Ali SC3

iTrader: (10)

I don't think it has much of an effect except you will need to gap the plugs down to around .024 with the stock distributor (at least I used to have to). the 4runner cap can cause problems but it also worked for a while for me. I have seen 500+hp setups on the stock distributor, stock cap and stock rotor, just the plug gaps were horribly low and they could have made more power on coils. for a basic na-t though its not needed but having to use that 4 runner cap always rubs me the wrong way.

Your issue might still be related to using a maf on a single turbo with the US ecu. it might need a map conversion to run 100% right, or it might run the same, hard to tell without experimenting.
The JDM ecu is so much easier really glad I have a 95 now, I thought this usdm stuff would be a walk in the park but not turning out to be the case.

187

Well I can't really be sure until the misfires are gone and the high idle comes down. Right now the goal is to get it drivable and be able to pass inspection. I kind of want to get rid of the distributor just for clearance, but the car has to run first lol.

I'll be investigating the distributor over the weekend along with a new battery. Also this whole distributor situation makes alot of sense because I did have a weird noise coming from the distributor not to long ago that went away after I took it off looked at it and reinstalled it.

I kind of wish I had a 95, but finding and sc at all around me is a challenge.


Update 1/31/15

Found a couple vacuum leaks that I solved, made no difference really. Cylinders 1 3 5 misfires + the random misfire code. Still need to look at the distributor but ran out of light for the day.

Looked for a little bit and some ppl have this issue with v6's so trying to look into that more. 1-3-5 are the first cylinders to fire so not sure if that matters but people who have this issue often having timing issues or ignition issues.

Any idea why the 1, 3, and 5 cylinders have different colored injector plugs?

Ali SC3

iTrader: (10)

1 3 and 5 have the same coloe, 2 4 and 6 have the same color, its so you don't mix them up when installing them they are supossed to alternate. so if you have 2 grey plugs or 2 brown plugs next to each other, you messed up, they should alternate.

did you swap the plug wires when you did the 4 runner cap mod. 2 of the plug wires need to be changed out I think, its been a while. I would get that off there its like 5 screws but rerouting the plug wires might need to take the intake off, can't remember. you can just run the stock cap and rotor, and run the turbo without the filter as a test, or fashion some sort of slimmer filter for testing. I remember I could clear the stock cap and rotor with a 3" intake pipe, and it didn't hurt the performance that much. since 3" is closer to the maf size on a supra TT you might just want to try that, can you tell how much I dislike the 4runner cap? its meant for a v6 not a I6, so while its close there are some small differences that others seem to gloss over, besides the fact that only 2 of the 3 bolt holes line up.

I cannot deny that it works, but it seems for some it works better than others. I had a bad distributor shortly after using it myself, but it might have been because my rotor went bad before I changed it, couldn't really say for sure what broke it, but I did end up replacing it at a certain point when I was on an aem ems, I couldn't go past 2400rpm's or so the crank signal was so bad.

187

Yeah I was just curious about the colors. The cap is set up correctly, I have to get some stuff from home depot to test the cap. I can't find any good info on this because all kind of people claim different things. Alot of subarus and v6's in random cars get the same symptoms with different results.

Hopefully the cap makes something happen or I'll have to make some significant changes.

Ali SC3

iTrader: (10)

there are hundreds of reasons to get the misfire code. I personally think its the maf setup after reading on supraforums. don't read just for any car, read for ones that are more similar to our situation, as in 2jz-gte ecu and single turbo with maf (which covers basically all obd1 and obd2 supra mk4's that are single turbo but still on stock ecu, obd2 will have the same code as yours). na-t or gte wont matter much in this situation. based on what I have read they all pretty much convert to map with the single turbo. in fact, I can hardly find a picture online of a single turbo supra which still has the maf.... you get what I am saying, its not commonly done probably cause of an issue like misfires.

187

I looked for information on 2jz and the misfires but didn't find much. The only threads were is300's with aftermarket intakes/exhaust with varying results.

For now I have the time to play around with the car so I don't mind so much for the time being. I see a new ecu in the future, but I still have to pass inspection somehow.

