illustrated_FC

iTrader: (1)

hey guys,

this weekend i went to take my rx to get inspected, and it failed for emissions.
ever since i got the car it smelled a lot like fuel and unburned fuel.

i have a '89 GTU with 180xxx miles all stock motor NA. Do you think its probl my cat thats done and is not doing its job with emissions ?

thanks

misterstyx69

iTrader: (142)

If it has a stock emissions system,then YES,The catalytic is most likely done.
The bset advice is to make sure you have a good Catalytic converter and a working Air pump on the car.A good overall tune-up such as new plugs,wires,fuel filter and an oil change also cannot hurt the car either.
Make sure that you take the car for a good "spirited run"(20 minutes highway is good) to get the catalytic hot so it does it's job at absorbing the Exhaust gases that can effect the car's outcome on the Etest.
Taking the car in Cold can give you higher readings in emission test numbers, that those results can make or break your chances of passing the test.So it is better if brought in HOT.

illustrated_FC

iTrader: (1)

how can i make sure that the cat isnt working and the air pump ?

The car runs fine just that exhaust smell is unbearable sometimes. Whats the main purpose of the air pump regarding the exhaust system ?

Roen

iTrader: (2)

If your cat is working, you probably won't be smelling any exhaust.

illustrated_FC

iTrader: (1)

Nice. okay thanks.

Another question i was doing research on the a basic exhaust setup for now, to eliminate this smell.

I was looking at the Racing Beat website and saw that they had the Catalytic Converter Replacement Pipe with Presilencer...if i was to go for this set up will that down-pipe be my cat and function as if there was a cat installed ? as far eliminating that exhaust odor ?

Or its better to just replace the old cat with a HIGH flow cat only.

My goal is to keep the car as stock as possible by still have that high quality OEM performance

misterstyx69

iTrader: (142)

A cat converter replacement pipe is just that,,A pipe that replaces the catalytic converter.It is not Suitable for any kind of Emissions testing.It is only good for modifying the Exhaust if you prefer not to run any Catalytic or emissions,etc on your engine.(suitable for Track,etc type vehicle.off road)
If you want to keep the Performance aspect of your car at a optimum level,then a Catalytic such as the BONEZ HI FLO or an Equivalent is what you should. be looking at.
If you get a Good Main catalytic converter,and a working air pump,your car should be able to pass emissions..(some guys even have JUST the main cat,no stock pre-cats.).
Note: if you have the STOCK catalytic on the car and have failed the ETEST,then most likely that Cat is Toast.( think about it..a 20 year old catalytic converter.bombarded by HI Exhaust temps.It is bound to Give up after a few good years of service.)
A good workin Cat will eliminate a fair amount of the Gaseous odor.The Rotary runs Pig rich though,so don't expect the Smell to be Forever Non existant!.I run with no cat.,My clothes have that Nice "Eau de Taco" cologne smell imbedded in them after a good drive.,lol!!

calpatriot

Before you go replacing to cat, first verify that the rest of the emissions system is working as it should. You may indeed have a toasted cat, but if the car is running rich (sound to me like yours may be) you will soon do in that cat as well (been there, done that).

Two quick and easy checks to do: pull codes, and check for closed loop operation.

There is a procedure in the online FSM to pull codes by counting pulses at the test connector. You can also make a simple test set to check for closed loop operation (ECU correcting the mixture back and forth across stoichiometric a little slower than 1x per second in steady rpm cruise condition). I made one for my S4 with one led, a resistor, some wire, and two male type crimp plugs. I think you can do the same for the S5, but see the manual.

If your car is not going into closed loop, it defaults to a rich condition. This allows you to drive the car, but if not corrected soon the excess fuel going into the cat overworks the cat, it overheats and melts internally, and then you dont pass smog. If you replace the cat without correcting the problem keeping it from going closed loop, you simply start over on the process of cooking the next cat.

