running crazy rich for no reason

[andrew600]

a guy wanted to try different ecus on my sr20det. stockish. ran fine, little to no issues. didnt run rich. after some yada arguing i finally agreed to pull my ecu out and swap his in to see if those two worked.

we did, i put mine back in and now im having idle issues and running very very rich. :picardfp:

i disconected the battery before i touched anything each time i went to touch the ecu. what the fuck did i do?

[Edwin562]

first, why were u swapping ECUs for???

[andrew600]

he cant get his car running and thought both ecus were shot. i told him they werent but after him calling and bugging me i caved in and let him bring them over so we could try them out on my running well s13 sr20det. the ecus were both s13 ecus, and all i did was start the car on each one idle for a minute or so then shut it off.

[Edwin562]

if 2 ecu werent workin on his sr, obviously something is not working properly... you might of just fried your ecu....

[andrew600]

both of his ecus worked fine on my car. his car wouldnt even start. that will blowwwww. is there any kind of trouble shooting i can do?

[fliprayzin240sx]

Try pulling a code on your ECU. Put the IGN to ON, go turn the screw behind the ECU all the way clock wise, hold it there for a 2 seconds or so, turn it back to normal. Look at the light in the ECU or check engine light and see if it starts blinking. If its blinking, count the long blinks and the quick blinks. Long blinks are your first digits, then the short ones are your 2nd digits. 3 long blinks and 2 short blinks means CODE 32. You may have multiple codes.

Reset the ECU by turning the screw all way again and back, then start the car.

[andrew600]

awesome. thanks ill do that and report back.

[andrew600]

investigation reveals i do not have a screw. any other way to trouble shoot?

[ultimateirving]

check to make sure all ur wires are properly seated on the ecu plug. Just the fact that you pulled it out and swapped it might have disturbed an already loose connection.

[andrew600]

i tried looking over the wires and when i put the ecu back in i firmly placed it back in its clip and screwed it back on. but i dont exactly feel great about wires, i will def check over those again.

[andrew600]

could i have possibly burnt up my o2 sensor? his was tiny and mine is blacktop big.
it would explain both symptoms.

[andrew600]

bump.
still having rich and idle issues.

[ultimateirving]

check to see if ur o2, is bad. disconnect with the vehicle on and see if anything changes.. normally it would just run off maps with no 02, so it could be alittle rich,

[andrew600]

uh i also unplugged my MAF today on a whim and my idle steadied out and didnt bog down anymore. getting ready to clean and reporting back.

i didnt know there was a way to tell if an o2 was bad or not?

[ultimateirving]

uh i also unplugged my MAF today on a whim and my idle steadied out and didnt bog down anymore. getting ready to clean and reporting back.

i didnt know there was a way to tell if an o2 was bad or not?

unplugging maf is interesting info, get an ohm meter and measure resistance, specs can be found online with some searching. Bad maf causes rich issues for sure.

EDIT: also, the o2 is not a critical component, ive ran with mine unpluged for a long time. so it really shouldnt create many driveability issues, mostly just fuel consumption

[andrew600]

awesome. i will get right on that and report back. thanks so much!

[airman]

If indeed that you pulled your working ECU out and stuck it in his, and immediately put it back in your car without changing anything else, it's probably the ECU...

Open the ECU and check for burnt traces. His wiring may have a short in it and his car won't start because of it, and he's trashed his ECUs trying, and then trashed yours too.

I'd check to make sure. It'd look something like this:
http://i55.photobucket.com/albums/g142/Naloo10/FRIEDECU.jpg

[andrew600]

fixed. ecu was shot. new ones running very well with good a/f ratios.

[Kingtal0n]

fixed. ecu was shot. new ones running very well with good a/f ratios.

Try to figure out why unplugging it and plugging it back in caused it to fail, that is not supposed to happen. It could have just been a freak incident but... who knows? maybe a wire is crossed somewhere?

[andrew600]

i think plugging it into his car where there was a short created issues for my ecu. so when it went back into my car it was burnt up. thats my take on it.