Cranks, no start

[Zed Head]

So, it does pop, I heard it.  You have spark.  Sounds like the timing is way advanced.  Is the distributor cap tight?  Check firing order and rotation direction, as suggested.  Maybe the distributor adjustment screw is loose and it got twisted when you were working up there, skewing ignition timing.

Could also be that something major coincidentally broke.  Timing chain, camshaft, distributor shaft.  You might remove the distributor cap and the calve cover and just make sure things spin like they should.

While the valve cover is off, set the damper mark on zero and reset your distributor and wires to be sure that ignition timing is correct.  Might be time to just start from scratch to be sure.

[siteunseen]

1 hour ago, Captain Obvious said:

You can "manually" disable the entire EFR system by pulling the tube off the underside of the throttle body and capping it. This won't work for you when inspection time rolls around, but just for troubleshooting this current problem, it would be easier if that thing wasn't hanging off the engine.

I did away with all that stuff on my '77.  Here's a picture of the plugged throttle body.

 

[charliekwin]

Well, I think I have a good lead here.

The source of my fuel pump leak...that was obvious. The other houses around the pump and damper look good, but the are some that I haven't replaced and will do the rest of them soon enough.

Anyway, when I fixed the pump, the same one-fire situation happened again. It really seems fuel related, so I pulled off the fuel rail to check the injectors. I've wanted to do this eventually, so this just forced the issue a bit.

Anyway, a couple of cranks later, I got this much fuel in each of the cups for the cylinders.

And I got this much from the cold start valve.

Sent from my SM-G950U1 using Tapatalk

[Patcon]

That's a good clue

[Zed Head]

On 2/1/2019 at 6:05 PM, charliekwin said:

Used real starting fluid, didn't get even a pop out of it. 

The facts are getting kind of random and don't fit well.  Your video showed that it l almost started, more than just a pop, it sounded like a short series of ignitions, on just gasoline.  But you said you didn't even get a pop before with a much more potent fuel, so the focus was on spark.  Now you're measuring output at the injectors but they really don't squirt much at low RPM.  Not clear if what's in the cup is a lot or a little.

You're kind of at the point where it might pay to just write down what you know and put a methodical plan of action together.

Many people get to this point via different ways.  A bunch of disconnected observations that don't really show a solution.  No offense, it happens to many.

[Zed Head]

If that's a lot of fuel for the amount of time cranking, and your temperature sensor reading at the ECU is in range, then bad ECU comes to mind.  Disconnecting all of the injectors might get it to run for a few seconds.  It might be flooding due to the ECU keeping the injectors open.

Just one thought, for the action plan.

[charliekwin]

Here's what the CSV is doing:

Won't open/fire if the connector is disconnected, so it's not stuck open. I can at least try putting it back together and leaving the CSV disconnected to see what happens, then try to track down the cause.

[charliekwin]

7 minutes ago, Zed Head said:

The facts are getting kind of random and don't fit well.  Your video showed that it l almost started, more than just a pop, it sounded like a short series of ignitions, on just gasoline.  But you said you didn't even get a pop before with a much more potent fuel, so the focus was on spark.  Now you're measuring output at the injectors but they really don't squirt much at low RPM.  Not clear if what's in the cup is a lot or a little.

You're kind of at the point where it might pay to just write down what you know and put a methodical plan of action together.

Many people get to this point via different ways.  A bunch of disconnected observations that don't really show a solution.  No offense, it happens to many.

There's some overlapping timelines in the posts. I tried starting fluid early on and it never fired with that. The almost-starts happened later on. With the amount of fuel in there, it's no surprise starting fluid didn't help.

And the cups from the cylinder injectors had maybe 1/4tsp of fuel. The CSV spit out a tablespoon or two. Now to figure out why...

[Zed Head]

I might do both, plus one.  Disconnect the injectors and it will probably start and run for a few seconds on CSV fuel.  Disconnect the CSV and see what happens with the injectors connected.  Disconnect them both and start it on starting fluid.

By the end you'll probably be certain about spark.

[Captain Obvious]

5 minutes ago, charliekwin said:

And the cups from the cylinder injectors had maybe 1/4tsp of fuel. The CSV spit out a tablespoon or two. Now to figure out why...

Figure out why about what? Why the cold start put out a lot more fuel than the individual cylinder injectors? Because it's designed that way. Seems completely normal to me.

I still think the obvious explanation is that you are flooding your engine by trying to start an engine that was working properly when there was a significant bypass around the throttle plate (the AAR). You removed that bypass and didn't add extra air from somewhere else, but you kept the fuel the same.

Did you try holding the gas pedal down a little bit while you cranked the engine? That might not be it, but it's so simple to try!

[charliekwin]

I tried searching for CSV videos and found nothing, so was just making assumptions about the CSV based on the other injectors. It seems like a lot of fuel to me, but that's just me guessing. And you know what they say about assumptions. I have tried holding the gas down a bit while cranking, but I think it's flooding before it can start. With your and Zed's help, I have a game plan for tomorrow.

[Captain Obvious]

Well I don't have any hard numbers for you, but IMHO that cold start valve looks perfect.

I took a quick look through the FSM to see if I could find some real numbers and came up empty. There may be some flow measurement numbers in there somewhere for the CSV, but with a quick review, I didn't find any.

Only thing I DID find was in the FI manual... On page 16 where they are describing the operation of the CSV, they say "the fuel injected Z-car needs a choke system which supplies very large amounts of fuel only during starting."

So the factory expected amount of fuel is "very large". I think you nailed it.