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.

[Lil-Joe101]

cardshark like you said it might be electrical. I noticed it didnt putter or stall out as it died it just died. The filter is clean, I tested it today by blowing compressed air through it, listening and feeling for any indication that there is in fact a clog. Air past right through with no issues. It starts right up with no problem and like I said idles like a dream. So if it is indeed electrical what exactly should I like at? Relays, distributer, spark plug wires? Also, is there any kind of safety that automaticly kills the engine if the charge cooler level is low? Thinking perhaps if there is then my fluid leve sensor maybe faulty if there is one.

[mgnt232]

Check your engine light code. There is a reason Toyota put it there
It may shed some light on the situation

[SupraKid]

A lot of the time a car will go into limp mode due to a knock sensor being triggered.

[cardshark525]

What code is your check engine light on for? That should be a dead giveaway.

Edit: saw you mentioned the level sensor. If that is it I couldn't help you too much as I had a similar gremlin. I ended up taking it to a shop to clear that up. It still pops up here and there but isn't on steady like it was before and is VERY rare and goes away on it's own. (not sure what's going on there myself.)

This post has been edited by cardshark525: Mar 22, 2014 - 11:27 AM

[playr158]

Limp mode doesn't always limit rpm....depends on the car.
Limp mode a car will run and drive, if boosted it limits your boost pressure, and usually dumps fuel and runs a base safe fuel map. Getting knock will induce limp. But what your post states....you don't have this issue but anothrr

[Lil-Joe101]

I haven't checked the codes yet. I only ran it last night before I went to bed. I will check the codes tonight after work. I can't imagine a fluid level sensor being the reason the car would die only seconds after starting it.

What would you suggest I do playr and please don't say take it to a shop because I just got it back from the shop after the months and still can't drive it.

[mkernz22]

Did you replace the FPR?

[Lil-Joe101]

Yes, pump, fpr, filter, and injectors are all brand new.

This post has been edited by Lil-Joe101: Mar 22, 2014 - 2:12 PM

[playr158]

What gen 3sgte did you swap in?

And currently my best suggestion is check the code and then let us know what you get. Otherwise you can't get any really decent advice

[Lil-Joe101]

3rd gen, and that sounds like a better plan lol.

[Lil-Joe101]

I think it's code 54. 5 flashes pause 4 flashes pause 5 flashes. So where to start looking?
I changed out the fp relay thinking it might be it. After I did that the car continued to die only thus time the pimp recirculated enough to keep it running for a few more seconds until it finally died. As long as I feather the gas pedal she will stay running but if I don't, then she'll die a couple seconds after.

This post has been edited by Lil-Joe101: Mar 22, 2014 - 9:07 PM

[jordisonjr]

A quick google search of a Toyota CEL's shows up "Inter cooler ECM signal".
Not sure exactly what that means, but its a start. do some more searching and digging into that and it may lead you to the issue.

[Lil-Joe101]

So I ran my CEL results through this site http://www.troublecodes.net/toyota/ and it said bad coolant temp sensor, bad o2 sensor, which would explain the richness and strong fuel angel while it's running. But still doesn't explain why she cuts out after 35-40 sec of idling.

[JasonTX]

my mr2 had a similar issue when i had a bad o2. i think it ran too rich and after about a minute bogged and died. when i replaced the o2 it ran like a champ. not sure if its the same as what your dealing with , but i thought i'de share anyway in case it helps

before i got the new sensor in i did like you and just gave it a little throttle to keep it going

This post has been edited by JasonTX: Mar 22, 2014 - 10:44 PM

[Lil-Joe101]

I never would have imagined that an o2 sensor or an engine coolant temp sensor signal whould be the reason my car doesnt stay running. How or why exactly is that? That is code 5 and code 4 or should I be looking at code 54? I might just work all three three just to be safe because I looked up symptoms of each code and how they corrdinate with my car and each one is pretty spot on with what my car is doing.

This post has been edited by Lil-Joe101: Mar 23, 2014 - 7:31 AM

[mgnt232]

Limp mode doesn't always limit rpm....depends on the car.
Limp mode a car will run and drive, if boosted it limits your boost pressure, and usually dumps fuel and runs a base safe fuel map. Getting knock will induce limp. But what your post states....you don't have this issue but anothrr

True. When I had my code 54 I could rev as high as I wanted but never build above 1lbs of boost.

[playr158]

I never would have imagined that an o2 sensor or an engine coolant temp sensor signal whould be the reason my car doesnt stay running. How or why exactly is that? That is code 5 and code 4 or should I be looking at code 54? I might just work all three three just to be safe because I looked up symptoms of each code and how they corrdinate with my car and each one is pretty spot on with what my car is doing.

I might start by replacing the O2 sensor (as long as you're sure your wiring harness is good). Coolant temp sensor I believe you would see the failure of this via the temperature gauge on your console. What is that doing? VWs will basically always tell you its cold when it fails even when the motor is warm.
But O2 sensors can be cheap and easy, I'd start there

[playr158]

I never would have imagined that an o2 sensor or an engine coolant temp sensor signal whould be the reason my car doesnt stay running. How or why exactly is that? That is code 5 and code 4 or should I be looking at code 54? I might just work all three three just to be safe because I looked up symptoms of each code and how they corrdinate with my car and each one is pretty spot on with what my car is doing.

I might start by replacing the O2 sensor (as long as you're sure your wiring harness is good). Coolant temp sensor I believe you would see the failure of this via the temperature gauge on your console. What is that doing? VWs will basically always tell you its cold when it fails even when the motor is warm.
But O2 sensors can be cheap and easy, I'd start there