Eat_at_Joes

i have everything hooked into my 93 pickup and still have the cel on.

the engine is from a 04 taco, harness and ecu are from 99 taco with a 99 throttle body. im using the o2 sensor from the 93 upstream with 3 or 4 resistance and the downstream from the 04. i do not have the ob2 port wired in so i cant pull codes.

other mods are spectre air intake (cone filter similar to k&n) and jba headers

when the truck is cold it starts then dies, but if i keep after it and let it warm up then it starts to get less rich and runs better. but if i punch the throttle it bogs and trys to die.

HELP ME PEASE!!!

BIG RON

I would start with the o2 from the 93 why are you using it? have you cleaned the mas air flow? get rid of that air intake and run a stock one.

Tragic Drive

I thought that Toyota started using wide band senors in 99 on the 3.4's.
You should really hook the diagnostic port up, but you already know this.
I'm also curious as to why you think its running rich.

Eat_at_Joes

im using the 93 because its closer to what the book (haynes) recomends for the resitance.
when it starts it smells rich and keeps producing a big smoke cloud.

ill try the sensor and swap the o2 and cross my fingers

BIG RON

closer to what????? the o2 made for the 99.............. close only counts in horse shoes and hand grenades........... get the right o2 sensor.

Eat_at_Joes

i fudged. the o2 is from the 04, but the engine still bogs. checked the mass air flow sensor and cleaned it, swapped it with a spare, cleaned the spare and still runs like crap. checked and rechecked all the vacuum lines and still come up with nada. i tried to pull the codes from the diagnostic under the hood on the 3.4 harness and failed. i dont know if im doing it wrong or what but need my truck!! i have 3 of the 4 wires to the ob2 hooked up and just need the batt wire to a fuse......... Could it be a fuse.....ill check that......but any other ideas would be great.

also on the mass air sensor does the plug side go toward the fender or the engine. i dont know if there is a right or wrong way but i could be wrong.

Eat_at_Joes

does the computer it self need to be bolted to the body for ground or does the not matter. right now i just have it resting in the corner and didnt really plan to bolt it down

vital22re

iTrader: (2)

there is a directional arrow on the mass air flow. Also if you feel like payin for a new computer later down the road, dont worry about bolting it. But um..I would. I also tapped into the 7.5 amp for ignition for my obd2 pwer source, only one when the key is turned on and its low amp rating just in case.

Eat_at_Joes

i got the ob2 hooked up and have the following codes.
p0100 mass airflow sensor error circuit
p0101 mass airflow sensor error
p0110 intake air temperature sensor circuit
p0141 o2 sensor heater fault (bank 1, sensor 2)

i also looked for the arrow and never found one on the MAF sensor

chopperbob04

Had a similiar problem turned out to be the cheap cold air intake.Threw the air filter away and put the stock air box on runs fine now.Do you have the rear o2 sensor hooked up?If not thats why its thowing the p0141 code.

Eat_at_Joes

cleared the codes and now it only has the p0100 code to it. i dont have the original air box so im going to try a few things on the intake tommorrow.

agusgus3

I had a similar issue with my 3.4 swap. My rich issue was due to running a '96 MAF and a '99 wiring harness. I found that there was a change in the MAF sensor pins, they switched like two of them between '96 and '99 as well as the design of the MAF. I just re-pinned the connector plug to the MAF and reset my codes, and ensured that all connections at the ECU itself are SOLID and tight. Now my 3.4 runs like a champ.

PS, don't worry about the intake or the headers, the ECU can compensate for that, as well as port and polished intake runners on my heads and 3" down-pipe/exhaust.

