1jz running rich, ecu problem?

kas14slider

New Member
May 18, 2010
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State College, PA
Hi guys, I have a 1jz in my s14. Over the last few weeks I would get a completely random hesitation. The car would run super rich and then it would run fine. As I was driving around, the hesitation was just on and off. There would be long periods of time where it ran fine and then other days it would hesitate, I would let it sit and it would be fine the next morning. Then finally a couple of weeks ago, the car started running bad constantly. It would barely idle and was pouring white smoke and gas out of the exhaust. I checked all of my injectors with a noid light and 1 and 4 were bad. The light stayed on with the key on and when the car was cranked the light didn't pulse at all, the rest of the injectors were fine. So after doing some research I determined that it was the ecu. Apparently I had a bad 1-4 Injector driver. I immediately e-mailed Aaron of Driftmotion and he said it also sounded like my ecu. I decided to open it up and take a look but I did not see any leaking capacitors, the ecu looked perfect to me. But I sent out the ecu, got it back, and the problem was still there. Injectors 1 and 4 are just constantly dumping fuel. So I ended up buying another ecu the other day. It will be here tuesday and I will see if that fixes it.

I don't really know anything about ecu's but I guess when you send it in to get recapped, it doesn't matter if damage had already been done to an injector driver, then it can't be fixed?
But is there something else besides the ecu that can be causing injectors 1 and 4 to just constantly be staying open?
 

Radial

New Member
Aug 20, 2011
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Norway
If you look at this wiring diagram, you will see that the ECU is running the Injectors Directly from the Injector-driver outputs.

http://www.clickdesign.co.uk/supradupra/assets/images/1JZ_EFI_Wiring_JZA-70_-_Full_Diagram.JPG

Your ECU is fucked :)

To make shure for reliability, check the resistance of injector 1 and 4, compared to the others... if resistance on 1 or 4 is lower than the other injectors, the higher current will cause the Injectordriver to go bad. Lower resistance = higher current = fucked Injector driver (the weakest link..).
 

kas14slider

New Member
May 18, 2010
77
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0
State College, PA
Radial;1780288 said:
If you look at this wiring diagram, you will see that the ECU is running the Injectors Directly from the Injector-driver outputs.

http://www.clickdesign.co.uk/supradupra/assets/images/1JZ_EFI_Wiring_JZA-70_-_Full_Diagram.JPG

Your ECU is fucked :)

To make shure for reliability, check the resistance of injector 1 and 4, compared to the others... if resistance on 1 or 4 is lower than the other injectors, the higher current will cause the Injectordriver to go bad. Lower resistance = higher current = fucked Injector driver (the weakest link..).


Thanks for the info man. Well that's actually good news. Because I wouldn't want my other ecu to get here and then me still end up having the same problem. Sucks that I wasted money getting a bad ecu recapped but oh well.
 

kas14slider

New Member
May 18, 2010
77
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0
State College, PA
Well, turns out I have a wiring problem. My 1 and 4 injector wires are getting continuity with the block so they are grounding out somewhere or touching something. Can anyone tell me which pin on a jzz30 pinout runs injectors 1 and 4? Pins #10,20,30 just say injectors. Anyone know which ones run which though?
 

Radial

New Member
Aug 20, 2011
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Norway
compare This:

clipboard02tt.jpg


With this:

201110221037%20JZZ30%201JZGTE%20ECU%20Pinout.png


And you will see that 1 and 4 runs through #10 :)