Test ECU?

The 1UZFE EGR Delete Kit is available for sale here.
Messages
31
Location
Atlanta, GA or Killen, AL
I have a problem with my ECU in my recently 1uz swapped 4Runner. I have ran the engine in the truck but not driven it yet. It ran fine the other night in the shop then I cut it off. I let my cousin borrow my battery to crank the racecar and after hooking the battery back up the next day in my truck, all I get is the engine turning over but no start. I'm kinda leaning towards a fried ECU, but I want to make sure before I buy a new ECU. The check engine light use to come on when switching the key to the on position and then cut off after a few seconds like it should. Now, the check engine light never comes on to say that the ecu is powered up. Anyone have any idea how to check the ecu or test it to see if it is coming on?
 
wouldnt it be better to see if u r getting power to the ecu first

plugging in a new ecu in a car that just fried the ecu is not a good idea
cause u could fry another one

test the 2 power wires to the ecu
u should have an efi fuse somewhere if it got wired right
 

Attachments

  • DSCF8149.jpg
    DSCF8149.jpg
    40.3 KB · Views: 9
  • DSCF8152.jpg
    DSCF8152.jpg
    43.6 KB · Views: 9
  • DSCF8153.jpg
    DSCF8153.jpg
    33.9 KB · Views: 10
Like side show said, make sure that you getting all the powers to the ecu. There are 4 critical power signals that are needed for the ecu to power up.

BATT = +12v all the time.
+B = +12v with key on
+B1 = +12v with key on
IGSW = +12v with key on

Also check and make sure that the MIL bulb is not bad.

Oh and Im sure that you probably checked this, but still have to ask, being that the battery was taken out and then put back in and the problem was there, are you sure that there is nothing else that was forgotton to be rehooked up at the battery??
 
wouldnt it be better to see if u r getting power to the ecu first

plugging in a new ecu in a car that just fried the ecu is not a good idea
cause u could fry another one

test the 2 power wires to the ecu
u should have an efi fuse somewhere if it got wired right

I checked but forgot to tell that part when I posted. I am getting 12.4 volts to the B+ pin at ECU constant. I have not checked the other three. I have not put another one in yet because I was afraid that it might fry it also like you said. I also checked the EFI fuse and it was fine. The harness was built by a reputable shop on these forums.
 
Like side show said, make sure that you getting all the powers to the ecu. There are 4 critical power signals that are needed for the ecu to power up.

BATT = +12v all the time.
+B = +12v with key on
+B1 = +12v with key on
IGSW = +12v with key on

Also check and make sure that the MIL bulb is not bad.

Oh and Im sure that you probably checked this, but still have to ask, being that the battery was taken out and then put back in and the problem was there, are you sure that there is nothing else that was forgotton to be rehooked up at the battery??


Like I said above, I have already checked and am getting a constant 12v to the ECU, but haven't checked the other three. I'll check them tomorrow. Also, the MIL bulb worked fine until now and now it won't start, therefore I assumed the bulb was fine. The battery is hooked up right, but I'm afraid that maybe my cousin hooked it up backwards or something when he stuck it back in the truck and then realized it and left it unhooked. Anyways, I'll let ya'll know what I find, so thanks for the help.
 
theres an easy fit to this
get yr bloody cousin to buy u a new one

to check it for sure find a 1uz with same ecu and try it in that car

so unless u have access to afew ecus like i do then u need to do more tests
or bit e the bullet and get another ecu
 
Okay, today right before coming to work tonight, I checked the other three power connections to my ECU. I am not getting anything there. The only one that is good is the constant 12V from the BATT. Where should I look from here? (I'm no electrician)
 

Attachments

  • Soarer kw.JPG
    Soarer kw.JPG
    57.8 KB · Views: 8
igsw comes from ign switch
b+ comes from efi relay
check to se if relay has power dont just look at fuse
check with multimeter or test light

otherwise check yr local paper for an auto elect
 
Ok, if your not getting power at the other 3 then the area to start looking is the IGSW.

Without the IGSW +12V supply, the ECU will not power up the EFI relay thus no power will be supplied to +B and +B1.

If wired correctly, the power should come from the ign. sw., then run through the IGN fuse, then to the ECU. Again, this is if it was wired as per a normal OEM type of install. Toyotas are normally set up like this.

The IGSW supply is critical so figure out and solve that issue and chances are the problem will be gone.
 
Yeah, thanks for the help CJSupra90. Today I went over to the shop and pretty much troubleshot the deal and traced it back as far as the EFI relay. Then I made sure it was in good and it was. Still no luck. Then I decided to swap the starter relay to the EFI relay location and my problem was solved! The check engine light same on with the key. The ECU was powered up. What's wierd though is that when I swapped the relays back into their proper locations, everything worked great. The truck started right up and ran great. The idle was low, but it ran smooth. I don't know what swapping the relays did for me, but it worked. I did drop the relay on the ground on accidently before putting it back in though. Could the problem be a stuck relay or something?
 
Yeah, it could have been stuck as you suspected. Usually they get stuck closed, not open though thus the engine would not shut off. I've had this happen before on my car, turned the key off and it kept running like I still had the key on. Walked out and tapped the relay with my key pretty hard and it shut right down. It is kinda strange how your situation was with it being stuck open.

Actually, might have been carboned up pretty bad on the internal contact points and dropping in knocked the carbon off or just had corroded connector contacts and pulling it out knocked the corrosion off or something.

As for the low idle, if you pulled the BATT power from the ECU, it lost its learned memory and idle is a learned memory function so you'll be fine once the ECU relearns the idle.

All in all, glad to see that is turned out to be something simple which usually it is....
 


Top