tptpete

iTrader: (2)

Here's what I found:

on the MAP connector I get GND, signal, 5V. Signal is 0.1V which isn't the 0.7 - 1.7 alldata claims. Is the 5V okay?

The ECU pin B62 does not have continuity to the signal of the MAP. Bad wire then or a loose connector. There is a connector from the previous owner a couple inches from ECU so I know it is the wire, not the pin specifically (although the pin could be an unknown problem still).

I tried jumping the MAP signal to the ecu pin B62 with a wire... no luck on fixing the problem. I didn't expect it to with the 0.1V signal though.

Thoughts? I can't imagine a bad sensor and wire at the same time...

tptpete

iTrader: (2)

I measured at the ECU and at the connector. Idk what 'Check harness A" is or where to find it at the moment. I thought that was what I was measuring at.

tptpete

iTrader: (2)

Map sensor just read 1.7V... had a bad jumper wire when testing... always my luck. So it's a bad harness wire. Car seems to idle better. Although it is rich but it's looking more normal. No CEL either. I'll report in once I wire it better and drive it. Thank you all! Hopefully I will wrap it up quickly after work tomorrow.

tptpete

iTrader: (2)

I ran a new wire from the signal directly to the ECU pin. I will sort out a new location and run a more permanent solution then. Idle is normal, but at 12.5 afr (was at 10
1 but drive it for 10 minutes to temp). Haven't boosted it much, but the fuel trims seem less than ideal. Held 14.6 pretty solid up to 4 or 5psi. I was under light load. Wasn't trying to push it...

Should I unplug the battery to reset the ecu and see if thag helps the fuel trim relearn? Idle is up to 12.8 at this moment so it's still sorting it out I think. Any reason my new wire wouldn't be the best method? Seems to be all that the map is connected to.

Ali SC3

iTrader: (10)

sounds like you found the bigger part of the problem. yes after that you have to reset the ecu, its fuel trims are probably all over the place unless you want to drive it like that till it relearns. I would suggest a reset and start it when its completely cold, like a morning first start.

these map sensors have to have continuity on the signal wire to see any voltage, so it did sound like a bad wire. once you have continuity if you still didn't have that right voltage range then it would be a bad map sensor. if there was no 5v on the third pin, then that would mean bad ecu 5v driver has been shorted out.

reset is and let it learn again on a cold start. make sure its getting the boost signal from a good spot.
Was the car ever boosting normally on this ecu, or all around driving normally? or did it just happen all of a sudden.

187

So gave the vpc tuning a go, forced the car into closed loop by unplugging the 02 sensor. I went from about 6.0 g/s of air down to 4.6 g/s which put my idle afr around 14.3 in cloded loop. Put the car back into open and the idle stayed between 14.6-15.5. Took the car out for a short time today, immediately noticed some hesitation between gear shifts (a problem I had previously). The car still hit 10.0 at WOT, it did feel/sound a little better but it was still pegged 10.0 after a second or two.

I know I'm forgetting a couple of things I wanted to mention so I'll probably edit this later.

Ali SC3

iTrader: (10)

sounds like the vpc might not have enough adjust ability because the tune as a whole is off. I just read they have like an A chip for stock, I think B for single turbo, c for single and cams etc... you might be having issues due to the wrong chip. I am no expert but might need the b chip I think?? that is why I just use the map ecu you can upload whatever values you want to it, although it still take quite a lot of time to setup.

check out these threads
http://www.supraforums.com/forum/sho...ip-info-needed
http://www.supraforums.com/forum/sho...o-ecu-question

seems like people who are single turbo on those USDM ecu's run the B chip which is 680cc injectors with single turbo and in tank fuel pump upgrade. so if you got the right chip and went with 680cc injectors, it might just work a whole lot better. that does seem like a whole bunch of fuss though so you may just want to flip the VPC and get something else which can work with your current injectors, or try and get the right chip and get the right size injectors again. if the B chip and 680cc injectors work though you wouldn't need much tuning but alot of those guys ran a VPC with B chip and a safc to also trim the fuel it looks like. thats a lot of piggybacks but if you can just get away with the chip and injectors thats not a bad idea.

tptpete

iTrader: (2)

I will reset the ECU tonight.. been on a vacation out of town and didn't get to it this morning. I will let you know what happens.

The car has ran well on this ECU up to this point. Other wires have continuity and good voltage. There was some oxidation on the wire when I cut it so that could be what happened after a little water got in there.

187

Thanks Ali, I'll double check those chip numbers over the weekend. The one thing I forgot to add is when you disconnect the 02 sensor it doesn't trip a code which I though was odd. The application I use says insufficient engine temp open loop.

I think I'm going to end up playing with the tps/throttle again and put the vpc back to normal. Probably do some more research on open loop. I don't think the car operates correctly in open loop mode at all.

Ali SC3

iTrader: (10)

open loop is without the o2 sensor, closed loop is with the o2 sensor.
it should trip t he code after it gets up to operating temp for the o2 sensor, wont always trip it right away.

the key to getting it to run well is open loop being decent without o2 correction.
make sure the map sensor has a good line to the manifold, if you have to tee it tee it with the FPR.
it can make quite a bit of difference if its connected to lets say like a vac block, usually causes hesitation.

187

Yeah that is what I found funny about the 02 sensor, it doesn't even trip a pending code in the ecu. I'll work on getting that open loop in line and see what happens.

The map is tee'd in with the fpr.

Ali SC3

iTrader: (10)

yeah I am not sure what is up with that, when I disconnected mine I don't think the light came up either but it was a while ago, might try it again and see what happens.

tptpete

iTrader: (2)

@Ali - I removed the positive cable from the battery for a few minutes, may not have been long enough.. but driving the last 20-25 miles it seems to be okay. Fuel trims don't seem exact, still rich across the board, but I will remove it longer and reset it or wait for it to adjust some more. Not bogging or any of that though.

Ali SC3

iTrader: (10)

it doesn't take long for it to reset, I only go like 20-30 seconds, so you probably did it right.
usually give it a few drives and it will learn some stuff.

187

So gave open loop a try, it works for a while until it trips a code and the AFR moves around like the computer is confused. I did check my chip today also, it has no number on it but is marked A in what looks like sharpie. I sent a PM to a guy on SF to see if I can pick up a B chip for testing.

After I pulled over and plugged in one of the two heated 02 sensors it was back to "normal". I did also get a P0125 which is basically the computer recognizing the 02's are not responsive. Kind of a weird code, because it references coolant temp but is actually caused by the oxygen sensors. I still don't really know why it cant handle closed loop, the only thing I could really do is try moving the iat around.

On a more positive note my new short shifter feels great.

edit- Also stumbled upon this while researching. Seems like the IS guys uise this because of some weird issues I'm looking into.
https://splitsec.com/product/esc1-na...l-conditioner/

I'm running just one of the two heatsed 02's currently, the ecu seems to be happier this way and no codes or anything.