Suddenly stalling on warm/hot starts

[Chris Barnes]

What are your fuel trims doing at WOT with the meth spraying? Mine was typically 8-11%, so around .92-089 lambda. That seems like quite a bit of nozzle if you're only seeing 2-3% correction.

Sponsored

 

[pmor4243]

What are your fuel trims doing at WOT with the meth spraying? Mine was typically 8-11%, so around .92-089 lambda. That seems like quite a bit of nozzle if you're only seeing 2-3% correction.

During a WOT pull the short term trims are typically around -2-3% and lambda reads around .76-.78. I was also pretty surprised that was all I was seeing with that much nozzle.

Here's a screenshot of what it typically looks like when it is spraying/working:

 

[Exploded_Muffin]

Was a bit skeptical at first but wow, this seems to be my issue as well!
I removed my meth nozzle for my Snow kit and the car hasn't stalled on any hot starts in 2 days now replicating the same scenarios where it previously used to.
Very very interesting.
Will test out for a few more days to fully confirm then I'll reinstall the nozzle with the meth system turned off and see if everything's still fine.
I'm on E85 so don't need meth but will prefer to have the nozzle installed for whenever I need to switch to 93.

@pmor4243 did you still have the hot start issue with your system turned off?
Edit: Just read through, seems you didn't have any issues with the nozzle installed but system turned off

 

[pmor4243]

@Exploded_Muffin sorry to hear you’re having the same problems but glad you were able to pin point it a little quicker than I was.

And yes, I can just leave the system off without any issues. I initially removed the nozzle(s) completely just to be extra sure no methanol was getting in there without my knowing.

I hooked up a pressure gauge over the weekend to see if there was anything noteworthy there as well as moved the MAP sensor to minimize vacuum line length, but unfortunately didn’t find any success. Pressure at the nozzle was showing 200psi and the map sensor seems to be functioning the same as it did in the previous location.

I currently have the nozzle holder with a check valve mounted directly to the solenoid to eliminate the chance of syphoning or excess fluid in the line getting into the intake. This is what has me thinking the only possible cause here is just too much volume when spraying that leads to pooling (at least for my car).

So long story short, I haven't had any success in all the testing and combinations I’ve tried. Still thinking through it and will update as I go as well as being open to any ideas.

 

[Exploded_Muffin]

@Exploded_Muffin sorry to hear you’re having the same problems but glad you were able to pin point it a little quicker than I was.

And yes, I can just leave the system off without any issues. I initially removed the nozzle(s) completely just to be extra sure no methanol was getting in there without my knowing.

I hooked up a pressure gauge over the weekend to see if there was anything noteworthy there as well as moved the MAP sensor to minimize vacuum line length, but unfortunately didn’t find any success. Pressure at the nozzle was showing 200psi and the map sensor seems to be functioning the same as it did in the previous location.

I currently have the nozzle holder with a check valve mounted directly to the solenoid to eliminate the chance of syphoning or excess fluid in the line getting into the intake. This is what has me thinking the only possible cause here is just too much volume when spraying that leads to pooling (at least for my car).

So long story short, I haven't had any success in all the testing and combinations I’ve tried. Still thinking through it and will update as I go as well as being open to any ideas.

Yes I'd lean towards it being an issue with pooling in your tubing. On my ESS kit I can see where the fluid pools up at the base of the piping just after my MAF whenever I take that tubing apart.
If I've driven recently some meth comes out otherwise I see the red markings where the boost juice pooled and dried up.
The response time of the meth kit is probably not immediate so when you let off the throttle after getting into boost it might still spray for a bit with the throttle body closed and/or not enough air flow to carry the meth all the way so ends up pooling at the base of the tubing.

This is all speculation of course but if that's the case then I don't see an easy solution really especially with the 30 gph spray.
You can get creative and set up an electrically controlled drain point that opens when the car shuts down but there's probably a better solution out there.

