so last night i took my car to get it tuned. told the tuner i have a small case jdm p30. he un hooked it and put in his usdm p28. within 10 seconds there was smoke and when the ecu was opened something was melted on there . he put my ecu back in after that and my car cranked and idles fine but i cant seem to go past 3500 rpm. at the same time there is no check engine light. i checked the bulbs on the cluster and they seem to be fine.

appreciate any input on this.

 

i was reading up on some stuff and the orange and blue wire comming into the ecu was already disconnected. i read that its for the vtec pressure switch.

regardeless. my CEL dosent come on yet im in limp mode. im about to check to see if theres even a bulb for the CEL light. since i bought this car i never noticed.

 

ok so the bulb was removed from the cluster thus me never knowing a code is being thrown. now that i put one it the engine light is on during idle. so im gonna go to autozone and see what code it is.

 

went to autozone. couldnt find the port to read the codes. now what ? is there another way to get the codes?

 

found the blue jumper pluug. still didnt read the codes yet. i did snip j1 so im out of limo mode an back to stock. soldered back j1 and trying to tune using crome on 750 cc injectors. cant get the car to stay running.

any inpute would be appreciated.

 

i think im about to give up. with the new 750 saturated injectors and the chipped ecu the car wont crank. my tuner said he has no idea what the deal is. he is running 750's in his car tuned on crome but but cant get mind ot crank and idle.

any help is appreciated.

 

ive given. two of my friendss fried q31 on both their ecu's after hooking it up to my car. i dont know why. my ecu runs fine but they fried their within seconds of hooking up. one of them had the same exact setup as mione just wasnt a p30..

i input will be greatly appreciated

 

The Q31 is a resistor in the EVAP control circuit. If your not planning to use the EVAP system disconnect the solenoid and see if that does anything. It will not throw a CEL if you disconnect the solenoid.

You may have the IAT and EVAP connectors mixed up. That may be why you can't get your idle set and your buddies burnt out Q31. Swapping these 2 connectors could cause these problems.

Q31 is a well documented problem with the P28's. Do a search for Q31 resistor and you will find lots of information about this problem. I googled "Honda ECU Q31" and it lead me right back to a thread here on H-T.


Modified by GhostAccord at 12:49 AM 6/25/2008

 

my concern is how come it fries their ecu but not mine ?

 

Have you tested your ECU to see if your resistor isn't gone as well? I'm not all that familiar with the characteristics of a burnt surface mount resistor. I don't know if it melts and leaves as much of a burn mark as a though hole resistor.

 

my ecu is fine. no burns nothing. also i jsut got it chipped from xenocron and they tested it saying it was working fine.

i have a p30 and p28 are the ones that keep burning q31 on it.