'75 280z - trying to set timing

[siteunseen]

I've always been suspect of the oil pump and spindle being off. Everybody goes straight to that but actually its easy to time those on rebuild. I'm not saying that's NOT your problem but it's like blaming the bank for non sufficient funds. It's too easy in my opinion.

Edited March 28, 2018 by siteunseen

[siteunseen]

1 hour ago, Zed Head said:

How do I learn to braid my distributor wires like that?

Use your nose hairs.

[Neb]

For the record, I did not braid those..

[EuroDat]

16 hours ago, Neb said:

Vrooom!  Its alive

I went to check the pressure in the system and bled a fair amount of air out in the process.  Got it to a steady ~38psi and then moved on to checking the plugs.  All 6 were wet and showed spark.  Put everything back together and it still wouldn't start.  So I went back to the distributor cap and started working it CW.  Eventually it kicked right off and ran.  I rotated the distributor cap CW until it was smooth and let it run for a few.  Then fuel pressure started to drop off and it died, which was a pretty big disappointment.. until I realized my little fuel can I'd been using in place of the gas tank (pulled for cleaning/lining) had run dry and fallen over.  Refilled it, re bled the system, and its starting/running consistently now.  f

Ended up with a couple questions though:

I couldn't get the CSV to click with my improvised (2xAAs and a switch) 'injector stimulator'.  Does it run off a different voltage than the other injectors?  Or is mine shot..

My fuel pressure while at idle when running was only about 28psi (picture below).  That being said, it idled smooth and was responsive and revved fine.  Is the fuel pressure supposed to stay at 38 or so while it is running?

My distributor cap required a significant amount of adjustment (picture below) to get it to run properly.  I'm assuming whoever installed the distributor didn't align it correctly?  I'm thinking if I just advance the spark plug order 1 plug and then grab a timing light I'll be able to get the timing set.

Anyway, you guys were great and definitely pointed me in the right direction, very much appreciated!

Good to hear you got it up and running. It's easy to under estimate how much air is in the system after stripping it down and cleaning it. Takes a while before it's all out and that can cause a lot of issues like hard to start and won't run.

On the pressure: These early EFI systems don't meassure fuel pressure. The ECU calculates fuel delivery based on a constant fuel pressure over the injector tip. The pressure regulator is connected to the manifold to messure vacuum and adjust the fuel pressure accordingly.

If you didn't regulate the fuel pressure: Say you had 10 in.Hg (-4.91psig) vacuum and didn't regulate the fuel pressure, you would have 40.91psig pressure across the tip and that would supply more fuel than the ECU calculated. The regulator would reduce the fuel pressure to an approximate 31psig.

28 psi is about right at idle. Depends on your vacuum in the manifold. It should have about -8psig or 16 to  17 in.Hg

The CSV uses 12 volts. A 9 volt battery will activate it. I don't think 2 AA will activate is. I also use a 9 volt battery to test injectors. I have never burnt one out yet. Mmm now Ive said that.....

In the circuit diagram you will see the CSV doesn't have a dropping resistor like the injectors.

Your distributor drive might be a couple of teeth out of alignment. It might be easier for now to do what Zed Head said and rotate the plug leads one position on the distributor cap. Then you can set the distributor back to approximatly the correct position. I am wondering how it got so far out of position. Maybe the PO dismantled it and reassembled it and the engine has never run since. There is a thread hear talking about setting the distributor.

 

 

Edited March 28, 2018 by EuroDat
added link

[Neb]

Wow, tons of great info   Looks like I've got some reading to do..

I'll have to dig up a 9v and have another go with the CSV.

I tried advancing the plugs one position; it is ALMOST to where it'll line back up with the adjustment screw slot, but not quite.  Its far closer to stock though.  I'll probably just figure out a way to secure it as-is until I get brave and decide to reset that shaft.

Speaking of which, I finally picked up a timing light.  I went to set the timing but I may be doing something incorrectly.  As I understand it, I ground the red wire from the water temp switch (on the harness side), and that advances the timing, and then I set the timing to the 13deg mark on the pulley/block.  I did this, but then when I removed the ground, it only shifted the timing about a degree.  So instead of it dropping to 7deg like in the FSM, it just went to about 12deg.  Am I messing something up here?

And as a total aside.. man the exhaust smells.  I'm not sure if its just years of it not running, or if its still off somewhere in the fuel/air/spark equation, but its got a funky rich smell that'll stick with ya.  I hope its just symptom of a cat not reaching its proper temp or something that'll be resolved by some proper driving/usage

Edited March 30, 2018 by Neb
Actually looked at the diagram for when CSV kicks in..

[Patcon]

Do you have a secondary bolt on the bottom of the distributor mount? Sometimes you can get enough adjustment between the 2 bolts

[Neb]

Thread resurrection!  Thanks again for all the help.. but I've run into another issue with this whole timing problem and would really appreciate a sanity check here.. ?

I finally got around to removing the oil pump, but ran into a problem when I went to re-install it. I've aligned the spindle and the pump as per the FSM (punch mark above the oil hole), and then reinstalled the assembly, but it still looks wrong.  I'm at about 1 o'clock, while the FMS is at about 1130.. what am I missing here??  I was very careful not to turn the spindle during install (actually put it in twice; ended up the same orientation each time).  Cylinder 1 is TDC.  Timing mark is right at 0deg.  My brain officially hurts.. I'm about to just skip the 'align the oil hole with the punch mark' and orient it so the top of the spindle matches the FSM so I can clear up this timing issue.  Would that cause any issues?  What could lead to this condition?  Improper rebuild of the oil pump by PO? 

Any feedback would be appreciated ?

 

[siteunseen]

There's a trick Tom Monroe tells in his book that worked for me a few times.  I'll take some pics with my phone but can scan it when I'm back from work. Maybe you can read this.

 

[siteunseen]

here's mine when I tore it down.

After it's back together

 

 

[Zed Head]

14 hours ago, Neb said:

 My brain officially hurts.. I'm about to just skip the 'align the oil hole with the punch mark' and orient it so the top of the spindle matches the FSM so I can clear up this timing issue.  Would that cause any issues? 

That's what I might  do.  I re-read my own comments above and couldn't figure out they'd guarantee distributor orientation.  Sorry about that.

Captain Obvious described using vise grips to hold the distributor shaft up then installing the oil pump.  Seemed to work.  Multiple paths to the same result.

[Neb]

Alright, I got under there again last night and took another stab (or rather a dozen) at aligning this thing.  The procedure mentioned in the book siteunseen posted worked; if I rotated the oil pump CW while I inserted it until flush, and then rotated it so the bolt holes lined back up after it was flush, it would produce the CCW rotation up top.  I ended up with 3 'options' (I'm assuming these are based on the gear teeth spacing) and went with the one that pointed the distributor rotor at the #1 plug (which was the most CCW one).  I think the vice grip method could work, but I didn't have vice grips long enough to hold the top of the spindle. 

Hopefully this resolves the timing issues. 

Y'all are awesome; once again appreciate the help!  I'll probably post again once I finish rebuilding the intake manifold and get it all back together and see where the timing is at..

this is the final orientation of the rotor:

This was the final config:

This one looked better, but the distributor still wasn't quite pointing to the no. 1 plug:

Edited November 2, 2018 by Neb

[siteunseen]

Looks good to me.  Your distributor cap should have a raised line on the outside that will line up with your rotor button at number 1.