blkb18

the ecu supplies a ground to the main relay called "fuel pump control". The ecu intermittently does not supply this ground so my fuel pump doesent work sometimes. I've checked the harness, checked the main relay twice (before i found the ground problem). Before i try a ecu, is there any other part that can be bad that would cause the ecu not to give ground?

JimBlake

Have you actually verified that the switched ground in the ECU is intermittent? I guess that would count as a fried ECU, since you don't routinely replace those components within the ECU. You can check for loose connections at the ECU plug of the wiring harness, or stuff like that?

I think it's more common for continuity thru the relay to be intermittent. (Cracked solder joints on that board...) Inspect those solder joints, sometimes they only go open when the main relay is mounted in place & it gets hot.

Duane_in_Japan

Create your own ground contact at the ECU pin terminal so as to not disturb the main relay itself, if the fuel pump never fails due to your ground then do a voltage drop check of the ECU's ground circuits to see if there is resistance causing these problems, Honda ECU's are pretty good but of course like anything, not bullet proof. I will do a quick search in my own large database and get back with any better info, no further answer, no better info.

deserthonda

try a quick test to see if it is the relay or ecu...give manual ground at green/black wire ( fuel pump contorl ) going into the relay if u still got problems it is the relay if not it is the ecu..

if a faulty ecu thus relay wont have ground and wont energize u can try bypassing the relay by jumping wires at relay blk/yellow and yellow...the black yellow wire only has power in run or start mode so when u take the key off your pump wont be energized all the time