Eat_at_Joes

well the o2 is hooked up and everything that i can tell is nice and snug, but i still have the p0100 code. how ever i was able to get it out onto the road for a quick trip around the town. i noticed that while i would accelerate the engine would lose power. if i backed of the throttle i would feel a surge of power. this could be due to the maf error code (possible)

would i consider my maf sensors (as in the actual and a spare) bad if im not getting any resitance between the two points depicted in the service manuals? the maf sensors are the 5 pin type so i have no idea on this matter

also a nother side qeustion is when im montering the engine on the ob2 scaner should my o2 bank 1 sensor 1 run with a lessor value than my o2 bank1 sensor 2?

you guys are awsome for all the help to this point

agusgus3

First, yes the surge thing sucks!! This is specifically because of a combo of the MAF, and TPS signals. the ECU directly calculates how much fuel to inject from those signals and the ECT sensor, in open loop. After the engine is warm, the ECU will go into what is called closed loop, where it strictly runs fuel control off the O2 sensor signal.

If your still getting the p0100 code then there is something wrong with your MAF. You shouldn't have an open, that would mean the MAF is bad. There are two sets of pins you can test resistance. 1st, pins 3/4 are for the IAT sensor. then, i believe pins 2 and 5 are for actual air flow signal, both of which need to be in spec or your going to run into the rich problem. Pin 1 is +5V, power.

MAF PINS in correct direction should go 5-4-3-2-1 front to back, with direction of airflow.

As for the O2 sensors, B1S1 is directly after the engine, before the cat, and is the signal for fuel control when in closed loop(low idle). The first O2 sensor should oscillate between 1-5V regularly(like a sine wave), some scanners are not quick enough to read and it and will return an avg of those oscillations. B1S2 is supposed to be the sensor after the cat which is just an efficiency test for the cat, and the signal should actually be a relatively small/flat oscillation between 2-3V if the cat is working properly.

Hope this helps for now, I can get those resistance specs for you tomorrow, and I hope you don't have to buy a new MAF, they're pricy...

Eat_at_Joes

im getting closer to figuring it out (hopefuly) somewhere in the mess of wires lays a broken wire between my computer and the maf. the wire is the middle of the connector and goes to the VG terminal on the ecu. also the engine bogging was due to a split in a vacuum line. i think that also the MAF had oil on it from the air filter. cleaned the sensor and when i get a minute i will wash the oil out of the filter.

however the 02 error code still trys to come up once in a while. This i believe is due to the fact that the o2 sensors are from the 04 tacoma with a dual cat setup while i am running with only 1 cat. i was thinking would it be better to get another o2 sensor or go with a o2 simulator?

Eat_at_Joes

I WAS SO CLOSE!!

found the cut in the wire about 3 inches down from the MAF and fixed that.

I then took it for a trip around the city again after i cleared the code (at this point i had no codes! then came into town and filled it for the first time in 6 weeks. started the truck and that heart breaking orange light in your face That code came up as the P0141 or the 02s heater circut malfunction. so back to my question above with the o2 or the o2 simulator.

But while i wait for that to be answered heres some pics

agusgus3

If you build the O2 simulator yourself, you'd save quite a bit over buying a new O2 or another cat, which you don't need, btw. No one likes restriction

The heater circuit code sucks, replace it or simulate a new O2, or resistor inline to drop enough voltage for the ecu to think the heater circuit is working...

Congrats on the truck running, I feel your joy, I just drove my runner home tonight

BTW is that scoop from Summit Racing by chance?

Eat_at_Joes

Its actually from jegs. its a Wade universal hood scoop

mt_goat

An O2 simulator is to get rid of a P0420 code. I'd say install a new rear O2 sensor that matches what your year ECU is looking for.

Kiroshu

Theres a thing about MAF..... once they are cleaned.... theres a strong chance they will never operate properly again. Whether you have done it before or not this is a prob. You can actaully ruin a MAF by cleaning it. I'd replace it and or get one from a junk yard. Coolant temp sensor? Coolant in truck? Enough coolant in truck? Dirty Air filter? take the air filter off and see if it helps. You will prob never have a proper fuel efficent ratio due to the whole set up you got.... Tune-up?