i have a 91 civic si hatch with a 95 obd1 gsr with (obd1 P28 Phearable.net chip) i have everything connected with a obd0 to obd1 jumper harness from jhpusa, the check engine light stays on steady soon as i turn the key to the on position...ive tried the pigtail & is will not flash any ideas???

 

try reseting the ecu and then check for codes again.

 

when you start the car orrr just turn the key on?

 

Start the car... then see if it stays on. And if you have a code(s) then with the key in the on position the ecu would be blinking. But reset The ecu first

 

Newb here. Name is Mike. I generally go by Sully. I just picked up a 91 CRX this past Sunday. My CEL is on as well (comes on after about 5 minutes of driving). The seller told me it was the O2, but I need to check for myself. I've already read the part on doing the jumper with a paperclip and all, but my question is this:

How do you reset the ECU? Just by unplugging the battery for a few minutes? If so, which cable? The positive?

 

What motor is in your crx? If its the obd0 factory motor then pull back the carpet underneath the dash and count how many times the light on the ecu blinks. Longer spaces in between the flash of the light indicates the start of a new code.
Here is the code list

Code 0 _____ Faulty ECU
Code 1 _____ Oxygen content
Code 2 _____ Does not appear to exist
Code 3 _____ MAP sensor
Code 4 _____ Crank angle sensor
Code 5 _____ MAP sensor again
Code 6 _____ Coolant temperature
Code 7 _____ Throttle angle
Code 8 _____ Top dead center sensor
Code 9 _____ No. 1 cylinder position (only on 1.6L)
Code 10 ____ Intake air temperature
Code 11 ____ Does not appear to exist
Code 12 ____ Exhaust gas recirculation system
Code 13 ____ Atmosphric Pressure
Code 14 ____ Electronic air control (EACV)
Code 15 ____ Ignition output signal
Code 16 ____ Fuel injector
Code 17 ____ Vehicle speed sensor
Code 18 ____ Does not appear to exist
Code 19 ____ Lock up control solenoid (auto trans only)
Code 20 ____ Electric load


And OP like stated does the CEL stay on when the car runs for a while and have you tried pulling the ecu fuse to reset?

 

What do I look for to determine which motor I have?

 

Have a look at this maybe this will help you out. Resetting your ecu by taking off you ecu fuse in your engine bay then put it back in after a few minutes. Correct me if I'm wrong.

http://www.hondahookup.com/forums/sh...d.php?t=115614

Since you have obd1 ecu you will have to follow the link above to see whats going on. Usually after 5 mins of driving means 02 sensor. Also to determine what kind of engine you have, take a look at one of your post and have a look at one of the photo a guy posted.

https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/newb-my-first-honda-2910627/


Hope this helps

 

Thread Jack much? Just messing w. Ya look on the block right under where the head and block go together on the left side of the header. Its a flat surface you probably will have to scrape clean. If your cars stock its either d15b2 (dx), d16a6 (si), d15b6 (HF)


And I just unplug the ecu from the wiring but others say just the neg, others the fuse. Whichever kills the connection for a few mins but mine comes on and goes. Ill drive to the store and it'll be on them ill leave like ten mins later and it wont be on all the way home. if the car runs boggy in low Rmps and you're getting bad MPG then ya its your o2. Just count the ecu blinks on your ecu. If its a constant blink, no long pause then its code one o2

 

I didn't mean to. Apologies to the OP. I do have my own thread now though. https://honda-tech.com/forums/showthread.php?t=2910627