well recently i have been havin problem with my car when it frist starts up it will get one good start on the p28 ecu but try to cut off unless i keep my foot on the gas until it warms up. if it cut off befor it warms up it will not start at until i swap ecus. it only seems to do this with p28 ecu on my h22a swap. i have tried both a jun chipped p28
and a stock p28.

i took the ecus apart and found both p28 had burned the same thing on both boards heres a pic
chipped p28

stock p28

it looks like what ever it was exploded not sure tho but if im correct its connected to the a17 pin which i think is IAB soleniod (what ever that is)

but what i am trying to figure out is why its is doing this and can i fix it some how i have had a jdm p13 ecu but removed it because the fuel cut at 120mph

correction i just look at me ecus and relized my chipped ecu has the same circut board numbers as my stock p06 so my chipped ecu that i was told is a p28 is a p06 chipped


please help me

 

It can be replaced if the board is not messed up just desolder and resolder a new one I believe xenocron sells them. Very common to find this issue.
http://www.xenocron.com/xenocron-q31...tor-p-335.html

 

you must have your IAT sensor's plug switched up with something else (the EVAP, IACV) b/c i've seen a few ecus now burn up that q31 transistor and the cause was switching the IAT sensor's plug. I'd also pull the IAT sensor out and check to see if its burned up too.

As long as the traces didn't get burned up from the transistor frying you should be able to fix those ecus, i've fixed a few myself over the years.

 

what is the iat? and what pin is it? also can this prevent my car from starting?

 

The iat is the intake air temperature sensor. It usually won't cause a vehicle not to start.
Concerning the pinouts, check http://www.phearable.net/tech

 

well my problem is my car will get like one good start and then just cranks lil it not getting fuel or spark but it is. if i heat up the ecu with a heater it will start fine and it will also start right up it i drive the car and cut it off and try to start it. a while back it used to cut off while driving when i push the clutch in if the car wasnt warrmed up yet. all i know is i replace the resister turned the car on started fine then stalled ather 5 secs and the resister burned up

 

the IAT sensor is one of the main fueling and ignition sensors for the pgmfi system. you NEED it to run right.

also, running a basemap doesnt help things.

 

i didnt know i was running a basemap im still just trying to figure out why its burnin up the 31a resistor

 

i just ordered some of these
http://www.xenocron.com/xenocron-q31...tor-p-335.html

and its say in the discription

Transistor for Honda ECU spots labeled Q34 or Q31

Q31 is the transistor that commonly blows up when someone plugs the Purge Control Solenoid plug into the IAT sensor.

can anyone tell me were the purge control soleniod and the i IAT sensor are

 

make sure your iat, iab, and evap connectors are all plugged into the right things.

www.ff-squad.com

http://technet.ff-squad.com/wiring.obd1.htm

 

thanks for the help im ganna try to move some plugs does any one know what colors the wires are for the

IAT
IAB
EVAP
IACV

 

did you not even bother to click the link i gave you?

 

yes i did check both of them but its only tellms me the colors at the ecu plug i was reffering to the sensores them selfs

 

You don't think those wires go to the sensors?

 

i wasnt sure if the did plus the sensor have 2 wires i only see one of the wires on the ecu. i was asking the plug wire colors so i could make sure the plugs were correct spots

 

well one of the two wires will be one of the wires coming from the ecu.

 

well i looked at my ecu and using this pic i wrote how my plugs are in my ecu


do the ones missing matter

 

bump any one that can help me please do

 

i think i may have something pluged wrong but not sure, so i took some pics to help explian.
IAT wires RED / YELLOW-black stripe

IACV Black- Blue stripe / YELLOW- black stripe
----(the other valve shown in the pic not sure what it is, i think it intake purge) RED-white stripe / GREEN- white stripe


and then the thing mounted to the box under the intake manifold
WHITE-ish wire/ BLack wire


can anybody confirm is this is right or wrong and if its wrong where to they go to make them right.

 

how about ur ecu thing?? can get it done?pls update, thanks

 

i replaced the blown relays and fixed the ecus. the problem was my ait and purge valve plugs were wrong so changed it around it running good.

 

im also have the same problem

p28 chipped gsr map
b18c with bolt ons

motor runs and hits vtec
vtec is at 4800/4900

should be at 5185
2step 4k

blown transistor must of messed up my settings?

the blown transistor is in the R135