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Hey guys, I'm stuck on my car and I can not figure it out. It runs nice, revs nice, idles pretty decent too. My problem is I can't get the car to go into diagnostic mode so I can set the base timing. No matter how I try to set the tps it does not work. I got a toyobd1 scanner and it does not show any movement for tps. It is a ffim with 90mm and counter clockwise tps. I have wired it both ways and still nothing shows up. I haven't given it a good drive yet but going around the block its smooth as butter. I'm scared to go into boost consider I don't know my timing.
92 sc300
aristo ecu, s360, r154, vvti coilpacks.
Ok, my Aristo ECU came in the mail today. I popped it in with fingers crossed, but as soon as I turned the key codes 31 and 41 popped up. Tried to start the car and no go...
First place I went to was the ECU pins. Pulled the yellow cap off and confirmed that everything was tight. The pins that I swapped were just as tight and flush with the female face of the connector as all of the others and wouldn't budge with a bit of a pull on the back.
I am thinking that the issue is potentially with the singal wire where I connected the MAP sensor into the old MAF harness, or somewewhere between there and the ECU. Again, I refer to my recent multimeter readings...
All are MAP Signal to MAP Ground:
@ MAP-
Ignition on, MAP plugged in = 2.70V
Ignition on, MAP unplugged = .14V
@ old MAF Connector-
Ignition on, MAP plugged in = 2.70V
Ignition on, MAP unplugged = .05V
@ ECU-
Igntion on, MAP plugged in = .05V
Ignition on, MAP unplugged = .05V
Here is where I connect my MAP into the MAF. The wires were all pulled out of the connector, then the insulation was pulled back, wires were soldered, then shrink-wrapping was slid over before the wires were popped back into the old MAF connector. I suppose I could have just cut this connector off and wired directly into it but I figured it would prove useful for troubleshooting.
A few notes:
The potentiometer was wired in parallel with the IAT in an attempt to bring the GM IAT in more closely to the factory Toyota IAT specs.
The IAT (and thus potentiometer) both use the brown sensor ground on the left
The black group of wires coming in from the top that says "22 3 C Rotor" houses the three MAP wires-
Red = +5V (connects to MAF Blue/Red)
Green = Ground (connects to MAF brown, with IAT brown and 1-side of POT)
Black = Signal (connects to MAF yellow/green)
Everything here look OK? There is some exposed wire on the MAP signal but it just happened as I cut the heatshrinking off these wires...i'll seal it up before closing them up again.
It kind of makes sense to do it like that but it doesn't look too great, I am not surprised you have a bad connection there with that kind of splice.
The stock wires are usually a little brittle by this age, my bet would be the signal wire strands that you tapped into have broken towards the ecu side of the car.
either that or the wire isn't moved from 66b to 62B and seated properly, but sounds like you checked that.
So open up the signal wire and make sure the connection is still good towards the ecu. you can even do a continuity or resistance test from the connector to the ecu pin, that will tell you right away.
My suggestion, cut all that off and rewire it directly to the existing wires, and leave out the potentiometer, you do not need it. I think the way you have it more wires could become detached in the future.
Leave yourself a few inches so you can reconnect the maf connector if you ever need to, I have never reconnected one personally once you go map you never go back.
The only wire that should have 2 wires on it is the ground wire. you could also try running the map sensor ground to the other ground wire, but since you are getting a signal on the map output, sound like you got the ground and power right and the signal is just not getting back to the ecu.
dav is that the GTE main tps? opposite of the GE tps? if so then flip the pins from stock like you noted. that should do it, maybe try another tps or check the wires for power ground, see what the signal is showing, and if the idl wire is opening or closing when you move the tps.
