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'97 TRD LSD Issues and intermittent P0420/P1512 Codes

2K views 29 replies 7 participants last post by  Gary Bechtold 
#1 ·
So I have a few issues, mostly just annoyance/nuisance issues but they all add up.

I had my TRD LSD put in my car last year. I moved about a month ago. I know that a clutch type diff behaves differently but I will say that it seems more sensitive lately. I have a three-car garage and the supra is parked all the way on the left "3rd car" spot". When I back up the car out of garage I have to turn in towards the center then once I actually start to back into the street I either continue turning that way or go the opposite way. Either way when going forward and the next few right or left turns I make as I go out of the neighborhood, you can tell the diff isn't happy. You feel like you are sliding the tire/rubbing instead of freely spinning the tire. After a few of those turns and the gears moving inside it seems happier. But park the car anywhere for some bit of time and it's back to dragging again. I had Redline 75w/90 oil and Redline clutch type additive put in the diff. Anything you guys recommend?

On occasion over the years I get either a P1512 or P0420 code. The P1512 codes I get on some random frequency at least a few times a year on average. The P1512 always happens on a part throttle, barely boosting at all. I never feel anything, I just notice the light goes on and that's all there is to it. I have a Greddy BCC in my car. The P1512 error has been happening for more than 5 years on random occasion.

I got a P0420 about 5 years ago and just got one last week. Other than the car seems it might be running a little richer (maybe) and I notice a little more water in the exhaust. Otherwise it has been mostly normal in performance. It has been more humid lately, so maybe that explains the water bit. Now I have noticed one thing, I am on stock twins and a few times lately I got on the go pedal and seemed to have zero boost. But then I let off the gas and got back on it and there was boost. Not long after that the P0420 code happened. The no boost has happened about 3 times. When I have boost it's otherwise normal most of the time. (99%+) Do I need a new O2 sensor? It is the original 23 year old one. I suppose that the cat could be going bad. It's a Random tech downpipe and cat converter I installed in 2004 and have put over 62,000 miles on it in the 16+ years it has been on the car but I don't think it's actually the cat yet. I was thinking it might need the downstream 02 to be replaced. What is the toyota part # and where woud you guys recommend getting it? With Elmhurst Toyota not having the good guys there right now it's a crap shoot on who you get. Or if you guys can think of a Denso alternative I can get from Amazon or somewhere, that would be great also.
 
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#2 ·
You don't need the LSD additive. I'd drain that fluid and fill it with normal Mobil 1 75w/90 available from most parts stores and see how it reacts. That could be your issue while the fluid is cold. As far as the codes go-I am sorry I can't help you there.


Steve
 
#3 ·
The downstream cat typically (I haven’t worked on the supras emissions equipment) just measures the catalyzer health. The upstream one is for fuel trim. The downstream one can definitely set the 0420 code. If both sensors are factory originals or you haven’t changed them ever, I would toss two new ones in regardless if its the root problem and see what happens. Otherwise it needs to be diagnosed by a tech with a scan tool.
 
#4 ·
Steve (1A1) nailed it on the diff oil recommendation. The Redline stuff is fantastic, but the TRD LSD seems to prefer less fancy gear oils for reasons I haven't ever been able to divine. The Mobil 1 should do wonderfully.

But before you change the oil, I would find a nice big empty parking lot and do some tight radius figure-8's at a low speed. Doing that for 10-15mins does wonders to break in an aggressive clutch type LSD. Change the gear oil afterward and see what happens.

As for the O2 sensor, the P0420 code from the original sensor is almost certain to be a failing O2 sensor. According to the EPC I'm seeing Toyota PN 89465-19595 as the correct O2 sensor for a 97 TT 6-spd rear O2 sensor. The downside is that it is discontinued from Toyota, as is the front O2 sensor for the same.

Starting with the 89465-19595 PN, I pulled a Denso PN 234-4215 as the Denso made replacement that matches. But I would be wary of that PN as I haven't found the cross reference from Denso themselves, only sellers of that kind of stuff all over the internet. I'd also be careful about buying Denso stuff from eBay, etc as there's a lot of chinese made counterfeit trash shipping in fake Denso boxes.
So far, buying stuff like that from RockAuto has done right by me, and they show both Denso and NTK made sensors in stock under that Denso PN.

The P1512 code is a common one from the old school BPU days. Thanks to Stu Hagen's keeping of much of the old knowledge, here's a description: http://www.97supraturbo.com/Trouble Codes/P1512 Boost High.pdf

Basically it means the ECU is seeing higher boost pressure than it expects under a low RPM and often part throttle condition. This is typically from using a boost controller or other method of boost pressure being elevated beyond stock. Hopefully someone better with BPU wizardry can chime in, but I believe there's a way to put a restrictor into the MAP sensor line as to bring the MAP sensor reading down just enough to avoid triggering these issues. Since the 2JZ-GTE ECU adjusts timing and fuel off of the MAFS signal and not the MAP, adjusting what the MAP sensor sees doesn't endanger tuning or engine function at all.
 
#5 ·

DENSO 234-4215 {#8946519595, 8946519695, 8946549075}
Downstream

DENSO 234-4514 {#8946519605}
Upstream

I found them like you mentioned on Rock Auto. Amazon can get them to me for essentially the same price and a little quicker.


So get this Mobil 1 75W-90?

Image looks different, but this is the same thing?
 
#6 ·
I strongly suggest not buying sensors, especially the front O2, from Amazon. The counterfeits are rampant on there and you won’t be able to tell the difference visually very easily. I personally don’t trust Rock Auto either. I’d bite the bullet and get an oem replacement from your local Toyota or online dealer.

Edit: What Wreckless said.
 
