3 and 5 cyl keeps flooding on 1JZ.

[Krister]

I have problem with my 1JZ. It seems like the ECU caps are bad, but nothing seems to help. Car works great when its cold, but after 10-15 minutes it starts running on 4 cyl and plugs 3 and 5 are soaked.

I made the test that is on SF.com where I plugged a bulb on nr 3 cylinders injetor plug. The bulb came on and wasnt flickering, on cyl 2 it was flickering like it should, so the injector is staying wide open.

So far I've tried:
-Changed ECU caps
-Changed ECU injector driver blocks
-Sprayed the ECU board with cold spray when the car is running
-New plugs


I havent tried:
-another ECU

Can it be something else other than the ECU that drives the injectors that is broken?

I have Mine's ECU coming to me from Japan, but it will take two to three weeks still and I'd like to keep this ECU as a backup, so I'd like to get it working.

Here's some pics I took from the ECU board:









Any help is grately appreciated.

Krister

 

[JonoTurbo]

That cap in the 4th pic down had definitely gone bad...and it looks like there is damage to the trace beneath it, I would check the continuity along that circuit. That area it's in is right around the injector control circuit. I'm willing to bet your problem is right there.

Also, I would get someone else do do your soldering next time...

 

[Rich]

That cap in the 4th pic down had definitely gone bad...and it looks like there is damage to the trace beneath it, I would check the continuity along that circuit. That area it's in is right around the injector control circuit. I'm willing to bet your problem is right there.

Also, I would get someone else do do your soldering next time...

I think that he had that cap replaced, at least if you're talking about the brown one. I agree the traces need cleaning up though.

 

[Slow_Sc3]

yeah 4th picture that cap on the bottom is burnt and the black cap that is second down on the left looks like the top is burn also. the new ecu will solve your problems

 

[Krister]

My friend did the welding. He said that the black trace came from the "welder" and shouldnt affect the ECU. None of the original Caps had leaked according to him.

Can I clean the traces my self with something?

 

[JonoTurbo]

To fix it your going to have a take a circuit tester and go over the areas near the caps. I'd start with that one with the burn. Cleaning it probably won't fix the problem.

 

[Krister]

To fix it your going to have a take a circuit tester and go over the areas near the caps. I'd start with that one with the burn. Cleaning it probably won't fix the problem.

I'll look in to this. Good news is that my ECU is on it's way from Japan, should be a week untill its here.

One thought that came up. Is there a injector resistor pack somewhere in the engine bay. Could that have broke and would it cause problems like this?

 

[Spaniard]

the resistor pack could be the problem. check your wiring.

 

[Krister]

the resistor pack could be the problem. check your wiring.

Where is the resistor pack?

 

[Ken]

One thought that came up. Is there a injector resistor pack somewhere in the engine bay. Could that have broke and would it cause problems like this?

That depends on what kind of injectors you're using. Stock injectors won't have a resistor box. Now if you're using low impedance injectors like the US MKIV ones, then yeah, there would be a resistor.

 

[Krister]

That depends on what kind of injectors you're using. Stock injectors won't have a resistor box. Now if you're using low impedance injectors like the US MKIV ones, then yeah, there would be a resistor.

The engine should have the stock injectors, so I guess there is no resistor pack then.

 

[Krister]

I took a closer picture of the EU board where the problem is, what do you think about this?


What can I use to clean it up? Paint thinner?

 

[Quin]

Why not just use a small wire to jump from the bad pad to a good pad? Have your friend solder a wire to the bad pad connected to the replaced capacitor to the next good pad along the circuit path.

 

[Krister]

OK, problem seems to be fixed. I bought a MiNE'S ECU from Yahoo auction. I plugged it in and car worked fine. Plugged back the stock ECU and it ran on 4 cylinders. Plugged back the MiNE'S ECU, and worked like a charm again.

Seems like I dont have a rev limiter at all on the tuned ECU. Atleast it reved over 7600rpm, didnt have the guts to rev it more. Here's a few pics:





I opened up the ECU and noticed there is one CAP that has leaked. I'll have to change it out before it starts to give trouble.