Tranny swap - Check Engine Light finally fixed!!!!! wOOOh0000!

[Ratko]

Well I finally did it, after 13 months of living with my Check engine light, I finally tricked the stupid 1MZFE A/T ECU into not throwing ANY codes. I could have done this from day 1 had I done more research into the electrical theory behind the solenoid circuits. Here it goes...

The codes I first got after the swap were:

P0750 - Shift Solenoid A Malfunction
P0755 - Shift Solenoid B Malfunction
P0770 - Shift Solenoid E Malfunction


Then after a while they changed to:

P0754 - Shift Solenoid A Electrical
P0758 - Shift Solenoid B Electrical
P0773 - Shift Solenoid E Electrical


These second set of codes are the ones I was afraid of, because the ELECTRICAL codes are the codes that specifically throw the ECU into fail-safe mode (aka. limp mode) which sets the ignition timing to 5 deg BTDC ACROSS THE WHOLE RPM RANGE and a predetermined injector duty-cycle! Can't have that, especially when performance was the purpose of the swap in the first place. Hence the significance of this solution!

For each solenoid, the ECU expects from 10-16 Ohms of resistance. So 12 months ago, I went to my local electronics depot and picked up three 10 Ohm - 1/2 watt resistors. When I tried them out, they all melted on me, so I figured that I was either wiring it wrong, or that resistors would not cut it. So i went out and got the same 10 Ohm resistors except in 1 watt versions. Melted the same. So I took it to my mechanic, who tried some ghetto tricks with a light bulb (hehe) but nothing came from it. I emailed all the big ECU boys from the Supra forums, MR2 forums, Celica forums, basically anyone with Toyota ECU experience. Everyone pretty much told me the same thing: A) Go standalone, or B) Get a M/T ECU. Little did anyone know that the 94 1MZFE that I have in my Camry was never offered in M/T and all the 97+ 1MZFE's that WERE offered in M/T, had altered ignition and EGR setups from the 94 1MZFE so that was also out of the question. For a car with no engine mods, I thought it was more than a little redundant to go standalone on a bone-stock engine just to clear the MIL.

Anywayyyyys... It dawned on my a few days ago, after reading up on Honda-tech about some turbo guys wiring up DSM injectors with resistors on them and using 10 ohm 10 WATT resisters to get them to run properly with their Honda ECUs. So it hit me that I needed to do the math for my particular circuit. Here it is:

------------

V = 14 V <-- car's electrical system
R = 10 ohms <-- solenoid resistance

V = I*R (ohms law)
I = V/R
I = 14/10
I = 1.4 amps

P = I*V
P = 1.4*14
P = 19.6 WATTS

------------

So there we go!! The resistors that I was using before were WAYYY too weak and couldnt disperse the power sent to them so they were burning up. This afternoon I rushed to the electronics store and picked up three 10 ohm 20 WATT inline resistors and wired them up each to the solenoid wires coming from the ECT Solenoid harness which used to plug into the automatic tranny. (MR2 guys with a V6 swap can do this straight from the ECU if they dont have this harness - pinout below):

Solenoid 1 (A) (S1) = Violet (Pin 11 - E7 plug on the ECU)
Solenoid 2 (B) (S2) = Pink-Blue Stripe (Pin 17 - E7 plug on the ECU)
Solenoid SL (E) (SL) = Yellow-Blue Stripe (Pin 27 - E7 plug on the ECU)

I just wired one end of the resistor to the solenoid wire, and the other end to a chassis ground - Here is a quick pic I took just now. I will grab a small project box from Radio Shack tommorow and make a clean looking resistor box:



...and the ECU gives NO CODES!!! Woohooo!! Hope this helps everyone who plans on doing a tranny swap in the future. I can now say to all the nay-sayers, that my swap was FLAWLESS. Thanks to Sharad for lending me his '94 Lexus ES300 Repair manual, big helpl!!

Happy as a pig in shit,
Ratko

[Silver Streak]

Holy crap, congrats!!! I thought you'd have to live with that prob forever. Funny, I was just reading about your tranny swap the other day and read that part about the broken EGR vac modulator....

Who knew physics would come in handy these days?

[Nick]

good job man! resistors are the way to go, had to add one when i switched my stereo

[Ratko]

Originally posted by Silver Streak
Holy crap, congrats!!! I thought you'd have to live with that prob forever. Funny, I was just reading about your tranny swap the other day and read that part about the broken EGR vac modulator....

Who knew physics would come in handy these days?

Yeah. That issue kinda came outta nowhere because i had the CEL on constantly so all the legit problems I was missing. And it turned out I had a "Insufficient EGR Flow" code which in turn affects the car's timing negatively. Glad I caught it.

[Nick]

is the car running better now?

[Ratko]

Originally posted by Oldman
is the car running better now?

Much. Its more consistent, but Im still cursed with the '94 knock sensors, and although I dont have an MIL anymore, I can feel the timing being pulled still - from the oversensitive knock sensors. But that will be taken care of soon, now that I have more free time.

[Nick]

relocation?

[Ratko]

Originally posted by Oldman
relocation?

Yes. But Im debating whether I should just get new sensors. You see, I have 265,000km on my engine with the ORIGINAL sensors, so I figure they might just need to be replaced. Another theory I have is that they may be over-torqued which would cause them to be overly sensitive. They only need about 25-30 ft/lbs of torque, so it MIGHT be possible that my mechanic may have over-tightened them during my last major tuneup (if indeed they were removed at all, but whatever - does hurt to see).

[alex]

hey ratko...can i have your car?

[Stealth]

Yay! Now you can do a tranny swap for my 4 cyl when I break my autotranny (been driving it a bit hard so maybe in a year or two ;-) ). Also maybe then I'll have money for a 5sfte, would be fun if nothing else to have a Camry sleeper, but you just can't have one that's automatic.

[Nick]

look at tony, once he has his super auto tranny,

[Tony the Tiger]

Congrats Ratko! When you asked me the question of how to fix your MIL codes, I was stumped at the moment. I never thought that your ECU only needed a constant amount of resistance because I always expected the resistance to be "varying" as the tranny shifts through each gear. It's amazing that you managed to hack through the ECU and fix the problem

Now all you gotta do is replace/relocate the stock knock sensors to get all your timing back...haha....damn Toyotas and their oversensitive knock sensors and "pull-timing-happy" ECU's

[Eye8Pussies]

congrats, man- know that was probably always a constant bitch in the pants having soemthing not perfect with your car!


and wheeeee......now finally moving on to fixing those knocksensors! :p

[Ratko]

Originally posted by Eye8Pussies
congrats, man- know that was probably always a constant bitch in the pants having soemthing not perfect with your car!


and wheeeee......now finally moving on to fixing those knocksensors! :p

No doubt buddy... I just gotta get rolling and order those gaskets. I know its gonna be at least $100 just for new manifold and throttle body gaskets alone.

[Tony the Tiger]

Originally posted by Ratko


No doubt buddy... I just gotta get rolling and order those gaskets. I know its gonna be at least $100 just for new manifold and throttle body gaskets alone.

You can get away reusing the old gaskets...they are metal and they are resueable. I am still on my old intake manifold, air intake chamber and throttlebody gaskets after at least 5 times of dissassembly Just give the gaskets a good cleaning and clean the mating surfaces and you are set.