Trouble again,My '94 failed emissions test 3 months ago and the cat converter seemed to be the problem.I changed it and passed but barely.The HC was right on the limit( limit 54 - car 54),the other readings were normal.I never had any codes on the car exept when the Catalityc died.
So,I started by putting new spark plugs,new O2,thermostat,i cleaned the injectors with a machine,new egr,new modulator,cleaned the throtle body(twice),intake gasket changed,timing belt done.I used seafoam few times on intake,oil and tank.
Basically i did everything i thought it will help and the damn thing runs smooth enough,power is good too but was still running rich,giving me 16Mpg mixed(city+highway).
Today this freaking unloyal car killed the new converter again in 2 months.Code:cat converter below efficiency,same code i had before i changed the damn thing.
Something is not right and for the life of me i can't figure it out.
The car never gave me any codes at any time and seem to have no vacuum leaks.Rpm on idle are very stable.
Scaner datastream shows everything nominal,no misfire whatsoever,fuel pressure its ok,no noises while running,no coolant or oil loss.
Anyone has any idea if there is anything else to look for?It has 350.000 km on it.Maybe is just old and tired?Damn thing is driving me nuts.

 

Well,i just checked the coolant sensor by reading the datastream and a thermometer in the coolant.It gives me the same reading,seems to be ok.For some reason i think it is not burning the fuel properly or it is getting to much fuel.Maf is looking good too, 3.6 g/s on idle and goes up properly when accelerate...No one had a similar problem before?I need a bit of help here,i am running out of things to check.

 

One thing you might be having an issue on is engine oil/gas interaction, particularly if you have worn piston seals. If that interaction occurs, it's really virtually impossible to detect unless you do a gas analysis test (a.k.a. emissions test) or UOA test on the oil. That kind of mix can result in a higher HC count because it simply isn't burning in the air/fuel mix and if that oil gets in the cats, well use your imagination with what happens over time. You might want to try something like Lubro Moly Motor Oil Saver or one of the Bar's leaks products (for rear main seals) and that should help that issue.

 

Well its worth a try,i am running out of things to check or change anyway,thanks.