Has anyone experience problems with the Sohn Adapter?
 

Has anyone else experienced problems with the Sohn omp adapter? I got mine about a week ago and finally got around to installing it, but my car started idling strangely. It would rev up on it's own when I first turned it on, then when I took it for a spin the rpms dropped when I was at a still stop and the car shutoff on me. It turned back on but it hesitated. When I got home I checked the cel code and it came back telling me the fuel trim was too rich bank 1 (P0172 and P2097) and that the Crankshaft position sensor was malfunctioning (P0335). My Rx8 was working perfectly before with only the Catalytic code due to a gutted cat.

Scared that I would damage the engine I removed the sohn adapter and put everything back to normal how I had it before I installed the sohn adapter and the car runs fine again. Does anyone have any ideas?

Those codes and symptoms don't seem to have anything to do with the adapter. Possible you made a mistake putting everything back together at the end of the install? Something in the intake tract, for example?

Hmm, I don't think so. It's a pretty simple install and I didnt even touch the intake box. I just removed the battery, the battery tray and the wheel.

Idk if this matters but I used Royal purple 2 cycle oil

There's no way that the Sohn OMP adapter itself could cause a P0335 error.

I also find it incredibly unlikely that it would cause a rich code, even if the reservoir was filled with gasoline and the OMP was at 200% duty cycle.

I'd double-check all of your electrical connectors just to be certain that you didn't bump anything while doing the work.

Well that specific code was probably caused by the engine not starting right away after it shutoff on me because it took awhile to start, but I feel like it all stems from the fuel trim being too rich.

Do you think it might be possible that, because 2 cycle oil burns easier, that the ecm is perceiving the burned oil as extra gasoline and cutting off fuel supply and causing all these problems?

Again, I am positive that the adapter was installed correctly. It is really simple...

The amount of oil you're injecting is miniscule, it doesn't factor into the fuel mixture. If it did we would all have such problems.

But, 'car not starting right away after it shutoff' sounds like a whole other issue, which may actually lead us to the root cause. Can you elaborate?

The next day after installing the adapter I drove about 60 miles and it started idling weird. On the highway I could already feel the rpms acting up, but it didnt shut off until I came to a complete stop. The rpms dropped really low and it shutoff. I turned it back on and it took longer than normal to start but it started.

Since I have removed the sohn adapter and my car is working perfectly again. I'm thinking of returning the adapter since it didn't work for me. Hopefully I can return it on ebay

Umm, what?
This often a sign of poor compression. Could be other causes (ignition, vacuum leak, etc).
I mean, if you don't want to understand what the underlying problem is, you could try that. But it's incredibly unlikely (like, "sun not rising in the east" unlikely) that the Sohn OMP adapter caused the symptoms you've described.

I think the sohn adapter is the problem...

Low compression would cause to act up all the time. I've said multiple times that the car worked perfectly, like it was working before the adapter, once the adapter was removed.

Sohn adapter = problems

No Sohn Adapter = no problems

The codes and issues you're describing have no relation to the OMP, with Sohn adapter or without. As I said, perhaps something in the installation process went off the rails. You had the battery out... Possible the cables were loose after you put everything back together? That would fit the symptoms much better than any OMP issue.

Then, when you undid your install, either you tightened the cables better or you'll haven't yet driven long enough for the problem to manifest.

You understand that the risk here is you return the adapter and come to find out you're still having the same issues?

Yeah, but I am absolutely sure the cables were tightened and I have driven the car for over 100 miles now without the sohn adapter with no issues. With the sohn adapter I noticed it immediately.

I think it's silly to say that the omp sohn adapter has nothing to do with the problems though. I mean, the fact that their is new 2 cycle oil going to the combustion chamber and the CEL is telling me that there is too much fuel in the combustion chamber is a clear connection. I don't get how you don't see the relation....

Furthermore, I take off the Sohn adapter and the car starts working again. I was really hoping it would work because I wanted to make my rx8 last longer but I feel like it's doing more damage than good. I do think it's weird that there aren't any other threads with sohn adapter problems though.

You still had oil going into the combustion chamber before, it was just engine oil. The difference in what the oil is is immaterial. Like I said, we would all have such problems if your theory was true. Instead this is isolated to your case only. So what's different in your install?

