also posted on pgmfi so i just copied it to here

94 gsr
b16 bottom p72 head
p28 ecu, phearable base "tuned with afc"
afr's from 12.5 to 13.7 when "tuned"
afr's still the same, no cel's, plugs look the same, no abs or brake lights, nothing seems out of the ordinary except for the burned up resistor

......story......

not driving the teg because i was driving my rsx-s......
friend called because his car was running really rough, it idled fine but sounded like a suby if you evan looked at the throttle, no codes, compression test normal(180-190 dont remember exactly) i couldn't figure out what was wrong so i put my ecu in and it instantly started to smoke???,,,,
said ohh well it happens,,,,,got back to the teg and it runs fine......this was about 6 months ago and i've ben driving it since with no problems, just to make sure there were no probability of a fire i cut out the resistor(there was no way of identifying the rings and colors).

the pics say it, Q31 or R135? and WHAT DOES IT DO?????

 

The transistor burnt because the two wire plugs were crossed for intake air temperature & evap.

The intake air temperature sensor on the car is probably damaged.

I have seen ecus function fine after q31 being burnt, yet I have seen them fail also.

You may need to replace the ecu with a chipped ecu.

 

so if its still running fine then i'll assume that it OK, is there any way to get a new resistor and solder it back in?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nateg &raquo;</TD></TR><TR><TD CLASS="quote">so if its still running fine then i'll assume that it OK, is there any way to get a new resistor and solder it back in?</TD></TR></TABLE>

You don't need it.

 

cool,, thanks for the info

 

Exactly the info I was looking for!

 

if u get it chipped it will throw a soild ecu without Q31.
Q31 is the transistor that commonly blows up when someone plugs the Purge Control Solenoid plug into the IAT sensor.ive fixed 3 of these ecus and everyone threw a soild cel untill i replaced the part.

and fyi from the looks of the pics it blew the tracer off the board so in other words it cant be fixed.did it leave bunrt marks on the underside of the lids?and like
mtber said u dont need it!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by zccr-xsi &raquo;</TD></TR><TR><TD CLASS="quote">if u get it chipped it will throw a soild ecu without Q31.</TD></TR></TABLE>

No it won't unless there was damage from the "blow up". The ECU doesn't care about the evap output and there's no code associated with it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HRTuning &raquo;</TD></TR><TR><TD CLASS="quote">

No it won't unless there was damage from the "blow up". The ECU doesn't care about the evap output and there's no code associated with it.
</TD></TR></TABLE>

well your right there and 95 % of the time when it does blow it blow a pad off the board hell it leaves burnt marks on the inside of the caseing.

btw ull know it when it blows cause it smells really foul!

 

Not sure if Q31 is the problem or if its the tracings around it, but the two ECU with burnt Q31 threw solid CEL's when J1 was connected but did NOT throw any CEL's when it was running with J1 disconnected.

Whatever the case I'm buying some Q31 pieces to re-solder into the ECU and see what happens...

 

If it works fine with J1 disconnected then the problem is in the chipping job or the chip, not Q31.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HRTuning &raquo;</TD></TR><TR><TD CLASS="quote">If it works fine with J1 disconnected then the problem is in the chipping job or the chip, not Q31.</TD></TR></TABLE>


question! this maybe a dumb one, but im goiing to ask it anyways.when u did your bin did u disable the checksum?

btw by one of them pic of the bottom of the board it looks like u blew the tracer off the board.


Modified by zccr-xsi at 11:58 AM 5/2/2008

 

Thats what I initially thought too, but I plugged the "SAME" chip into another ECU and the car started up fine and ran off the chip. No CEL or anything...

So in conclusion, I'm suspecting its Q31 or something related to it being burnt. I'll update this thread once I replace the Q31 piece and if it makes any difference.

 

Im having the exact same problem my engine runs a bit sluggish and my rpm idles when i rev the engine around 6000 rpms ... I opened up my ecu and come to find out transistor Q31 is burnt .... Also my ecu wont communicate with my obd2 scanner