What Exactly is Limp Mode?, Can anyone explain this? Options

[Lil-Joe101]

So I'm wandering if my car is in limp mode. Why? Well the check engine light is on and she idles fine for a minute or two, then completely drops fuel pressure and dies. If this is not limp mode then what is causing this? I just replaced all for injectors, believing that this was the original cause for it not running right i.e. rough idle, fluctuating fuel pressure before it completely drops and dies. I've also done the general maintenance as well like change oil, flush and change both radiator and heat exchanger, replace h spark plugs and also the battery. I have replaced the fuel pump, filter, and now injectors. She idles fine now, like a dream then given a minute or two drops pressure and dies. Also she's running really rich, so much in fact, you can smell the extra fuel that's being dumped to compensate. Can anyone tell me what's going on, or what it is I'm doing wrong here, cause I'm lost, frustrated beyond belief, and almost fed up with the whole thing.

[cardshark525]

Limp mode or "safe mode" is when the car will not allow you to rev it beyond a certain RPM due to a check engine light (in our case 4,000 rpm). The car will run fine and is drivable, however the car will not allow you to rev higher than 4k rpm so you don't potentially damage the engine because of something not functioning correctly.

What you are experiencing is something different. Since you have replaced everything and the car is still running as rich as you say, the problem is probably electrical in nature. Either a loose connection somewhere, something not reading correctly, or flat out a bad ECU (or connection point on the ECU). The other possibility (although unlikely) is that you're not getting enough air in to get you a/f ratio where it needs to be. Filter completely clogged or obstructed intake/intake manifold/throttle body would be the cause for this.

Those would be my best guesses as to the cause unless someone else would like to chime in.