187

That vsv is connected currently I never had a problem with it and its the same pins apparently on the gte ecu.

I confirmed today that the full lean condition is all misfires above idle. The fuel trim trys to add fuel like before but just misfires until it maxes out the fuel trim. The weird thing is once the trim is high (around 15%) and returning the rpm back down to idle from say 1500 rpm the misfire goes away and I get a super rich 12.0-15.0 as the trim corrects itself. So basically the fuel is igniting at idle but as soon as you get above idle it misfires and trys to add fuel thinking its lean.

The only question is why is it missing above idle?

Ali SC3

iTrader: (10)

that blue vsv is pure evil please bypass it with the vacuum hoses, you can leave it plugged into the computer to make the computer happy, just bypass the vacuum hose around it to eliminate any issues there.

that is what I was thinking since you guys are getting misfire codes it can tend to trip up the ecu and make it add fuel sometimes. maybe you guys need to gap down the plugs some, or could even be having some sort of coil issue. it could be that the obd2 tune is too aggressive, only thing I can think of is try backing out some more timing on the distributor as a test to like 4-6 degrees and see if that helps. if the problem is the same then its not a timing thing.

Hi PSI have you read this thread on SF, could also be part of your issue. also 187 do check on this cause its related to obd2 specifically and could explain your issue also.
Read the part about the heater ground needing to be added to the harness
http://www.supraforums.com/forum/sho...2-ECU-Upgrade&

it says sometimes the harness doesn't have the ground wire for the heater sensors to come on after cold start, if you have misfires that are there after cold start that go away later when warmed up, then this could be the answer because the ecu thinks the o2 sensor should be warm, only the o2 sensor isn't warm yet so it will read the wrong thing. let me know if there is a chance this could be it. I do remember changing some ground around on my harness but I couldn't tell you where the original spots were anymore.

187

So you basically ground out pin 78? Whats going on there, pin 78 doesn't come up as anything on the wiring diagram? This would make sense because the car uses the 02 for fuel way before I thought it would when I was monitoring it with my scanner.

Ill see if there is any change with the vsv bypassed, I also need to double check the igniter wiring is nice a secure.

187

PSA : Don't ever touch your coil wire when the car is running.

Well I found this nice slice in the coil wire after it nearly diffbulated me. And just to add insult to injury I replaced it with my old one which was fine and it still didn't do anything.

I'm done.

Ali SC3

iTrader: (10)

yeah that is what it says, it should be like E01 or E02 on the wiring diagram, usually chassis grounds are numbered like that, but it could have a different name, usually there are a few more on the turbo ecu than the non turbo ecu, but on obd2 they should have been there, either way this would be a good one to try out and you can even tie it into the other ground wires that are already on the ecu, or just find a nice bolt next to the ecu and scratch a little paint off.

yeah touching the coil wire is a no-no while its running, glad you are ok.
BTW those 4runner distributor caps are not the best for eliminating problems, but not sure if its related to your issue or not its more likely the o2 sensor part.

the vsv will only mess with the tune when you start it and the coolant temp isn't cold, unless its leaky or sticking etc..

what you could do is just unplug the o2 wire at the connector (signal or all 4), reset the ecu the long way, and see what the AFR's are across the board, it wont be able to correct but if gives you an idea of what it would inject when it has no feedback, sometimes it can help you figure out what is wrong, like it if clears up completely we will know to focus in on the o2 sensors.

187

I have no problem grounding that pin, I have to go back in there to fix the P1658 anyway.

I know the cap is suspicious but I've had it run fine on it and I checked the air gap yesterday and it was all good. Plus I confirmed today with the timing light it is working and firing through the wire when I idle and when I rev the engine.

I tried running with the 02 unplugged and it did the same thing where it's not igniting the fuel.

I want to examine all the wires I have in there now for cracks ect now that I know those wires are worthless.

*edit- also need to make sure that current didn't jump into the vpc temp sensor and destroy that thing.

Ali SC3

iTrader: (10)

hard to say with those 4runner caps because they are not ideal, I don't have 100% evidence to back it up but the issue I suspect happens with those sometimes is that the pins for 2 of the cylinders under the cap are spaced differently on the v6 compared to the I6 cap, and most people don't notice that.

edit* I thought the pins in the cap were spaced differently (been a while) but its actually the post types are different.
all the pins could also be the same amount off phasing wise but turning the rotor should correct that, but if you look the posts arent the same distance from the bolt holes (The 2 that work on the 4runner cap anyways).