The raw fuel smell you are reporting suggests that the cat may be a symptom, not the cure. A likely fault is the ECU unable to see the O2 sensor, either due to bad wiring, bad sensor, sensor not hooked up, or ECU fault.

illustrated_FC

iTrader: (1)

misterstyx69 : lol yea thats how i was the other day, smell it so much my head hurt tho.

but doesnt the car have some pre-cats that i might need to change too, if i go for the cat replacement?get oem cats? or oem performace cats...

calpatriot : well im hoping its not the ECU and its the o2 senor orf something along that line and maybe one of the cat sensor is messing up my fuel and air ratio mix....

how many senors should i change; the air sensor , exhaust sensor and pressure senor maybe ...?

i think i might go with a oem cat or a replacement cause i want that smell to leave. I wanted to so a dp and presilencer but will that eliminate some smell like a cat would ?

calpatriot

I wouldn't change any sensors until you find out what is not working. You can make a code checker for under $3, and an led checker for the closed loop test for about half that.

Check and see if there are any codes. If there is a failed sensor or wiring to a sensor, it probably will trip a trouble code.

If the closed loop check fails, it is probably the O2 sensor, the wiring to the O2 sensor, or the ECU.

Then set the idle, idle mixture, and TPS per the FSM procedure.

If you verify there are no codes, and you get the closed loop check to work, and you still think there is a problem, backprobe every pin on each of the three connectors on the ECU and compare the voltage you find there with that published in the online FSM.

If you show no codes, and the closed loop test is good, then you can look at the cats. You can replace the main cat, and just inspect the pre-cats to see that they are not melted/blocked. If they are, you can just knock the elements out of the cats, or get new or used ones.

illustrated_FC

iTrader: (1)

calpatriot: the closed loop operation, i would have to open the ECU still little confused on that test ?

Well when i turn on the car it doesnt show any engine lights on. Than again car is new to me so idk if the previous owner over ride the lights.

Lets say the case was that the closed loop operation test was good and i had to change my cats whats better replacement get pre cats and cats or high flow car or straight pipe it ?

In the FSM there is a way to control the mixture of air and fuel manually ?

illustrated_FC

iTrader: (1)

just thought about this...maybe it could be a gasket as well...

ericgrau

iTrader: (1)

Find the smog table in the FAQ. Running rich probably destroyed your cat by now, but the cat probably isn't the main problem. Figure it out, then after that you'll probably need to replace the cat too.

calpatriot

No. Closed loop is one of the easiest tests to do. (Note: yours is an 89, and mine is an 86. Check the FSM for how to check the trouble codes, it is a little different than mine). All you have to do is hook up a 12volt led to the center two pins on the green, 6 pin test connector in the front left corner of the engine compartment. Search this forum for my posts on the 'green lamp test' (its other name). If you use a longer wire, you can remote the LED into the cabin, lay it up on the dash and go driving. The LED tells you if the ECU is evaluating the mixture to be rich or lean. On is rich, off is lean. After warm up, the LED should be on at idle, on during acceleration, flashing on and off during steady cruise (closed loop), and off during decelleration.

You can get a 12v LED at radio shack for a buck or two.

If you make an LED code checker (12v LED with spade connectors), you can check and see if the ECU is initializing when you first turn on power (key in RUN). Your check engine light should come on for 2-3 sec after turning the key on. If the ECU is reporting trouble, it will show up as the LED pulsing on and off in a sequence after the first few seconds.

You will never pass smog with a straight pipe. You need a cat. I would check and correct any trouble codes first, then check for closed loop operation at steady cruise. If both of those are OK, jack the car up and bang on the cat with your fist or a rubber mallet. If it sounds like stuff is rattling around inside, your cat is done and will need to be replaced.

If nothing sounds like its rattling inside, go try the smog check again after clearing the codes and verifying closed loop. It may pass. If it still does not, try replacing the main cat only, and then try again.

No.

illustrated_FC

iTrader: (1)

calpatriot : okay doesnt sounds too hard. So when its off while de-accelerating its good.


I was reading a thread on this fourm and show your reply about the teamfc...site[i probl spelled it wrong]. And was reading it...very helpful.
Im going to try this and get back to you...because before i get my hi flow car or straight i want to know why its burning so rich.

btw would you recommend a Bosch o2 sensor ? i want to replace mine because i think my fuel/air ratio is all messed up..

again i dont think the previous owner gave maintenance to the car.