Hondata

Dear Hondata,

I found that the low cam timing map of the H22A 10lbs 550cc JRSC base map (as supplied from hondata) shows surprising numbers. There is an average of 10-15 deg of advance across the board when compare to the one found on a USDM P13. Be advise, I'm talking about numbers under vacuum here.

So here are my questions :

- Is there a reason for such numbers ? (you can elaborate on the subject please...)
- I also saw that the H22A 6lbs 440cc JRSC base map have also sligthly different numbers for the low cam timing map (Is it for the same reason ?)
- Why not using the timing maps found on a P13 USDM ECU for the vacuum portion of the H22A base maps ?

At this point, I'm suspecting the low cam timing map to be responsible for my improper tuning. After many hours of tuning, I still have engine hesitations when making a small accelerations. The tuner did everything he could without solving the problem. A/f ratio is in the acceptable range during the engine hesitations. So it can't be only fuel related. And I'm also convince that I was earing pinging under vacuum.

Hoping to get an answer soon.

DO I need to say I have a S200 P28 ...

First, make sure the software is the lastest version. The timing was the result of dyno tuning. The ignition timing looks higher than we would normally expect but that was what gave the best result with the vehicle that was used. If you get any pinging then retard the timing - especially on a stock engine as the H22A has weak piston ring lands. How are you comparing to a P13, which is a different ECU?

As you know a P13 is the OE ECU for an H22A1 engine. I have a H22A1 engine from the start (even if 1996 is OBD2 though). I have uploaded the bin file from a stock USDM P13 ECU in order to compare the timings maps, especially under vacuum since it is not easy to tune. Timing is timing, especially for a given stock engine under vacuum.

I know that my P28 have different RPM and Pressure axis values than the P13. After extrapolating the values, it was obvious that the base map had A LOT of timing advance compared to the P13 (low cam, especially in the 0-500 mBar area).

When the tuner (well 2 different tuners tried to solve the problem) retarded the timing, engine hesitations were feeling worst. So they both came back with the low cam timing map of the above mentionned base map. They apparently used the latest software version (I didn't check their version myself though and I doubt they were sayinfg the truth). So now, I have an apppointement with Payn Technologies, which is a 1200 miles trip for me.

For your information, I put back the Stock ECU (Fuel pressure lowered to compensate the bigger injectors) and the car runs perfectly (with the SC blow off valve tie-raped open to avoid boost). This is the only way I can expect to drive on highways without engine hesitations at this point. So yes the engine hesitations may be the results of an older ROM editor version.

But since a stock H22A_ is a stock H22A_, and vacuum is vacuum, please tell me why it doesn't make sens to use the P13 timing map (knowing all USDM H22A has a base timing of 15 +/- 2 deg.).