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dpfi to mpfi using obd1 injectors

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Old 06-28-2005, 06:16 AM
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Default dpfi to mpfi using obd1 injectors

just bought this 91 crx dx auto, the previous owner sold it cuz he swapped in a jdm sohc vtec and couldn't get it to start.


i looked at the injector wiring and this guy had wired in a resistor box, which i think is not needed when using obd1 injectors? i cut out the resistor box and took the 4 yellow and black wires and wired them to the two wires left from the injectors.

after doing this i tried starting it and it coughed alittle but thats all i got was a cough. so i tried spraying some ether in the intake while my gf cranked it, the car started up.

this leads me to believe that the car is not getting fuel, what are the reasons for no fuel?
1. the fuel pump is dead , but it sounds like its turning on.
2 the main relay is shot, but again the pump sounded like it was on.
3 the injectors are still not wired properly and are not pulsing the fuel.

anything i missed? if it stops raining i plan on cracking the bolt at the end of the fuel rail to see if fuel is getting at least that far. if it is i should be able to rule out option #1 and #2 correct?

thanks for all your help guys
Old 06-28-2005, 06:30 AM
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Default Re: dpfi to mpfi using obd1 injectors (elmalouno)

obd1 injectors run on 12V, so wire all 4 of the blk/red wires leading to the resistor box to the 12v wire (the yel/blk in this case). Also volt meter each injector wire that leads to the ecu. Positions a1,a3,a5,a7


Ryan


EDIT: so to sum it all up you want each injector to go to the ecu (colored wire), and the other wires(striped) to a 12v source(the yel/blk on the eng harness).
Old 06-28-2005, 06:35 AM
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Default Re: dpfi to mpfi using obd1 injectors (droppedcrxsi)

right, thats how i have it as long as this guys wiring is ok. going to go double check hit work i guess. so if i take a test light to each of those yellow and black wires i should get 12v when cranking or?
Old 06-28-2005, 07:15 AM
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Default Re: dpfi to mpfi using obd1 injectors (elmalouno)

So when running 0bd-1 u dont need a resistor box?
Old 06-28-2005, 07:43 AM
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Default Re: dpfi to mpfi using obd1 injectors (Fleas_Ef)

correct.

Old 06-28-2005, 08:06 AM
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Default Re: dpfi to mpfi using obd1 injectors (elmalouno)

i would go through and check all the wiring yourself. never trust anyone elses work
Old 06-28-2005, 08:15 AM
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Default Re: dpfi to mpfi using obd1 injectors (tdocrx)

yeah i hear ya, i was just trying to make sure i had it right before i did that.
Old 06-28-2005, 09:45 AM
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Default Re: dpfi to mpfi using obd1 injectors (elmalouno)

ok well i have double checked the wiring at the ecu and at the injectors. there IS fuel at the rail. and i resoldered the main relay just for good measure. car still just cranks and gives me one cough per fresh turn of the key.


does anyone know if this is possible? running obd1 injectors with a obd0 ecu?
Old 06-28-2005, 09:49 AM
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Default Re: dpfi to mpfi using obd1 injectors (elmalouno)

oh i forgot tto mention, i checked the spot that i joined all the yellow and black wires for the injectors and i am getting 12v
Old 06-28-2005, 10:06 AM
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Default Re: dpfi to mpfi using obd1 injectors (elmalouno)

are you getting proper spark?

So when you got it to turn over did it stay running or did it just start up then die?
Old 06-28-2005, 11:31 AM
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Default Re: dpfi to mpfi using obd1 injectors (vtecn8ive)

checking the spark now... but i figured i had spark cuz it seemed like it started up on the ether when i sprayed it.
Old 06-28-2005, 12:54 PM
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Default Re: dpfi to mpfi using obd1 injectors (elmalouno)

got nice strong spark on all four .... i am starting to reach the end of my rope. what am i missing here? can anyone confirm that you can use obd1 injectors running a 0bd0
pm6?
Old 06-28-2005, 01:02 PM
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Default Re: dpfi to mpfi using obd1 injectors (elmalouno)

Yes you can. You just need to rewire and cancel out the resistor box.

