Jump to content

IGNORED

'75 280z - trying to set timing


Recommended Posts

My '75 280z isn't running yet, but I think I'm getting close.  I just finished going through the fuel system (new pump, lined tank, new filters, cleaned/checked function on all injectors, checked pressure, replaced hoses, inhaled copious amounts of gas fumes, etc)

Next up, I'm starting on the ignition.  I visually verified spark on all plugs when I did the compression check, and replaced all the plugs with fresh NGKs.  The plugs are wired in the correct sequence coming off of the distributor cap.

The car still isn't starting/running though.  Within the normal range of adjustment (with the distributor adjust screw still in place), the best I get is a few chuff-chuff-chuffs before it dies.  I was able to get it to very briefly come to life by removing the distributor adjustment screw and rotating it almost 20deg CW.  It revved to about 2k rpm for about 2 seconds and then died.  That was somewhat repeatable around that same point in distributor cap adjustment.

I dug into it a little further and set my #1 cylinder to TDC (utilizing the wife+stick+flashlight method), and then checked the marks on the block and the distributor arm position.  It doesn't seem like things are lining up as they're supposed to.  The mark on the pulley is somewhere in the range of -15deg, when (in my limited understanding) its supposed right around the 0deg mark.  The distributor seems to be past the #1 point, and I was under the impression it should be right at the #1.

I really don't trust anything in this car, so my next inclination is to pull the valve cover and make sure the cams are in the right spot as well for a third check. 

Or am I totally missing something obvious here.  Whats the next step?  Picture attached of the notch/marks on the block with the #1 at TDC (marked the pulley with a silver marker at the tick).  Thanks!

IMG_20180325_105242.jpg

Link to post
Share on other sites

First question. Are you sure it's getting proper full? Pressure good, maximum 36psi, no air in the system from rebuilding the system. It could be firing on the fuel from the CSV and no fuel from the injectors

Do you have a timing light? It would be easier to crank the engine, check the timing and set it to 5 degree btdc. I say 5 because cranking speed is about 300 rpm and lower than idle speed. You can adjust it properly when it runs.

The rotor button gives a reasonable indication that the timing is in the right area, but the pickup coil under the rotor button is the before indication. One of the pointer of the 6 pointer star (reluctor rotor) under the rotor button should line up with the pick up coil or a fraction past it.

Link to post
Share on other sites
15 minutes ago, EuroDat said:

First question. Are you sure it's getting proper full? Pressure good, maximum 36psi, no air in the system from rebuilding the system. It could be firing on the fuel from the CSV and no fuel from the injectors

Do you have a timing light? It would be easier to crank the engine, check the timing and set it to 5 degree btdc. I say 5 because cranking speed is about 300 rpm and lower than idle speed. You can adjust it properly when it runs.

The rotor button gives a reasonable indication that the timing is in the right area, but the pickup coil under the rotor button is the before indication. One of the pointer of the 6 pointer star (reluctor rotor) under the rotor button should line up with the pick up coil or a fraction past it.

Hmm good point with the fuel.  I checked pressure BEFORE I went through and checked the injectors (and it was ~36psi, so I'm assuming the regulator is good).  I definitely should recheck that now that I've been in there.  Would you still see ~36psi if there was air in system? 

I still need to grab a timing light.  I think the starter in my car is aftermarket, and turning the engine faster than 300rpm (I want to say it was hitting something like 700rpm), but I will double check that tonight. And I'll take harder look at the distributor.

What should the indications on the block look like if #1 is TDC?

Link to post
Share on other sites
29 minutes ago, Neb said:

What should the indications on the block look like if #1 is TDC?

TDC should be at the top of your timing plate. The plate has timing makes from 0 to 20 degrees btdc. If you crank the engine, adjust the timing to somewhere in the top section of the plate. Once you start the engine, you can adjust if properly.

Just lining up the rotor button is not very acurate. The rotor has a "phasing" function because it has to transfer spark through a wide range of advance (from 8 up to 36 degree of advance).

