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Hi guys,

can a bad ECU cause misfire? May be a very general question but want to gauge opinion/experience. Also if I get a new ECU do I need any kind of programming? Even if it is out of a running another 77 280z?

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I’m no expert and there are guys on here that know more about this than me.

- I would target my ECU for a misfire but it is possible. There are more likely causes. The best bet is to go through the Fuel Injection Book. It will walk you through troubleshooting everything you should do.

 

- no you don’t need to reprogram your ECU. I think you need to make sure the ECU you replace with comes from a manual or Auto transmission...which ever you have. I had problems with an Auto transmission ECU on my manual car. Could have been a fluke.

 

http://www.atlanticz.ca/zclub/techtips/efisystem/280zfuelinjectionbook.pdf

 

 

Sent from my iPhone using Tapatalk

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The ECU opens all of the injectors at the same time, and they're grounded through only two transistors.  So, unlikely to be the cause of misfires.

There are many other potential causes of misfire.  Describe more about what you mean and there might be some ideas.

Here's a list if you decide to get another ECU anyway.

 

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21 minutes ago, Zed Head said:

The ECU opens all of the injectors at the same time, and they're grounded through only two transistors.  So, unlikely to be the cause of misfires.

There are many other potential causes of misfire.  Describe more about what you mean and there might be some ideas.

Here's a list if you decide to get another ECU anyway.

 

So we found cylinder 4 misfire and also coolant in the oil. Seems like there is some issue with the new N47 head holes aligning with the block we have put in. Replacing the head first to fix the leak and try again shortly...my old head was N47 too so not sure why this one is different. It did say N47.

 

update in a few days...

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10 minutes ago, MH77280Z said:

So we found cylinder 4 misfire and also coolant in the oil. Seems like there is some issue with the new N47 head holes aligning with the block we have put in. Replacing the head first to fix the leak and try again shortly...my old head was N47 too so not sure why this one is different. It did say N47.

 

update in a few days...

I looked back and found your old thread about the different head.  Not really sure what you're saying here, but it sounds like you think that you have a leak at the head gasket. There are several other ways to get coolant in the oil.  It might be that your other head was not actually cracked, if coolant in the oil is why you thought that it was.

If you've had two heads that do the same thing the problem might be with the block, or the timing chain cover.  The water pump passages can corrode and leak  in to the crankcase.

 

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20 minutes ago, Zed Head said:

I looked back and found your old thread about the different head.  Not really sure what you're saying here, but it sounds like you think that you have a leak at the head gasket. There are several other ways to get coolant in the oil.  It might be that your other head was not actually cracked, if coolant in the oil is why you thought that it was.

If you've had two heads that do the same thing the problem might be with the block, or the timing chain cover.  The water pump passages can corrode and leak  in to the crankcase.

The previous head was cracked and we identified that. It was visible. It came when I bought the car. Car had been sitting for 5 years and we never tried starting the car with that old head. 
 

This time we added a new head and the car started fine, getting good vacuum as well but found coolant in the engine plus cylinder 4 misfire. The guy I work with is very professional and he told me it is head which needs to be replaced or checked. We will be getting a new head soon. What you think?

 

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I thought you said that the first head was cracked.  Now the second head is cracked also?  Or is it warped?  Is it a used head, or a reconditioned head?

Don't know.  Seems like he would have checked the second head before installing it.

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