Cold Start Tuning, Choke Mode

[Dr.Danger]

I'm having cold start woes. I have a 473" Ford backed by a manual trans running a 454 TBI with a Moates emulator on a 1227747 ECM. During the warmer months, I've had very little issue running with a mildly tweaked ATPY map with about 17 PSI fuel pressure. Now that it's gotten cold out, I can't get this thing to start without stumbling in choke mode like crazy and just dumping fuel out of the tailpipes. Once 50 seconds or so passes of stumbling, it snaps out of it and it falls to a steady open loop purr, reading 10-10.3:1 AFR on the wideband I recently installed. Once the engine is warm, I can kill it, start it up again, RPMS go much higher and smoother than when cold (2000 or so) and it still runs a rich 10-10.3:1 AFR for the same 50 seconds until it falls into normal open loop operation again. Open loop idle is a tad rich but it quickly falls into closed and gives me a steady stoichiometric idle at that point.After playing with and reducing the values for Choke- Time Out AFR vs. Coolant Temp. I'm not getting any different effect. I've been reluctant to play with Choke- Cold AFR vs. VAC kPa, opting to reduce the Time Out AFR vs. Coolant Temp. values instead, since they are supposedly lowering my startup AFR which I surmised was far too rich for this engine.Not getting anywhere, I got fed up and loaded up a new bin (ATPZ) to see if maybe something was wrong with the other bin or I had adjusted something previously and forgotten about it. I turned off the EGR and air diverter, and started it up. It did a little better, but still can barely idle due to excessive fuel until the choke mode quits between 30 and 50 seconds later.My questions are, which tables should I be focusing on in regards to choke tuning to get this thing to at least have a steady start up without all the fuel? I'm not worried about closed loop, just choke mode and the transition to open loop at this point.What is the main control for the idle speed during the choke mode? When it's around 65-80°F outside, the choke mode on startup moves up that 2000 RPM and hangs for the 50 seconds until it falls out of the startup mode. I'd expect maybe 12-1300, not 2000 for close to a minute. It will often do it when the engine is brought up to operating temp, shut off, and restarted again a minute later. Should I be reducing the IAC - Position vs. Temp values for colder temperatures? Thanks for any pointers. My coolant temp sensor is indeed reading properly, it was at 84*°C warmed up and idling with the outside temp at 40°F last night. IAC is brand new, the old one would stick and not move, even after cleaning. TPS is operable and reads .49-.51 with the throttle closed. It was at .66 but I adjusted it back down. Vaccum at 19-20 idling.

[mmigacz]

Can you post your bin and a datalog of it starting when its cold?

[Hog]

I'm having cold start woes. I have a 473" Ford backed by a manual trans running a 454 TBI with a Moates emulator on a 1227747 ECM. During the warmer months, I've had very little issue running with a mildly tweaked ATPY map with about 17 PSI fuel pressure. Now that it's gotten cold out, I can't get this thing to start without stumbling in choke mode like crazy and just dumping fuel out of the tailpipes. Once 50 seconds or so passes of stumbling, it snaps out of it and it falls to a steady open loop purr, reading 10-10.3:1 AFR on the wideband I recently installed. Once the engine is warm, I can kill it, start it up again, RPMS go much higher and smoother than when cold (2000 or so) and it still runs a rich 10-10.3:1 AFR for the same 50 seconds until it falls into normal open loop operation again. Open loop idle is a tad rich but it quickly falls into closed and gives me a steady stoichiometric idle at that point.After playing with and reducing the values for Choke- Time Out AFR vs. Coolant Temp. I'm not getting any different effect. I've been reluctant to play with Choke- Cold AFR vs. VAC kPa, opting to reduce the Time Out AFR vs. Coolant Temp. values instead, since they are supposedly lowering my startup AFR which I surmised was far too rich for this engine.Not getting anywhere, I got fed up and loaded up a new bin (ATPZ) to see if maybe something was wrong with the other bin or I had adjusted something previously and forgotten about it. I turned off the EGR and air diverter, and started it up. It did a little better, but still can barely idle due to excessive fuel until the choke mode quits between 30 and 50 seconds later.My questions are, which tables should I be focusing on in regards to choke tuning to get this thing to at least have a steady start up without all the fuel? I'm not worried about closed loop, just choke mode and the transition to open loop at this point.What is the main control for the idle speed during the choke mode? When it's around 65-80°F outside, the choke mode on startup moves up that 2000 RPM and hangs for the 50 seconds until it falls out of the startup mode. I'd expect maybe 12-1300, not 2000 for close to a minute. It will often do it when the engine is brought up to operating temp, shut off, and restarted again a minute later. Should I be reducing the IAC - Position vs. Temp values for colder temperatures? Thanks for any pointers. My coolant temp sensor is indeed reading properly, it was at 84*°C warmed up and idling with the outside temp at 40°F last night. IAC is brand new, the old one would stick and not move, even after cleaning. TPS is operable and reads .49-.51 with the throttle closed. It was at .66 but I adjusted it back down. Vaccum at 19-20 idling.
What year is the TBI unit from? The 94-95's run smaller injectors with approx. 30psi of fuel pressure
\
peace
Hog

[Dr.Danger]

Ok I'm a bit fed up. I've been trying to get a successful startup log of this issue to no avail. Unit is the early 454 TBI with the low pressure injectors, I'm feeding it 17 psi via a 40 psi in tank Ford Tempo pump. So, I did a lot more playing with closed loop idle and some other fuel tables and WHEN it works, have started successfully working my rich running issue out. These things are just programmed to give a lot of fuel in stock form. The problem now is connectivity. In the mornings when cold, it appears this thing is forgetting whatever .BIN I have fed it previously and falls back on what feels like the rough stock tune. I don't know this for sure, but it's my guess since no matter what I do, I cannot get Tunerpro to acquire data from the ALDL connector at all. I've checked drivers. I've checked port settings and latency. When I first fire it up in the morning, it runs like crap and there is no way to get the laptop to connect. It does say it will read the emulator, but no feedback from sensors. Now, I can go out in the middle of the day, fire up the laptop, connect, and sure enough ALDL will connect, and allow me to reflash the .BIN back onto the Ostrich and the thing will run like it's supposed to again, closed loop idle and everything, and the stuck IAC is now fully functional, starting from the standard 145 steps and quickly falling to my settings on startup. CTS is fully functional as well.What gives? This is feeling like colder temperature is causing either the emulator or the ECM to go haywire.

[Dr.Danger]

Forgot to update this.Issue has been figured out. The Moates Socket Booster was faulty. I didn't know it, but apparently the TBI computers will run without a chip or emulator even plugged in to them. If I had know this I probably would have figured it out much sooner; I always assumed it wouldn't even run in those circumstances. :mad1:Anyhow, I soldered a new DIP socket into a spare '7747 computer with no luck, and checked the cable connections from the emulator to the socket booster and everything stayed the same. What I was assuming was bad cold start tuning, was actually the truck firing up and running like it would with no chip at all. I didn't realize it until I just yanked the emulator while running to see what it would do. Sure enough, it stayed running as was with no changes, so I killed it, started it back up, and then realized what the computer was actually doing. Weirdly enough, flipping the 28/24 switch back and forth on the Socket Booster right after start up would cause it to start reading the chip and the truck would then run fine until it was shut down again.I contacted Moates and they fixed me up with a replacement under warranty even 4 years after purchase. Solid service from those guys. :happy: Anyhow, sometimes even good products can fail or be faulty so if anyone has this issue don't rule it out without a little diagnosis and contact to the company that produced the part.

[brian617]

They warrantied my burn2 many years after I bought it. Good people.