1977 280z no power on fuel pump

[240zadmire]

@wal280z

 

in term of wires, it’s always setup like this. I forgot if all connection need to connect or not.  But to answer your question, the wire I lift up come from positive terminal with a female out out.  The wire cable come from negative is male connector that connect to a female connector that has black and white wires.

 

It is very likely incorrect connection or one of the wire does not need to connect to anywhere.   If that is the case I must have drop/lost the adapter when I strip down the car.  Otherwise, the possible connection would’ve from the positive, the wire I lift directly connect to negative.  Doesn’t make sense to me.

 

Yes.  The connector you circled.  I found it and it is right near the combine power/fuel relay.

i will check pin 70 again.  Possible reverse power.

 

stay tune

 

regards and thanks for the new wire diagram/schema

 

 

[240zadmire]

Have I gone mad?

pin 70 goes nowhere.  Please see picture.

i decided to disconnect a pair of wire at the battery and only connect the fusible link from positive to the pin 70. But then again, pin 70 goes no where.  Am I reverse connect something?

 

[240zadmire]

This is how I interpret pin 70 in red and 74 in green as shown in arrows 

[Captain Obvious]

As Captain Obvious, I guess I just have to ask... You sure you don't just have the connectors swapped? Is it even possible. or are they keyed to only fit one way?

I didn't look at any of the wiring diagrams to confirm, but I believe that all the populated locations do something. So just using the populated locations as a guide, I come up with this  :

Edited August 6, 2020 by Captain Obvious

[SteveJ]

I'll just leave this link here for now. I'll look at it more tomorrow and add to the discussion about the pins on the relays. There is some good information here: https://www.ratwell.com/technical/DoubleRelay.html

[SteveJ]

27 minutes ago, SteveJ said:

I'll just leave this link here for now. I'll look at it more tomorrow and add to the discussion about the pins on the relays. There is some good information here: https://www.ratwell.com/technical/DoubleRelay.html

Well, it took less time than I thought. Line up your connectors this way.

From the wiring diagram

[Zed Head]

I don't recall any problems getting the right plugs on the right terminals on mine.  I think that they are "keyed" somehow.

SteveJ, is that a suitable replacement for the Nissan combined relays?  Is it available?  I think that you were involved in the past in writing up a way to use two Bosch relays to replace the Nissan NLA relay.

Maybe? https://www.amazon.com/Bosch-0-332-514-120-Injection-Combo-Relay/dp/B005JCN1M8

The plugs might not be right but they could be made to fit.

Edited August 6, 2020 by Zed Head

[SteveJ]

5 minutes ago, Zed Head said:

I don't recall any problems getting the right plugs on the right terminals on mine.  I think that they are "keyed" somehow.

SteveJ, is that a suitable replacement for the Nissan combined relays?  Is it available?  I think that you were involved in the past in writing up a way to use two Bosch relays to replace the Nissan NLA relay.

Maybe? https://www.amazon.com/Bosch-0-332-514-120-Injection-Combo-Relay/dp/B005JCN1M8

The plugs might not be right but they could be made to fit.

The original 280Z EFI system was licensed from Bosch. If you look at the link I posted, you'll see that Nissan used many of the same terminal numbers, such as 36 & 39 for the AFM flap. Why re-create relays on a licensed system?

Over at ZCar.com many years ago, there were threads about using the VW EFI relays to replace the NLA Nissan EFI relays.

The "two Bosch relays to replace the Nissan NLA relay" is for the ignition relay. ZCarDepot sells it now. They can beat me on cost, so they can have the business.

I can be pretty sure my answer is correct because @Captain Obvious basically posted the same idea about the connectors. I just put some terminal numbers on mine to line up with the wiring diagram a little better.

 

[240zadmire]

Hi all,

There are only 2 possible ways to plug then white and black connectors.  Leaving as is, is one way, the other is swap white with black.  The face of the relay has number on it. Don’t know if you can see it but it is 88d on top left

 

 

 

 

Edited August 6, 2020 by 240zadmire

[240zadmire]

Ladies and gentlemen, please sit down as I'm so ecstatic to share the news.

I swapped the black and white connectors places for the main and fuel relays.  White on left/top and black on the bottom/right.

the kicker here is that common sense, in the USA, we're driving from the right side of the street.  No one need to tell us.  We intuitively just know that without paying any attention.  So, as you've seen my previous posts about battery terminals and everyone is saying fusible link need to be on the positive side.  Long story short, we commonly known that red color represent hot/positive and black is for cold/negative at least for battery.  Guess what, for whatever reason, the previous owner either replace or got a spare one ... and swap it around.  Black is positive and red is negative.  I swapped the black and connects to the positive terminal and the starter and red to the engine block from the negative terminal.  Took 2 cranks and she fires up right away.  Boy, what a sensation I tell you.  Better than a cold beer after working under the sun till your lips crack.  Better !!!!.  I've been working on this for 3 years and I had this car worked before.  It probably too long ago and memory play tricks on me as I'm near the finish line.  Plus the relay is a real killer as well as @Captain Obvious stated, perhaps try swap it and see.  Well, swapping battery terminals and relays did the trick.

 

I'm not out of the wood yet ?

The idle is so violent.  as soon as see starts, she climb to 2500-3000 RPM and fluctuate repeatedly.  Like some one keep pressing/releasing the gas pedal.

Any ideas I should look at is much appreciated.

 

Thanks again for all of you helping me and continue so.  Much appreciated.

 

regards,

 

 

[240zadmire]

I think someone has similar problem here as well and suggest the EFI bible.  Will look into it next.  Let’s rest today, a successful day ? 

[Zed Head]

The red wires at the battery have fooled many people.  Nissan did that, not a previous owner.

I must have looked inside the plug for populated terminals when i was working on my relay.  I thought that they could only plug in one way.  Having two plugs right at the same spot that can be swapped just seems way too illogical, especially for a part that highly engineered and complex.  If I had a car here I'd run out and check, just to be sure it was true.  Seems unbelievable, but, apparently it is so.

Keep going....