280Z Requires Starting Fluid for Cold Starts

[S30Grit]

Yeah, sorry about the pic.  Photo was taken a few days ago during troubleshooting.  Definitely had the issue regardless if the CSV was connected or not.  Either way, I'll be sure to do some more tests on the CSV soon.

Zed Head - thanks for the clarification, that's very interesting it's an independent system.  I'll try that starting procedure to see if I have any luck.  There's definitely been some starting attempts, waiting various amounts of times, and trying again with no luck.  I'll give that timing a try tho.

However, given that it will fail to start in 80F weather, doesn't that mean it's likely not a CSV issue?  I'm still operating under the assumption of this question: "Is it correct to assume that the CSV is only used in conjunction with the normal injectors?"  

Still extremely puzzled why injectors refuse to fire when engine is cranking regardless of CSV, thermotine, etc... not to say it's not the cause, just having trouble putting the pieces together.

[Zed Head]

I had a problem once with a weak, not completely bad, ignition module.  The spark was too weak during starting to fire gasoline, but would fire on starting fluid.  Once it started it seemed to run okay,  Probably low voltage during starting through a weakened ignition module.  The module has to have good current through it to create good spark.  I damaged the module by leaving some spark plug wires disconnected and starting the engine.  Forgot to say that I did change the module to a new HEI module once I figured out that it was weak spark.  Orange, not blue.  The new module fixed it.

So, if you're still baffled, trying the HEI module swap might be worth a shot.  Pretty cheap and you can wire it up under the hood using spare wire pretty easily, as a quick test.  These old modules die on a regular basis anyway, yours will eventually.  Might as well be ready.

Edited October 17, 2019 by Zed Head

[S30Grit]

Ahhh, I knew I forgot one thing on the "new parts list".  It has a brand new ignition switch assembly btw.  I didn't install it, so maybe I'll re-check the wiring.

Spark could be an issue, but I know fuel is an issue (99% sure at least) since the injectors aren't putting fuel in during cranking.  

Is the OEM 1978 module HEI? I'll have to do some research, is there specific part/manufacturer you recommend?

[Zed Head]

1 hour ago, S30Grit said:

Spark could be an issue, but I know fuel is an issue (99% sure at least) since the injectors aren't putting fuel in during cranking.  

If you're absolutely positive that the injectors aren't opening then that should be your focus.  Check the Pin 1 circuit at the ECU.  Maybe it has too much resistance or something weird happens during starting.  Pin 1 is connected to the negative terminal of the coil so the ECU can "see" when the coil fires.

On the module don't assume that new is good.  1978 does have "HEI" but the module I was talking about is the GM HEI module swap.

 

[Dave WM]

3 hours ago, Zed Head said:

I'm just reading the words in the FSM.

prob something got lost in the translation.

use a stethoscope and listen to the injector while it is running so you will know what it should sound like, then try it again when cranking.

[Patcon]

Do you have a volt meter?

If so:

1. Check the battery voltage

2. Check the battery voltage when cranking

3. If it's low when cranking add a second battery with jumper cables or a jump box would be even better. Let's rule out low voltage possibilities to start with

If you do not have one, consider going to Harbor Freight and getting a cheap one. It will make diagnosis much easier

[ensys]

 

Mr.Grit:

Well, you've certainly been given a whole bunch of issues to attack, eh? That's called "mental dazzle", and is the enemy of a methodical approach.

If I may be so bold, I would suggest that since you know the injectors work just fine, the logical place to begin is with the Cold Start Valve. When you look it up in the Shop Manual, you will see that it is itself, a single injector mounted in the intake tract before the manifold.

It's job is to act as an electronic choke that enriches the starting mixture for a "cold" (a term that has more to do with engine temperature than air temperature) engine. It is controlled by the Thermotime switch, much like a choke pull-off.

Your job is to first see whether or not it is squirting at startup, usually by dismounting it (still connected electrically) and aiming it into a jar while someone starts the car, as the Manual directs.

If it squirts (which I doubt), you can check it off the To-Do list.

If not, the fun begins. The Manual will guide the way.

Bon chance

 

 

[S30Grit]

There definitely hasn't been a shortage of ideas, which is much better than the alternative!  Gives me plenty of things to check.

The main question I have right now is regarding the CSV.  If the CSV is used during startup, is the computer not supposed to pulse the injectors?  Just good to know what the expected behavior is.  I didn't see anywhere in the FSM describing if the car is supposed to use the CSV AND the injectors while cranking.

If car is supposed to only use CSV or injectors: very likely a CSV/thermotine related issue.

If car is supposed to use both fuel methods: I'm looking at some much tougher troubleshooting.

[Zed Head]

15 minutes ago, S30Grit said:

The main question I have right now is regarding the CSV.  If the CSV is used during startup, is the computer not supposed to pulse the injectors? 

It's a good question and maybe Nissan had a plan for that.  Easier to just measure what's actually happening though.  As I mentioned above my engine started with no CSV at all.  If the injectors weren't squirting there'd be no gas to start with.  And there are no pins to the CSV or thermotime switch to the ECU.  So, no way for the ECU to "know" if it's squirting.  I think that the CSV is extra, added on top of injector fuel.

[S30Grit]

Ahh, good point, seems then that CSV alone likely isn't the cause then. But it's easy to test so I'll check it out. 

Im swapping the injectors right now because one is seeping gas, and a bit of a safety harazard. More to come... 

[Captain Obvious]

The cold start spray is in addition to the normal injector squirting. Both the regular injectors and the CSV will spray at the same time if the engine is cold enough.

So, I got a question.... When you say it won't start without a spray of starter fluid, how long are you cranking it for before saying it "won't start"? Reason I ask is that I removed my cold start valve completely and it definitely takes longer to start without it than it did before I took it off. Maybe five seconds of cranking? I'm wondering if you just are giving up too soon.

What happens if you crank the engine for fifteen seconds straight? Sounds like a short amount of cranking, but with your hand on the key, it doesn't feel like a short time.

[Dave WM]

Next time try this when its cold.

disconnect the starter solenoid spade connector (this disables the starter), Turn the key to start and count to 5, release from start position and reconnect the starter solenoid connecter, now try to start it. If it starts right up this way then you have something causing the fuel to drain back out of the lines, requiring the pump to run a extra long time to build pressure. Normally the pressure will come up from 0 to 36 psi in about 2 seconds (not long enough to notice during starting). If the lines are completely empty of fuel it will take much longer as you have to fill the filter and all the lines. The completely empty scenario should NOT happen, but maybe a faulty drain back valve could cause it. A proper operating pump will fill the system but will take the extra few seconds to do it

 I notice that if I drive every day the start is nearly instant, if I take a week off it takes an extra 2-3 seconds.

 

BTW, you may hear a "CLICK" sound under the hood when you turn to start, that would be the CSV IF its cold enough to activate. It almost sounds like a loud spark, so do be concerned if you do hear it.

Edited October 18, 2019 by Dave WM