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3rz low end power problems, feeling like a sad mower engine, struggling under load

11K views 16 replies 5 participants last post by  ZIP671 
#1 ·
I've got a 2003 3rz thats been put into a 1985 toyota hilux, I have a problem where when accelerating with low rpm the car starts to chug, struggle and hesitate, when the rpm gets to about 4grand or more (bit of a guess as I dont have a tachometer) the power kicks in and it feels like a toyota motor again. Initially thought this was a fuel pressure issue so I changed the fuel filter and fuel pressure regulator but still have the same issue. Its progressively getting worse and when the engine is warm after some 4wding it has barely any power to climb up even the smallest of hills has been starting to stall lately. Also where I would be able to read any codes from the ecu, I've searched the thing over and havent found an obd port, there's a diagnostics port in the engine bay right next to the intake manifold but I'm not sure what scanner will read off that.
Anyway I would appreciate any help at all thanks, Sam, from down in Australia.
 
#2 ·
(1) Welcome to CT! :waytogo:

(2) What ECM are you running with the 3RZ? Did you transplant a 2003 ECM along with the 2003 engine?

(3) Has this been happening ever since the engine transplant, or ....?

(4) What vehicle / model did the 3RZ come from?

(5) Are you still using any 1985 sensors with this 2003 engine and whatever ECM you're using?
 
#3 ·
(1) Thank you!

(2) the ecu/ecm is the same one from the 2003 car, I didnt do the swap myself and the wiring is a mess of spaghetti but it seems to work.

(3) No, just over the past few months the power loss has come up, the engine transplant was done in 2014, ive had the car for well over a year now but this problem has slowly become worse.

(4) From what I know the engine came from a 2wd 2003 hilux.

(5) Most if not all of the sensors on the car now are from the 2003 donor car, I think some of the sensors have been wired to the old dash so the fuel and temp gauges work but other than that they all seem new. I will add though that when i was looking for where the O2 sensor was on the exhaust i found that there was a blocking plate where it should have been, it does have an aftermarket stainless steel exhaust but when i first got the car it drove quite nice with smooth power.

Cheers for the reply, Thanks Sam.
 
#4 ·
Thanks for the background info ...

There are big problems affecting my ability to say much about the situation ...

The US Domestic Market (USDM) Tacoma was a totally new vehicle from the ground up, introduced in 1995.5. It was a completely different species from the earlier Toyota pickups (aka "Pre-Tacos"), which were more similar to the Hilux models marketed elsewhere in the world.

It wouldn't be until the introduction of the completely new 2005+ model Tacomas that Toyota once again displayed some common features between the USDM Tacoma and other markets' Hilux models.

Here's my point ... USDM 1995.5 - 2004 Tacos were a totally different species from both the PreTacos that *might* share some features with a 1985 Hilux as well as any / all Hilux models sold elsewhere in the world in 2003. I have no idea whether anything I could offer based on USDM Tacos has any relevance to a non-US Hilux with the same engine.

Additionally, there's the fact your '85 with a 3RZ is a completely custom rig. This means there's who-knows-how-much DIY "frankensteining" that's been done to it. There's no guarantee that a frankensteined vehicle is built / wired / works like either or all the OEM vehicles from which its components were merged.

Having said that ...

IMHO your #1 priority is to check the engine codes. This means you need to figure out what you can connect and which OBD format is used.

If the connector in the engine bay was a legacy item from the '85, it's probably an OBDI (OBD-1) format.

If it was transplanted with the engine and ECM it's probably an OBDII (OBD-2) format. My *guess* is that this is the situation with yours.

On USDM Tacomas there were 2 OBDII connectors - one in the engine bay and the main one underneath the dash left of centerline (around the area of the driver's right knee). These two connectors used different plugs, but both allowed you to check codes.

I have no idea whether non-US Hilux models had the OBDII connector in the cab / under the dash, so I have no idea whether you're stuck with the engine bay connector alone.

It will probably be a hassle to figure this out and finally get to read some codes, but it's the fastest way to make the most progress on diagnosing the problem(s).

The fact that your rear O2 sensor on the exhaust is blocked off / missing suggests the ECM was basing its fuel / ignition manipulations on the front (engine bay) O2 or AFR sensor alone. If it had been a USDM Tacoma, it would also indicate some mod was done to fool the ECM into ignoring the absence of a rear O2 sensor input.