To be honest I'm not sure what tps it is. Its the only one i could find thats counter clockwise. I have already flipped the pins and still cant get it in the right spot. I'm not too good with the multimeter but I will do some more research on it and give it another try. One more question for the o2 sensor, my sc is calispec and it has a 4wire third sensor. I extended the plug and attached to a new 4 wire i have on the downpipe. Now for the pin swap at the ecu, will it be the same color at both ends? I would have to swap B46 into B48? I've been following this thread since the beginning its just so long its hard to find anything. Thank you for starting this thread!
you should just have to swap the signal wire over at the ecu to the right spot.
I don't remember anymore but its one the first post where you need to move it to, where the pin is I would look it up.. wire color should be the same color but cant say for sure.
you will know about a minute after you start it if you have an afr gauge, itll start moving around and go from 14-15 a bunch.
It's hard to say for sure with this mod. everything has to be working and with used stuff its questionable.
I can say that a majority of the time its a wiring issue, then followed by bad map sensors, and I think there have been a few bad ecus.
If everything was working though and it just randomly started doing that one day, I would think there is a bad connection or wire damage somewhere, or a pin that wasn't fully seated came loose.
As i said earlier, I would check the pins at the ecu again, pull off the connector, remove the yellow cover, remove and check the pins and also the locks, make sure you hear the click when you put the pin in.
how did you install the map sensor, you said you could check the maf connector, normally you remove that and reuse those wires, please don't tell me you used wire taps off the original connector.
you need a really good connection for the map sensor back to the ecu, crimp or solder is about the only right ways to do it.
I remember at least 3 people in this thread somewhere that didn't seat the connector pin correctly, and I have done it myself a few time early on.
I don't think you can fry anything by unplugging the tps or the map sensor, even if the key is on.
its just if you short the signal or power wire to ground, then you have a chance of things getting damaged.
I personally would not bother with rebuilding the ecu. I would find a used working one but your problem could be wiring still.
Ok, all fixed, and it was something so simple I'm embarassed to post it but for the sake of giving people one other absolutely ridiculously simple thing to keep an eye out for...
So I went through all the wiring and focused on the connections at the ECU. I'm using a fields harness as I didn't want to hack up the factory harness when I was originally doing this mod. It also made it simpler to solder in all of the connections. Anyway I did notice that the connection from the factory harness into the fields harness was a little loose (i.e., not bolted all the way in), so I tigtened that up a bit and it moved in maybe 1/8". As I was doing so I also realised that I needed to check the connections on my SAFC NEO connections as this was obviously in-line of the map sensor wire. That all looked OK, so I was going to try to set up the NEO so that it effectivelly acted as a node and didn't influence the settings when I realised that, somehow, the sensor type was not set to pressure, but to Karmen or something else.
Not sure how/when this was made...I seriously doubt my father would have touched the computer. My money is on me accidentally doing it when I was trying to get into the "sensor check" function to see if I could read TPS voltage now on the SAFC NEO with the new TPS sensor. I will say that I don't know if it is my color settings or what but the menu selections are a bit hard to see, and it is also ridiculously easy to mess up the sensor settings; just highlight and hit "back", no confirming or anything. Thus it would have been simple for me to make the change without noticing. This still doesn't explain how/why the AFR's miraculously changed from 10:1 to 14.7:1 and all CELs when off when the car was idling one time though.
Anyway, as soon as I both tighened up the harness and fixed the sensor type the car started right up and ran as per normal. I took it out for a spin and the car effectifely ran like it did last summer; rich without the SAFC NEO leaning things out. I used the NEO to tune it to about 11.2-11.4:1 AFRs and still would break up a bit under boost (running up to 12psi - stock head gasket). The break-up got worse and worse pull after pull as I tuned the car until it was running on 4 or 5 cylinders and sounded like a Subaru even at idle. I limped the car home and found again that you could actually see the center coil arching to the head. I was worried I had fouled my IK22 plugs but using a long screwdriver I managed to better sit the coil onto the #4 plug and the idling cleaned up immediately. The car runs great now, except under boost it still breaks up.
I have had to head overseas again but thankfully will be back in early September for a week and a half. While away I will be ordering new IK22 plugs (that I will gap down a bit) and coils to drop in. Fingers crossed that cleans it up under boost which will be the last of my issues.
