Hondata

Hi. New to this forum, although I am a moderator at accordwagonclub.com and have been a member at cb7tuner.com for a few years.

I have a 1997 Accord wagon to which I have done some mods (camshaft, H23 intake manifold, Bisimoto header, mild exhaust porting, shaved 0.030" off head, H22A fuel injectors). For tuning, Aaron at PureTuning in Toledo Ohio installed a S300 in a P72 ECU, which is installed in my vehicle using a OBD2a to OBD1 wiring harness. Just to get the build running, Aaron uploaded a basemap and I fired the vehicle up recently.

It runs, but it is running rich and it appears to be ignoring closed-loop. It is also throwing a code 9, for the CYP sensor. The code comes up again within a second or two after I clear the codes using the S300.

I followed the troubleshooting instructions for the 1997 Accord CYP, as I still have the OBD2a distributor. I have 737 ohms across the sensor at both the distributor and the ECU, versus a spec of 800 to 1500 ohms. The continuity checks did not show any problems and I verified that the wiring harness adapter was wired properly.

I also swapped in the original POH ECU. I was somewhat surprised when the engine started (as the engine will run very rich with the H22a injectors). I didn't try to drive the vehicle, just let it idle for a few minutes. It did NOT throw a P1381/1382 code, which means that the POH ECU thought the CYP sensor is fine.

Questions I hope someone can help me with:
(1) Has anyone experienced problems using a OBD2a distributor with the S300 in an OBD1 ECU? I am wondering if there is some kind of mismatch between the CYP sensor signal in the OBD2a distributor and what the OBD1 ECU is expecting.
(2) Will a code 9 (CYP sensor) cause the ECU to enter a default mode and/or ignore closed-loop?
(3) Is there any indication from the S300 that the ECU is in a default mode?

Try the ECU in a know workgin car that already has an s300 and see if it throws the same error. If it does not then there is a wiring issue with the distributor/adapter harness.

Good advice, thanks. Unfortunately, I live in Ann Arbor, MI. SE MI is a wasteland when it comes to Hondata (big 3 dominates here). The closest Honda tuner I know is in Toledo (60 miles away) and I don't know anyone in the area running an S300.

I have an OBD1 distributor laying around. I think I will wire it up and see if I still get the code 9.

it is a obd2 h22 correct usdm engine correct? just making sure. if it is you will need to put the obd1 distributor and make a conversion harness for the odb1 8 pin to go into the obd2 4 pin at the distributor and the other 4 go to the crank sensor by the harmonic balancer. I had this problem when i put the s300, It would run fine but the code was annoying so I swapped to a obd1 dizzy and everything is perfect now. check out these links, It'll make sense once you read it, couldn't really explain it that good. excuse my typing skills.

http://www.preludezone.com/general-tech ... pping.html

http://www.rywire.com/product-p/dis-prelude-2-1.htm

Great info! Thanks.

However, do I need to run the other 4 wires from the OBD1 distributor to the crank sensor? I was just planning on ignoring these wires from the OBD1 distributor, as the crank sensor replaces these distributor functions and is already sending the proper signals to the ECU.

the 4 that go to the crank sensor is the cyp.iirc obd1 h22 do not have the sensors behind the harmonic balancer thats why you wouldn't have to make a harness but since obd2 does the obd2 dis only has the 4 wires and the other 4 are the ones at the harmonic balancer. the obd1 distributor has the sensors in it so to send it to the ecu but it has to send it to the ecu which goes through the crank sensor connector in a obd2 car.. you can leave the crank sensor disconnected as the obd1 distributor will provide those correct signal to the ecu. wiring this part on a obd2 car, with a obd1 ecu is what gets rid of the cel 9 with obd1 dis. and harness.

ckp OBD2 harness grey plug--------------------------to the obd1 distributor plug 8 wire plug
red --------------------------------------------------------------white/blue top dead center senor TDC "M"
green----------------------------------------------------------- orange/blue top dead conter sensor TDC "P"
white------------------------------------------------------------white Crank angle sensor CYP "M"
blue-------------------------------------------------------------blue/green Crank position sensor "P"

"I was just planning on ignoring these wires from the OBD1 distributor, as the crank sensor replaces these distributor functions and is already sending the proper signals to the ECU."

obd1 dis. provides different signals readings so you would have the code still until you wire those 4 to the crank plug on the engine harness side (not the actual sensor just saying in case someone misreads). Trust me I literelly spent hours checking the connectors, wires, ecu pins everything to see if it something was wrong and it wasn't and as soon as i put the obd1 dis and the conversion harness it ran perfect and no cel ever came back.

The easiest thing to do, is to buy the rywire harness for $50 install you obd1 dis. plug it in and you done, if it dont start flip the dis. 180 degrees and try to start it again just in case you forget which way it came off. I made myself the harness for about $10 but it took time lol. I know it sounds like I repeated myself but just trying to explain it all, didn't feel like retyping it all properly.

basically the obd1 ecu wants to see the obd1 cyp and crank readings for it not to throw a cel, as a obd2 ecu wants to see obd2 readings. thats why it didn't throw a cel when you plugged in the other ecu. if its obd2 car converted to obd1 with a obd2 dis. it will throw cel 9. and if its obd1 with obd2 dis. I don't know what happens, anyways if you have more questions just ask.

