hi guys i have just bought myself a 91 sc400 and it is coming up with a engine electrical system warning light on the dash and i have no idea what is causing this to happen and it seems to happen at random if anyone can point me in the right direction it will be much appreciated. When this warning light comes up it starts missing badly and wont rev past 2000RPM and sometimes the light will go away and it will fix it self the only other light i have seen pop up is a cat converter light but it only comes up when the engine stalls and goes away when you start the car again
3 posters
my 1uzfe
SC400slide- Admin
- Posts : 86
Join date : 2013-04-02
Age : 27
Location : Rio Rancho, New Mexico, USA
- Post n°2
Re: my 1uzfe
Welcome to the forum Zuffy!
Your issue can be several things. It can be a failing ECU, a failing Fuel pump ECU, (serach 12v mod on google and DIY), or most likely the coils, or "ignition coils/coil packs. Unplug each coil your car has 2 while the car is running if the car changes idle when coil is disconnected that means the coil is good.
The ECU could need a rebuild. Search 12v mod fuel pump ecu on google there is a DIY.
Please report back when you find the issue! Good luck!
Your issue can be several things. It can be a failing ECU, a failing Fuel pump ECU, (serach 12v mod on google and DIY), or most likely the coils, or "ignition coils/coil packs. Unplug each coil your car has 2 while the car is running if the car changes idle when coil is disconnected that means the coil is good.
The ECU could need a rebuild. Search 12v mod fuel pump ecu on google there is a DIY.
Please report back when you find the issue! Good luck!
zuffy87- Individual
- Posts : 5
Join date : 2014-02-18
- Post n°3
Re: my 1uzfe
ok so i pulled each lead and each one made a difference so it cancels out coils leads and plugs but since then i have taken it to a mechanic and he cant get the scan tool to get a reading the data will pop up then go away straight after, it also has a MINE'S piggy back on it. the maf sensor may be stuffed as well while the warning light is on the maf sensor can be unplugged and it makes no difference to the engine performance. while the car is at idle it runs with a slight miss so we unplugged the piggy back and it now idles beautiful but will start missing when the revs get to about 3 grand. What i really need to know is will an ecu and maf sensor from a different car running the same engine fit and work.
zuffy87- Individual
- Posts : 5
Join date : 2014-02-18
- Post n°4
Re: my 1uzfe
The mechanic doing the work for me has a spare ecu and maf sensor from a early 90's toyota crown running a 1uz also and we want to try swapping them to see if it fixes the issue before i go spending money on trial and error
SC400slide- Admin
- Posts : 86
Join date : 2013-04-02
Age : 27
Location : Rio Rancho, New Mexico, USA
- Post n°5
Re: my 1uzfe
Hey Zuffy, check this out. Have your mechanic run this test on the MAF. I'm guessing that the test will fail and that the MAF is indweed bad. If not, though, then the ECU could be the next thing on the listy. Just crack it open and look for any leaky capacitors. If there are, you have found the problem.
Here is the diagram.
https://2img.net/h/i916.photobucket.com/albums/ad3/brad11140/airmeter.jpg
Here is the diagram.
https://2img.net/h/i916.photobucket.com/albums/ad3/brad11140/airmeter.jpg
zuffy87- Individual
- Posts : 5
Join date : 2014-02-18
- Post n°6
Re: my 1uzfe
ok so we switched out the MAF sensor with a different one and no change but i have since taken the car back home and opened up the computer and found a few leaking capacitors so im thinking that must be the problem do you know how much its going to cost to have them replaced cause i dont want to have to buy a new ECU since it has a mine's chip
SC400slide- Admin
- Posts : 86
Join date : 2013-04-02
Age : 27
Location : Rio Rancho, New Mexico, USA
- Post n°7
Re: my 1uzfe
A rebuild off of eBay would take a few weeks at most, but the price is good at $150. Search eBay for the guy that does it, he lives in Cumming GA.
SC400slide- Admin
- Posts : 86
Join date : 2013-04-02
Age : 27
Location : Rio Rancho, New Mexico, USA
- Post n°8
Re: my 1uzfe
How did a rebuilt ECU work for you? Did it fix the issue you were experiencing?
zuffy87- Individual
- Posts : 5
Join date : 2014-02-18
- Post n°9
Re: my 1uzfe
sorry for the late reply the rebuild didnt work but they said they couldnt fully test every part of the ecu without having the car there but i have recently found that the wires for the knock sensors have been played with and spliced so only one knock sensor is connected to the 49 and 50 sensor plugs so thinking i might look into buying some new knock sensors. will i need the model specific sensors or are they interchangeable between models
SC400slide- Admin
- Posts : 86
Join date : 2013-04-02
Age : 27
Location : Rio Rancho, New Mexico, USA
- Post n°10
Re: my 1uzfe
The sensors are interchangeable from 92-94. 95-00 will not fit.zuffy87 wrote:sorry for the late reply the rebuild didnt work but they said they couldnt fully test every part of the ecu without having the car there but i have recently found that the wires for the knock sensors have been played with and spliced so only one knock sensor is connected to the 49 and 50 sensor plugs so thinking i might look into buying some new knock sensors. will i need the model specific sensors or are they interchangeable between models
Snocone- Individual
- Posts : 4
Join date : 2013-04-10
Age : 34
Location : SOCAL
- Post n°11
Re: my 1uzfe
So what is the ending result in your SC? FYI there is only 92 and up SC's. They were manufactured in 91 but weren't sold till 92.
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