yeah let us know, I had the same results a majority of the IS threads did not come back to list a result but many had similar issues. I guess obd2 fuel trims are not fun to deal with across the board.

I did have a thought though with the heater circuit. I was reading the older ecu's tend to have the heater come on all the time, cause its simple.
and the newer ecu's some of them only turn the heater on for a short amount of time because with how close it is to the exhaust it doesn't have to be on all the time.
Now if you are missing the ground wire you wouldn't have it come on at all.

so what I am thinking is you can try and do the ground wire and see if the ecu will control it well enough on its own (or it might make no change if it was already working just not on long enough),
or you could take the wire for the heater going to the ecu, and just ground it to the chassis yourself. this should turn the o2 sensor heater on all the time, so it will definitely be warmed up by the time closed loop kicks in.

does your issue go away or change when warmed up usually?

 

The 1 3 5 issue used to go away after 15 min 10 of which it was already full warm. This new issue it doesn't go away at all.

 

dang when did it start doing that, after messing with the tps? it was probably better when it was going away after 15 minutes.

 

It seems to have come out of no where. The car was running kind of leaner than I liked so then I did that smoke test on the intake and removed the egr now but the problem is still there. It doesn't seem to have to do with the tps as I've tried multiple positions with no change. I get spark and fuel but for some reason it just misfires randomly from cylinder to cylinder above 1200 rpm.

Do I need to do something with the rest of the egr system? I have all the stuff I pulled off capped and my idle vacuum seems to be normal. I'm pretty frustrated at this point and I am pretty much out of things to trouble shoot.

 

just need a block plate at the lower runner and another block plate on the Y part of the intake where it goes into.
cap off some of the ports on the top of the throttle body, and the vac lines going to the egr hardlines vary from line to line.
did you remove your charcoal canister? one of those vac lines by the egr goes over to the charcoal canister.
make sure that it is hooked up right so that it can purge properly, otherwise it can cause pressure buildup and that will create a lean mixture as well.
if you removed it, make sure it is able to vent properly, as in do not block the line to the tank, route it under the car and if needed use a fuel filter inline to keep smells down (well sorta).

the USDM ecu might be officially be a lost cause, we spent alot of time trying to get it work and even deleted the maf and still have issues. not sure what to recommend anymore. seems like no one has escaped the misfires on those ecu's, makes me wonder if an obd1 usdm ecu would be any different or not.

did you ever try turning the base timing down alot? its possible the obd2 ecu is aggressive off idle to combat emissions, drop it down to like a 4degrees BTDC and see what happens as a test. it may sound a bit boat-ish but might work, I know those gte motors can handle mad timing in the lower rev ranges, and the ge motor cannot, I have had to tune down a few gte standalone maps in the lower load ranges for my engine before, above 2000rpm's the engines can pretty much take similar timing, but below 2000rpm's the lower compression motor can tolerate loads of timing that the GE will usually misfire or knock itself till it shuts off.

did you do the headgasket cannot remember.
I might need all you usdm ecu guys to make a mod list so I can keep track of who has tried what, although the others might have given up already, havent seen them in a while.
Buff moved to a standalone that much I can remember =)

 

I'll have to check on those canister lines, I didn't touch them as far as i know. I installed block off plates today but no change.

The timing has been fine and has had little effect on the whole thing. I have tried really low (4) and stock 10 and seen no real change. And yes I'm still on the stock head gasket.

 

I reset the ecu by pulling the battery cable. Re-adjusted the idle set screw to stock and adjusting the tps accordingly and it started and idled without any misfire or hesitation in the 1500-2500 range like it was before.

I don't know how it went from running fine to starting with hesitation like that which made me think it was something ignition related. I was relieved though to reset everything and it corrected it. These ECU's really are affected by the TPS adjustment if it's not within "spec". I never had a check engine light either.

On a side note about the evap canister and relieving the gas tank pressure. I reinstalled the evap canister / hooked up the vacuum lines and VSV but I'm still getting a ton of pressure when opening the gas cap at the pump. Is it still normal to have pressure like that with it all hooked up? Makes me think it's not setup right.

 

could still be a timing thing on stock compression, but not really sure to be honest a lot of different variable. stock compression does seem to work on the jdm ecu though.
the canister system has one line that goes to a vsv and then to the intake manifold nipple by where the egr was. there is also a tee before the VSV and a line goes straight to the throttle body. i removed this line after I went FFIM I was having fueling issue because of too much vacuum there. since I have only had the vsv side connected it has been good, maybe try that.

yeah its funny how the smallest adjustment on that thing will affect how it drives, you guys should have seen me ripping my hair out when I was troubleshooting it by myself lol.

you can try what I said above, it normal to some degree to have pressure on a hot day but it shouldn't be so much that little droplets of fuel "spray" out at you.

the tank purges 2 ways.
1) line from canister to vsv, then to the intake plenum.
this line is controlled by the ecu to come on at times when enrichment is desired and when in vacuum to allow some pressure in the tank to purge. ecu pulses it to relieve a little pressure at a time.

