Hey, I had my H22A in my 4th generation prelude on a dyno today. Didn't book a tuning session but they gave me the usual air fuel ratio and a chance to tune it my self. I have posted up my first run, the rest didn't get any better even though I leaned out the curve with my air fuel controller. Any how here is the senario. My H22A has 210k km on the clock but is still running very well, recently had a valve adjustment and a really decent service (done by me).
Only has minor changes from stock (Custom CAI, custom rear muffler, new Vision ignition leads (old ones had too much resistance) and new iridium spark plugs, a lower km good condition dizzy, new denso O2 sensor and a Field air fuel controller (VTM wire not hooked up and left stock to prevent my car from entering limp mode- it does this when the VTM line is cut and fed through the controller) and also some gauges (only one that could affect my run will be the vacuum gauge)). Other useful information, its an JDM automatic (sad I know but it may become a manual when my bank balance grows in the positive direction), has 17 inc 215x40 wheels and has the stock p13 ECU but has a ECU code of 390, which is rare-ish (JDM auto only I think).

Any how my run wasn't too bad, was done in second gear. Was way too lean for my liking at the start of vtec (which seems to be around 4.5-4.7k rpm if my calculations are right). I used an excel file that uses the gear ratio and wheel sizes etc to calculate the RPM based on speed (not sure who's the creator of the excel file).

My question is, what and why is my car riching out, up to 11.1:1, as the rpm moves beyond 5.8k rpm. It seems to climb well in the initial 1000rpm of Vtec and then it all goes down hill, air fuel ratio turns to crap and runs very very rich. All I can think of is clogged Cat, problem with ignition coil, clogged intake manifold, MAP sensor? Anyone ever seen anything like this? And yes the air fuel ratio needs to be fixed up around the Vtec engagement point, it is way too lean to be healthy. One other thing, does anyone know how to convert the wheel torque figure to actual torque?

Thanks, any and all input will be appreciated.

 

The graph above is a bit hard to read, see below for bigger pics. Thanks

 

do not tune this motor yourself. do not tune on a p13 auto ECU. do not drive the car hard until you have a professional tuner look at it. your motor will go -boom- otherwise.

 

Thanks for the input, could you elaborate why please? I have driven (regular visits to 7k rpm) this lude in this condition for 40k km and its still going well. The fact that its running so rich (6k rpm and up) means something is wrong some where but its only occurring at high rpm. Yes it's too lean at 5k and this has been sorted now. On the dyno it was possible to use the field controller to lean the mixture out up top, I changed the settings form -3% to -7% above 6k rpm and it yielded a change of my air fuel ratio, at 6.7k rpm, from 11.8:1 to 12.1:1, which was good for a power increase from 107.5whp to 117.5whp. All I need to do is figure out why the car is running so rich above 6k then I can restore the torque curve. I'm not going to use the field controller to take out insane amounts of fuel to get it to run better, I need to work out what is the cause, fixing it and then tuning it. The field controller has worked well with the P13 tuning wise thus far. Thanks

 

I just typed up this loing speel and hit the page back button.

So Ill make this real quick.

You dont seem to be from the States, your unit of measurement appears to be metric. If you examine your peak Tq and peak Hp to the engine outputs on any H22 information sheet, you will see that your numbers are just on par.

Peak TQ is around 4800, and peak Hp is around 5700.

The reason why you go rich like that is if you are running 14.7 at 4.5k RPMs and above, you will heat detonate your engine eventually.

Running a high RPM at a lean rate will be the end of your motor. Running rich means to cool your motor down so it can handle high RPMs.

Emmission levels pass at 13-14.7 A/F ratio.

 

Thanks for the input. Your bang on "The AW Alchemist", I'm not from the states, I'm in New Zealand. Interesting, so your saying that running lean at 4.5k would cause the ECU to self correct by making the car run excessively rich after it to compensate for the change in combustion temps?

The leaning out at 4-6k rpm has been corrected on a subsequent dyno run, I don't have the graphs for them. Just added in some fuel at the 4-6k rpm marks on the Field fuel controller. Think the air fuel ratio came down to 13.6:1 around the 5k mark by adding in fuel (3-4% on the controller). I'm also well aware that running rich is very beneficial in the sense of cooling the engine down after the combustion stroke (unburnt fuel has a cooling effect on the cylinders) so running at 14:1 can't be helping to keep the cylinders cool at WOT, detonation and severe damage will follow. What is the best range to aim for when tuning on the H22A? I believe 13.5 is the level to try not to exceed, but naturally 13.0:1 will be best for a street car.

 

Sorry to bring an old post back up but i think I may have found the problem with my h22a's leaning problem at 5k rpm. I took out the fuel controllers (I used a Field and a Gizzmo fuel controller for reference) and returned the loom to near stock. The car is definitely driving like it’s supposed to above 5k. Before one could feel the loss of power and could see a cloud of black smoke behind the car after 5k rpm. With the wiring of the MAP signal near stock the car drives well again, which leads me to conclude that it must be the extra wiring that affects the signals that the ECU receives.

Here is my theory, fuel controllers require the MAP sensor's signal and a few others to be cut and fed to them directly and then from there the signal is fed back to the ECU. Note that the rpm signal is not fed directly to the controller but is simply spliced in. If the rpm signal remains stock, but the MAP signal's overall wire path length increases wouldn't that create a discrepancy in the pairing of MAP and rpm signals???

So, for example, the rpm signal at the ECU is 5.5k rpm, the MAP signal corresponding to this is rpm is fed to the fuel controller. By the time this MAP signal reaches the ECU the next rpm signal is already there, for argument sake, and thus the MAP signal is incorrect for the particular rpm, which will mean the ECU will be using the wrong fuel map/ignition timing, which yields a potentially lean fuel mixture. Detonation occurs due to the cylinders being too warm after combustion and spontaneous combustion occurs (compression stroke). Knock sensor picks this up, feeds it to the ECU, the ECU cuts ignition timing as a protective measure. My Hp figure and torque drops due to the ignition cut, the ignition cut makes it seem like the car is running really rich above 6k rpm when in fact it’s probably just the lack of spark that leads to incomplete combustion?

Sorry for the ramble but I would like to figure out what the cause of lean condition is, I think this might be it? Or am I missing something/making incorrect assumptions? One thing that I am unsure of is the actual MAP signal, does it change from rpm to rpm at WOT or is it a steady 2.75volts that's produced?

Thanks, any input/ridicule will be great

 

I think you may be overthinking things a bit. The way these fuel controllers work is by intercepting the MAP signal and then modifying it before it reaches the ecu. Doing so effects the way the ecu fuels the engine, and also the ignition timing as well. The controller basically lies to the ecu to get more or less fuel by telling it there is more or less load then there actually is. IMO its kind of a hack way of tuning but some people have luck with them. I think you will be much happier without the controller, your stock computer should suffice just fine for what you have done.