Engine dies when coming to a stop and the clutch is pressed down

[KGTM]

Hi All,

Few time my engine has stalled only coming to stop from speed and putting the car in neutral at low rpm ( may be 1000 to 1200) any ideal as why?

This is new LS376 with Crate engine ECO. does not happen any other time.

[Aircontroller]

Can u share more details?

Carb? Efi? How old/miles?

[beeman]

Even without the A/C on?

[VRaptor SpeedWorks, LLC]

Beeman beat me to my first question. My second question would be, do you have a VSS signal going to your ECU?...and if so, is it running off of the FFR "sprocket"? There's a pretty good discussion on this issue here:

https://www.gt40s.com/threads/vss-ecm-stalling.41687/

[KGTM]

I am using the wheel sensor in the hub, infact works since I use it for Speedo signal input and ecu output for Speedo,

The ratio set in ECU may not be the same as the 48 tooth wheel sensor, but it should know it is moving.

The ECu manual say there is no divider and it is pulse to pulse for every tooth on sensor, but that does not seem to be true, not sure if anyone has check the output radio to input pulses.

No AC on, it never does this if idling, high rpm back to low and so on.

What is typical IAC for LS376? some say 100 to 120, and some say to 5 to 10

Mostafa

[LCD Gauges]

If you have HP Tuners, you can disable or re-curve the "Proportional and Integral" Idle RPM maps


These values subtract airflow to reduce RPM as you brake and come to a stop. As the
RPM comes down, the Idle valve doesn't move quick enough to save the stall.


I can have a look at your tune if you can send the file.

hpTuners.png

[KGTM]

Thanks for offer, I do not have a tuner so have to find another way.

It is also hard to test this in garage.

Mostafa

[KGTM]

BTW, this only happens in sixth gear, I have a very tall six, it is about 1350 rpm at 50mph, is does not happen in other gears as the RPM may be higher and I first clutch the CAR.

So generally I put my foot on clutch and may be put car in neutral for coast to stop.

Mostafa

[Joel Hauser]

I built a roadster using a 1996 4.6L SOHC engine, and have the same problem; the engine occasionally stalls when coming to a stop. I have been trying for years to solve the problem but no luck. I have an SCT tuner, but even new tunes didn't fix it. If you figure it out, please, let me know.

[DavidW]

BTW, this only happens in sixth gear, I have a very tall six, it is about 1350 rpm at 50mph, is does not happen in other gears as the RPM may be higher and I first clutch the CAR.

So generally I put my foot on clutch and may be put car in neutral for coast to stop.

Mostafa

Could downshifting to slow or stop help overcome the stalling?

[VRaptor SpeedWorks, LLC]

Did you read thru the link I posted above?....seems to be lots of great info there for you....

[KGTM]

Yes, if down shift no issue,

first time it happened, I was in six and sudden stop, so no time to downshift and once I was stopped I notice the cars has stalled, it never happen when I am going slow and in lower gears I think regardless of speed, but I will pay more attention and see exactly at what RPM or lower it happens.

I read through the post for most part they did not apply, I think the big one is VSS but I have that.

Year has not started great, heat house heater vent bad, and every one wanted thousands of dollars to fix it and on the top of that they do not show up, then my water heater vent bad and just 1500 to replace it plus the heat cost , I think I am going to forget being EE and planning to become plummer. Crazy in bay area.

Mostafa

[crash]

I have said many times that if I had it to do all over again I would strongly consider being a plumber or HVAC person. The rates are INSANE and you don't even need a college degree.

[acmikee]

crash I have said many times that if I had it to do all over again I would strongly consider being a plumber or HVAC person. The rates are INSANE and you don't even need a college degree.

HVACR service does pay well even when the economy takes a dump service guys are busy

[DavidW]

Yes, if down shift no issue,

first time it happened, I was in six and sudden stop, so no time to downshift and once I was stopped I notice the cars has stalled, it never happen when I am going slow and in lower gears I think regardless of speed, but I will pay more attention and see exactly at what RPM or lower it happens.

I read through the post for most part they did not apply, I think the big one is VSS but I have that.

Year has not started great, heat house heater vent bad, and every one wanted thousands of dollars to fix it and on the top of that they do not show up, then my water heater vent bad and just 1500 to replace it plus the heat cost , I think I am going to forget being EE and planning to become plummer. Crazy in bay area.

Mostafa

Probably the speed sensor is bad, good luck.

[KGTM]

I use the speed sensor from ECU output for my dash and it all work and the speed is correct at all times, so not sure if it is bad sensor, I do know that the number of teeth table is not correct, since s it possible that ECU is set from input from transmission and not wheel hub sensor, I my code adjust for that difference to make the speed correct.

And yes Crash I often think the same, may be once I retire, but I need to be a bit stronger to pick up the 170lb water heater. but for most plumbing issues all you need is a snake.

Mostafa