BuffNStuff

Hey Ali, do you think this could apply to us as well? I started getting multiple missfire codes even though the car seems to run fine.

http://forum.clubna-t.com/archive/index.php/t-20433.html

BuffNStuff

Also, any idea as to how I would figure out what resistors I need to wire in for the EGR insufficient flow and wastegate circuit malfunction codes?

187

Interesting bit on the misfires. Can you actually hear yours? I have audible ones when the car idles where I have it currently because it leans out misses then richens the mixture .

The egr is a 10k ohm resistor on the plug that connects to the egr (small gray plastic plug right near the egr).

The wastage code I had a 1k ohm on the pin for it but I think you need a 10k because mine came back later on. Also I believe it's pin 60 but double check the pinout.

BuffNStuff

I found what I needed for the EGR code just minutes after I posted. 10k ohm 1/2 watt resistor in the EGR plug.

Thanks for finding that for me on the wastegate code!

My car runs great..Pulls smoothly. Cant hear any misfires as far as I can tell. Yet i have the codes. Gotta do emissions by the end of the month too lol

187

We all seem to have misfires with pretty different set ups, so there should be something to point at. Maybe someone of the supra forums has something similar.

Let me know if the 10K works for your code, hopefully we can figure something out before the months end.

BuffNStuff

Welp, now I really am getting misfires. I can feel them now. I am almost certain its from the fuel dumping at WOT. I went for a while with no issues because I couldnt go WOT because of my new clutch. Im pretty sure we all are fouling our plugs. Can you pass emissions with a safc? Im thinking about getting one to pull fuel and then ill replace my plugs.

Mad-Dax

Wiring looks easy lots of stuff to get rid of.....but what about sensors that I won't be hooking up? Like VSV and park neutral switch, egr, maf....if I leave these unhooked will it cause the computer to not let the engine run properly...remember I don't care about emissions or even care if it throws the code just as long as the engine starts and runs with the minimal sensors I want to use. For example the tranny park/neutral switch show it sends a signal to the ecu or when you crank the car it sends a 12v signal to the ecu to let it know the car is trying to start.....I was hoping that I didn't need to wire up false signal to the ecu to get it to start/run without these sensors hook up.....You know what I am meaning...I may not have explained properly.

BuffNStuff

Okay, so I have been looking at wiring diagrams and scouring the internet for answers to our OBDII problems and I think I have them sorted.

For our EGR codes: (Mine is P0401, but I believe this will apply to other EGR codes as well)

*Solder in a 10k ohm 1/2 watt resistor inbetween the 2 wires for the EGR temp sensor that goes into the big EGR pipe on the back of our engines. In the link, it looks like he just cut the wires a few inches away from where the EGR temp sensor plugs into the wiring harness connector, soldered in the resistor to the 2 cut wires at the back of the plug, and then connected the plug back up. I will probably just cut the wires pretty close to the sensor and solder it in there so that I don't have to unplug the connector at all (that's the most difficult part because its in a hard spot to get to.

https://www.clublexus.com/forums/sc-...istor-fix.html

For our Wastegate Circuit Malfunction Codes: Solder in a 1k ohm 1/2 watt resistor between pins B60 and B69. Pin B60 is for VSV4 which is the VSV that controls the stock wastegate, and pin B69 is ground.

If you are getting other VSV codes that you haven't fixed yet, this same resistor should work for them too. (I had other VSV codes a while ago but I fixed them quite a few months ago)

http://mkiv.com/techarticles/obd2_co...svs/index.html

For our random misfire codes: I just replaced my sparkplugs today and my misfiring is gone. This proves that my plugs were fouled from the massive amount of fuel dump during WOT. We need to do what MyLex400 did and get a SAFC or something similar to pull fuel during WOT to prevent fouling the brand new plugs.

After this we should be home free. I don't see another way around needing a SAFC to stop the misfires from happening. I am fairly certain that if I stay out of boost forever, my misfire codes will never come back, which helps since I need to pass emissions by the end of this month. I will be trying to wire in the resistors tonight. When I am done, ill let you guys know after a few days if the CELs go away.

By the way, these resistors are dirt cheap at any radio shack. Its like $1.70 for a pack of resistors.

187

1K wasn't enough for the waste gate when I did it. How much fuel are you dumping at WOT?(AFR)

I think mine are going because when I rev down my afr goes into the 10.00 range and tries to choke the motor out. I was always 11.1-11.2 at WOT.

Also what are you plug gaps?