You can return the adapter if you want, I just think it's the wrong call given thr situation. Been doing this for more than a couple of years ;)

I'm reminded of the guy that insisted his Home Depot intake was fine and his problems were something else. Then he came back a month later to report his problems went away when he reverted his intake to stock.

Yeah, but the difference is that the engine oil didn't completely burn and that this 2 cycle oil is burning completely so there must be a difference in the composition of the exhaust fumes after combustion takes place. Is it crazy to say that the A/F ratio sensor is confusing this for extra fuel since it measures the oxygen content post combustion?

I guess I'll give it another try this weekend, but how did you know that oil was actually going into the combustion chamber once the sohn adapter was installed? This worried me initially because there is no way of knowing.

Whenever I removed the sohn adapter the royal purple came out of the omp so I know there was 2 cycle oil flowing, but the oil level in the reservoir didn't go down much. I know it uses only a small amount of oil though so this isn't the best way to tell.

You're saying that this logic only applies to your engine and not to the thousands of other owners who have reported none of these problems?

Let's look at the new symptoms introduced into the system:
-Code generated, P0172 - Fuel System Too Rich
-Code generation, P0335 - Eccentric Shaft Position Sensor Circuit Fault
-Unstable idle/stalling

System changes:
Installation of SOHN adapter (assuming full kit with the two bottles?)

Questions:
What other modifications do you have besides the gutted catalyst?
How many miles are on the vehicle and engine?
Any preventative maintenance performed? This includes replacing intake gaskets, o-rings during service/removal, fuel injectors being sent off for professional cleaning, etc
What items were removed or moved/adjusted/shifted to fit the SOHN adapter kit in your installation?
Have you visually inspected the ESS to assure it is clean, as well as checked the connector for corrosion or dirt and wires for burning, rubbing, or wear?

These cars are old and the ownership base isn't known for taking good care of them (sadly). It is possible you are suffering multiple concerns and that the SOHN adapter is conveniently highlighting them.

-ESS issues are usually related to a dirty or damaged sensor, a damaged sensing ring (on the eccentric shaft, or wiring harness damage. Visually inspect all elements for possible concerns. If a wiring fault is to blame, it is possible the shifting of components to fit the SOHN adapter is affecting the ESS. It is rather unlikely as the ESS runs on the opposite side of the engine, in a separate trunk, though the entire harness joins together over the top of the engine, and slight adjustments to the OMP lines and associated wiring may shift pressure further up the line.

-Fuel system rich code may relate to a leaking fuel injector, injector with poor responsiveness, or a wiring fault causing it to remain open beyond the commanded duty cycle. Again, check wiring for concerns as the SOHN may be introducing a shift in components that exposes a wiring break or short already present in the vehicle. The oil injected should not be a factor, but if you want to remove the fluid itself from the equation, use the SOHN, but fill the reservoir with traditional motor oil and see if your car responds differently to it compared to the 2-stroke specific oil.

-Idle issues are most often related to airflow concerns. This could be a MAF sensor issue, an air leak in piping, vacuum lines, fuel-injector o-rings, or gaskets, a solenoid that is not cycling as intended, allowing air to flow into an area at a time when the ECU is not commanding it, etc. Wiring faults can also cause this as they could be shorting a solenoid into an open state when the ECU is expecting it closed; this should show up as a dedicated code, but wiring shorts and faults can be unpredictable.

If the car drives how you expect it to without the SOHN and it is too much trouble to deal with, return it and move on. Be sure to keep an eye on your oil level and change it often to assure the cleanest oil available is being injected. I feel like this issue should be resolvable, allowing you to keep the SOHN, but personal preference weighs heavily for work outlay to the benefits gained.

Let's bring in the KISS principle, have you tried to turn the drive shaft in the SOHN adaptor? Mine turned with absolutely no hard spots or drag. I don't think it could be the 2 cycle oil throwing things off in the combustion chamber because it took close to 500 km's (300 miles) before my 2 cycle oil even got all the way thru the lines (so was still using the residual crankcase oil in the lines).

At a 3500rpm cruise, the car injects about 70 grams of air, 4 grams of fuel per second, and about 0.02g of oil. So yes, yes it is crazy.

It takes 2-3 tanks of gas to drink a liter of injected oil under regular driving. That's over 1000 kms. So you wouldn't see it going down on your first drive. Not sure what you were expecting.
It's usually recommended to premix oil in the gas for 1 tank after you install the adapter, so any air gaps in the omp lines don't create periods of no injections.