Hey all. two part ques. Lemme get this straight. Open loop is when the computer sees a code and then runs in 'safe mode'? Which means it uses a certain set of tables and values when it doesn read certain elec power (signals) from certain sensors?
Secondly, I have an 88 prelude Si 5 spd (B20a) with underdrive crank,full exhaust and cold air intake (as far as engine mods ).I see that the egr solenoid (i think) is throwin a check engine light. I think its code 17 or 12. I gotta re count. Also the speedo code came up. My speedo sensor doesnt work but thats gettin replaced! Would the egr vavle or sensor code make the computer run in 'safe mode'? Same ques for speedo code. And if it does what exactly does it do? For instance run rich...timming...etc. Im waiting to get these problems solved before i install the ihi t3 turbo i have for it. MSD fuel pump and FMU are also installed just need to do the rest for turbo. What wud it do if I went and installed the turbo without addressing these codes? Sorry for long thread. Im new to tuner honda and turbo world. Thanks for your help!


Modified by radioren at 1:23 AM 2/8/2005

 

open loop is a different set of fuel tables and ignores a bunch of sensors..but that is whe you first start the car..or go Wide Open Throttle as it always does it the same way. The safe mode is another set of values even more conservative, pulled timing etc. when any one of a specific set of engine error codes are pulled that are dangerous in the ecu's opinion. Some aren't and the car runs as normal. EGR isn't one of those so it will run rich and generaly 'safe' until you fix it, becuase it may think detonation etc will be happening or some emissions problem. Speed Sensor I'm not sure..on the 4th gen lude I think it would have run safe because the power steering and VTEC control are speed dependant. on an 88 prelude I can't think of what might need it..

 

so it is running in safe mode when its seeing that egr issue? Like I said its code 17 or 12 i think but again i will check tomorrow. Time to start counting on fingers!! lol SO basically it will run rich and timming pulled in 'safe' mode. Open loop is WOT and first crank to get everything goin. I have already retarded the timming just to squeeze some power outta it. This should help then. Also, when i install the turbo it should be ok since a) i pulled timming already and b) running rich is just not great fro tunning and gas and at least its not lean (BOOM). Correct? Thanks to all for any insight
p.s. whats easiest way to fix anything with egr? Just replace sensor, solenoid etc? I have a online helms and chilton but i was just looknig to see what others who have had same problem have done to fix it.

 

sometimes the egr just needs to be cleaned.

I wouldn't install a turbo until my car was running properly.

 

from my personal experience if you get a CEL code that will put your car into limp, the CEL won't just light up, it will flash. When it comes on solid it's a "Somethings not right so you better get to the dealership as soon as you can". The blinking CEL means "something just totally f'ed up, you shouldn't even drive this right now!"

 

i never understood CELs, well i do its just, how do you know what code it is?

 

jump the service connector, count the blinks and go to hondata.com for all the code listing

 

or mine being an obdo(88 prelude pk2) the light is right on the computer just gotta count....

 

bump