I'm still kind of bothered by only the first half of the firing order missing.

Ali SC3

iTrader: (10)

has it only ever been those 3 cylinders?? maybe you have a problem with one of the 2 cam sensors... one indicates top dead center for cylinder 1 and the other for cylinder 6. any discrepancy could confuse the ecu such as an erroneous trigger on one of the cam sensors would throw those 3 out of alignment and potentially cause a misfire, but I would expect other codes to come up though such as a sync error which is a general crank sensor error in all honesty so I don't think its that.
just trying to think what would affect half the cylinders, particularly the first 3 in the firing order (is a bit weird).. you sure you got those injectors wired up right?
you may want to even just test the injectors with a multi-meter just to make sure one didn't short out or something (longshot.. last resort sort of thing).

I would still change the cap at this point and disconnect that extra crank sensor like I said and see how it fares.
It could just be as simple as the cap (hopefully), cause the first 3 spots on the cap will fire off those coils, and as I said before there are only 2 screws out of the 3 that hold the cap down, and any misalignment of the cap/rotor could cause issues as the spark has to jump the gap remember. as the gap increases so does the resistance and then the spark fizzles out. If you play with the cap and the misfires change cylinder numbers, that is probably the issue.

did you remove the distributor at any point and re-insert it?

187

Yeah the injectors are fine you can't make a mistake with the stock plugs, I also checked #1 with my multimeter and it was within stock spec.

The cap certainly has some play though I couldn't get any change out of moving it. And the distributor did come out way early in the build when it was still N/A and was returned properly. Never had any misfires after it came out or after the install of all the parts.

Ali SC3

iTrader: (10)

so you still have the misfire issue... what about mylexsc400?? did he abandon ship?
was there anyone else with misfires on the US ecu.. just trying to take inventory.

have you disconnected that extra crank sensor yet, its just 1 plug behind the alternator.

187

No I didn't try unplugging that sensor. What was the idea behind that again?

Ali SC3

iTrader: (10)

that it might make your problems less severe.

the gte has one 12 tooth crank sensor on crank (actually on the oil pump next to crank), and two 1 tooth cam sensors. All 3 of these have their own grounds.

The ge distributor has one 24 tooth crank sensor (1 cam revolution = 2 crank revolutions), and two 1 tooth cam sensors. All 3 of these share a ground.

The 96+ge has an extra crank sensor on the oil pump (same place as the gte one but not the same use) and on the GE it has around 30 something teeth (more accurate enables ecu to easily detect misfires on 2jzge 96+ ecu's for emission purposes), and I forget if it uses the same ground wire as the distributor or a separate one, but I do know that all the grounds for cam/crank sensors are connected INSIDE the ecu on both a ge and gte ecu's.

So basically what I am saying is that leaving this extra crank sensor in that the gte ecu does not know about and is not looking for could potentially have a small effect on the main crank sensor signal (noise). its a longshot but makes sense to me, as I am looking for something that would cause all the obd2 na-t's to have misfires, and all of you have this extra crank sensor from the factory that obd1 just does not have at all, nor does a gte and that goes for obd1 and obd2 gte neither have it as the main crank sensor 12 teeth is already in that spot.

myLEXsc400

Sorry,

I haven't been looking at this thread for a couple months, because the car has been in storage for the winter. What is it that i missed? Because, yes, the car is still misfiring on all cylinders.

Ali SC3

iTrader: (10)

Still trying to figure out the whole obd2 issue. the misfires can't just be a coincidence, I am thinking something might be messing with the ecu to cause it. so disconnecting the second crank sensor is my latest theory, the plug is right behind the alternator if you guys want to disconnect it and report back any changes. its not needed with the gte ecu at all. This might be less of a USDM gte ecu issue and more of a 96-97 SC issue.

187

I'll give it a try after I try the distributor swap (if it doesn't solve the problem). Hopefully I can get it done Saturday after work.

lilSCsteve

iTrader: (71)

Tons of useful and great information here! I can't believe I didn't look into this sooner? Hey thanks Ali-you're knowledge shared has helped so many folks out! Thanks man.

steve