Ok, I had this problem on my 1990 Honda Civic Si where when I turned a bunch of stuff on and the voltage dropped, the ELD wouldn't kick on to regain that lost voltage. You know, that little jump in voltage you see after turning on your a/c or something. I replaced the alternator three times, replaced the whole engine compartment fuse box, ran tests on all the alternators, ran tests on both ELDs...could not find the problem.

I later picked up a 1990 Honda Civic DX hatchback. It started, ran and drove but the motor bogged under throttle and consumed a lot of oil. One thing I made sure to check out was if the voltage regained when stuff was turned on, and it did. I was going to use this car for parts to finish my Si, but the Dx is way nicer and 100% complete so I decided to make this my project instead. I did the DPFI > MPFI conversion and swapped in my Si motor, trans, linkages, PM6 ecu, axles, front knuckle assemblies, front brakes, master cylinder, front and rear struts, coilover kit. Just need to finish putting the knuckles back on, hook up the linkages and exhaust and she's done.

Anyways, it has the SAME exact voltage problem the Si did. I am still using the DX harness and engine compartment fuse box obviously...so this points directly at one of two things. It's either the alternator on my Si motor, or the PM6 ECU. I replaced that alternator several times, it CAN NOT be the alternator...this one isn't even a refurb, I paid extra for a brand-new one. Does this mean it is for-sure the ECU? This ECU came out of a '90 EX, according to what someone carved in to one of the lids. The ECU is the switch that is triggered by the ELD to crank up the output of the alternator so this could very well be what's bad...

Need to figure this out fast, I was supposed to be done with this project a long *** time ago.

 

Is the ECU bad or not compatible with my stuff?

Also...I have an obd-0 PR4 ECU here. I'm told it's possible to chip them, I've only chipped obd1 ECUs. Is this true? If so, can I just install a chip kit and have someone like phearable hook me up with a 90-91 Civic Si basemap?

Edit: I'm reading an article on pgmfi.org about obd-0 chipping. Apparently my PR4 is one of the obd-0 ECUs that has an external eeprom, all I do is de-solder it and install a ZIF socket in its place and that's it? Then I just need to buy a Si-map loaded SST chip from someone like phearable and I'm done?

 

send me a PM guy...

 

Sent.