looking for any new ideas here its pgmfi (fancy tbi = garbage)
i have 18in hg at idle, 185lbs compression in all 4 cylinders,
just did full master tune up (plugs wires cap rotor air filter element pcv valve fuel filter)
also replaced timing belt and tensioner w/ water pump
did valve adjustment to spec, even backed all valves off till they rattled and it still backfired
measured cam lobes for wear, all within spec

pcm only flags one code, for an 02 sensor, but sensor functions within proper range, heres the wierd part using a DMM voltage at the 02 sensor is 450mv, and since a DMM averages the voltage the low is .1 and the high would be .9 making it operate withing spec

now it gets stranger, disconnect the 02 sensor and the pcm will never flag an 02 sensor code, but at the wire plug that connects to the 02 sensor the pcm is supplying .4 volts, wherre it should be 0 if im right here not sure how honda substitutes base values

ive ran out of ideas and am tired of working on it... i believe pcm is fried but im not a honda tech mostly work on toyotas any suggestions would be appreciated

thanks,
chris

 

Did you align mechanical timing properly? There's a pair of timing marks for the 1.5 and a single mark for the 1.6 engine all on the same cam gear...

 

yeah timings dead on or compression would be consistently low, along with a fluctuation on a vacuum gauge, the vacuum would be + or - 1-3inhg at idle if timing was off...
believe me my first thought was timing, spent 4 hours going one tooth back half a tooth forward you name it i tried it. timing is on

 

also, ignition timing is not the issue, figured this out by checking timing advance and by shorting blue jumper plug underneath the passenger kick panel and retarding and advancing timing as much as possible to no change, played with ignition timing for a few hours and no change reverted to base timing eventually

 

How was it running before you did the tune-up?

 

it didnt, crank no start with weak spark replacing distributor tonight since it contains both cam and crank sensors and there is slop in rotor shaft, may cause incorrect timing information to pcm

 

replaced dizzy, now when shorted to base timing have a crank no start and a code 16 (fuel injector circuit) finally got a code just cost me 200 bucks aint that a bitch

will work on this tomorrow time for a beer

 

code 16 was due to main relay being a bitch, managed to get it running again same problem though.... still backfires