Man I know I have a write up on it but don't know where it is . But it is very much possible.

Timing was on the mark? How'd it run after you got it started?

Battery is good?
Old 06-28-2005, 01:03 PM
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Default Re: dpfi to mpfi using obd1 injectors (elmalouno)

If you have fuel at the rail, then it sounds like its the injectors arent firing.

Is there an injector pulse?
Old 06-28-2005, 02:25 PM
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Default Re: dpfi to mpfi using obd1 injectors (vtecn8ive)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtecn8ive &raquo;</TD></TR><TR><TD CLASS="quote">Yes you can. You just need to rewire and cancel out the resistor box.

Man I know I have a write up on it but don't know where it is . But it is very much possible.

Timing was on the mark? How'd it run after you got it started?

Battery is good?</TD></TR></TABLE>


i have already wired out the resistor box as mentioned b4(i know its a pain to read all this). i haven't checked the timing yet. i haven't gotten it running yet at all just fired up on the starting fluid. the battery is good.
Old 06-28-2005, 02:25 PM
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Default Re: dpfi to mpfi using obd1 injectors (type Gendy)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by type Gendy &raquo;</TD></TR><TR><TD CLASS="quote">If you have fuel at the rail, then it sounds like its the injectors arent firing.

Is there an injector pulse?</TD></TR></TABLE>

i hate you gendy
Old 06-28-2005, 02:58 PM
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Default Re: dpfi to mpfi using obd1 injectors (elmalouno)

injector pulse (lab scope and check the waveform if you have one at your disposal)
fuel? teh pump is good and there are no obstructions?
Old 06-28-2005, 03:13 PM
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Default Re: dpfi to mpfi using obd1 injectors (kylefakesi-r)

pmed ya...


also the fuel is getting to the injectors just fine. but there doesn't seem to be a inje4ctor pulse.
Old 06-28-2005, 03:26 PM
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Default Re: dpfi to mpfi using obd1 injectors (elmalouno)

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

i hate you gendy </TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by elmalouno &raquo;</TD></TR><TR><TD CLASS="quote">
also the fuel is getting to the injectors just fine. but there doesn't seem to be a inje4ctor pulse.</TD></TR></TABLE>

Old 06-28-2005, 03:44 PM
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Default

First thing to do is make sure you have gas. Put in a half-a-gallon. You may be like me who at time ran out of gas because the needle was stuck mid-way. Got gas? Good. Now it begins:

You can run an OBD-1 engine with an OBD-0 ECU and keep the injector resistor box as far as I know. Some people get a Zedyne EMS (I don't know why) and run a single wire for VTEC. Chances are the last dude that worked on it tried jimmy rigging the **** himself without enough info. If I were you I'd just say **** it and re-do the wiring. That way, you know exactly what's sitting in your engine bay and exactly how it's hooked up. And of course, check all connections.
Old 06-28-2005, 03:56 PM
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Default Re: (knwldge54)

i have checked all his work and it looks kosher. some connections are not soldered so i will be resoldering them but for now it should go... i cracked the bolt on the end of the rail to check for fuel and it shot out all over so i think i have gas.
Old 06-28-2005, 04:22 PM
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Default Re: (elmalouno)

now my fault I guess I was just stated the obvious. But I swear I saw a write up on how to use obd1 injectors with obdo system. And it actually cancels out the resistor box.

haha, I read front to back so I dont repeat someone else


how was your timing by chance?
Old 06-28-2005, 04:29 PM
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Default Re: (vtecn8ive)

I think I saw a little write up on on rywire.com.
Old 06-28-2005, 05:05 PM
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Default Re: (knwldge54)

not throwing any codes... maybe the ecu is bad?
Old 06-29-2005, 03:07 AM
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Default Re: (elmalouno)

up cuz i still need help....


so i have fuel to the rail and spark at all four cylinders... do u have to pull an injector to tell if its shooting fuel? what else could be off?


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