Wouldn’t a big vacuum leak be apparent In a wacky idle?

 

I would think. I've looked it over pretty well but havent pulled the UIM.

So to recap, car was hard to start a few times and now it does this. Trying to thing of anything else that may be gradual like that. Primary injectors maybe?

 

Alright, got a hand for a minute. It runs with starting fluid. I'll pull the UIM this week and check for power at the injectors and go from there. Done with it for today lol

 

Primary injectors have power, the signal wires from ecu tested out good for continuity.

 

Did you physically pull out the primary injectors and ensure they are spraying? Might be good just to check that off the list as youve tested quite a bit already.

 

No. I gave them a few taps and threw it back together, same result. Not looking forward to pulling those, at all. But I suppose there's not much else beside the injectors themselves or the ECU. I tried to back probe the wires from the ECU to check pulse but not sure I got the probe in there or if my multimeter reacts fast enough. Before I pull them ill probably check for pulse at the injector connector, just didnt have help earlier when I had it apart.

 

Definitely pulling, testing, and cleaning the injectors will take one variable out of the equation, but I'm thinking it may be more of a fuel pressure/control issue. Have you checked your fuel pressure. In the short time it ran before cutting off, did it seem to run normal (for the most part). If so, it may not be the injectors. If they are failing, i would think you'd have constant response (maybe crappy or no idle, but not running and then dying).

That said, it never hurts to have your injectors serviced if they've never been serviced and your already into it

 

I can start the car and it shut off immediately over and over, every time just like in the video. My only explanation is that it will start with one injector firing and then die once the idle shoots up, or something is killing the injectors once it starts.

I don't have a gauge to test fuel pressure. I suppose I could crimp the return line and see if that does anything, I hadn't thought of that before. So I appreciate the thought to juggle the mind

 

Is there any chance you got fuel with a very high ethanol content? I don't know how long the stock PFC startup enrichment or the startup enrichment on your tune is but perhaps it's getting plenty of fuel and when the enrichment ends it dies, a super ghetto way to test this theory (if you don't have a datalogit to use with a remote tuner to look at startup enrichment) would be to pull off the TPS and "trick" it into seeing a higher voltage by simulating an increased throttle input (holding it partially open) while the throttle plates are closed. That will give you more fuel after the startup enrichment ends, doing that should normally bog the car and cause it to die from being too rich/fouling plugs but if the octane rating is down in your fuel it should keep it running.

The fact that it runs on starting fluid and starts, dies, and restarts without trouble leads me to believe that it is 100% a lean fueling issue. Dropping the return line will verify a fuel delivery issue but if you have a fuel pressure gauge your shouldn't need to do that.

 

I may give that a shot. Before the track day I topped off about 5 gallons of fuel from a place ive never got gas before. Since the issue started I added ~5 gallons of gas I had at home. Thinking about it, the car got gradually worse as I burnt off fuel. Hard to start at the track a few times, hard to start at home. And now this. You may be onto something.

 

Case closed, for now.

Got home today with plans to adjust the TPS as above. Decided id hook up the laptop and go into FC edit to see what I could play with instead to do the same thing. Before I messed with anything I figured id reread the tune and write it again. Car started up and idled perfect let it get warm, shut it off. Reassembled everything I had apart and started it again 4-5 times all good. Guess we’ll see what happens in the future.

 

So it sounds like your tune data got corrupted and shut off the fuel once it started... Gotta love computers...

 

Wow! Weird but hey, you've solved the problem. That is very out of the ordinary, the PFC doesn't typically corrupt the map.

Dale

 

I'm glad its working but kinda worried because I can't be sure if the re write fixed it or if something else (like a stuck injector) decided to start working. Just have to wait and see if it happens again I reckon.

 

Yep, Perhaps someone messed up a setting on the commander unintentionally.

 

i suppose its possible but the car was running great on a modified newer (7.xx?) base map. After the problem arose I put on the modified 5.08 map I had been running before, which gave no change. Yesterday all I did was rewrite the previously mentioned 5.08. No tweaks or changes in between via commander or fc edit.