 26th of june to resolve it to have the car looked at, other wise I'll have to pay the 148.00 ticket.

Sorry this is so long.. any ideas? I'll try anything.
 

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Discussion Starter · #2 ·
okay some more notes. New plugs in there for about 1000 miles now, NGK 6097s, gapped at .032". Fuel filter has about 10k on it I'd guess.
 

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Alpine Hardtopper
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You definitely need to determing if the smoke is from oil consumption or from too much fuel. Usually if it's too much fuel the you'll have a very sooty/black smoke, and everything the exhaust touches will be black too. Have you pulled your sparkplugs to see what they look like?

Since you say it's greyish/blue, I'd be more likely to think it's still oil. Have you pulled any piping between the turbo outlet and the throttle? If so, is there any oil in there? Also, if your last turbo leaked a ton of oil in to the IC and piping that wasn't cleaned out, you could still be burning that off. It could also be leaking out the turbo to the exhaust directly, though that's much less common of a failure.

The other thing it could be is a very bad leak in the valve stem seals. If that were the case, the intake would be clean, but the combustion chamber and exhaust manifold would be oily.

Do a little detective work as to where there is oil in your system (intake, exhaust manifold, or just exhaust) and let us know what you find.
 

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Discussion Starter · #4 ·
I pulled the exh manifold off the other day when I installed the new front turbo. The head ports were not oily at all, just black carbon.. dry and sooty.

My exhaust tips are oily as well. When I first built the turbo system, I built 2 complete 2.5" dp/exhausts.. one from each turbo, so i could verify the cause of the smoking. It was only from one pipe. Satisfied, I went ahead and crossed the exhaust back into one using a 3.5" borla inline muffler and crossed it back out to duals at the rear. Of course both tips smoke now though b/c of that.

My plugs were clean when I pulled them a few weeks ago.. pulled out the BKR6e-11s (gapped to .028") to insdtall the 6097s. Nice ash gray on the plug. New coil pack clips. What is the resistance spec for the coil packs? I could test them..maybe not enough spark?

I removed the intercooler and all piping the other day to pull out my AC condensor and let the fmic stand on end for a few hours.. thinking there was oil trapped in it. Nothing. My one charge pipe from the known bad turbo had some oil residue, but the other was clean. (I have 2 hot charge pipes, running all the way to the fmic) The cold charge pipes were clean too.

The valve stem seals were all replaced when I rebuilt the engine. OEM Toyota parts. I did a compression test on the engine shortly after rebuilding it and was from 168-150 across all 6. #5 was the low one, and was before I rebuilt the engine as well. I read up on here and decided it was not all that uncommon. I had the head and block resurfaced, but no cylinder work done when I had it apart.

I have never replaced the oxygen sensor yet. It is still the one that came with the Aristo motorset. Could this effect idle fueling that much? Is it the same as the USDM Supra? It is a 3 wire.

I'm using Mobil1 10w30 oil. I had a leak in my oil return until the other day, and was needing to add about a 1/2 qt a week between the leak and the smoke.

Is it possible that maybe the exhaust had so much oil run thru it for so long that it is still just burning off the inside of the pipes, or worse yet in the muffler baffles and packing in the Borla?

Thanks for the quick reply!
 

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Alpine Hardtopper
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Thanks for all the info. Lets try to track where the problem *isn't*

If the charge pipes from turbo to IC to intake manifold are clean, then you're not leaking oil out the compressor(s).

Since the plugs and exhaust manifold are dry carbon (and the valve seals were done recently) then there's not likely any oil getting in the combustion chamber.

That mostly leaves the option of oil between the exhaust manifold and exhaust tips. When my twins blew up, I got a LOT of oil in the exhaust. It was a full spy hunter smoke screen. I flushed/cleaned all the IC and piping, and as much of the exhaust as I could. But there's still 4 resonators in my system (HKS Dual Dragger). When I started it up, there was a lot of smoke once the exhaust warmed up. Driving down the street for the first day I could still see a bit of blue/grey smoke out the rear view. I headed for some long hills and flogged the car pretty hard off and on up the hills. Mostly I wanted to heat the exhaust up as much as I could. Even two weeks later, after pushing it hard when warm I could still detect a small amount of oil burning off in the exhaust.

If you're confident that the new turbo isn't leaking anything in to the exhaust side, then I'd hazard a guess that your Borla has a lot of oil in it still. This is *no* fun to clean out. But if you can get the Borla off, I would pull it and sit it on end for a few hours and see what comes out. If there was a lot of oil in it, you may consider flushing it a few times with a solvent (and letting it air out for a day before sticking it back in!).

