First off I have a 88 hf crx with a ZC swap in it ( motor runs great when running ) my problem is that I dont 12 volts on the yellow and black wire at main relay or at resistor box ( same wire ) when at start position it shows 10.50 vots on meter at crank it drops to 8.50 volts which in turn causes my main relay to click like crazy and not start , know when I add 12 volts to the yellow and black wires at the relay it starts every time I have no idea what is causing this to happen , grounds have a been checked and rechecked . Im running a pm6 ecu with no cels showing up at all when car is running . The main relay is new and the resistor box is good working order , like I said the motor runs perfect when you jump the relay , if anybody has any info that you can send my way it would be greatly appreciated . Thanks for your time.

 

It really sounds like a bad ground to me. I know you say you've checked it. But are you 100% sure your not missing one?

 

Where are you adding the twelve volts from? The vehicle's battery, or another source? If it's from the vehicle's battery, you have a poor connection somewhere. Not enough current is available and the result is a lower voltage reading. Troubleshoot the circuit path. Ignition switch might be the culprit, or maybe a loose fuse.

(You also state...""" like I said the motor runs perfect when you jump the relay """. Does this mean you are bypassing the relay, or are you applying twelve volts from "another source" to the relay coil?)

 

Have you tried a different relay

 

i was thinking relay :/

 

Tried brand new relay from honda , also tried different ignition switch not it . Thinking about swapping out fuse box next , also when i say im jumping the relay im taking jumper wire between the two yellow and blacks and the two black and yellows pins 5, 3 on main relay, also let me tell you this must be running on some type of cycle the other night went out and tried starting it and car cranked right up ( no jumper? ) six times in a row then it went right back to not starting again . I honestly think its in the fuse box myself , i have another one to try , maybe this weekend , also the battery is fairly new red top optima . Thanks everybody for your info and help .

 

make sure that the ground connection at the thermostat housing is good and that the fuel pump ground is good