When the computer goes in to "Limp Home" Mode what exactly does that do besides kick the fans on all the time? My ses light was removed by some idiot before I bought my car and it stays in limp home mode. Does this retard the timing or anything like that? And what else might it do?

 

me curious too??

TTT

 

I think it retards the hell out of the timing.

 

Depending on the code(s) present, the computer may reduce performance.

 

if thats true...i wonder if my car is in this mode with its 25+* of timing retard

 

When I fried my PCM my car went into "Limp Home Mode" and ran fine, but wouldn't shift out of first gear. I don't know if that is standard, but is what happened to mine.

 

Are you sure you are not just looking at advance and not retard. That does not sound right.

 

Normally the computer makes decisons on the info flowing from the sensor network. In limp home, it decides it can't trust sensor data, and reverts to a stored chart of "safe" values. It's no longer listening to the MAF, TPS, O2 sensors, etc. Those values are sucky for performance and economy, but they're safe. You get rich mixture, conservative timing, etc. Meaning that you shouldn't burn a piston, or overheat, or fry the trans, and so on. Later.

 

yes, its negative. everyone i talk to says it doesnt sound right, maybe my tool im using is exagerating a bit, but its graphing out that amount. apparent problems are the ses light for crank position sensor, header primaries glowing, well today 2 middle ones on the drivers side were glowing slightly, and on the passenger side, down towards the collector was glowing read, and it runs rich as hell

 

limp home mode adds more fuel (25% more according to my 89 camaro manaul) it also retards timing a bunch. i've heard of it triggering on the fans full blast on some cars, but don't know if it does on a 3rd or 4th gen. never happened to either of mine. i've also heard it changes the tps level input or something like that. basically it thinks you suck at driving. lol