Ali, do those flaps that control the long and short runners in the tb effect any of this stuff?

edit* I don't get how the jdm ecu works better when were specifically metering our air and still having issues. Would swapping in a jdm ecu solve any of our issues? And just keep the usdm around for inspection times? Or are we just missing something completely

BuffNStuff

Update: EGR resistor trick worked. My CEL went right off. Havent tried the wastegate one yet.

Mine was at 10.0 WOT. Still pulled like hell though so I didn't really care..until my plugs fouled. I gap my plugs at ~.022. Don't know EXACTLY as my gap tool only goes down to .025 but I gap them down to where they just barely don't fit the .025 wire.

If you swap to the JDM ecu then you will have to swap injectors as well. Plus there will be some rewiring. We are having issues because we are the first ones to do this. Its all trial and error. Notice how we all have the same issues? Were doing it right, we just have a bunch of extra crap we have to deal with compared to OBD1.

187

I forgot about the injectors. Sounds like your ecu was dumping fuel up top to save you or maybe it is more tps shenanigans.

Your gap is pretty low, any particular reason?

HiPSI

iTrader: (2)

OBD II definitely seems more involved or "finicky" compared to OBD I. When I deleted my EGR on mine I originally had a CEL on the stock ecu, the JDM ecu actually removed that for me and I haven't had a single CEL since .

Ali SC3

iTrader: (10)

It could have something to do with the location of the o2 sensors I guess, but I wouldn't jump to that as there are lots of single turbo supras out there on the stock ecu with an aftermarket downpipe, I doubt they all have misfires.

you guys did note that there should be 2 o2 sensors on the US ecu right? not 1 like the JDM ecu uses.

plugs and plug gaps are always common sources of ignition issues. thats why I said check the coilpacks/wires/plugs and plug gaps. thats good that you think you got it solved so its running so rich with aftermarket 550's that its fouling stuff out. makes me think the stock injectors actually flow a little less.
a safc or any piggyback will let you correct that, safc doesn't affect emissions generally speaking.

What type of plugs are you guys using. I have the Bkr7eiX in mine around a .030-.032 gap.
The non Iridium versions will seriously foul out very fast, I don't even use them anymore, but some people say they perform better I feel like the iridium's performed better than the coppers I had in. I dunno I keep doing weird things to my car for several years and I am on the same set of Bkr7eix and they have been through several tuning sessions.

The reason the JDM ecu works better is cause its more simplified. Also since they never went obd2 the ecu monitors stuff the old fashioned obd1 way, which means just barely. Maybe us obd1 guys are misfiring at times and the ecu does not care to tell us about it. I really haven't noticed anything like that though.

The ACIS flap in the intake shouldn't affect the system that much, you can always cap the line going to it and that will leave it in the open position.
I recently saw the only case of one breaking online where it ended up in the actual cylinders when it disintegrated but it doesn't happen very often.
If you are pushing 18-20+ psi consistently though I would think about removing it permanently just to be safe.

187

Im running some ngk or something double platinum plugs gapped at .032. I was told iridium's foul faster because of the smaller area it take to cover to foul it, but I never ran iridiums.

there isn't even enough stock wiring to flip the position of the 02 sensors. I guess there not doing a really good job leaning out our mixtures....

I'm just stuck on how me and buff have such contradictory problems. I didn't want to gap mine down really low for safety since I'm still on stock compression. Going to pull #1 cylinders and heave a peek tomorrow

Ali SC3

iTrader: (10)

The Iridiums are the best plug you can use not sure who told you that. Platinums I stay away from their only good thing is that it lasts 50k, other than that I can't think of anything else good. There is no downside to using Iridiums other than cost and they are a little tough to gap down they are the best plug. If you buy the right plug you wont even have to gap them I just dropped mine in (I checked it of course).

I would Highly recommend to get some BKR6EIX or BKR7EIX as soon as possible. gap them at .032 and drop them in. if you have issues then gap them further. Our cars/coils like coppers and Iridiums. The Iridiums last longer, are much more foul resistant (best part) to running rich for cycles, only downside is they are a little more expensive. Really though in the end they are worth it in my honest opinion the coppers are better than the platinum plugs, I have used them on my motor before with no issues the BKR6E or the BKR7E. IF you run more than 14 psi choose the 7 range. If you run less than that then get a 6 range plug that is actually the replacement plug for a stock supra TT in Iridium and in copper in a 6 range is a BKR6e or BKR6EIX, and then they say 1 range colder for each bar of boost you run as a rough guide, so 1 bar would be a 7 range so 7 instead of the 6.

The coppers are generally as good performance wise and cost less but you must change them out more frequently, If you tune on them you could foul them out easier, probably wont happen with the stock ecu, but if you have a FFIM or like to change spark plugs then give them a try and you will see what I mean.