Deuce217

First off, I know i suck and I am new. I read posts and all that good newbie ---- first, then I ask my dumb questions. So I am wondering if one of you has ruined a map sensor due to wiring it wrong or heard of this happening to some other guy? When I bought my car (99 civic 4 door y6 turbo) the sensor was in a pile of tape so I wanted to re-wrap it. Well i fukt up and plugged it in wrong. when I started it it ran like ----! It would barely idle and was spitting gas into the exhaust, which came out of the leaks of the exhaust and so I ordered new gaskets, turbo, manifold, because they sucked. Oh and a map sensor. I am installing the parts now but was wondering if you think i fried the map sensor or my ecu with the wiring f up?

busa4

what did you do to the map sensor? just untaped it?

Deuce217

I untaped it then of course decided to take a closer look then reroute the wires so when i plugged it back in, I messed up and plugged it in upside down. so that reversed the wires.

busa4

ouch! you may have shorted the ecm. i assume you fixed it already and now it runs poorly? check the signal wire and find out what voltage its producing.
its a 3 pin connector:
one pin is the 5v reference
middle pin is the signal to ecm
third pin is the ground.

Deuce217

I have a new map sensor i need to put my turbo back on then i will see if this solves my problem. I hope so. If i fried the ecu will i have to get it tuned again? I have it running chrome now. Will all that be gone?

busa4

yes. if the ecu is toast then it will need to be retuned as all the information will be lost. c r o m e has a couple of options. if you have the piggy back then no. if you have the option where the ecm chip is modified to be able to reflash then yes it will have to be redone and retuned.

Deuce217

you said check the voltage how do i know if the ecu is good? if i get 5 v from the wire?

busa4

the map sensor has three wires. 5v power, reference, and ground. the sensor has 5v going into it from the ecm. the reference wire is the signal going back into the ecm. the sensor will change the 5v reference voltage depending on what the map sensor is reading. for ex: if your engine is at idle with vacuum the sensor will take the 5v reference voltage and send a 0.5v signal back to the ecm. under max boost the sensor will take the 5v reference voltage and send a 4.5v signal back to the ecm.
the ground is well the ground. without the ground the sensor doesnt work.

if your getting 5 volts to the reference wire and low voltage to the signal wire at idle and a ground then you know your ecm is working. if you dont have that 5 volt reference from the ecm then the ecm is fried.

thumper64

Do you have a chip, emulator or what in the ECU? Maybe that could be taken out and put in a new ECU and it would still hold your tune? It'd be worth a try.

BoosteD16cx

Sorry to thread jack...but I had a very similar experience with a motorola map sensor. I was going to reroute it as well and I plugged it in backwards. I checked my voltage from the ecu and I got 5v from reference, o at ground obviously, and .3 volts from signal (car not running) I couldnt check while it was idling because it wouldnt stay running long enough. If i replace the sensor and it still runs like crap its most likely the chip in the ecu?