DoWnfall

went to chip the ecu this week and found a burnt ic on the board, does anyone what this is or what it does? the car still runs fine and no CEL's but i dont want to run around with a melted board


it says q31 next to it i believe

Relic1

drives the EVAP purge solenoid.
will not set a CEL.

it's also a sign that your EVAP purge and IAT plugs are switched.

I CRX I

wow, my boys ecu has the same thing fried on his...did it happen before or after you chipped it? and what do you guys think would cause that aside from switching those wires??

zccr-xsi

pm sent!!

Q31 drives the EVAP purge solinoid, to pop it like you describe means he has the EVAP purge and IAT plugs switched.
This is very common with swaps since the plugs are almost the same and are located in the same area.




Modified by zccr-xsi at 11:21 AM 10/24/2008

DoWnfall

i discovered that it was burnt when we opened the ecu to chip it, but we did it anyway because the car was running when i brought it to the shop, xenocron has q31 chips for 2 bucks each im gonna check all the wires and make sure theyre not mixed. if not it maybe just a plug swap that blew it up.

anyone have any busted ECU's i can practice soldering chips into or can steal a q31 out of it

0mtber

iTrader: (2)

You don't need q31, just remove it & leave the evap module disabled.
I suggest checking the IAT sensor for damage on the vehicle this ecu was on.

zccr-xsi

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mtber &raquo;</TD></TR><TR><TD CLASS="quote">You don't need q31, just remove it & leave the evap module disabled.
I suggest checking the IAT sensor for damage on the vehicle this ecu was on.</TD></TR></TABLE>

whitericethinktwice

same exact thing happined to me... first swap, did it in one day. D'OH!
i dont think mines fixable tho because of how burnt it is on the bottom

0xenocron

its unreal how many ECUs come in like this...

the only reason you would want to fix that Q31 is if you wanted to use the EVAP output to drive something.

0mtber

iTrader: (2)

Makes you wounder how many people are driving around with damaged intake air temperature sensors.

NJIN BUILDR

When the IAT sensor is damaged is it a complete failure? Do they read incorrectly or fail to read altogether.

0xenocron

eh, if they fail completely they will throw a code...but it wont cause a hard code i dont believe and we know how many people roll around with CEL lights on.

if the resistance across the IAT is a normal value that the ECU thinks it should be seeing, it wont throw a code...I have seen sensors that wont move, meaning something is wrong.

Generally, you can remove the sensor...and look at the tip, if its bubbled or melted, get a new sensor regardless. The IAT is an important sensor...

0xenocron

What's scarier than that, is how many times a shop I have tuned for or a customer that has come for a tune told me their previous tuner said the IAT wasnt important, and should just be "disabled"

zccr-xsi

LOL RIGHT!!


IVE chiped a p28 that had q31 burnt out and it threw soild but i think that was becuase when it blew it burnt the board bad and blew a pad off so that could hAVE been the problem.

Relic1

**edit** another thing that made me cring(mainly because I didn't notice it earlier) the OP's first post, the pic... has the MCU in the wrong place...


Modified by Relic1 at 2:44 PM 11/12/2008

DoWnfall

would the iat sensor still work if i sanded it with 1500 to get some of the color off?
i thought there may have been a metal tip to it so i sanded some off and it was just smooth so i sanded the whole thing, was that a stupid idea or will it work fine after i get a new q31 in

zccr-xsi

no!!

replace it.i got mine from honda for less then 20 bucks.