This strikes me as setting up a single-point failure possibility (only one O2 or A/FR input) that might explain your problem - i.e., your front sensor is bad or dead. Whatever front sensor is being used, this is one of the things I'd suspect and check first.

This is only a guess, and because of all the differences I have no idea whether it's even a reasonable guess.

Years ago there was an Australian Toyota forum site that had tons of info on engine swaps and other customizations done in your neck of the woods. If that site still exists, I'd recommend you visit it. Unfortunately, I don't remember its name, and all my records were lost in a residence fire some years ago.

That's about all I can offer. Sorry about that, but we're really talking different versions of different species here.

The only thing I'm certain about is that you need to figure out how to read the codes. You'll be shooting in the dark, and probably wasting time, until you can do that.

Good luck with it ...
 
#5 ·
Cheers for the advice mate.
Yeah I'd say there'd be quite a few differences between USA and AUS versions.

Ive definitely gotta figure out reading codes on this thing, the only port ive seen that could be used to read code from is the diagnostic port in the engine bay but it doesnt look anything like an obd port to me (maybe im severely wrong).
Anyway i read online somewhere about checking engine codes manually using this port and watching the check engine light but nothing comes up when i try that.

Ive seen an adapter that goes to obdII that looks like it could fit this port, might grab that off ebay and see how we go.

This thing has been "Frankensteined" for sure but it works (for the mostpart), i do appreciate the help though.

I'll have a look at the front o2 sensor and see if thats the problem.

Cheers again for your help, im gonna have a snoop around on some aus forums and hope someone's come up with a solution to a similar problem.
 

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#6 ·
Oh wow, it looks like whomever did the swap, they kept the original OBD-I port! I haven't seen one of those since I sold my Pickup (pre-Tacoma). You are right, a reader will most definitely not hook up to it! I remember pulling codes on the old Toyota and you have to put a wire jumper or paper clip between like E2 and ground or something like that... look it up though don't guess since if you jump the wrong terminals you'll blow a fuse.

Once you insert the jumper, go inside and turn the key to "ON" but don't start the car. The Check Engine Light will flash slow then pause, slow, then pause, several times. Count the flashes in between the pauses and you'll end up with a number like "313" or something like that and that's your diagnostic code. That's if the OBD-I system even still works. Not very many Tacoma guys will know how to use it since they are all OBD-2, which is a digital system.
 
#7 ·
Hi I hope I can explain this enough for you to follow. This is from a 2000 3rzfe manual, 1 check battery voltage is above 11 volts. 2 check throttle is fully closed, transmission is in neutral, and all accessories are off and the engine is at normal operating temp.
3 turn on ignition to on but do not start.
4 use a jumper wire to bridge terminals TE1 to E1 on early models and TC to E1 on later models.
5 Read diagnostic codes by chech engine light on dash.
Not sure if photo is any use but once you get codes list them and I will check against my manual.
Ps I am down in NSW.?
 

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#15 · (Edited)
Hi I hope I can explain this enough for you to follow. This is from a 2000 3rzfe manual, 1 check battery voltage is above 11 volts. 2 check throttle is fully closed, transmission is in neutral, and all accessories are off and the engine is at normal operating temp.
3 turn on ignition to on but do not start.
4 use a jumper wire to bridge terminals TE1 to E1 on early models and TC to E1 on later models.
5 Read diagnostic codes by chech engine light on dash.
Not sure if photo is any use but once you get codes list them and I will check against my manual.
Ps I am down in NSW;
From what I could find on the web, It was compulsory in Australia to be OBD2 compliant as of 2005. Im not sure if manufacturers began switching over prior to that, but seeing as a new Hilux model was introduced in 2004, it would seem logical that the new model had OBD2 and your truck was still OBD1.
This fella seems to have the repair manual you might need. Contacting him seems like your best option right now.


I checked the Toyota TIS system and it unfortunately starts with the new 2004 2TR model Hilux ... so no use to you.

once I connected everything the test light just stayed on, it didnt flash or anything just stayed on so im not sure what thst means.

