The H22A4

Ack…  So tired that my eyes are still crossed.  Its 4:27 – Plenty of time.

 

Symptom:

Engine was producing close to 200hp, revving up past 7,500RPM, producing steady torque with no dead bands or hiccups.

Something blew out (or sucked in?)

At this exact moment in time the engine performs flawlessly in economy mode.  As soon as the secondary lobes (and secondary runners, fuel map, ignition timing etc) switch –  the engine has a range of trouble.

It can be as bad as “wont run” to as good as “its is almost working”

There is very heavy blow-by coming out of the oil cap (more than previous motors, I think this is the 4th H22 the chassis has seen).

The plugs are reading (by my account…) lean.  Now…  I read plugs for forced induction and I am looking for maximum power…  so tan, maybe like coffee with cream.  These plugs are pretty white (Far from the whitest I have seen) and there are signs of preignition/detonation (specs).

Now remember…  It starts perfect, idles as expected, free turns as expected, drives under load, below 30% throttle, up to 7,000 RPM – just as perfect as you could ask for.

The engine will also produce torque and low RPM if I step into it.

Its High RPM, High Load (after the switch-over point) where it either stutters or bogs or just does not work well.

An engine needs an Air to Fuel ratio along with a spark to operate (I will not get into compression, dynamic compression, spark timing, or any second order stuff)

An appropriate (translated functional) A/F Ratio is anywhere from…  eh… 8:1   ….  all the way up to 15:1, maybe 16:1  (those are numbers from my tuning with my WB02 with my engine in my operating environment).  8:1 is considered “PIG RICH” and results in poor performance.  Climbing into 9:1 gets you close to the optimal window where “you cant tell”.  After 10:1, 11:1, 12:1…..  most of those, with forced induction, “will work” for the most part…  if you must.

12.5:1    Good place to aim for for Supercharged High Compression (says the guy who is on his 4th motor lol…)

Climbing up into the 13’s, 14’s 15’s….  distinct power loss can be butt-felt above 15:1.  Up into the 16’s (outside of my accurate measurement range) you can flutter the power.

Anyway – these plugs are reading 14.7:1  (i.e. Normal…  not my tune)

 

Troubleshooting:

We all have our methods and ways.  Sometimes it is to get the car running NOW, sometimes to get the car to a certain LEVEL, sometimes just to tinker and learn.

First is learning what you are working with.

 

 

AIR:   What affects it

Factory with a Cold Air intake.  Remote actuated flapper upstream of the filter (to reduce noise with a resonant chamber) – likely…  not wired up…  need to check it.

Air Filter – duh they clog up

Throttle Body & Plenum – Big vacuum leaks here can allow unmetered airflow (NOT TRUE FOR HONDA) into the combustion chamber without fuel to match it.  Yes…  the Primary O2 SHOULD detect this and go rich on the table by a few percent…  but that is not the correct way to go about it…  as (its a 2D table) at any given time we are in a cell (Spreadsheet) which correlates to Manifold Absolute Pressure and RPM.  HALT.  We are measuring the vacuum on the plenum so a vacuum leak WILL register – unlike with a MAF vehicle.  The only thing that will be affected is the IAB (Intake Air Bypass) PWM and a little of the TPS (Throttle Position Tuning).

Secondary Runners – 4 intake runners are open all the time.  A matching 4 are on a set of butterflies which are spring loaded.  They rest OPEN (Free flow).  A vacuum chamber with a check valve and a pneumatic switch control them.  At apx 4200 or 4500 RPM they open up.

Valves – 4 per cylinder, 2 on the job of intake, 2 on the job of exhaust

  • In the airflow path we must respect the exhaust!

So….  there is a CAT that can get packed full of oil and debris.  Several resonators (pretty clear shot) and a muffler (also a clear enough shot) – with the highest probability of back-pressure developing at the CAT….  due to running an engine which burns oil and runs rich at lower temperatures for extended periods of time (Packing).

So…  Yesterday I went ahead and swapped the air filter.  There is something VERY LOUD in the exhaust or attached to the exhaust.  Will see what later.  Probably a valve or a head bolt.

 

SPARK

 

TIME