It is very difficult to foul iridiums that fast, I have abused them over and over again and they usually work just fine after a proper cycle.
I would guess maybe just the gap is too large then. pull one of your easy plugs and see what gap you are at.
I always ran the Bkr7eix or Bkr6eix. the ik22 should be fine. at your boost you should be ok with a .032 gap but maybe start with .028 and then work up from there.
I have done that before with the safc, its not difficult to do. sometimes it can even reset and needs all the input info again.
glad you got it figured out, should be easier from this point now lol.
It is very difficult to foul iridiums that fast, I have abused them over and over again and they usually work just fine after a proper cycle.
I would guess maybe just the gap is too large then. pull one of your easy plugs and see what gap you are at.
I always ran the Bkr7eix or Bkr6eix. the ik22 should be fine. at your boost you should be ok with a .032 gap but maybe start with .028 and then work up from there.
I have done that before with the safc, its not difficult to do. sometimes it can even reset and needs all the input info again.
glad you got it figured out, should be easier from this point now lol.
Haha, yeah definitely easier to drive the car with the MAP signal not being broken by the SAFC.
The IK22's are at the factory .032. I do recall you saying that they are ridiculously hard to foul. The car also runs perfect off or part boost so perhaps I will just go to .028 and pick up one or two spare IK22's so I don't get stuck if I accidentally break one of the electrodes when re-gapping them.
I will let you know how I make out with the re-gap and new coils.
Yeah gap them down to .026-.028 then. you are getting breakup earlier cause of the stock compression. gapping them down is the easy part, its if you go too far and have to open up the gap.. that is usually when they break.
Just want to post this here as it may or may not help: on 12 psi, you shouldn't be getting breakup. Im currently on 15 psi with the stock hg, 8 degrees of timing (Jdm TT 6 speed ecu btw freshly rebuilt), Vvti coils and BKR7eix on drop in gap. Pulls good no break up.
My boost controller kills boost at 15.5 psi but on some pulls it wants to pull beyond that and pulls clean too.
Yeah i'm at 18 psi on is300 vvti coils and drop in plugs, don't remember exactly but i think TT Supra spec Densos... no breaking up under boost at all and i'm running super rich on my 440s that raise to 500's 50 psi
I remember having to gap down to .026-.028 on the stock distributor, but with the vvti coils I was fine with the .032 stock gap but I did have the tt headgasket.
maybe grab a set of the Bkr7eix isntead of the ik22. there may be some slight differences between the 2 plugs even though they are both iridium.
you could also have an issue with a coil being loose, make sure they are seated well.. if the boots are worn you may need to find a way to wedge them in place in the valley above the coil.
Also its worth mentioning that with the SAFC, you shouldn't make alot of changes while its running.
I have found that it really confuses the ecu cause the ecu records the map signal when you first turn the ignition on so it knows atmospheric pressure with the engine off.
then it makes adjustments from there, so if you adjust the map signal while its running, you have messed with the whole offset the ecu uses, and when you start it up the next day, it wont run the same cause it will grab a different atmospheric pressure reading cause of the safc changes that were different the day before...
It does this so the stock ecu can compensate in different altitudes easily, for example, in denver at a mile high we see almost negative 2 psi on the gauge with the engine off. so making map changes on the fly without correcting the original reference will just make you keep going in a circle.
like on a map ecu, you can actually set the initial reference point at 0 rpm's that goes to the ecu so it doesn't change and means more consistent.. until you try and drive up a mountain or something. I always preferred the ecu grabbing this value from the map sensor vs always using the same value, so you could drive up and down across the country.
In short, this is how I do it. Set the SAFC where its close and then drive it around a full cycle. you should have a decent idea of the adjustment you need to make as its usually across the board except for the high rev ranges. adjust the SAFC before your next drive, and be sure to cycle the key on and off before starting the engine.
after a few drives you will home in on the right value.
08-09-18, 12:12 AM