If you do try to manually adjust the distributor (enough to start the engine). Line up the rotor button with number one spark plug terminal, remover the button and then adjust the distributor until the reluctor rotor fractionally passes the reluctor (see red circle in third photo). The metal strip in the reluctor is what you should line up. It is not very acurate, but it will be enough to get it started.

Dist-01.jpg

Dist-02.JPG

Dist-03.jpg

  • Thanks 1
Link to post
Share on other sites

fuel pressure check (36 psi).

Spark check (observe while cranking).

EFI check (listen for injector clicking with stethoscope).

are the plugs coming out dry after trying to start? if so prob no fuel if spark is good.

 

  • Thanks 1
Link to post
Share on other sites

If you checked your timing and it is ok and you have spark at the plugs then I would grab a can of aerostart and see if it will start on that.

If you spray it in the intake (air filter removed) you should be able to get it to fire and run, all be it very roughly by spraying it every second or so.

Now if you can get it to do that, you have problems with your fuel delivery. 

That would be my next step. Work one problem at a time, solve it or cancel it out and move on to the next.

  • Thanks 1
Link to post
Share on other sites
21 minutes ago, EuroDat said:

If you checked your timing and it is ok and you have spark at the plugs then I would grab a can of aerostart and see if it will start on that.

If you spray it in the intake (air filter removed) you should be able to get it to fire and run, all be it very roughly by spraying it every second or so.

Now if you can get it to do that, you have problems with your fuel delivery. 

That would be my next step. Work one problem at a time, solve it or cancel it out and move on to the next.

Great info.  I'll get in there tonight and check fuel pressure, verify spark/wet plugs, and then start on the distributor.  I do have a can of starting fluid, so I can give that a shot if I get that far. 

I really appreciate the help and pictures.  What a great forum!

Edited by Neb
grammar
Link to post
Share on other sites

Vrooom!  Its alive :D

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!

IMG_20180327_200946.jpg

IMG_20180327_200416.jpg

Link to post
Share on other sites

You might be okay with moving the plug wires one over.  Worth a try.  That's pretty far off but it looks close to 60 degrees, which would be one wire spot rotation.

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

  • Haha 1
Link to post
Share on other sites
49 minutes ago, Neb said:

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?

With the Datsuns it's the oil pump and distributor drive quill that is out of adjustment.  Once the oil pump is installed the drive quill, or shaft, is locked in to place on the crankshaft gear that turns both the oil pump and the distributor.  (Never really put the whole picture together before).  The oil pump is below and the distributor above, but they both get their energy from that long spindly shaft.

So what you're really seeing is a function of how many teeth off the the drive quill is, to the crankshaft drive gear.  That's why people use vise-grips or rubber bands to hold it in proper spot , before matching the oil pump to it, to get the distributor right.  The oil pump doesn't care, but the distributor does.  Also why there's no "180 off".  We could count the teeth on the gears and come up with the various points of "off".  I'm surprised we haven't done that yet.

image.png

  • Thanks 1
Link to post
Share on other sites

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 by siteunseen
Link to post
Share on other sites
16 hours ago, Neb said:

Vrooom!  Its alive :D

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.

 

Engine Fuel 1977.jpg

 

Edited by EuroDat
added link
  • Thanks 1
Link to post
Share on other sites

Wow, tons of great info :D  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 by Neb
Actually looked at the diagram for when CSV kicks in..
Link to post
Share on other sites
  • 7 months later...

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 ?

 

IMG_20181031_205316.jpg

IMG_20181031_205325.jpg

IMG_20181031_204457.jpg

Link to post
Share on other sites
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.

  • Like 1
Link to post
Share on other sites

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:

IMG_20181101_135609.jpg

This was the final config:

IMG_20181101_134252.jpg

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

IMG_20181101_131032.jpg

Edited by Neb
  • Like 1
Link to post
Share on other sites

The one that "looked good" looked more right.  Did you rotate the distributor within its adjustment range, the slot on the lockdown screw, to see if the rotor points at 1?  And don't overlook that it's the front of the rotor electrode that sparks not the middle.   Imagine rotation in action.

You'll find out when you set ignition timing.  Might be fine, there is another adjustment on the distributor itself.

  • Thanks 1
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.