2) there is a direct line that comes off a tee before the vsv, and this goes to a port on the top of the stock throttle body via all the hardlines on the bottom of the Y part of the intake, and you will notice there is a blue/black check valve on this line to prevent boost from going towards the canister. this vaccum nipple is "ported" meaning its designed to only have vacuum when the throttle plate is slightly cracked open, so at idle there is no vacuum and nothing gets purged, but as soon as you tap the throttle it gets vacuum and allows the canister to purge.

what I found was there was an issue with (2) using the q45 throttle body, or even if you were to raising the idle some via the screw on the stock throttle body, cause if you open the throttle plate enough then that port will get vacuum all the time (stock design). as I said earlier, the canister should not be under vac all the time cause instead of getting rid of small amounts of pressure, you will likely in short time create a vacuum in the canister and gas tank, and then that will affect the AFR as the fuel pump has to battle the vacuum to pump out fuel.

so I found removing the tee and the line going to the top port on the throttle body, corrected my issue and the AFR's stabilized. I do get some pressure when I open my gas cap, but I think the vsv keeps it under control via the ecu so that its not too much.

not a whole lot of info on the subject I did alot of trial and error and found that second line for the canister to create problems for me when I switched to the q45 throttle body. before that I did have it connected to the stock one but wasn't causing as much of a problem then.

 

thanks for that pro tip Ali I had no idea how functional that vsv was. I had taken that line off, after replacing it I'm back to "normal" 1 3 5 status but at least my fuel works.

So I'm good to go and try pin 78 for tomorrow or Saturday.

 

yeah keep the vsv line it connnects to the same spot on all the ecu's and will control the purge, its a pretty standard toyota process there is a purge vsv and a ported throttle body nipple on almost every model I have worked on, even the jdm ones.

do try the heater ground, at this point it makes the most sense, and if its not that we can cross it off and keep going. so the obd2 port on your car worked right away with the obd2 gte ecu? that is nice at least, should be some way to get it to run normally. does it say what the advance is at idle or when you rev it? I would really like to see some more data on that stuff I might even be able to find it faster that way.

I can't help but think the obd2 map is more tuned up now and thats why you guys are misfiring without doing headgaskets, but to install a headgasket and have it still happen would be alot of work so yeah, maybe add some e85 and see if it helps? do you have it in your area? I have added around 2 gallons to my half a tank several times (gas is heavy I only run a half tank) and it boosts the octane considerably, and since the gte ecu runs pretty rich anyways it actually works out pretty well.

 

Yeah I have been trying to get the logging function going with the scanner, I'll see what I can do. The advance is around 15 at idle.

I don't think the misfiring has anything really to do with the gas or head gasket since it eventually goes away. It seems more like a communication issues since it's specific to only three cylinders. There is some e85 around but it's pretty far out of the way.

 

So quick update, Pin 78 was already there and connected to ground. So pretty much at the same place as before.

I need to reset the tps, but I'm pretty lost on the misfire still. I might put up a quick post of supraforums as see if I can get anything.

Also I'll see if I can get the log function going tomorrow, it ended up raining on and off so I haven't taken the car out.

 

So the ignition break up / sputter is still there on cold starts.

What happens is when the car is completely cold, fire it up, it starts and idles fine. If I give it any gas it sputters / breaks up / wide band goes lean upon any throttle input.

The car warms up, and all symptoms go away. Nothing has changed, this is a new issue as it wasn't doing this before.

 

187, not sure what to suggest looking into at this point, I am fairly certain now that the USDM ecu is not going to run as well as the JDM ecu with this misfire stuff, and I am running out of ideas to look into on that front.

Hipsi, maybe you pulled too much fuel via the safc or its an idle air tps issue.
mine was doing similar with the 550's before I got the map ecu dialed in, and now that I did some adjusting in the software it runs perfect again. maybe do some fiddling around and make sure you are in the right tps zone, always put the jumper in after you are done setting the tps to see if you can hear the change in timing, if you can you are on the right part, if not then you need to lower the tps %

 

I tired to make a log today however the program reset all the parameters I had previously set so it basically logged nothing.

I'll upload a cold start log so maybe we can look at that and come up with something.

I would say the next steps for me would be coils, then if they don't work try the jdm ecu.

*edit- trying to attach a log of a cold start then a little driving.

the real data starts around 7000th cell down in excel.

**second edit- Also discovered to day that when trying to hold a steady 2500rpm if I turn on the a/c it stops it from surging up and down. I can't find anything on that.