If that is indeed the "W" terminal, staying on steady is normal when "keyed on" and not running.
With TC and E1 (or TE1 and E1 depending on year) jumpered, you should get an evenly spaced series of blinks if all is normal.. so its possible the ecu is not seeing the jumpered terminals.. or that's not the "W" terminal. you need to be sure.
Sometimes if you remove the cover from the ECU, you can read the terminal designations printed on the board down by the pin connectors. If so, you should be able to locate terminal "W" , TE1, E1, TC etc. and jumper at the ECU terminals (backprobed while connected)
You also might want to check your fuel pressure under load to make sure whatever pump they put in that tank is still good.
And, a basic read of the spark plugs may lend some clues as well
 
#9 ·
After being away for a week im ready to work on this thing again, thanks for all the advice guys.
So I used a jumper wire to connect both the E1 and TE1 conections (I also tried E1 and Tc) both had the same result and nothing came up on the dash.
Problem has become worse as it struggles to start when hot sometimes and accelerating is excruciatingly slow with my foot planed through the floor.
Reguarding using a test light to read the code seeing as the check engine light most likely isnt connected, which terminal is the W terminal on the ecu?
I've attached photos of the ecu but nothing on it labels the terminals, also there are a couple plugs that are just floating around the ecu idk what they do, they've been unplugged since ive had thr car and theres no other ports for them to plug into.
Anyway, I'm pretty frustrated with this thing to say the least but hopefully ill figure out something soon, thanks for the advice, cheers Sam.
 

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#10 ·
So I found a pinout diagram online for a 3rz ecu that said the W terminal was the 5th pin on the E5 connector, once I connected everything the test light just stayed on, it didnt flash or anything just stayed on so im not sure what thst means but thats the result i got out of it so far.
Any help would be great as im clueless at this point, thanks Sam.
 

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#11 ·
Here (attached) is the ECM pinout diagram for a 2003 USDM 3RZ Tacoma.

On a Tacoma the W (CEL; malfunction indicator lamp) connection is pin 6 on the ECM's E5 connector.
 

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#12 ·
It might be a good idea to post the part number (and any other data) shown on your ECM.

We're probably wasting everybody's time unless we can determine what ECM from what vehicle you're working with ...
 
#14 ·
As far as I can tell, that ECM was only used on the Hilux and the 4Runner models.
 
#16 ·
Hello again,
It has been a while, but im back,
Had a bit of a mishap with the ecu,
I saw on another forum that to see what terminals are what you can open up the ecu and read the print on the circuit board. And although that claim is very correct with my unsteady hands and overall absolute recklessness i accidentally dropped the back plate of the ecu box onto the circuitry of the ecu.
Long story short, smoke bellowed out of the thing and i realised it was dead.

So here i am $200 down and 2 weeks later with another ecu (with the same part number) from a wrecked hilux (3rz) shipped from the otherside of the country (Victoria). The car runs again (yay!) But still has the same problem as before (not yay).

I figued out the correct points to use a jumper wire for and found the w terminal, the test light flashes continuously for over 100 flashes so im assuming that the ecu hasnt picked up any issues yet or at all based off of what ZIP671 said.
I've only driven the car once since getting the 'new' ecu but the same problems from before are present.

I guess next is to check fuel pressure and spark, ive heard from another forum that a poor ground from coil pack can sometimes cause such an issue, i havent yet found where that grounding point is but that would be a nice one to fix if that was the case.

Thanks for all the advice and help, im glad i at least know how to check the ecu codes in future if anyother issues arrise.
Bit of an expensive and frustrating learning experience but i know to take more care and unplug! when dealing with electrical ciruits now.

Thanks, sam
 
#17 ·
Sorry to hear about the ECU mishap Sam :doah:
I cant tell by your pics... but is this a dizzy motor, coil packs, or coil on plug type ignition system?


I would check fuel pressure under load first. ..as a failing pump seems it could be a very likely cause.
Also, airflow meter problems don"t always register codes, so make sure no debris has gotten past your air filter and onto the meter element... again... cant see your airflow meter/filter setup on this conversion. Its delicate so handle with are if you decide to look at it.
Lastly, a knock sensor issue could cause the symptoms you descrice.. but should have stored a code.
 
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