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-   -   Mustang EV14s No Start (https://www.miataturbo.net/megasquirt-18/mustang-ev14s-no-start-93008/)

ByteVenom 04-28-2017 07:43 PM

Mustang EV14s No Start
 
I just got around to installing my Mustang (Ford 2005-15 Mustang GT 60lbs 8 Fuel Injectors EV14 USCar | eBay) Injectors.
They're supposed to flow around 625cc - 640cc.
Using the calculated required fuel I got 4.9ms, however from what I've seen that number is fairly high for the amount that these injectors flow. I arbitrarily chose 3ms instead.
I lowered my VE table values around the starting area to about 12 and attempted to start the car. The car would not start, and the engine shook violently. I smelled gas after attempting to start the car and I figured that my fuel values were too high.

However, I fiddled around in the engine bay and happened to bump off the MAP sensor tube. I started the car with this exposed to open air, and the car started fine. It was running extremely rich, however once I leaned out the values it ran perfectly fine at 2300.
Why would my car start and run with the MAP value stuck at 100, but then die out with a real world MAP value?

Another way to calculate the req fuel was to use the (old injector/new injector) * old req fuel. This gave me 4.7ms.
Basically my question is: How should I go about calculating my req. fuel? and: How come my car starts with a default map value?

SpartanSV 04-28-2017 07:49 PM

Sooooo have you actually tried using a req fuel of 4.9 instead of your randomly chosen number?

ByteVenom 04-28-2017 07:59 PM


Originally Posted by SpartanSV (Post 1409771)
Sooooo have you actually tried using a req fuel of 4.9 instead of your randomly chosen number?

Yes, still didn't run. Raising the number will only make the car run richer.

18psi 04-28-2017 08:46 PM

ev14's don't use anything near stock injector values in idle cells

stefanst 04-28-2017 10:03 PM

Use the correct req fuel value. 5ms or so. Raise your idle cell values. Most afaik are between 40 and 60. 12 seems incredibly low.
Smelling fuel when it won't start doesn't really tell you if you're rich or lean, since you'll also get fuel in the exhaust if the mixture is too lean to combust.
Then play with the cranking fuel. Mine is set to 160 at 80*F. YMMV. If it doesn't fire after a few seconds of cranking, floor the throttle while you keep cranking. That will put it in flood-clear mode, meaning it won't inject any more fuel. If it starts coming alive under flood-clear, you had too much fuel. If not, it was likely too lean.

ByteVenom 04-28-2017 11:04 PM


Originally Posted by stefanst (Post 1409792)
Use the correct req fuel value. 5ms or so. Raise your idle cell values. Most afaik are between 40 and 60. 12 seems incredibly low.
Smelling fuel when it won't start doesn't really tell you if you're rich or lean, since you'll also get fuel in the exhaust if the mixture is too lean to combust.
Then play with the cranking fuel. Mine is set to 160 at 80*F. YMMV. If it doesn't fire after a few seconds of cranking, floor the throttle while you keep cranking. That will put it in flood-clear mode, meaning it won't inject any more fuel. If it starts coming alive under flood-clear, you had too much fuel. If not, it was likely too lean.

That makes a lot of sense.
Any idea to set cranking fuel specifically on a Diypnp? I've been using the VE table where the cranking engine is.

hector 04-29-2017 08:02 AM

And take a look at the dead times and battery voltage correction numbers. Won't idle very well if these numbers are vastly different.

ridethecliche 05-01-2017 01:48 AM


Originally Posted by hector (Post 1409832)
And take a look at the dead times and battery voltage correction numbers. Won't idle very well if these numbers are vastly different.

How does one change the battery voltage correction numbers? I mean, I know how to, but the numbers on the FF website are absolute while the numbers in TS are all in percents. Just convert?

hector 05-01-2017 06:47 AM

Its in percent per volt which makes it a compromise since the dead times by volt are not linear at least not on the data given by FF for their injector. Yet another reason to go MS3.

edit: I thought you were referring to a DIYPNP which has it in % by voltage change from 13.2v. So yes you would have to do some math. I can't do spreadsheets but this would be easy peasy on one.

ridethecliche 05-01-2017 10:45 PM


Originally Posted by hector (Post 1410201)
Its in percent per volt which makes it a compromise since the dead times by volt are not linear at least not on the data given by FF for their injector. Yet another reason to go MS3.

edit: I thought you were referring to a DIYPNP which has it in % by voltage change from 13.2v. So yes you would have to do some math. I can't do spreadsheets but this would be easy peasy on one.

A good link with all the info was just posted on my brain ms3x idle issues thread!


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