 

[pmor4243]

Yes I'd lean towards it being an issue with pooling in your tubing. On my ESS kit I can see where the fluid pools up at the base of the piping just after my MAF whenever I take that tubing apart.
If I've driven recently some meth comes out otherwise I see the red markings where the boost juice pooled and dried up.
The response time of the meth kit is probably not immediate so when you let off the throttle after getting into boost it might still spray for a bit with the throttle body closed and/or not enough air flow to carry the meth all the way so ends up pooling at the base of the tubing.

This is all speculation of course but if that's the case then I don't see an easy solution really especially with the 30 gph spray.
You can get creative and set up an electrically controlled drain point that opens when the car shuts down but there's probably a better solution out there.

All good thoughts and I would agree with you. I actually had the same thought of trying to figure out a way to have an automated drain of some sort to see if that helped but havent gone that far yet. I think your theory on the slight delay in the system both turning on and turning off is also a big contributor.

If you think of anything or try something that help, let me know!

 

[pmor4243]

So after a little more pressure testing, I came to the realization that the way the snow kit seems to ramp in is really not all that linear.

With a pressure gauge in line of the nozzle, and simulating boost with my air compressor I was able to watch things a little more closely with the nozzle out of the intake and from what it appears, at the lowest activation point, the system is still putting out a lot off fluid as the pressure jumps to around 50-75psi. As it ramps, the line pressure then jumps to 100-150ish psi very quickly.

The takeaway here is that I was clearly off in my thinking of how the progressive controller worked. From what I could tell, it seems that the initial activation point actually equals more like 70-80% flow that then ramps to 100%. I was thinking it would line up a little more linearly as in initial activation at say 5% would equate to roughly 5% of total flow depending on what the nozzle is rated at. From what I can tell, this is not the case.

This may be why I am running into issues with the amount being sprayed. If at peak boost I need 20-25gph to keep knock in check, when the system kicks on around 3-4psi it is probably spraying somewhere in the range of 15+gph when I only need/can use around 6gph. (just using rough number to explain what I think is going here)

So I suppose that starting the injection later on in the boost curve may help but I haven't tried that yet. I would also think that using something like the power nozzle option on the VC50 snow controller would be useful in this case as well, but unfortunately I ordered the kit with VC30 controller and it doesn't support a dual solenoid injection like that.

 

[Turbolag87]

Well, I got a new MAF sensor in, new fuel pump control module, checked the plugs, checked the injectors for leaks, pressure tested the system up to 10 psi with no leaks, have had 2 tune revisions from Wengerd with no change am now completely out of ideas.

Before I take this to a shop and pay more money for troubleshooting, does anyone have any other thoughts as to what might contribute to the car firing up immediately when hot, but then immediately stalling? This is very repeatable and it will always fire up and run great on the second try.

i had that issue that progressivly got worse. It ended up being my TB.

 

[pmor4243]

i had that issue that progressivly got worse. It ended up being my TB.

Ya, that would be a good thing to check if anyone runs into similar issues. In this case it is a byproduct of the water/methanol.

Spraying enough methanol to give me the right knock suppression leads to pooling up that then creates a rich condition on start up when hot and the car chokes out. Unfortunately, I have still not been able to find the right balance on this as backing things down to the point where I don't stall, also means the car starts pulling timing at WOT.

So if anyone has this issue and has a water/meth set up, just turn the system off for a couple of days and see if the problem goes away.

 

[stars_fan]

Have you considered the Fuel Vapor Canister purge valve? My 2012 F150 5.0 had these issues and it's a cheap item to swap out.

 

[pmor4243]

Have you considered the Fuel Vapor Canister purge valve? My 2012 F150 5.0 had these issues and it's a cheap item to swap out.

Definitely a good thought as well. I did test that in the process of elimination but unfortunately that wasn’t it for me. Like I mentioned, this was/is all a byproduct of the methanol injection. Too much/too much too early and it pools.

Sponsored