Mercedes-Benz Forum banner

1 - 4 of 4 Posts

·
Registered
1990 190E 2.6
Joined
·
13 Posts
Discussion Starter #1
the first time we took the 1990 190e 2.6 to emissions testing it passed the HC loaded test with a reading of 191. the HC idle reading failed with a reading of 242. they told me it needed a tune up. we replaced the distributor cap, rotor, spark plugs, spark plug wires, air filter, and oil change.
we went back for the retest and it failed both tests, the loaded HC reading was 376 and the idle HC was 549. it passed the CO test both times. why would the HC reading go up? whats happening here? :mad:
 

·
Premium Member
1986 190E 2.3-16, 1992 190E 2.3, 2015 GL350 BTC, and 2020 GLS450
Joined
·
2,395 Posts
On these cars, tinkerers dig into the air fuel mixture and improperly lean it out. This will cause HC to go way up. Another problem is that most tinkerers disconnect or remove vacuum hoses and plug up their connectors thinking that doing so will increase power. This also causes high HC. You already corrected the ignition hardware which is good. Timing is another factor that will cause high HC but these cars do not allow for timing adjustment easily.

Two additional factors are low compression which can come from a bad head gasket or a bad catalytic converter if the car is very old.
 

·
Registered
1991 190e 2.6 automatic
Joined
·
760 Posts
what kind of cat is on your car?

is it DEALER ?

or is it aftermarket

get a rubber hammer and hit the cat and liseten if you hear anything rattle inside...

if you do the cat is bad

if you don't it could still be bad especially if the car ran like shit for a long time, the extra gas particles would have messed it up.
 

·
Registered
1990 190E 2.6
Joined
·
13 Posts
Discussion Starter #4
after double checking and thinking i noticed that one of the leads to the distributor was not fully seated or "clicked in". i pushed it on and it finally made a "click". would one cylinder misfiring cause such a high HC reading? also they did not mention a oxygen reading on the printout. the CO reading was 0.43
loaded, and 0.32 at idle.
 
1 - 4 of 4 Posts
Top