Yes, that is exactly what is happening to me. Code 9 for CYP sensor when using the OBD2A distributor and OBD1 ECU.

However, the OBD1 ECU is only throwing a code for the CYP, which is inside the OBD2A distributor. The signals from the crank sensor to the OBD1 ECU are not throwing a code, which means that I don't have a problem with the crank sensor signals, even though this is part of the OBD2A system. This is why I thought I could ignore the extra wires from the OBD1 distributor and only wire up the signals that come from the OBD2A distributor.

Well, BB6 was exactly right. There is an incompatibility between the CYP sensors in the F22B1 Accord distributors (both 94-95 OBD1 and 96-97 OBD2) and those used for F22A (1990-93 Accords) and the F22B2 (1994-5). Thus, my OBD1 P72 ECU threw a code 9 with my 1997 F22B1 distributor.

After putting this off during the coldest February in Ann Arbor since 1904, I finally installed a 1991 Accord distributor (1990-1 distributors had an internal coil, as did my F22B1 distributor, but 1992-3 and F22B2 distributors used an external coil). I created a custom wire harness from the 1991 distributor to the 5-pin distributor connector on the 1997 Accord wiring harness for the F22B1, starting with the harness adapter recommended by BB6.

I did differ from BB6 by only wiring 5 pins from the 1991 distributor: CYP +/-, ECU signal, power, and tach output. I left the CKP/TDC signals from my crankshaft position sensor to the ECU and did not wire up the CKP/TDC signals from the 1991 distributor.

Codes are all gone - everything is working fine.

Well scratch my last post. Code 9 reappeared today. I checked resistance on the CYP sensor - at the ECU - and got 450 ohms, right in the 350-700 ohm spec and a lot better than the 787 ohms of the original distributor. Frankly, I'm stumped.

And my tuner (Pure Tuning in Toledo, Ohio) won't tune the engine with a trouble code. Not that I blame them.

Hey wagon-r,

I didn't have exactly the same problem as you do, but I had the Code 9, CYP code before and everything checked out. I'm using a B16A2, w/ OBD2 distributor, and it ended up being that a small amount of water got into my ECU (through the USB port) and somehow only affected that part of the ECU. I was able to clean it off with some contact cleaner and all was well (for a while). Because of other issues, I replaced my ECU anyway and now all is really well. Maybe you can take the lid off of your ECU and check for any corrosion or water marks.

Also, I'm in Novi, MI so it's nice to see another person with an S300 in the area. If you still have issues, maybe we can meet up sometime somewhere to diagnose your ECU with mine or something.

Thanks,
Huacha

Novi! Wow, I didn't think there was anyone in the area tuning Honda engines.

Pure Tuning in Toledo chipped my ECU and installed the S300 v2 for me. He rejected the first ECU I brought him and I had to buy another, so I don't think he would have missed any corrosion or water marks. And I've had the cover off a few times and didn't notice anything. Also, there are no other trouble codes from the ECU and it seems to run OK.

If you are serious about letting me see if your ECU also throws a code 9, I may take you up on that. I have 345 cc H22 OEM fuel injectors and I am running a H22 base map until I can get it tuned.

First, I'll ask on cb7tuner if the distributor could be bad even if it passes the diagnostic checks. I have a 1993 Accord distributor lying around. It's an external coil (my original 1997 distributor and the 1991 I have in now both are internal coil), but I'll see if I can add in one of my internal coils.

Yeah, I'd like to see what other Honda's are like around here. Weekends typically work better for me, once in a while, my wife and I will make a day trip to Ann Arbor to eat and walk around, so we can work something out for sure.

Finally fixed!!!! After swapping to an OBD 1 distributor (as noted in an earlier post) and trying two more OBD1 distributors, including a new one, trying Huacha's S300 to see if it eliminated the code 9 (it didn't), and revising wiring several times, I finally figured out what was going on with the Code 9. It turns out that the ECU must be checking the timing of the signals from the CYP, TDC, and CKP sensors.

I am still using the TDC and CKP signals from the crankshaft sensors on my 1997 Accord. When I swapped in the OBD 1 distributors, I installed them so they were in the middle of the adjustment range. The position of the distributor doesn't affect ignition timing (which I verified with a timing light), as this is from the crankshaft sensors. But it does affect the synchronization of the CYP versus TDC/CKP sensor signals. It finally occurred to me today that the ECU might be checking the synchronization of the signals, so I retarded the distributor - viola! Problem solved.

So, I feel kind of stupid. I spent a lot of time and some money troubleshooting distributors and ECU, revising wiring, and buying distributors. All I needed to do was rotate the distributor.

Bottom line - if anyone is using an S300 in a 1994-97 Accord EX, you need to:
- Buy a 1990-91 Accord distributor (internal coil like the 1994-97)
- Rewire the distributor signals to the engine harness (I didn't bother changing the TDC/CKP wiring from the crankshaft sensors to the distributor sensors)
- If you get a code 9, rotate the 1990-91 distributor to eliminate.

I think the distributor in the 1994-97 Accord LX is compatible with the S300, so you don't need to do this if you are starting with an LX.