#7 ·
For what it is worth, both 02 Sensors are listed as being sold by Amazon, not some third party vendor.

Local Toyota dealer is useless, never has anything in stock, charges way too much for parts. I'd have to get it from someone out of state if that is even possible. Elmhurst Toyota is useless, doesn't show anything on their webpage.

Any thought about the Mobil 1 75W-90?
 
#12 ·
I recommended RockAuto for a reason.

On at least two occasions I've seen counterfeit items sold as genuine by Amazon, including one that was over $450. No luck, Amazon refused to even consider that it was a counterfeit item even though it was clearly demonstrable when compared to a genuine part.
After a few other issues I experienced with car and non-car related Amazon purchases, I'm avoiding Amazon if at all possible.

For Toyota genuine parts, I've had good luck with Olathe Toyota's parts department for MR2 and Celica stuff, and sometimes Supra stuff too when Elmhurst was unavailable.
 
#10 ·
I use the Amsoil Severe Gear 75W-90 along with 2 oz of their LSD additive. If the car sits for an extended period, the clutches chatter a little on the first few turns. The clutches get dry from sitting and the fluid has to get worked into them. I'm talking about 6+ months or more, but a shorter period could do it to a lesser degree.

Al
 
#14 ·
Well I have the Denso O2 Sensors in hand and the Mobil 1 Gear oil, so I'm ready. Last thing unrelated is some Motul RBF 600 brake fluid for a brake fluid flush is on the way later this week.
251342
The bottle at the Auto Zone store and ordered from Amazon looked like this.
 
#15 ·
So a little update, I have not had the P0420 code since clearing the code. I have also changed both o2 sensors. I can't say I notice anything different but the car was fine before.

As for P1512, it has happened once. I just clear it and ignore it. If I could eliminate it from happening that would be great.

Now as far as the TRD diff is concerned, I changed the diff fluid to the Mobil 1 stuff. I still have the same problem. It's incredibly annoying to me when I back out and pull out of the neighborhood. First few turns it feels like I am dragging a tire. It behaves differently than the Redline, but not really much better initially. Once it is warmed up it is basically ok. This diff seems to not be a fan of part throttle cold start turns. I'm kind of regretting putting this diff in the car even though the original is basically an open diff. (My car did not have the torsen diff.) Any ideas?
 
#16 ·
Again, the P1512 is an overboost code from the MAP sensor. To eliminate it you either need to turn down the boost via your boost controller, or put some kind of restrictor into the MAP reference before the MAP sensor.

For your LSD woes, Add some of this LSD friction modifier to your existing oil fill:

I'd start with 2oz (half the bottle) based on your impressions and I'd drive it for a couple of weeks like that to see what happens. If that solves the problem, enjoy, and save that remaining 2oz for the next time you change the diff oil in another 20-30k miles.

If the behavior persists, add 1oz at a time and giving it a few drives to circulate each time before adding more. You have a motorsport diff in your car, some NVH harshness should be expected.
 
#19 ·
Like I mentioned, the Amsoil Slip-lock is very good, put the whole bottle in. Will have to drain a little fluid first. Go to a parking lot and do a few figure-8's and you'll be good to go.

If will mention, if you never drive the car, you'll be susceptible to diff chatter. You can work the additive into the clutches, but if the car just sits afterwards, the chatter will come back. Got to drive it!

Al
 
#20 ·
I drive the car every weekend. So it doesn't sit long. If I drive it on Friday, I will have the problem again Saturday morning. I need to do something for that. Redline Limited-Slip Friction Modifier or Amsoil slip-lock? Do you guys have a strong preference?
 
#21 ·
What size tires? If they're shorter then you're going to need more turning around to get the diff up. Full lock the steering wheel and do donuts (very low speed circles, not burnouts) in reverse in both directions a couple of times. Neighbors might think you're nuts, tell them you have a dissability and get invited to watch parties/bbq and enjoy the free beer.
 
#23 ·
The gear shop I'm working with recommends Lucas 85W-140 conventional oil in everything. It is really sticky, they claim it rides up the gear and keeps it cooler. You can see in those little displays in Autozone, the oil rides up the gears with Lucas additive. The shop claims synthetic slips off the gears too easily. They work mostly with 4WD stuff.

I have it in my car. At first, I didn't like it because it would chatter on the first couple turns when cold no matter how well you worked it in there. Now, after driving the car at least a dozen times and 400 miles or so, it stopped chattering on the first couple turns.

The TRD can be finicky about oil/additives. The original recommendation was for TRD conventional oil, which is no longer made, or at least available in the USA.

Al
 
#24 ·
So after draining a little of the Mobil 1 fluid to put in some more Redline Friction modifier I still have the chattering after 1,000 miles I have put on it in the last 5 months. The chatter is terrible backing up or going forward at any low speed turning. I'm kind of at a loss on what to do. Go back to Redline gear oil with two bottles of friction modifier or something else. Get another LSD? Is my TRD diff a TiRD?

Who made the TRD diff for Toyota. Anyone know?
 
#25 ·
I use - Red Line 58204 Heavy ShockProof Gear Oil & ACDelco 88900330 - Limited Slip Lubricant Additive

Been running this in my TRD Diff for over 13 years - Absolutely no issues. No chatter, noises or vibrations, just like stock.

I've been using the GM additive, for all my clutch type POSI differentials, for over 40 years.
 
#27 ·
No idea. You may want to send it to a shop like Sound Performance or someone familiar with them and have them take a look. The pumpkin w/diff weights around 125lbs so I'd slap it on a pallet and ship it to them freight.

Steve
 
#28 ·
I agree, you should take out the diff and inspect it.

Check the driveshaft universal joints also.
 
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