So here is my problem, car does not start, only starts when i spray starter fluid into manifold. Sorry forgot its an 88 dx hatch with obd1 b16. So many will ask all wiring has been done and has worked fine in my previous mpfi motors. so my car was sitting for about 5 months and ive only started about 3 times during those 5 months when i had my ls in it. any ways i pulled injectors and nothing was coming out of them when i would try to start. I trouble shooted injector circuit like manual states to, my grounds are fine, all fuses are fine, fuel pump works, and i have fuel pressure, resistance at every injecto is 2.4 ohms, specs are 1.5-2.5 ohms so i know i have good injectors. the only test that came negative while i was trouble shooting injectors was the positive wires at each injector plug. i had no battery voltage, so next step was to check for voltage at yellow/black wire on resistor plug and also no voltage. i then checked for voltage coming out of big engine harness plug located on driver side to see if i had voltage there and no voltage either. therefore i check for an open circuit in the wire that runs from the main relay to the injector resistor box, and there was continuity. so that lead me to think that i could have a bad main relay. i did some research and i noticed ppl say main relay can go bad if your car sits for a while and weather is hot, I live in Las Vegas, and weather is really hot. so then i tested main relay like manual states too and main relay came up good. which makes no sense cuz then that leaves me at a dead end. Can my fuel pump still work if relay is bad? what can be my problem?

 

did you check for power coming back from the resistor box to the injectors? if you have power going into the resistor box but not coming back out i would say its your resistor box.

 

uumm yea i forgot to do that, but could im still not getting power to the resistor box so does that still leave the main relay as a possibilty for that problem? and can i use any resistor box? or does it have to be off ef si or DA? can i use accord or prelude?

 

sorry this is late,but i just realized you shouldnt need a resistor box for an obd1 b16.

 

i forgot to ask you, what injectors are you using? i think the problem is your using a dpfi harness with an obd1 mpfi engine. worst case scenario, you will need to do some re-wiring. you might want to take a look at this....... http://fourthgenhatch.net/mpfi.html

 

From other threads that the op has posted I think he is running a set of peak & hold (low impedance) injectors. That's why he has the resistor box.



x2 on the main relay, there is a DIY on how to solder the week joints if you are into soldering. If not replace the main relay.

You can ignore the first part of this thread. It pertains to how to get the main relay out of an Acura Legend. The bottom half shows you what to look for and how to re-solder the main relay.

Note* to make it easier to solder the main relay board. I suggest that you lightly spray the solder surfaces and main board down with carb/throttle body cleaner. Scrub it lightly with an old tooth brush then wipe off all of the gooey clear coating that covers all the solder joints. This will also help keep you from having any contaminants in the joints.

 

im running obd0 injectors so i still need resistor box. i read that only if im using saturated obd1 or obd2 would not need a resistor box.

 

i already did the dpfi to mpfi conversion, i used to have an obd0 ls. but that website did show me that pins A13 and A15 are also for the resistor box. I should check to see if im getting voltage there.

 

What ECU are you using? I'm pretty sure that link is for an OBD0 DPFI to OBD0 MPFI swap, not an OBD1 swap.

If you are using an OBD1 P28
Pin A13 = MIL - Malfunction Indicator Light
Pin A15 = A/C clutch relay

The only ECU pins that have anythign to do with the main relay in an OBD1 PGM-FI system are A7 & A23. A7 powers the fuel pump relay part of the Main relay and A23 is the ground.

A25 (IGP1) & B1 (IGP2) are both OBD1 12v power sources that you can use to power the resistor box. The 12v power for the resistor box doesn't have to come from the main relay. You can go direct from Pin A25 or B1 to the YEL/BLK wire of the resistor box.

 

it seems like main relays are notorious for crapping out all the time on our cars, so this post makes me wonder if we should just bypass them all together. what do you guys think?

 

Sorry..... I was a wee bit hung over & I wasn't thinking right this AM when I posted that. It is the main relay that supplies the 12v power to the ECU @ Pins A25 & B1 & the injectors/resistor box when the ignition is turned on.

I'm surprised that no one else caught that. Epic failure on my part!

 

sorry man didnt explain myself, i have an obd0 car so my my jumper harness lets me check for voltage at each prong when ecu is hooked up so i know whats coming out and whats coming in, i meant A13 and A15 if your looking at the obd0 female plugs of the jumperharness but then those two go to the pins you are describing on obd1 male plugs, idk im on my way to my car right now to check.

 

And yes thats what my manual shows, so yea its fine, like i said im on my way to my car and my friend's crx who is running. i am gonna use his relay. using his relay should show voltage to my injector resistor box, but if it doesnt and i've checked for continuity, could it be something to do with the ignition switch? but then again i doubt that cuz i already check for coninuity on the harness side...idk i hope main relay is the problem

 

yea sounds right but i think they put it there for a reason...,idk sounds good let me know if you figure a way to do it

 

i forgot to ask what does igp1 and igp2 stand for

 

those stand for power sources. when you tested your relay did you ground pin#3 then apply voltage to pin#1 and then test at pin#4?

 

[QUOTE=GhostAccord;39884042]From other threads that the op has posted I think he is running a set of peak & hold (low impedance) injectors. That's why he has the resistor box.


i knew he was using peak and hold injectors... wasnt sure if he was using obd0 or obd1 injectors. i also use peak in hold injectors with my h22. but thank you for that GhostAccord

 

guess what you guys! i got a huge break, so this whole time on the ef service manual i was looking at wiring diagrams for mpfi 1.6 motor because since my injector harness had been converted i figured that was the right one to use. long story short as i followed injector wires back i realized that it didnt match up with the wiring diagram but it did match with the dpfi diagram. 1.6 has 2 prongs that have to deal with fuelne prong sends voltage to fuel pump and the other prong sends power via one wire which then splits into 3 wires, one for resistor and other two to ecu pins. on the 1.5 harness the prong that sends voltage to the fuel pump also sends power to the injectors, and the otther prong just sends to ecu pins. now here is my question, can i have fuel pressure but my fuel pump not be working? because i test for voltage at fuel pump and there isnt any so my fuel pump isnt turning on but i do have fuel pressure initially when i turn ignition on because if i open fuel rail, fuel shoots out. so i really think its main relay now, i didnt have a chance to check with my friend but i will tomorrrow...thanks you guys!

 

k so i retested and only one injector isnt getting power, the injector closest to the passenger side, believe injector#1...can one injector cause my car not to start?