limp home mode

lazymtnlady · #1 09-08-2009, 08:04 PM

my daughters 99 ford ranger is having issues, we have replaced the plugs wires, distributer thing, egr sensor, co2 sensor and have unclogged the catalatic convertor, now the moter runs like a top but wont accerlate, the computer has it in limp home mode, how do i fix that or what does that mean, does anyone know. if you do PLEASE let me know. thank you

surfer03133 · #2 09-08-2009, 08:12 PM

have you reset the computer? i know it seems kinda silly, but my boat had the same issues and we replaced everything but the boat would not go because there was still a code in the computer for a knock, and it automatically tries to protect itself by not allowing full use of the engine. ill grab my haynes manual and let you know how to reset it if you havnt.

lazymtnlady · #3 09-08-2009, 08:16 PM

how do you reset the the computer, is it by unplugging the battery terminals? we have a guy with a computer thing, we will give the reset thing a try, hopefully that works, this thing is becoming a nightmare. thank you

surfer03133 · #4 09-08-2009, 08:29 PM

i believe you will need to gain access to a scanner and reset the codes found on the pcm. do you know if there are codes still on there right now?

surfer03133 · #5 09-08-2009, 08:31 PM

if you dont have one already, i would suggest a scangauge II, its a lifesaver. it will read the codes the pcm throws at you and you can reset the codes if it does find them. it will also tell you like 24 other functions, like rpm, mph, mpg, gph, map, water temp, air intake temp. to name a few

lazymtnlady · #6 09-08-2009, 08:39 PM

i'm not sure if there are codes on it right now, my hubby said it was reset after all the stuff was changed, it says limp home mode right now, thats all i know so far. it wont accelerate at all, if you put it in 4 low then it gets some rpm's other than that it dogs out.

surfer03133 · #7 09-08-2009, 08:52 PM

i just read up on it at a few other forums, and i would give the disconnecting the battery a try, make sure its disconnected for at least 10 minutes before its reconnected, if the OD light flashes right after you connect it again, then somethings really wrong with the engine, if it stays off then its fine.--> thats from one source, another it was just a loose battery connection and tightening it up fixed the problem.

lazymtnlady · #8 09-08-2009, 08:59 PM

i guess we've tried that also, hopefully the computer thing tomorrow night will fix things. will let you know what happens. thank you for all your info

surfer03133 · #9 09-08-2009, 09:08 PM

no problem, sorry i couldnt be of much use lol

02'4.04x4 · #10 09-08-2009, 10:51 PM

HI I would definately leave the battery disconntected longer, capacitors are micro batteries and can hold charge for some time. So I suggest with both cables off turn the key to on and let it pull the system down. It is possible that this system has a battery back up for the code and it would have to be cleared by a service tech, don't know this for absolute, but if it is still present after draining for 30 minutes then it is likely. BOL

lazymtnlady · #11 09-09-2009, 03:48 PM

will definatly give that a try.

02'4.04x4 · #12 09-15-2009, 09:53 PM

Hmmm, it seems not many people do follow ups to their issues. It is important so that others can benifit from the knowledge. Please post results. Thanks

lazymtnlady · #13 09-16-2009, 11:20 AM

the lil ranger is now still broke down, won't even give a code now, not sure what is going on.. we've reset it, changed stuff, reset it again, still no power, runs like a top but has not power at all.

02'4.04x4 · #14 09-16-2009, 06:01 PM

Quote:

Originally Posted by lazymtnlady

the lil ranger is now still broke down, won't even give a code now, not sure what is going on.. we've reset it, changed stuff, reset it again, still no power, runs like a top but has not power at all.

Well I would have someone check the fuel pressure, mech's know how to do it. Are you getting any abnormal sounds? i.e. motorboating, droaning, etc.
By running like a top you are saying that it idles smooth right? See if it will run the rpm's freely in park or if it bogs down there too. It is starting to sound like a fuel failure to me. Another thing I found out from my anonymous friend is that you should have the overdive light flashing if you are in Limp Mode. . . Again I am believeing more and more this is a bad fuel pump.

Allthough I have to put this in there for the respect of the knuckleheads. It is possible that your EGR valve is stuck. but I would stick with checking the fuel pressure.

lazymtnlady · #15 09-16-2009, 08:39 PM

it runs the rpm's in park really nice, it revs up and all that but once you put it in drive, you have to pin it and it has no power whats so ever. the overdrive isn't flashing at all, and the check engine light is no longer on. its runs great but has no power to go anywhere.