TBI stalling when put in neutral

[BA_051]

Well, I just finished my 406 stroker build and Expletive Deleted!Expletive Deleted!Expletive Deleted!Expletive Deleted! its a powerhouse motor, but now im having an issue with the TBI...

Starts right up when hot or cold, runs great and will break 37's loose in 1st and 2nd gear with 3.73's, idles great too... the issue is when im driving and put in in neutral when coming to a light or sign it will drop to 300ish rpm and sometimes recover, but most of the time it stalls out... turn the key to start and it fires right back up and idles fine...If i leave it in gear as I come to a light and just pop it out of gear when it hits its idle rpm, its fine or jab the gas and its ok too... Sounds like my Idle VE tables are off?

I adjusted my BLM's since they were a bit off from my previous low comp 360 and adjusted my TBI so the IAC counts were 40-41 at idle...

[babywag]

I'd play with IAC throttle follower settings, and look @/turn off all the auto trans parameters.

The manual trans. bins have a lot of differences in idle logic vs. auto trans. bins.

Do a search maybe you can locate a manual trans. bin if you started with an auto bin?

[BA_051]

I started with the BJLJ 454/sm465 bin... It's funny it didn't do it with my previous low comp 360 with the k8600... Idle MAP was 45ish with that motor vs now it's at 30-32 with the stroker/mta-1...

Maybe my idle VE table? I didn't mess with it when I calculated my BLM's this last data log... I'm still a bit new with the 7427 over the 7747...

I'll import my VE tables, spark, and cylinder volume and stuff into the BMHK bin and see what it does...

[babywag]

If you're already using a manual .bin, and it was okay before, idle VE table.

Both VE table(s) would need to be redone after a cam swap alone, let alone a complete change of engine internals.

[BA_051]

I can't seem to find a BJLJ bin in the repositories, closest was BJLH... I think I'll switch over to BMHK $0E which I know is a '94 454 with a 5 speed...

[BA_051]

Ok well I looked through my log of the BJLJ bin and sure enough it is for a 4L80E and not a manual... I changed the flags to set it as a manual... So I imported my spark tables, VE tables, and another few parameters, scalars, and flags into a fresh BHDC bin I pulled from gearhead efi...

So We will see what it does tomorrow when i head to work!

[BA_051]

It does the same thing still... I just copied the bottom half of my off idle VE to the idle VE table then interpolated the in between values...

Is there a way to change the speedo pulse per rev on the 7427? I'm using a ford np205 with their 2 wire sending unit so I think it's 8 pulses per rev and the PCM is looking for 2...

[babywag]

Have you retuned the VE tables to the new engine?
If everything was fine before the engine changes, should be fine after re-tuning.

You could maybe use a GM vss buffer box to change output?
The 7427 needs the vss not from drac (or something like that) flag changed for vss input.
By default i believe it's looking for 40-pulse input.

[BA_051]

Yea I did retune it and all my BLM's go from 125 to 130... It was just the first iteration and log so far... And I adjusted the idle VE as well... it didn't do it the first time I ran it with my old 360 tune but the BLM's went from about 105 to 140.

The tables were 105-120 in the low rpm/low map area (idle)
120-130 in the mid rpm/mid map area (cruising)
130-140 in the high rpm/high map areas (high load/accel)

Also trying to dial in my map and tps AE as well since those requirements changed as well...

I'll be driving it about 60 miles tomorrow so I'll be sure to data log it...

It's just getting a little frustrating... I have 2 months to get get everything g squared away so my wife can drive it if needed. Then it's off to OTS in October...


Quick Update on the drive home from work, about 8 miles... When engine temp is less than 170, it drives perfectly, no stalling, sputtering, or even a rough idle... its only when its between 180-195 that I have these issues...

[BA_051]

Ok so I updated my idle VE and off idle VE from the data I logged on my 60 mile trip... The higher map and rpm areas were hovering around the 130 mark so not bad... Mid range good at 127-129...

I added about 15% to the idle areas of both tables and no more stalling issues, but the BLM's are in the 110-115 area... If I run them around the 126-128 the I have stalling issues again....

[babywag]

Double check for an exhaust leak upstream of O2 sensor.
Air will cause the O2 sensor to read richer than the engine actually is.
PCM pulls fuel out to attempt to correct and engine goes leaner than it should.

BLM's are ok to tune by, but people often think they are rich/lean indicators.
They are simply telling you if the pcm is adding or pulling fuel.

Merely speculation on my part, limited data, and harder to diagnose via the 'net.

A vacuum leak can also cause problems.

[BA_051]

Yea that was my first thought was a vacuum leak. I went over everything and checked with brake cleaner and didnt find anything. I will go over my exhaust as well to make sure there isnt a leak...

This was also attached to the 454's TBI unit and have no idea what it is... It bolts to the side and looks to slowly lower the throttle as manifold vac increases...

[JeepsAndGuns]

That is a throttle kicker. It is supposed to have a vac solenoid (just like the egr, evap,purge, etc solenoid) to control it. It will physically hold the throttle open a small amount.
We spoke about this in length over on gearhead. At first we did not know all the parameters were for that thing. Its a long read, but if you are bored:

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?1178-Throttle-kicker&highlight=throttle+kicker

[BA_051]

Thanks for the link! I read through it and it seems to have IAC logic with it too... I do remember turning off the Kicker flag and error code as well as setting the limit blm corrections during AE... Ill set the flag to set again and see what it does tomorrow!

[BA_051]

Well, after some slight adjustments to the VE tables and resetting the kicker settings to 'set'... there is no more stalling... even though there is no kicker on the tbi...