Quick run down:

- 91 STD EF hatch DPFI
- d16z6 swap w/ STOCK P28
- ConversionHarness.com OBD0-OBD1 DPFI-MPFI conversion harness
- wiring for DPFI-MPFI conversion, VTEC, CKP in dizzy, etc has been done and done correctly.

Got swap up and running and was getting CEL for 8 (TDC Sensor), 10 (IAT Sensor), 14 (IAC). Figured out my IAT was busted so I replaced it. Know I need a IAC as I have the classic idle problem from that. Here is where it gets funky:

I tried the first replacement dizzy to fix the TDC sensor problem I was having with the dizzy that came with the swap. "New", known-to-be-working dizzy was installed and at this point CEL Code 8 disappeared and CEL Code 9 (CYP Sensor) appeared. At that point I remove the CYP Sensor out of the original dizzy and swap it into the "known-to-be-working dizzy" and reinstall. Reset ECU, still get CEL Code 9. I then tried yet a THIRD good working dizzy and received the same results, CEL Code 9. I then tried the spare P28 I have and yet the same thing, CEL Code 9. I turned back to the second dizzy and it was at this point I figure a wiring problem on my part. I start with the OBD1 8-pin plug I swapped onto the OBD0 harness:



Pin #4 and #8 are the CYP pins for the dizzy that lead to the ECU. #4 Orange wire is the CYPP and #8 White wire is CYPG. #4 Orange leads to B11 and #8 White leads to B12 on OBD1 ECU. I have there position correct on the 8-pin dizzy plug ALONG WITH leading to correct pins at the P28.

According to the Helms manual, resistance between the Orange and White wire should be in the 350-700oHms range. My reading was 425 or so therefore I know the CYP sensor in the dizzy is in good working order. I then check continuity of the wires all the way back to the ECU. Continuity was good from dizzy plug to OBD0 ECU plugs, where they connect to conversion harness, where OBD1 ECU plugs are, and even IN the ECU itself telling me no broken wires from plug to computer. While I was at it, I also checked continuity of ALL dizzy wires on the 8-pin plug and ALL were good.

Here is where I am STUMPED! I have a CEL Code 9 with what appears to be a working CYP sensor in my dizzy. I have tested 2 different dizzys and 2 different P28s yielding the same results. I have tested the resistance between #4 and #8 on the 8-pin dizzy plug and my reading was within range according to the Helms manual, I have checked for continuity between #4 and #8 on the 8-pin dizzy plug and its good all the way into the ECU. All of this still yields a CEL Code 9 for CYP Sensor.

What in the HELL could be causing my CYP code? I feel that I have exhausted ALL options for correction and NOTHING has helped. I am turning to you guys for advice.

If you can help me, or give advice for things I may have missed, feel free to say so. I am not afraid to admit if I over-looked or forgot something as I know it will be a GREAT lesson learned for down the road.

TIA guys and I look forward to hearing replies!

 

Just to be clear, since you never mentioned it, you are using an OBD1 or OBD2 distributor correct? you will get code 9s all day with an obd0 distributor because the waveform emitted by the obd0 distributor is not understood by the obd1 computer. just trying to rule out the dumb things first.

For sanity sake, have you swapped the CYP wires just to see if anything changes? i know you said you checked continuity on the distributor(s) and continuity to the plug from the distributor harness, but having them simply flipped will cause that problem as well, and you have done due diligence to rule out a bad computer, and as long as the distributors were obd1 or 2, you have ruled those out too. the last possible thing it could be is the wires are flipped.

 

Check the pins on the jumper harness. I had a similar problem before and the pins on the jumper harness broke there connection.

 

I had this same problem but with a B series, I did the same steps you did but I converted my car back to OBD-0 and found out that it was actually throwing code 4 and low and behold the car no longer threw the code. My wire from C2 came off so I resoldered it and shrink wrapped it and been good to go since. Hope this helps you out.

https://honda-tech.com/forums/showthread.php?p=38517353

Here is a link to my thread maybe it will help you out if for some reason the code 4 doesn't pan out.

 

I am using a OBD1 dizzy w/ OBD1 8-pin dizzy plug unpinned and repinned to DPFI harness.

I have not attempted to switch the wires as they are in the correct position on the plug according to all diagrams I have seen ALONG WITH Helms manual.

I can try and it see what happens though.

Pins on jumper harness have been checked. I checked continuity from plug -> end of DPFI harness @ OBD0 ECU plugs, plug -> OBD0 ECU plug side of the ECU jumper harness, plug -> where ECU jumper harness wires enter back of OBD1 ECU plugs, plug -> pins in the OBD1 ECU plugs on jumper harness, plug -> pins entering the P28. Everything was good.

Thanks man!

 

Looking for some more insight!

 

 

dealing with the same problem. was it ever resolved?

 

usually a wiring issue...was with mine

 

I never found anything but then again I havent had time to mess with the wiring to the dizzy. Soon as I get some free time I am going to run a wire from the ECU to the dizzy plug and see if that solves anything.

Thanks for the inquiry!

 

when i had this issue, it was my b10 and b12 being mixed up. i was really ignorant and wouldn't admit to myself that i had a wiring issue, and over-looked something like that.

so i switched those two wires at the distributor and she fired up first time. I was using an obd0-obd1 harness, did the dpfi conversion myself.

How are you verifying wires?
Connecting one lead to the pin in the distributor plug on the harness sidewith a circuit tester, and adding a power source (i use a 9v battery), and connecting the other lead to the position on the obd0 ecu plug? I ended up cross-referencing a bunch of pinouts to get the info I needed...

 

B10 is White or Black and is CYP ground. Which pin does B12 lead to and whats it for? I am up to give anything a try

TIA for your input!

 

dunno on your engine, my zc b10 and b12 are cyp sensor wiring, but i believe b12 was something to do with the auto trans on my old d15...lockout selonoid?...but it could be the wiring to the ecu if it's ever been touched, not just the wires in the engine bay

 

instead of figuring out what each one is... figure out what position on the distributor the wire should be.

however, it might be easier to just plug in your conversion harness and troubleshoot that way... and use this pinout to see if it helps.



i had to troubleshoot by figuring out what wire corresponded to what pin on the distributor. i.e blu/grn goes to pin _ on the ecu. it's not a fun process. i'll try to help, but it confuses me about why you need to use the dpfi plug on the new distributor.

 

For people having this issue, even after already double and triple checking their wiring, I recently did a z6 swap in an ek hatch, repinning oem d14 harness (its basically a dpfi) and added the b plug, lambda heater and dizzy sensor wires, the whole nine yards.
Started the car, first try, but had a slight sputter at idle ran on original ecu but it threw code 9 (cyp) and an expected 22 (vtec pressure switch I didn't even wire in since it's turned off in the map).
after 2 days of fiddling and 3 dizzys i solved the problem by switching out CKPP and CKPM wires.
CKP is the highest resolution sensor in the distributor and if it has a valid waveform it will be considered valid, but if it has polarity reversed the variable reluctance signal will be conditioned reverse and will have a 15 to 18 degree offset, making the CYP sensor seem invalid (since it will not align with CKP signal at TDC).
after wires were swapped around i check ign timing and it was spot on with no ignition drift (sputtering).
I am posting this everywhere on HT since it's often unanswered question.