Starts then dies when warm

[yeastieBoB]

Wouldn't start when warm (>150 ECT), so I kept increasing Crank PW ECT Modifier FN348 until it would start. After that it would start, but then almost immediately shut off unless I worked the gas pedal. Once I drove a little ways it seemed fine after that. It's done this a few times since loading A9L2.

Is there something in the tune I can adjust to help with fuel after startup? Or should I worry about that after I have my WB installed? Thanks

[decipha]

It seems a lot of people confuse cranking pw with startup enrichment. Cranking PW is the time you have to hold the key in the crank position before the engine fires off. From that point on startup enrichment takes over.

It sounds like your cranking pw are fine now and you need to dial in enrichment fuel thats assuming your base fuel is dialed in (injectors and maf).

Ford fuel control can be broken down in to 3 modes. 1st is cranking pw, thats the time you have to physically hold the key in the crank position before it fires off meaning >1000 rpm's. 2nd is base fuel i.e dialing in the injectors and maf which can only be done on a warm and stabilized engine. 3rd and last is startup enrichment.

If you dont have to hold the key in the crank position with the starter engaged for long to get the engine to fire then your cranking pw is fine. If you haven't dialed in base fuel yet then you can't dial in startup enrichment yet. Once your base fuel is dialed in you can then for dial in the startup enrichment "lambse subtractor" table.

The other big contributor to startup is dialing in the isc multiplier fn1861 / fn1862.

it all covered in the startup enrichment write up on the homepage

[decipha]

i just added this to the fuel write up, give it a check over has more details

[yeastieBoB]

Yep, I was confused. Thanks for clearing that up!

[yeastieBoB]

So I need to be able to make some adjustments so I can drive this thing. I can’t tune base fuel if I can’t drive it or fill the tank. It stalled at a stop sign today and it wouldn’t restart. I’m currently waiting on the side of the road for it to cool off completely to see if it will start. This sucks.

Edit: I did notice that when it stalled ACT was >160. I’m guessing that’s contributing.

I did get my WB installed today and it’s set up for data logging.

[yeastieBoB]

I made it home! I don't know what's going on with this thing. Had to wait until ECT and ACT were near 130.

I know heat soaked ACT sensors can cause problems, but I wouldn't expect that to just start happening all of a sudden.

Anyway, I got to get to bed. I took a log of my drive home. Car was running rough. Note that I haven't completed validating the WB logging. Watching it vs the dashboard, it looked accurate so far.

[89mustangcoupe]

I was actually going to make a thread I'm having the same problem my car starts right away I went down the road and went back home and it got to 170 degrees etc and Iat were like 90. Now I tryed to restart it after shutting off in driveway and it keeps cranking. Im running the supercharger belt off because I just put new head gaskets on motor and trying to get it tuned without supercharger belt on for now. So I need to dial in my base fuel table? Then dial in my start up enrichment?

[89mustangcoupe]

I believe start up enrichment is off because I tuned injectors and maf already but didn't really mess with start up yet. I'm assuming it's dumping to much fuel on start up when it's warm

[89mustangcoupe]

i uploaded a screenshot of my tables does this look right? not sure if i need to up the numbers around 150 degress or decrease the numbers.

[decipha]

base fuel table cannot dial in fuel and should not be touched unless running an alternate fuel

read the fuel write up i state it numerous times

you need to determine if its cranking pw or startup enrichment causing your issues

[yeastieBoB]

edit: removed post

[yeastieBoB]

In regards to my issue, I was verifying my tune and noticed Injector Breakpoint FN389 was all 0. Each time I update it, save it, and then re-open it, all the values are zero again. What am I doing wrong?

[decipha]

your plugging in the wrong value for that specific breakpoint function

there are two different functions with different equations, the one you use depends on the injector breakpoint data your given

AS WITH ANY PARAMETER, ALWAYS PAY ATTENTION TO WHAT YOUR CHANGING FROM AND TO

compare your breakpoint to the a9l2 and see where you went wrong

[yeastieBoB]

your plugging in the wrong value for that specific breakpoint function

there are two different functions with different equations, the one you use depends on the injector breakpoint data your given

AS WITH ANY PARAMETER, ALWAYS PAY ATTENTION TO WHAT YOUR CHANGING FROM AND TO

compare your breakpoint to the a9l2 and see where you went wrong

Thanks. I see the two Injector Breakpoint parameters (lbs/mass and lbs/rev), but I don't understand how to know which parameter to use based on my injector data. I assumed FN389 lbs/rev since that is the only one mentioned on the A9L2 Base Calibration page.

FRPP 30 lb/hr @ 55psi
B302

• Low Slope 37.504
• High Slope 35.952
• Breakpoint 0.0000253007

[decipha]

lbs/mass is what the reference data is giving you

i thought i had the equation *1000 in there

regardless of what the software shows you, the stock breakpoint I have in the a9l2 is 0.000010 lbs/mass

[yeastieBoB]

Thanks, but I'm not sure what you mean about the equation. You're correct about the stock breakpoint in the A9L2.

Am I not just updating the Injector Breakpoint lbs/mass using the breakpoint 0.0000253007?

[decipha]

yep thats it plug it on in

[yeastieBoB]

I could use more help with this issue, please. My next step is to verify my WB is logging correctly, but I can't do that if I can't drive it.

Let car idle 7 minutes. Restarted fine with ECT 196 and ACT 138.

Let idle another 8 minutes. Would not restart with ECT 178 and ACT 148.

Those two ECTs are within the same range in the Crank PW ECT Modifier table, so I don't think that table needs adjustment.

I have not modified my Startup Enrichment table. I believe that at those ECTs no startup enrichment is done.

I'm not sure what else might need adjustment. Any ideas?

[decipha]

startup enrichment is always needed regardless of temp

sounds like you have mechanical issues, verify spark fuel and air one of the 3 is missing or not enough