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!