Toyota Tacoma Forum banner

2RZ-FE with simultaneous injection

4K views 15 replies 5 participants last post by  crystallattice 
#1 ·
12345
 
#4 · (Edited)
Sorry for the first few numbers in my posts, couldn't post this thread as it "contains URLs" ??? and I can only post those after 15 posts. Then you also have to have at least 5 characters in a post....

So I procured a secondhand 2RZ-FE ECU as a donor for a Mega squirt conversion if all else fails....

Wasn't expecting it until next week when Santa showed up on my doorstep today!

I opened the ECU to have a look inside and saw two transistors mounted on a heat sink: "Yes, those are the injector drivers..." I said to myself...

Bu the part numbers differ?? Then on closer inspection I realized that the #10 and #20 pins are wired together and go to one transistor?? WTF??

So my mission to find out why this thing is so heavy on fuel might have paid off!! I guess that splitting them up into 1&3 and 2&4 as they are wired up in the loom would improve it quite a bit over the current method right? This will obviously require a aftermarket ECU or ECU swap...

What does the 2RZs have around there in the states??
 
#5 ·
What is the part number on the ECM you received, and what vehicle was it designed for? :shrug:

Pin designations can change from year to year and model to model. I've seen cases where pin designations vary between Tacos with the same engine.
 
#6 ·
My vehicle is the 2RZ-FE base T.U.V known as the Condor/ Unser/Kijang

As my original posts state this thing is notoriously heavy on fuel, yet a 22R or 4Y carb motor can get better economy.

I'm determined to improve it or at least find out why it is so bad. So far I've discovered the following:

SOHC vs DOHC in US version engine
No oxygen sensor vs Narrow band in US
No Knock/CAM pos/crank pos sensors
VAST distributor system
No EGR

Now I've discovered the injectors are simultaneous. Not sure how the US ECU fires the 2RZ injectors.

I think that these small refinements will make it perform like an EFI system should!
 
#7 ·
Ps. I will get the partnumbers later as my ECU is still mounted in the car but I can tell you that it is ONLY used on this particular vehicle, I would love to try a U.S. based 2RZ ECU and see what it does but I'd rather spend the money on an aftermarket ECU like a mega squirt.
 
#8 · (Edited)
You never stated the model year of the vehicle you are working on..
Your injection control sounds similar to the MFI used on the early 95/96 Tacomas which used a batch-fire system see attachment.

The 98s used SFI sequential fuel injection system see attachment.

In another post, you said your system utilized a MAP sensor...our Tacomas use MAF.
You may want to check that MAP sensor and hose/connections.

Are you able to pull flash codes by jumpering terminals TE1 and E1 on your DLC ?

As far as Toyotas immobilizer system..maybe the 2nd ECU you got is for a vehicle NOT equipped with immobilizer..therefore the reason for a PN difference and it starting easily?

Is your fuel pressure within spec?
Is your thermostat operating properly (not stuck open)?
Coolant temp sensor operation?


Not sure of your location so don't know temperature or elevation so...If the system is operating properly, and is just trimmed rich from the factory...

Where does your fuel pressure vacuum hose connect?
If you have a rail mounted regulator with the vacuum hose connected post air filter/pre throttle body as is the norm with most N/A Toyotas, try moving the hose to post throttle body (manifold). This should lean you out at all but wide open throttle. If you're not blasting around all the time with the gas pedal to the floor, it is probably all that is needed to increase your fuel economy.
Messing with the ECM may just be making things overly complicated...
 

Attachments

#9 ·
Ok, are you ready for this?

It's a 2004 model!

This is simultaneously fired, not batch.

The MAP and FPR connection is on same point after the TB.

Pressure is perfect, FPR working so is thermostat and temp sensor. Have spare MAP sensor which I still want to try.

The donor ECU is from the same model except it didn't have 4WD. It most certainly had an immobilizer. The guy replaced the engine with a 4Y carb engine to get better mileage!!! I might replace mine with a horse to improve it even more!!!

Also my ECU worked again straight after without performing the ECU/IMOB reset procedure.

Yes the diagnostic error codes work but I have non, there are hardly any sensors on this thing so not much that can go wrong.... Also it does not have OBD!

I also think the factory trimmed it rich and the fuel map maybe not of the best. Two of the previous owners got better mileage than what I'm getting now, so something is not right. But even perfectly running models are heavy, that's why I'm leaning (no pun) towards MegaSquirt now. I think just the addition of an oxygen sensor will make a huge difference.
 
#11 ·
So you guys get a single-cam dumbed down version?
FYI - I think the ECU connectors are available at DIY-autotune, so you don't have to butcher a CPU.

The first thing that I'd do is get the 02 sensor looped in (megasquirt) - otherwise you're just flying blind and of course it's going to get bad mileage...

Sequential or batch won't make much difference for MPG. Both the 1995 and 1998 look to be batch fired to me - the injector drivers are all driven by the same pulse to the transistor. (at least per supplied wiring diagrams)

Splitting them in the loom will make no difference... Sequential injection alters when the injector is fired, not how much fuel is required to run the motor.. Generally helps idle, but not fuel economy.
 
#14 ·
Yes, no OBD2.

Sequential or batch won't make much difference for MPG. Both the 1995 and 1998 look to be batch fired to me - the injector drivers are all driven by the same pulse to the transistor. (at least per supplied wiring diagrams)
dcg9381 Those connectors are expensive, I paid about $150 for a secondhand distributor, plug leads, MAP sensor, A/C amplifier and also the ECU. I don't think you can beat that. Also the injectors are wired for batch, but the ECU pins are factory shorted inside so it can only ever do simultaneous injection. I think batch does make an improvement on fuel economy over simultaneous, not so?

Here are some engine pics:









 
#15 ·
I thought the connectors were like $20, which beats buying and de-soldering from an ECU.

No MPG advantage sequential or non-sequential injection. Sequential is known to idle better and improve some emissions output at low RPMs.

Interesting motor.. kind bare bones. Can you not import a 16 valve version?
You guys have a diesel option over there? :)
 
#16 ·
When I looked for the connector I think it was about $46, I've been soldering for about 20years, I'm not put off by a few pins!

Yes, it's a donkey, not much that can go wrong! I've not tried importing a complete engine but would think it would be expensive, getting a 16V head might be a cheaper option.

Not sure what you mean by the diesel version? I think they used the 5L engine as the diesel, it was a 3000cc which was even slower and more retarded than the 2RZ version!
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top