cr@ves4wheelin

'98 T100 ECU w/ 2004 Tacoma Wiring, all in my 1990 Toyota Pickup.

Prologue: I got it running, stumbled pretty badly. Checked the code, it was for MAF. Figured out the pins were mismatched, fixed that. Next, the truck was still stumbling, checked the spark plug wires, found out half of wires was "gutted out". Replaced them, and motor runs a lot smoother.

But there's a problem, the engine light is flashing, while it is running. But there is no code the ecu is throwing. Also the motor still kinda stumbles and runs extremely rich.

So I looked into the test data, here's what I got.

Attachment 122623
Attachment 122624

The chart from toyota techinfo:

Attachment 122625
Attachment 122626
Attachment 122627

So basically, according to this mode$06 data:

1. My new cat is getting screwed up based off of what the ECU can read.

2. The ECU is detecting a pressure leak because of a disconnected vapor sensor?

3. The O2 sensors heater circuit is incomplete, because they are non-existent.

So my questions are:

1. Were the symptoms the same for you guys when there are no O2 sensors in the system?

2. Why are all the vapor pressure sensors I've found have 3 pins? And all the wiring diagrams only show 2 wires going to them? Where's the connector even at? And do you guys even run them? I've searched, but most threads kinda avoid the answer when people ask.... Can you show me what you guys did, wiring-wise?

I currently just have the 3.0 evap canister, with the purge port hooked to a constant vacuum. That is it, no vsv or nothing.

cr@ves4wheelin

Never mind I found the actual vapor pressure sensor wiring on the EWDs, there are 2 labeled the same name. But they do different things. Still curious on your input though.

cr@ves4wheelin

Just wanted to end this thread by saying, the o2 sensor and evap stuff did solve the issue. It's runnin great now, but I got a high idle issue to figure out now. ECU is saying TPS circuit, which I just figured out, by continuity test, was because I put the pins in wrong on the TPS side. I don't know if it will solve the high idle issue, but we'll see i guess. Really nervous.

89934runr

Are you still running the constant vacuum to the purge port? If your cannister is still linked to the tank, that will basically be in a state of constant purge (not good). normally, the ECM knows when it is in this state & compensates by running a slightly leaner mixture with a small bump on the IAC.

Since the engine doesn't 'know' the purge path is open, your mixture will wind up being fat (short term corrections will probably be a little high as well).

cr@ves4wheelin

Thanks for saying something, but no, I ended up running the correct evaporation system vacuum routes with the diagram from elvotas 3.4 swap. So it doesn't have constant purge as it did before, and it has all the vapor sensor and vacuum switches now.

Fraser

Were you able to fix the high idle problem?

cr@ves4wheelin

Yeah, just a stuck open IAC.

Oregon'sLoneWolf

By stuck open were you able to just clean it with carb cleaner or something? Maybe varnish from it sitting? What cured this man?

cr@ves4wheelin

In some cases you can, but I ended up breaking mine trying to get it loose. That big green Plug under the intake is an electromagnetic coil I'm guessing. Cause when you take it off, you see there is a round magnet attached to the flap, that will turn at a certain degree depending on what the ECU tells it. The magnet is super brittle by the way, and mine was rusted to crap so I just had to get a new one. The flap should turn super easy, and I couldn't budge it, so when I took off the plug to turn the magnet manually, it shattered lol.