The problem was raised at clubna-t before back in the day, but was never concluded as it was a real thing or not. I do know I had a distributor stop working after I used a 4runner cap about a few thousand miles after I installed it but my rotor could have been worn as well.
you will have to read and judge for yourself
page 4
http://forum.clubna-t.com/showthread.php?t=4921&page=4

Can't guess your guys exact problems on the first round but I am good at spotting problems I have encountered and troubleshooting the rest after eliminating those. IF you are on VPC, I would just pull the turbo intake off and put the stock cap back on and run a 3" pipe into a filter or just leave it open air and put a fine screen over it for the time being. do not insert any fingers in there.

also what gap are you running, with the stock dizzy you should be running a pretty low gap. I would try .024 to .026 with that setup to be safe and work up the gap from. definately check out the rest of the wires, if you have one shorting to the head it would also cause issues but I would imagin you would be throwing an rpm or distibutor code as it makes the ecu not able to pick up and cam or crank signals when the spark grounds out like that. when it jumps in the cap it more just weakens the spark because the more air it has to jump the more resistance is created and that soaks up spark energy. when you try and ignite a lean or any mix with a weak spark your success ratio sort of plummets.

that being said I know tons of people run the 4runner cap and are successfull, but some arent and I am just trying to cover everything. don't blame me if it still does it lol.

4runner cap


2jzge cap

187

I have the plugs gapped at about .030 and they have been fine in the past and they look fine as of last week.

I can't use the stock distributor even if I wanted to due to the physical location of the turbo itself. I know we tried this before.

I'll be checking the plug wires and vpc temp sensor now.

Ali SC3

iTrader: (10)

you can even try the resistor instead of the temp sensor I read it works for some better like that.

I drove my car with the 550's in and the the stock map sensor and its not really that bad it seems like the o2 sensor can do quite a bit of adjusting. haven't had a chance to test the boost out but it seems to be running pretty well. the map ecu was being difficult to setup but I am going to try the autolearn mode and see what it does.

187

Everything seems like its working except cylinder 1 3 4 5 6 don't want to ignite the A/F mixture above 1100rpm.

1 3 5 are the worst offenders but I can see the plugs are getting spark with the timing light, I just need another set of hands to see if the gap is jumping enough from the wire. I haven't been able to point to the distributor as the problem but I'm trying.

Ali SC3

iTrader: (10)

that blue vsv is not on a gte motor, so not sure what you mean by its on the same pins. the gte ecu might have a vsv there, but its not for that. it could very well be opening the fpr to atmosphere whenever it feels like.

thats pretty much all your cylinders there, sounds like the ignition is too weak if it works at idle then doesn't above that but its hard to be sure. I would try new wires or stock wires and gap the plugs down a bunch more. .032 is what I run on coilpacks and the stock distributor isn't nearly as good at delivering spark. it could just be a spark issue, its actually harder for it to ignite a lean mixture than a rich one, that would be where I would start I ran that same setup on the GE ecu at one point and I had to gap down to .024.

read, there are tons of is300 guys with misfire issues which may be similar obd2 problems.
http://my.is/forums/f114/boosted-plugs-gaps-246616/
http://my.is/forums/f87/is300-misfir...lllppp-446718/


fix the vsv, confirm your o2 sensor is working via your wideband early or try the heater groud wire we talked about, replace the wires or check them at night you should be able to see any grounding out, I would gap down the plugs while you are in there as well.

187

I did the vsv the other day. If I go in to gap the plugs I might as well just get a set of coils and wire them up. Its only like 100 something for a set + the connectors. Initially I just did it for ease but at this point I rather just get rid of the distributor if it proves to be weak spark.

I can try gaping one down after I get to test the spark and see if it makes a difference.

Thanks for looking up the is300 info I didn't think those guys had any issues like this.

High PSI

iTrader: (1)

What's the deal with the UK/Euro Supra ECU's? I can get my hands on an early non-vvti RHD 6-Spd ECU for my 1995 SC300, but wanted to confirm that it would work first.

[EDIT] Scratch that, just found that the UK/Euro Supra's had MAF's.

Ali SC3

iTrader: (10)

187, those is300 guys have literally the same problem you guys seem to be having, its rather odd but I couldn't find a conclusive thing it seemed to be coils for some, sensors for others, gaps for others, alot of random stuff throwing misfire codes to be honest. I would do some more reading there and on supraforums related to misfires on most cylinders and start checking things off the list.

I think the o2 heater could be a really good one to check cause if its not operating like its supposed to it will confuse the ecu till it warms up.
also like I said I would also take the gap way down since you are having issues.
not sure if you want to try the coils as I am not sure that is the problem but it probably wouldn't hurt if you get a good set of vvti coils.

high psi, yeah most of the uk and canada got the maf version, other countries it sort of varies, also with imports you find a ton of each everywhere so the sure way to know is to check the part number on it.

187

I'll take care of that pin ground later this week or Friday and report back. Also getting some block off plates to install and that wastegate resistor to install again.

Edit* also did some more research over on the IS forum and found an old thread with the 1 3 5 problem with no follow up and there is even a youtube video where a guy got it from non oem plugs apparently. So no luck there.