The other thing I didn't comment on was your fuel system. Are you still using the stock ECU for fuel tuning? Having two FPR's in series isn't a great idea. But the pressure shouldn't compound. The fuel rail should still be ~35 psi if that's what your gauge says. But depending on the flow and resistance of the two FPR's, the actual rail pressure may not be as consistent as the gauge says it is. If you want to keep the Sard FPR, I would recommend gutting out the factory FPR completely.

A bad O2 sensor can certainly mess up the fuel any time the ECU is in closed loop mode (or if it's bad enough the ECU can go in to open loop mode - and everything will be overly rich). No idea if the Aristo is the same as the USDM Supra. I believe the Supra's are 4-wire though.
 

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Discussion Starter · #6 ·
Good stuff. I was suspecting the oil in the muffler idea. I'm somewhat handicapped right now from carpal tunnel surgery on my right hand, but if I can get a friend to help me Monday, I'll pull off the exhaust and run the car with just the 2 open downpipes and see what happens. At the same time I'll tip up the Borla and see if it drains anything. The Borla should be 100% stainless even thru the packing, so a grease eating solvent like SimpleGreen should do the trick, as long as it is rinsed out fully. I'll let it drain for a few days to drip dry and re-install the old straight mid pipes in the mean while.

I'm still on a stock 93 Aristo ECU, only mod is a Sard speed cut defencer, and an SAFC2. The piggyback fpr situation was kind of accidental. I unscrewed the banjo bolt for the stock return line and screwed in the 1/8npt to -6AN adapter for the Sard fpr without thinking to gut the stock one. Right now the Sard is out of the picture though.. stock fpr all the way.

I just went for a drive and was messing with the SAFC2 settings. Hi throttle needed to have -5 to -10 from 4200rpm on up to avoid stuttering and basically fuel cutting I guess. I couldnt get over about .80 bar and about 4800rpm with it sputtering and jerking with the map at 0% or even adding 5%. I would have thought with larger twins more fuel would be necessary up higher.. I had the TH point at 85lo/90 hi, now is back to what i had before of 35lo, 65hi.

i did dyno it a few months ago, convertor was not locked, roll on in 2nd gear and it made 333 rwhp at 1 bar. A/F was decent thru the run at 11.5-12.0 or so..

I'm going to research the o2 sensor a bit and see what i find on that. Mine is definitely a 3 wire. My motorset is a 93, ecu is marked 10/21/93.. I remember that b/c it was made on my 20th b-day :bigthumb:
Thanks!
 

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Alpine Hardtopper
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Bummer to heare about the surgery! I broke my right wrist last Fall, so I understand a little how hard it is to be w/o that hand.

The Borla being all stainless should work great. If there's anything trapped in there, it should wash right out.

Couldn't tell you anything helpful for teh fuel settings with the SAFC2. Wish I could help there though. For what it's worth, if you have a 3 wire O2 sensor, a 4-wire will work just fine. One wire will be the input from the sensor to the ECU. The other two wires will be a power with the key on, and a ground (for heating the O2 sensor). The 4th wire on the 4-wire units is just another ground and was not used on your Aristo engine. So if you can't find any 3-wire sensors at your dealer.....a 4-wire can work just fine.
 

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Discussion Starter · #8 ·
I'm about 2 weeks into recovery from the surgery. iI's frustrating.. things I can do.. things I cant.

Working on the car the other day like this took a friend and I almost 10 hours.

i'll look into the o2 sensor and using 4 wire if necessary. I know at least that it is not the stock lexus GS300 one, it was a single wire o2.

I'm pulling the exhaust on monday. I'll post up the result. Thanks for the tips.
 

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Discussion Starter · #9 ·
oh, and about the safc2 settings. I'm not worried. There is no knock and it feels smooth. I'm going to schedule some dyno time very soon and wire in a lock switch for the convertor this time though. Last time I think it was slipping a little in second.

Thanks!
 

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Discussion Starter · #11 ·
Update. Havent had a chance to drop the exhaust yet. Havin trouble finding a friend to lend a hand, they are all working. I'm off b/c of this hand surgey and cant do it myself. I have been driving the car a good bit though and the smoke is still there. Cant tell if it is more or less.

