1978 280z will not start without ether

[Captain Obvious]

Crash, But before you start testing complicated things... Try this.

Pull the small Black/Yellow wire off the starter and then turn the key to START. The starter should not spin (because of the wire you disconnected), but the fuel pump should run.

 Can you hear the fuel pump running in START?

[crash131313]

i have not had a chance to try anything yet since i work all night and sleep all day like a damn vampire but i will try this first captain.   when i was first sceptical if i was getting fuel i pulled a few plugs and they seemed to be dry when cold. so this makes sense that maybe the fuel pump is not running when the key is engaged in the start position.    again i thank you all for the attention and advise for my z car.      and zed i have done nothing internally to block. its a stock l28 with a p79 head and flat top pistons but i will do a compression test just to make sure.     this motor ran great before i pulled it out of the car with great compression.   

 

list of modifications:

cold air intake with k&n filter 

flame thrower coil

accel 8mm wires 

iridium plugs 

electric h2o pump

electric fan

aluminum 3 core radiator

fidanza 10lb lighter than stock flywheel 

stage 2 centerforce clutch 

short throw shifter 

all new vacuum lines and fuel lines 

6-2-1 header with true twice pipes from the header collector 

kyb gas shocks 

vogtland lowering springs 

1.25 inch sway bars front and rear 

strut tower bars front and rear 

slotted and drilled front rotors 

new factory front calipers 

stainless braided brake lines all four corners 

stainless braided clutch line 

240z front and rear bumpers ( rear not installed yet because its a pain in the arse to fab brackets)

new badges ( not installed yet)

jdm fender mirrors ( not installed yet)

new seat skins and foam 

new floor mats with 280z embroidered logo 

 

i know most of this is irrelevant to the issue at hand but i thought id let you know what i have done to my old baby.  i will post pics as soon as figure out the major problem at hand 

 

 

[crash131313]

oh and captain where are the fuel pump relays located???

[Captain Obvious]

Glad to help. Since it runs fine once you get it started, it's got to be something relatively simple. Just need to find it.

On the 78, all the fuel pump control relays are on the bracket in the engine compartment forward of the battery. The same bracket that the fusible links attach to.

Let us know what happens when you pull the black/yellow pulled off the starter.

[crash131313]

well i have disconnected the starter wire and the fuel pump is pumping just fine in the "on" and "start" positions.   however the electric h2o pump shuts off in the "start" position.   could that have anything to do with it????     i am at a loss of thought now

[crash131313]

i also pulled three opposing plugs and they are dry

[Dave WM]

I don't know anything about electric water pumps, but it would make sense that it not run during starting. You want max voltage for the starter, so outside of the fuel pump, seems no other electrical items should be on.

[crash131313]

thats what i figured dave thanks.     this is so frustrating 

[crash131313]

On 9/29/2017 at 7:15 AM, Dave WM said:

don't forget to check out the start switch itself. you want to make sure the ON stays ON when the key is advanced to the start position, I had an intermittent ON that caused a lot of grief. You need to test it to be sure.

how can i check the start switch??

[Dave WM]

1. solinoid connection off (small spade connector on starter
2. Key switch to START
3. Fuel pressure gauge reads 36 psi return to ON and it will slowly drop off since the car did not start.

is all that correct?

if so try slowly moving from on to full start position see if there is any changes, you are listening/looking for pump sound/pressure to change as if the there could be an intermittent connection between the RUN and START.

If all that seems fine its prob NOT the switch. The FSM has a guide that shows the terminals on the back of the switch, with a ohm meter/continuity checker you should be able to confirm proper functionality using the matix provided.

If you are still interested in checking the switch (however if you passed the 1-3 checks I doubt its the problem, but could be, I had the same issue but I never did the slow moving from on to start to test for that).

 

 

 

 

 

 

 

[Dave WM]

One of the problems IMHO is you have done a LOT of changes, if that is when the problem started up then you have the possibility of multiple points of failure, which if you do have, makes it very hard to find the combo of problems.

For future reference, only make one change at a time, make sure everything still works, then make another. that way if something goes wrong you can zero in on the likely suspect.

[crash131313]

wow that video is very informational.   and makes perfect sense.    i guess thats what im troubleshooting next    thanks dave