90 civic, b16, dual point > multipoint fuel injection swap.

Thought you ef/crx guys might know...


It ran ok for a bit then progressivly got worse. Injectors ended up being out of spec on the ohm readings.

Decided to check all my wiring. So I back probed pins A13 and A15.

From ECU to Main relay it has continuity.
But From Resistor box to either ECU or Main relay has no continuity.
I must have a open in the line at some point. From the Resistor box to the splice point.

Here is a Wiring diagram.



Is it possible for the car to run for a short period of time normally?
Then would this fry my injectors? Because the voltage has no place to go?

 

if u r usein obd0 injector u have to use the resistor box if u dont use the box ur sentin u much voltage 2 ur injectors obd1 injectors dont need resistor box they r high voltage

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 90civicturboed &raquo;</TD></TR><TR><TD CLASS="quote">if u r usein obd0 injector u have to use the resistor box if u dont use the box ur sentin u much voltage 2 ur injectors obd1 injectors dont need resistor box they r high voltage</TD></TR></TABLE>

I know, but will the injectors still work?

 

they might not u cud had fryed them

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HatchBox &raquo;</TD></TR><TR><TD CLASS="quote">

I know, but will the injectors still work? </TD></TR></TABLE>

They should, but who knows for how long.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mr. S &raquo;</TD></TR><TR><TD CLASS="quote">They should, but who knows for how long.</TD></TR></TABLE>


hmmm i have now heard mixed reactions....

 

doesnt all the resistor box do is take the voltage the ecu puts out and lower it to a voltage the injectors can handle? 12 volts to 6 volts? I just finished a dpfi to mpfi swap this weekend, so im up to date on all this

with that being said, that means your injectors were recieving a higher voltage than they were supposed to and over time this fried them... just like how you can give higher voltage to anything than listed than over time it will eventually stop working and fry

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LShatchie &raquo;</TD></TR><TR><TD CLASS="quote">doesnt all the resistor box do is take the voltage the ecu puts out and lower it to a voltage the injectors can handle? 12 volts to 6 volts? I just finished a dpfi to mpfi swap this weekend, so im up to date on all this

with that being said, that means your injectors were recieving a higher voltage than they were supposed to and over time this fried them... just like how you can give higher voltage to anything than listed than over time it will eventually stop working and fry </TD></TR></TABLE>

Thank you, this does make sense...

 

I'm no expert electrician, so I forget how the power flow goes between the ECU, injectors and power source. But IIRC the ECU can also be damaged if you were to say run peak and hold injectors on an ECU originally designed to run saturated injectors. The ECU injector drivers are likely to be burned out/fried before the injectors.

 

I sure hope i didnt fry my ecu....

We shall see today..

 

Finally got around to looking into the car. Got the car all wired, but im unsure where i should splice in the wire from the resistor box (yellow-black)
Im not sure where that splice point is. The one that connects the wires from A13/A16 to the Main relay and the reisor box.

Do you think it matters where I spice it between A13/A16 and the main relay?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LShatchie &raquo;</TD></TR><TR><TD CLASS="quote">doesnt all the resistor box do is take the voltage the ecu puts out and lower it to a voltage the injectors can handle? 12 volts to 6 volts? I just finished a dpfi to mpfi swap this weekend, so im up to date on all this

with that being said, that means your injectors were recieving a higher voltage than they were supposed to and over time this fried them... just like how you can give higher voltage to anything than listed than over time it will eventually stop working and fry </TD></TR></TABLE>

The resister box contains resistors; they limit the current. The voltage stays the same. The ECU just grounds the injectors; if you dont run an resistor box with low impedence injectors(peak and hold), then you will fry the ECU because it cant handle all the amperage. Hondata did a test and it's posted on their website.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HatchBox &raquo;</TD></TR><TR><TD CLASS="quote">
Here is a Wiring diagram.



</TD></TR></TABLE>

how do u make that power conecton from dpfi to mpfi? i did the mpfi swap and now the main relay gets hot as expletive. i did a voltage drop test and it's .02 i know it's not shorting out to ground or other wires b.c i checked evreythin. i'm running obd1 injectors. so no injector box. just the obd1 distriuting plug. also when i turn off the ignton the main relay sticks. like it gets so hot it melts the contacts together. i gota hit it fairly hard (think back hand slap) to stop the main relay back feeding the igniton though the ecu. i've gone though 3 ecus for this.

oh i put an infared thermomiter gun on my main relay and when i say hot as expletive that means the relay it's self was ~230 degreases F

EDIT: sory didnt mean to hijack post just a related problem.