Still having a hard start problem when cold too. I noticed on the fp gauge that there apparently was no prime signal when I turn the key to the second position. FP does not start to build until I start cranking the ignition, then I need to floor the gas pedal for it to catch. Idle is lumpy for a few minutes until she warms up. Related problem?? No smoke at that time though?

I'm going to drop the exhaust off tonight at our weekly drift event and run her with open DPs to see if it smokes. It is the only venue that I can safely do that, b/c of the twin 2.5" dp's it is very LOUD.

I'll post up the results tonight or tomorrow.
 

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Discussion Starter · #12 ·
Okay. Dropped the exhaust tonight and ran the drift event with 2 open dp's. The DP coming off my new turbo is still smoking. :blast:

I can think of 2 possible reasons.. other than the possibilty of a bad rebuild on the turbo.. but it looked and felt great.
1. There could be SO much oil in the dp that it is still burning off.. this is the one I hope, b/c it should be an easy fix. Just have to get some new gaskets and take a few hours to clean it out.
2. The oil return is backing up?? As I said I have restricted -3ANs feeding each one, and -12ANs draining, but they are teed into one at the factory Aristo fitting.
Here's a pic..

Do you think it is possible that the front turbo drain is backing up?
 

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Discussion Starter · #13 ·
No advice?? somebody give me something else to try.. some idea. please? :1poke:
 

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Discussion Starter · #14 ·
Update

I decided to dig in a little deeper, getting desperate for a solution before the ticket comes due on the 26th.

Found out that 1000 miles ago when I changed out my plugs to the 6097s, when I plugged back in the coilpacks, I missed one of the pins on #5. It was bent up and not making contact. SO.. there is the source of my strong fuel smell and lumpy idle for the last while.. not to mention the car has been running on 5 cylinders! Still felt pretty good. Well, since #5 has been bathed in pure gas for the last month, of course the rings were washed out. Compression of 60psi. Rest were between 170 and 160. Added some oil and it comes up a little.. Decided to drench the cylinder in brake cleaner, thru the plug hole.. let it sit for a minute, put the plug and coil back in and fired it up. Wash rinse repeat.. did this 2 more times, then moved to ATF in the cylinder. Of course.. TONS of white smoke here, but ATF tends to swell the rings and hey, it works to rehab the apex seals in old rotaries.. so why not? Let the car idle for about 15 minutes and then held it at 3000 rpm for another 2-3 minutes. Drained the Mobil1 out and put dino oil 10w30 back in and changed the filter. Put a fresh plug in #5 and she idles smoother now, and no strong fuel strench from the exhaust.. Still smoking
though.

Started looking at the crankcase vapor ventilation. I have a greddy catch can with the factory vent hose on the ex valve cover going to it and then to the intake. Should be alright huh.. nope. I also am running a GE intake valve cover b/c my GTE one cracked on one of the corners. I tapped fittings into the vc so I could equalize pressure between the halves like the small hoses on the GTEs that go over the coil packs. My PCV is just a hose off the valve running out over the tranny.. I started pulling the vent hoses off and re-arranging them, observing the effect on the smoke from the exhaust. Hours later i figured out that i have so much blowby (see first paragraph) that i couldnt evacuate it fast enough thru the catch can. I directed the rear fitting hoses out over the tranny like the PCv and the front two equalize from side to side. The factory crankcase vent is still going to the catch can, but now it is just open, not run to the intake. Been driving for 2 days now and the smoke is gone. I will be trying to get another intake vc and tap it for -12 AN along with the ex vc and run them to a custom open filtered catch can as soon as i can find the time. I'm just enjoying driving my car again so much after it smoked for so long.. it was an embarassment.

**CLIFFS.. fuel issue fixed, coil pack pin bent. Smoking issue fixed.. excessive blowby from washed rings (coil pack pin bent) new crankcase vent hose routing. Car is fun to drive again!

Thanks for the tips and input.. hope this helps someone else.
 

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Discussion Starter · #16 ·
More news.. on the way to get the ticket cleared today it started smoking a little sitting in traffic. I took the long way around to get the exhaust nice and hot, so it would clear up. Went to the police station, got the ticket cleared and left.. all with out him seeing the slight smoke. Pulling out of the police station, I noticed my low fuel light was on, and at the stoplight it started smoking again slightly..not oil but fuel. Went and put a a half tank of 93 in it, and it hasnt smoked since?? I'm thinking I was getting some old gas off the bottom of the tank or something?? Going to throw in some redline SI-1 fuel injector cleaner tomorrow and fill her up just in case. Maybe some DryGas (Isopropyl) too.
 
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