jonathan13

Okay guys, we are trying to finish my buddy's b16 swap... we are getting spark and we are getting fuel to the fuel rail but I do not think the injectors are pulsing.. It was previously converted to multi point and the resistor box was removed..

I'm thinking during the swap the wiring for the injectors/removed resistor box may have gotten messed up.

My question is can the injectors be wired directly to the ecu? and if so would this be down by running the positive from each injector to the appropriate pin at the ecu and then grounding all the negatives from each injector?

Any help is greatly appreciated. thanks

jonathan13

i checked the wiring diagram in the 92-95 civic haynes manual and all the positives from the injectors go to the ecu to their appropriate pin....

The negatives on the other hand go to the main relay... would i be able to ground the negatives from the injectors? or where would they go? especially since this isnt really a 92-95 and is supposed to have a resistor box that has been removed.

D16SiHatch

if the box has been removed that's fine, you just need to run obd1/2 saturated injectors. the way you're looking at the injector wiring is all kindsa fubared lol. the power from each injector is a constant one. the ground on the other hand is what goes to the ecu and is pulsed to make the injectors fire.

jonathan13

so does that mean that the colored wires are the gound that go to the ecu and all the black and yellow wires are switched 12v(come on and stay on with the key turn)?

D16SiHatch

pretty sure it would be always on with the key turned to run. if not then it would definitely be always on once the car was started

love_ek9's

bump

crx_si-r

What are u bumping?



OP the injector plug will distribute power when the key is switched to the "on" position and stay on until the key is removed.

jonathan13

so all the black and yellows can go straight to a switched 12v and the colored wires go to the ecu for negative signal which causes the injectors to pulse correct? and if so we have a different problem because i have all the black and yellows ran to a 12v and still no injector pulse... what could cause no pulse?

Is there anything that would cause the ecu to not send the signal for them to pulse?

the reason he bumped it was because its his car

sabideefoo

Last Post..Your Correct sir....

sabideefoo

all the black and yellow go to either a dummy or solder together....Let me find you my link to my question

sabideefoo

https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/z6-dizzy-mpfi-conversion-confusion-2825917/

jonathan13

okay so from that im getting the idea that all the blk/ylw wires get wired together but go to nothing... like its just a dead end where they are all wired together

crx_si-r

the block off plug doesn't just end. if you look at it, it supplies a constant 12v power source for all the injectors. much where the resistor box would do the same, only it would reduce the 12volts to 5.5v (i could be wrong on the amount). here are some pics of the plug and block off plug. if your injectors are not pulsing try swapping out the ecu for a known good one, double check to make sure you have correct block off plug and not just a de-pinned plug. also make sure you have the yellow/black wire coming from the block off plug and in the correct spot on the white (8 pin round plug).

hope this helps

sabideefoo

That should be a15 on the ECU right CRX_Si-R?

crx_si-r

You have it connected to a stock body harness, right?

sabideefoo

Yes stock body harness.....Stock lx d15b2 engine harness that I am converting to mpfi....Then I will be running a p28 ecu.

hatchet_honda

the wires that went to the resistor box should be connected to a dead end plug.

jonathan13

so all the blk/ylw wires should go to A15? i looked that up in the pinouts and that is for the AC clutch on obd1 so is it A15 on obd0 pinouts? and if so what is that on an obd1 pinout?

crx_si-r

Yes the main power wire (from driver shock tower plug) should be connected to the obd0 ecu plugs not the obd1. Obd1 ecu has different locations for the pins compared to obd0 ecu plugs

jonathan13

I'm confused. So what do I run the yellow and blacks to since we are running an obd1 p28?

jonathan13

IVE GOT IT.. i think lol.... all 4 of them go to B1 on the obd1 harness portion which is the "power ground" and i assume the reason they werent pulsing was because i just had them ran to a positive 12v and the ecu didnt have the complete circuit of having them ran to the power ground which is why they werent pulsing.. SO... im going to run all 4 to that pinout and pray. Wish me luck everyone lol

jonathan13

alright guys i am at the end of the road.. i cant figure this out to save my life..

I cut all 4 ylw/blk wires and connected them to the power ground at the shock tower plug on the drivers side and still nothing.. this means that everything is for sure wired like it is supposed to be and i have no reason to think that the ecu is bad since it was working fine before the swap..

SOOOO.. is there anything else that would cause the injectors to not pulse? maybe a sensor in the dizzy or something that is bad and doesnt send signal to the ecu so the ecu does not pulse the injectors? that is the only thing i can think of .. someone please help us!

crx_si-r

Your ground at the thermostat housing is good, right? Seeing as that is the ground for the ecu.

Also which injectors are u running? What car did they come out of? I know 92-93 integra's have obd1 injector clips, but some still use a resistor box. I would highly consider starting from scratch with a completely new harness.

jonathan13

yeah the ground is good, i checked that. injectors are from a 92-95 civic ex. and yes sir after much debate we just yanked the motor back out about 30 seconds ago and are about to start fresh with an uncut stock 91 dx harness.

jonathan13

okay guys.. swapped harnesses and redid all the wiring and still no pulse from the injectors.. the power ground wires are all sending signal but the ecu is not sending the negative signals to actually make them pulse.. what would cause this?

We are getting spark, and the fuel pump is pumping fuel to the rail.... im stumped.

Ecu is also for sure good because we put it in another car and that car started up no problem.