The car is running really well now. Dan, come drive it again. You will be pleased with how much better it is with the new spark plug wires.

The only thing that stands in the way of it being a really confidence building daily driver now,(with no back up car) is start up tuning. It does not start the first time, every time, and it is really hard to tell why. It is hard to do trial and error tuning in this case because you only get a couple of chances to fiddle with it each day, and it is really hard to tell if the things you changed helped or not, especially since the weather changes so dramatically around here from day to day. And if you go the wrong way and flood it, at least at this point, there is no clear flood mode built in. Believe it. That will get added by me.

So, anyone who has an EFI slant out there, can you look and see what value you have in your VE table for the crank mode? I guess that would be very low vacuum and RPM. Does anyone know what kind of vacuum is pulled during start up cranking? I have never looked, but should. Does anybody have any practical clues as to how to tell if the engine is flooded or too lean short of pulling a plug and sniffing?
Sam

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Glad to read things are on an upward path. Didjya order that alternator hot-post insulator boot yet?

I may not quite accurately recall your "initial start always takes two tries" issue, but if I remember correctly, it will crank but not fire on the first attempt, then crank, fire, and run on the second attempt. If you will confirm or correct my recollection, I will write up the applicable ideas.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Wild guess-- Your fuel pressure in the rail is too low. It is probably leaking back at the fuel pump, or through the regulator valve.

Less likely-- You have a leaky injector. It leaks just enough to release some fuel from the rail, and again, you lose pressure, until it cranks a bit.

I had this symptom on my old jeep 4.0 motor.

Greg

When I watch the fuel pressure gauge, it shows good pressure through cranking. Dan, I am not sure I have seen a pattern. I have changed so many things, so often it is hard to tell. The short nose plugs started better, but ran like (bad) when cold. The standard tip plugs run great when cold, but seem to be fussier about the initial start up. I am imagining that they get a squirt of fuel closer to the electrode, which might make them more prone to shorting out from wet fuel. My image might be all wet though. Why not asume that it does what you are asking. What then, if this is so?

Sam

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concur.

If the fuel regulator is defective, this causes hard starts as pressure is lost and takes awhile to build up. Also some adjusting in controller needed if everything checks out on the mechanical side.

Easily diagnosed with a fuel pressure gauge.

Can you monitor status LIVE (megasquirt supports this feature BTW.) during starting when it happens on hard-start? 1. Ignition triggering issues, 2. fuel amount for cold engine? etc.

And where it is injected does matter. Port injection less bit less compared to TBI which need big fat rich mix (nearly equal to WOT mixture ratio that what choke did).

Cheers, Wizard

Fuel pressure seems to hold steady while in start up mode. I might be able to monitor something about fueling during startup. I wil have to check it out. There is a diagnosis screen I can opn, with tons of things visible. The fueling duty cycle is always visible, and I could compare this to at idle duty cycle, and then do the math relative to the RPM to figure what ratio it was trying to deliver. At the very least. It may have a function that is easier to work.

Anybody got a VE figure for low vacuum , and low RPM? How about you MAtt? What figure you got in there? How about you Lou? Pierre?

Sam

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Well, a couple of things occur to me. I wonder how low your line voltage drops during cold cranking. It would likely be educational to put an accurate voltmeter on and watch it closely during cold cranking. I might also try the same thing at specific points in the electrical system (ECU power and ground, fuel pump power and ground, ignition box power and ground if it's separate from the ECU, etc.) It's possible that during cold cranking, line voltage (or individual-component voltage) is dipping below what is needed for the ECU or ignition box to work correctly. If this is what's going on, it's probably a borderline/marginal condition, such that once everything's primed by the initial crank (oil, fuel, etc.), it makes cranking just a leetle bit easier, the voltage doesn't go below critical, and the engine lights off.

All of this could be down to trying to light the engine with 25° of advance. That makes the starter's job a great deal harder, which causes it to draw more current, which drops line voltage lower than it would otherwise go. You might never know it except by secondary symptoms like this; IIRC you're running a mini starter, and those are quite strong. This, BTW, is in addition to the primary mechanisms by which overly advanced timing makes an engine difficult to start reliably.

Then again, it could be something else entirely. I think I told you about Hemi Andersen's modified minivan, which first thing in the morning would crank all day but absolutely, positively would not fire unless the driver kicked the accelerator during cranking. Once the ECU saw a change on the TPS, it OK'd the engine to light off. There was no reason why this should have been the case, and no trouble (per se) was ever diagnosed, and it was a "cold start only" issue. That's just the way it behaved, and kicking the accelerator was easier than trying to figure out why the accelerator needed to be kicked. I point this out to illustrate the perversity of inanimate objects. YMMV.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

All this sudden new info coming out concerning the DIY FI is really awesome!

That makes this more confident to pull this off for mine when I go over to FI & spark instead of that carb and what more, more flexible to set up.

Cheers, Wizard

It's just new here but still it is awesome

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1970 Vitamin C Duster 225 2bbl 904 eventually turbo efi r154 5 speed

1969 B5 blue roadrunner 383/727 soon to be turbo slant (JK)

1972 Barracuda was green 318 who knows?