What's your Hydrocarbons, what does it tell us

[heliolps2]

What's your Hydrocarbons, and what does it tell us

It cost me nothing to get this test done.

When was the last time that you had your car tested for Hydrocarbons basically an emission's test. We often check the CO/AFR's... Mine is at 14.7, but we often overlook the HC's , While I was at a friend's Emissions shop, I had it tested, My friend Kevin at RPM Racing was very surprised at how low my HC's where with no cat, My Turbo tested at 68ppm, I had no clue what that meant to me,

Then Kevin told that was a good indication of several things that the motor was running very efficient and plus other things like the low blow by ,good timing, spark, and AFR's and turbo, All working excellent, Basically the motor was strong, The acceptable level without a cat is between 300 and 500, That is what Kevin told me, Anything higher, the engine may have some sort of problem. What do you think? Is Kevin right?

Together with my leak down that was an average of 2% on all cylinders and the cam lobs with no pitting, So I was a happy camper with this news,

I had a friends 81 930 checked, it was in the 1400's HC's and the co was set 1.5 CO = 13.9 afr. it needs some work.

I think that it would be great for Turbo owners to check your HC's once in a while.

Helio

[heliolps2]

I miss read the test, Here's y actual numbers, My HC ppm is super low. which seems to be a good thing according to Bosch, I copied and pasted below, the rest I kind understand but not really, What's your thoughts ?

RPM 989
Temp 89"

HC ppm 22
CO % 0.80
CO2 % 13.1
02 % 1.3
NOx ppm 155



Catalytic Converter Failures Bosch: Three Reasons for Gas Analysis - 5 Gas Analysis - Bosch Technologies Group

Three Reasons for Gas Analysis

* Identify engine performance and mechanical problems
* Test the running efficiency of the engine
* Test for exhaust emissions against state and federal standards

Combustion Chemistry and Gas Analysis.

* The combustion process releases the energy stored in the fuel
* Fuels consist basically of carbon(C) and hydrogen(H) referred to as hydrocarbons (HC).
* Under ideal conditions all of the HCs would be converted to H2O, CO2 and heat.

Combustion Chemistry and Gas Analysis.

* Unfortunately this complete combustion is rarely if ever achieved
* Short burn times, continuously changing mixture ratios and air temperatures, and combustion chamber quenching produce conditions which give rise to the formation of pollutants

Pollutants

* Incomplete combustion produces carbon monoxide (CO)
* Unburned fuel produces hydrocarbons (HC)
* High combustion temperatures produce oxides of nitrogen (NOX)

Other Exhaust Gases

* Carbon dioxide (CO2) is a product of complete combustion. Therefore the higher the level of CO2 the more efficient the engine is running.
* Oxygen (O2) level in the exhaust indicates the fuel-air mixture.

High O2=lean

Low O2=Rich

Gas Analysis as a Diagnostic Tool



Gas analysis

* Is a quick and accurate way to determine the running conditions of an engine
* By observing the 5 gas readings and understanding their relationship to each other you can diagnose the 3 major engine areas:

Fuel delivery

Ignition

Engine Mechanics


High HC Only


Hydrocarbons are unburned fuel. This can be caused by:

Ignition Timing (base and advance)

Vacuum Leaks (hoses, brake booster, manifold, evap. etc.)

Ignition (misfires, coil breakdown, etc.)

Mechanical (low compression, bad cam, etc.)

Catalytic Converter Failures


High CO Only


* Carbon Monoxide is a result of incorrect fuel/air mixtures. Causes include:
* For Carburetors (float level, power circuit, choke circuit)
* For Injection (injectors, pressure regulator, temp sensor, MAP/MAF sensor)
* For Both Systems (air filter, PCV, Evap, O2 sensor, air injection

High Nox Only


* NOX is caused by high combustion chamber temperatures. Check:
* EGR (valve, controls, solenoids, passages, vacuum hoses)
* Ignition Timing ( base and advance)
* Engine Temperature (cooling system, fan restricted exhaust, Thermostat)
* Vacuum Leaks (hoses, booster, evap, etc)
* Mechanical (carbon deposits, converter, etc)

High CO and HC


* Normally, when HC and CO are high it is the result of a CO failure driving the HC high.
* Correct for high CO first (Excessive fuel, restricted air, Evap., etc.)
* If HC is still high, test as high HC (ignition, timing, mechanical, etc.)



High CO and Nox

* These problems are normally incompatible. If they occur on the same test they will most likely occur at different points on the drive cycle
* Correct CO failure first
* Retest and locate NOX failure in drive cycle and correct as NOX failure only

HC and NoX

* High HC and NOX normally occur as the result of a lean misfire. Check for:
* Lean run (vacuum leaks, mixture problems, fuel delivery, etc.)
* Mechanical (oil burning can cause high combustion chamber temperatures)

CO, HC and NOX

* This is a complete breakdown of the emission systems or multiple failures.
Check:
* Catalytic Converter (missing, damaged)
* PCM (closed loop, wiring, etc.)
* Drive cycle ( if failures occur at different points diagnose each failure separately)