1977 280z no power on fuel pump

[240zadmire]

didn't know that is what Nissan did that.  Apologies to previous owner.

did read through the high idle section of the EFI bible.  Follow instruction religiously.  At least turn out the culprit was bad electrical connection at the 3 pins throttle body.  Sand lightly about 30 strokes each pins... last instruction section page 61-68 or so to test voltage when key is in "On" position and notice some pins, the voltage is not the same as battery.  Which lead to some resistant somewhere.  Approximate 11.6 volts instead of 12.34 volts.  Probable cause of this would be the dirty connectors somewhere.  I will trace down later.  When all instructions were completed, fire her up.  Had to crank 3 times and she is up from a cool night.  Pretty happy.  The idle is approximate 2500 RPM or so and slowly drop down to 1500.  Adjust the air intake from throttle body and able to bring her down to 1100 rpm and she is steady.  No flickering on the RPM needle at all.  I couldn't find the needle when using the strobe light.  I must have painted the mark on the pulley.  Will need to get under.

one notice I see is that when rev her up, she is not return to idle immediately.  She hovering around few hundreds where she peaks.  Meaning if I rev her up to 2000rpm and release, she will come down to around 1500rpm or 1700rpm and stay.  If I gently rev her up again and release, she goes down immediately to idle, which is 1100rpm.

 

Just want to repeat my gratitude again for all the helps.  Was beyond my expectations.

any thoughts?

 

regards

 

   

[Zed Head]

Is the throttle return spring intact?  They tend to rust and break off.  The throttle body itself has a weak spring but there is an external one also.  You can check if the throttle is sticking by pushing the blade close by hand or lifting the gas pedal with your foot.

[240zadmire]

one more thing forgot to mention should someone have similar issue is that the auxiliary next to the CSV also has bad electrical connection.  Clean that as well.  Placed order for the new connectors too.  Lesson learned is that all new connectors work great.  The ones I haven't replaced cause the issues.

about the spring on the throttle, yeah.  It is weak.  I don't think there is a stronger spring out there.  I might have to add another spring to the rod and pull it back and mount it to the throttle body. 

 

regards,

 

[240zadmire]

Dug into my boxes (btw, boxes getting smaller and smaller... pretty happy about it) and found this.  Look at the spring on the throttle body and notice there has to be something connect to that pin hole... low and behold, it supposes to bolt into one bold of the throttle bolt to the intake manifold.  She now is so snappy.  RPM goes right down when release the throttle or gas pedal.  Need more clearance of the carpet but even with the obstructing of the new carpet, she is snappy.

 

regards

 

 

[Captain Obvious]

21 hours ago, Zed Head said:

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

Agreed. They did a pretty good job of making sure stuff could only go together one way, but maybe they missed this one. I don't have the spare parts laying around to check for keys, but looking at the pics, I don't see anything.

I had my FI harness out of the car a couple years ago to replace a bunch of the connectors etc, and I don't remember any issues getting that FI relay back in correctly. I suspect that after fifty years, my connectors just kinda fell where they belonged. Either that, or as you mentioned,  I just checked where the populated contact positions were.

[Captain Obvious]

OP. Glad you're making progress and got it running!  

[SteveJ]

48 minutes ago, Captain Obvious said:

Agreed. They did a pretty good job of making sure stuff could only go together one way, but maybe they missed this one. I don't have the spare parts laying around to check for keys, but looking at the pics, I don't see anything.

I had my FI harness out of the car a couple years ago to replace a bunch of the connectors etc, and I don't remember any issues getting that FI relay back in correctly. I suspect that after fifty years, my connectors just kinda fell where they belonged. Either that, or as you mentioned,  I just checked where the populated contact positions were.

That's the problem when you license and replicate someone else's design. You usually copy the design flaws, too. You won't find connectors/narrow pins like the 75-77 EFI relay connectors anywhere else in the Z. Those came the Bosch design.

Of course, if my designs were perfect, I wouldn't need another engineer to review them...and there would never be red-lines on the drawings from the production floor/startup. Heck, I just carry a red pen with me at work to save time. I never have to hunt for one.

[240zadmire]

Hi all,

when I took the harness out, I don’t remember remove any connector if not necessary.  I told myself this is a long term project.  I want to leave things as intact as much as possible.  Beside, the harness didn’t have to go to any holes like the passenger side where wires need to get into engine bay.  I must have took it off but can’t remember why.

 

in case anyone interest how the connectors orientation, take a look at the picture below.

 

time to put rest of the lights in and hopefully by weekend, have her around the block.  So eager.

 

order of executions

- registration

- insurance

- break the car in for few hundreds miles

- readjust valve clearance

- looking for ac drier/receiver and r134 conversion terminals

like to keep as much original as possible.  Replaced worn out parts and rebuild when parts “unobtainium” or cost prohibit ?

then enjoy fruit of labor ?

Then smog check at some point.. ughhhhh ;(

 

we can mark this thread as solved

 

Lookout, there will be a post about AC coming shortly

much appreciate everyone.

 

 

 

[Zed Head]

2 hours ago, Captain Obvious said:

 I don't have the spare parts laying around to check for keys, but looking at the pics, I don't see anything.

A faint memory has crept in to my brain of colored stripes on the relay and maybe the plug.  Very faint...  Black and green?  The funny thing is I also vaguely remember wondering why they were there.  Maybe I missed it.

Edit - I just looked at the picture and see a blue stripe.  Maybe that's the one.  I  don't see a match though.

Edited August 7, 2020 by Zed Head

[Dave WM]

 

another area to watch out for is the hazard flasher vs turn signal flasher. IIRC they have the same plug and the units are located in the same area (under dash driver side), Think it may be that one cable is too short to allow incorrect plugin but not sure about that. The actual flash units are much different is size (same pin out), I don't know if they are interchangeable.

[SteveJ]

51 minutes ago, Dave WM said:

 

another area to watch out for is the hazard flasher vs turn signal flasher. IIRC they have the same plug and the units are located in the same area (under dash driver side), Think it may be that one cable is too short to allow incorrect plugin but not sure about that. The actual flash units are much different is size (same pin out), I don't know if they are interchangeable.

There are different part numbers for the hazard flasher and turn signal flasher in the parts manual. The hazard flasher part number is still available in the Nissan system, but the turn signal part numbers are NLA. Of course, when I swapped out all of the lights to LED, I went with electronic flashers that for all intents and purposes are interchangeable...but I digress.