Stalling when coming to a stop

[01yellercobra]

I'm tearing my hair out with this one. Part throttle is good. Once I'm stopped the idle is good. But coming to a stop it'll dip and sometimes die. The TPS is set to .98vdc. I've noticed my ISC duty cycle is around 50%. Which I think is pretty high. The idle integrator is around 0.00 +/- .02. The car seems mechanically sound. No vacuum leaks that I can find. What am I missing?

Edit: I don't think my combo is showing up in my sig since I'm on tapatalk. 323 BB/stroker, Vortech T trim, BA5000 in a 3.5" pipe, 80lb injectors, twin GT pumps, stock intake and heads.

 

[fastmach01]

How is your fuel system ran. Also do you notice it going fat right when it dies?

 

[01yellercobra]

I'm still running the returnless set up. Twin GT pumps, wire upgrade, and 80lb injectors. I'll have to watch the wideband next time. I'm usually watching the cars in front of me and the tach.

 

[Noisy Crickett]

Check the dashpot decay rate.

 

[01yellercobra]

Check the dashpot decay rate.

I've already slowed it down 15%. Which is the difference in size between my old engine and this one.

 

[fastmach01]

I'm still running the returnless set up. Twin GT pumps, wire upgrade, and 80lb injectors. I'll have to watch the wideband next time. I'm usually watching the cars in front of me and the tach.

I was running returnless with dual -6 feed lines. I was having the same issue where die when i go to stop or just idling. My issue was sense there was 2 feed lines ad only 1 FPS. We were able to tell what fuel pressure was on one side of the rail but not the other side causing it to over fuel and kill it self

 

[01yellercobra]

I was running returnless with dual -6 feed lines. I was having the same issue where die when i go to stop or just idling. My issue was sense there was 2 feed lines ad only 1 FPS. We were able to tell what fuel pressure was on one side of the rail but not the other side causing it to over fuel and kill it self

As soon as I stop it's fine. My buddy is driving it right now and pointed out it dips when slowing down and down shifting. I never noticed because I usually heel/toe or keep it in gear until the last minute.

I'm still running the stock single feed line. What adjustments did you end up making?

 

[boost4me]

what spark plug and gap?

 

[Yellazxr]

Check the dashpot decay rate.

I concur, I would slow down the dashpot decay rate a bit and increase the preposition a tad.

 

[01yellercobra]

what spark plug and gap?

NGK TR6. .026"

I concur, I would slow down the dashpot decay rate a bit and increase the preposition a tad.

I've slowed down the decay and it seems worse. At least according to my friend. I haven't driven since I made the change. What's the preposition? I haven't heard that one before.

 

[xsellr8]

There are a few things that come to mind from my experience. They may be irrelevant, maybe not. Maybe they can lead to towards the problem.

1. My Mach 1 had the throttle body stop in too far, thus the car would under-idle. I unscrewed the stop until the digital RPM readout was exactly what I had on my handheld tuner. Watch this video if you don't know how to access the digital readout on your trip/odometer.
https://www.youtube.com/watch?v=9SbtGvOqhzM&feature=c4-overview&list=UU1Vqfx0Fd2qtCSgVo5Su05A

2. On the 32V cars there is a mesh screen that goes in near the MAF. If this screen is removed when a different intake is added, it's just enough of a change on the air system that it stalls the car out. Not likely the issue for you being FI, but who knows.

3. If you have enough load on a bad a/c compressor/power steering pump/other pulley, it could be enough to stall the car out.

Hope you find the issue.

 

[01yellercobra]

Is that digital rpm the same as using Livelink? According to Livelink it's around the commanded 850rpm.

That mesh screen is long gone. It probably went when I got rid of my stock intake.

It actually does better when I have the A/C on.

It does fine once I'm stopped. Im fact if I stop while it's bouncing it'll straighten out pretty quick.

 

[sleepermobile2]

Does it feel like when you come to a stop that it sometimes dies, but then starts idling after a second or two then some times rarely does die? Sometimes no problem ? I just went threw this ......dirty air filter and dirty maf was my problem.....also the vacume line from my Pcv that runs behind my supercharger was pretty loose, I put a zip tie around it. I did all three things I mentioned at the same time problem solved . Just a thought

 

[01yellercobra]

Sorry I haven't updated with anything. My buddy borrowed my car last week and I won't get it back until this weekend.

Does it feel like when you come to a stop that it sometimes dies, but then starts idling after a second or two then some times rarely does die? Sometimes no problem ? I just went threw this ......dirty air filter and dirty maf was my problem.....also the vacume line from my Pcv that runs behind my supercharger was pretty loose, I put a zip tie around it. I did all three things I mentioned at the same time problem solved . Just a thought

No. If gets too low it'll die. It won't recover. I don't have an air filter and the MAF has been cleaned recently. Something that I need to check is that evap hose that connects under the throttle body. I seem to remember mine was getting pretty bad. And talking to another buddy he says it's sounds like a vacuum leak.

 

[01yellercobra]

So it looks like it was the dashpot decay. According to the description a smaller number slows it down. So I reduced the rate 15% and it got worse. I was pulling the car into my garage after my buddy dropped it off and it stalled twice. So I went into the tune, reloaded the stock values, and added 15%. I've driven it twice with no issues yet. The last drive was into downtown San Diego with traffic on the freeway for class this morning. I'll see how it does on the way home.