Im trying to get my prelude running so I can get it aligned and go to the rollers, but I am having an issue. I am using Neptune RTP, and I adjusted my overall fuel trim to where it was idling good at around 13-14:1 afr when cold, and it runs for a minute or so then the wideband just goes lean quickly and the car sputters out and dies and I am wondering what I should be troubleshooting to figure this out, thanks.

 

ttt

 

one more try. What happened to old school honda tech with actual help within minutes?

 

It sounds like one of the fuel trims is tapering off and the regular fuel map does not have enough fuel to sustain idle. How long does it run for until it stalls?

 

Thanks Muck. Usually it will run for up to a minute before it will stall out and it runs great up untill. Also I dont know it would play into the problem, but I have a surge tank fuel setup, I have a walbro 255hp, feeding an A1000, and I notice that the fuel press dies off very quickly with the ign off due to the tank, not sure if it has anything to do with it but I thought I would share.

 

I know that I have seen fuel pressure drop real quick on a wrx, when the pump wasn't fully sealed against the upper mount, but that was just with the in-tank walbro. I would think that the A1000 would not flow backwards, thuse eliminating the surge tank from the equation. Maybe the A1000 is leaky, which would also keep it from building enough pressure.

My only other thought, is that some sensor is seeing a warmer temp after about a minute of running, and is making the ecu go to the next fuel trim level? I wish I knew more about how Neptune worked!

 

I think the pressure drop should be common, because once the surge fills up it just returns to the tank, so it seems like it should be normal, I just didn't know if there was an issue. That makes sense about the fuel tim level, I also don't know a boatload about neptune. I just sent the ecu out to get modded for PWM boost controll so if I can get this issue figured out then I can take it to brent at PFI and he can get me a good base so I can get aligned and figure out registration and whatnot, and then hit the rollers if I get some $$.

 

The pressure drops quickly on my system too when off - Dual walbros and Weldon regulator. Just watch the pressure when the engine is on. If it can't maintain pressure then your issue isn't tuning.

 

Yeah thats the thing, when running its a solid 43-45 psi, just with no ign it drops, so I am assuming it has something to do with the tune.

 

Yeah, sounds like I'm with Muck on this one. I don't know if you are capable of looking at the map and understanding it or not, but sounds like as idle drops it's interpolating into a really lean area. Like a zeroed out cell or something.

Fuel pumps keeps going when the car dies right?

 

Just looked at the maps and they looks good, I think I might be missing something else somewhere in the parameters, I will have to look into it some more.

 

Highlight the entire primary low cam fuel map, right click and select adjust selected, Add percent "25". That may be too much but you can dial it back if needed. Make sure you have live update on or upload the changes afterwards so it takes effect.

 

^^^ Thank you very much sir!

 

Did you setup your cold start enrichment? Sounds like when the car warms up the compensation goes way lean, like the car doesn't know its in "cold start" when its first running.

 

I didn't mess with those settings I will have to double check them. Im also gonna loook at the iacv and make sure everything is working there.