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No power to inectors after OBD0-OBD1 conversion HALP!

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No power to inectors after OBD0-OBD1 conversion HALP!

Postby CRXguy_88 » Fri Feb 17, 2017 10:29 am

Hello guys and gals, I have an issue with my car. Car has been on the back burner now on and off for the last 4 years or so and I started back up with working on it again. It's a fully built B20v and the car was originally auto and dpfi. Previous owner converted to manual and MPFI which was done correctly. (I went back a retraced every wire on that aspect.)

Here's the deal.. I did have an OBD0 B16 running in the car in the past just fine with no issue but ever since I went OBD1 I no cant figure out why I have no power to the High impedance injectors I have. A1, A3, A5, A7 are directly wired to the injectors from the ECU and all four red/black wires i have ran off to where they would normally go to the resistor box. I can see where the previous owner took the two yellow/black wires from the C313 driver firewall connector, spliced them together to run to the resistor box, in conjunction with the four red wires shorted together should be all I need to delete the box. But I still get no power at the injectors with key on engine off with a test light... BUT if test for power at the end of that spliced yellow/black wire I get power with key on engine off.. WTH is going on!? :shock: I have gone over everything multiple times and have searched and searched online for weeks.. I have used different MPFI conversion write-ups as guides to retrace steps and wires with no prevail. However, I did notice that the few write-ups were different In some ways from each other and I'm confused on which is the correct way to go about this.. I apologize for the novel but I just want to be clear as possible.

ANY HELP WOULD BE MUCH APPRECIATED AS I AM STUMPED! :?
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Re: No power to inectors after OBD0-OBD1 conversion HALP!

Postby 4drSpankR » Fri Feb 17, 2017 11:43 am

Sounds to me like you have a break in the wiring where all the injector wires are tied to the BLK/YEL power wire. If it was me, I'd redo that entire connection, or better yet, use Rywire's OEM style connector just for the box delete. I've been using it on my swap no issues for 3-4 years.
1991 HF - previously '90 B18A1 now '97 B18C1
1989 Si - running parts car/gone
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Re: No power to inectors after OBD0-OBD1 conversion HALP!

Postby msc » Fri Feb 17, 2017 5:39 pm

Depending on what mods have been made you may be looking for voltage at the wrong time. The DX is different from the others. On the Si and HF the injector power is on with the ignition. With the DX wiring the injector power is on with the fuel pump. Try measuring for injector power during the couple seconds the fuel pump is priming. If the sum total of mods to your car leave the injector power as original for the DX you will have this issue. When the engine starts to crank the injector power is turned back on with the starter and kept on while the engine is running. You can also disconnect the small wire to the starter and hold the key in crank position to keep the injector power on.

It's also possible your car has been modified to have injector power on with the ignition and there is something else going on.

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Re: No power to inectors after OBD0-OBD1 conversion HALP!

Postby CRXguy_88 » Tue Mar 07, 2017 6:45 pm

4drSpankR wrote:Sounds to me like you have a break in the wiring where all the injector wires are tied to the BLK/YEL power wire. If it was me, I'd redo that entire connection, or better yet, use Rywire's OEM style connector just for the box delete. I've been using it on my swap no issues for 3-4 years.



I used a spare eg dead plug and ran all 4 injector power wires to it as well as the wire which I ran directly from A15. (just like the write up said to) and now I have power at each injector as well as every terminal in my dead plug with key on engine off... still have a crank no start. I retested for spark and I'm getting that. Getting fuel up to the filter (have yet to check if I maintain fuel pressure while cranking) but that's where I'm at right now with the car.. :?
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Re: No power to inectors after OBD0-OBD1 conversion HALP!

Postby CRXguy_88 » Tue Mar 07, 2017 7:51 pm

Compression test reads

#1 250

#2 265

#3 265

#4 260
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Re: No power to inectors after OBD0-OBD1 conversion HALP!

Postby 4drSpankR » Wed Mar 08, 2017 11:54 am

This sounds exactly like the problem I had in my daily driver. '98 Civic EX. (D16Y8) I had fuel, spark, compression and all. Injectors were firing, fuel pressure was good, compression was normal across the board and still no start. Swapped Main Relay just because it was original, nothing. Swapped known good ECU, and still nothing. And no CEL.

It was a distributor. I believe it was either the CKP or CMP sensor internal to the distributor. (not crank angle...) I'm thinking the ECU sent the signal to fire and never got a return signal from one of those sensors to know exactly the correlation or position of the cam/crank. Hence, not starting.

Installed new distributor and she fired up like I just shut it off.

Hope this helps!
1991 HF - previously '90 B18A1 now '97 B18C1
1989 Si - running parts car/gone
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Re: No power to inectors after OBD0-OBD1 conversion HALP!

Postby blazercrx » Wed Mar 15, 2017 1:33 pm

Are you powering the 4 red wires that are attached to your injectors with the yellow/black wires at the resistor box? Pics would help.
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