My Catera Wont Pass Etest, Need Help Badly!!!

[Lov'n'Da'Catera]

So iv went for my e test twice now and failed both times. My first etest the car hadent been running for about 2 months, finally got it running and drove about three blocks and tried my e test but it failed so i figured that it just needed to get driven around a bit. So i put some off the shelf e test stuff in my gas, and drove about 900km, went back today to try again and still failed with little improvment from the first time.

So im in need of serius help/advise on what to do. Im passing my HCppm and CO with amazing results but im failing my NO ppm horribly!!

Here are my results from the first test:
- HCppm limit is 52 and i got 7, so i passed
- CO limit is 0.29 and i got 0.01, so i passed
- NOppm limit is 385 and i got 786, so i failed by far

Here are my results from the second test after e test additive and 900km driving:
- HCppm limit is 52 and i got 7, so i passed
- CO limit is 0.29 and i got 0.00, so i passed
- NOppm is 385 and i got 668, a little better but i still failed by far again

So does anyone know what my problem might be?

Has any ever had the same problem?

Every shop iv gone to so far say that if im passing HCppm and CO that my cats a fine and that my problem is heat essues. So baisicly every one thinks it could be my egr valve but problem is both shops that checked out my car cant find it under the hood or on there computers.

Does anyone know where it is located?

[CateraMV6]

I will have a look in my Service Manual and get back to you... otherwise the NO refers to NOX emissions correct? those are related to combustion so I would say something with the fuel mixture is messed up so the car is messing things up...

Could be ambient air temperature, Mass Air Flow sensor, O2 Sensors... or even coolant temp sensor... something is messing with the fuel mixture and I am guessing that its making it too lean and thus the low production of the other CO, and HCppm, but that results in increased NO emissions...

Now I am hoping someone else will correct me but thats my initial thought...

I will get back to you with my findings...

[investor74]

Are you getting any DTC codes from the on-board diagnostic computer? Usually, any emissions related problem shows up as a Diagnostic Trouble Code (DTC). In fact, my state used to measure the emissions at the exhaust pipe and switched to just hooking up a reader to the car's computer and reading the codes. Many states do that now. Cheaper and better.

I checked in my service manual but could not find the EGR valve. Sorry.

Barry
'97 forrest green catera

[ewill3rd]

NOx is Oxides of Nitrogen. Those are formed when combustion temps get too high, or a bit normally once the engine is at full operating temperature and under load.

Two things handle NOx. The EGR valve is number 1 and the Converters are the backup.
I don't even know if Catera has an EGR valve, I don't recall having ever seen one. Look at the emissions decal under the hood. At the top of the sticker there should be a list of items that the car has for emissions equipment. Like HO2S/ TWC/ EVAP/ and things like that. If you see EGR on there then it has a valve and you need to start your diagnosis there.
If it does not say EGR then it doesn't have one. If it doesn't have one then you have a couple of choices. The coolant temperature could be too high, this should be easy to figure out. Look for things like leaks or improperly functioning components in the cooling system. Otherwise that car uses what we call a "dual bed" converter. TWC means three way catalyst which identifies it's ability to handle the 3 gases. The components that control HC and CO are too different from the NOx portion so usually there are two strata components in the cat to handle all 3.
The NOx control portion of the cats can be wasted. Sadly you won't know which one is failing, I believe that has 2 cats on it but they go in to a single pipe.

Anyway, that is just to get you started, look it over and post up what you find. If I get a chance I'll do some follow up with you to point you in the right direction.

[CateraMV6]

Originally Posted by ewill3rd

Sadly you won't know which one is failing, I believe that has 2 cats on it but they go in to a single pipe.

Just a small correction, the cateras had their engine designed to run as 2-3 cylinder engines, and the two never cross paths...

Air is sucked in through 2 throttle plates, then into each sides of the engine (I don't count the crossover valves) Then out the exhaust and all the way back to the rear resonator, and even there the gases still have their separate passages....

I think that if you get a sniffer and you hook it up to the one exhaust pipe and then the other, and say the one Converter went bad you should be able to tell the difference...

I still think you have a lean condition in your case... so go to the auto zone and have them scan your car, and see if the coolant temp sensor and the ambien temp is working properly...

[Lov'n'Da'Catera]

Thanks for the replys guys and i will try to to go over everything you guys have mentioned.

I bought two magnaflow cats but im affraid to put them on and still not pass the etest.

I also went to gm and found out that we indeed do not have an egr in our cars and also to find out what i could about my problem and they couldnt be much help, all they could really tell me is that there is some sort of pump that shoots air into the exhaust and they say if its not working that it could be causing my problem, they couldnt tell me exactly where it is but after looking at the pictures on there computer then checking my car it seems to be underneith the drivers side of the front bumper, but then again im not sure? I priced it out and gm wants 950$ but i can source it used from a buddy for 40$

Has anyone herd of this pump being a problem?

Gm also told me it just might be my thermistat just not working right and causing the motor to heat up.

As far as codes go i do have an evap code comming up on my reader but everyone has reasured me that this wouldn't be causing my problem.

I have only driven my catera for about three weeks now and have never owned one before so im not sure exactly how they are suppose to run as in temp. My car tends to run usually half or a little over and sometimes it will will a tick or just a bit over but usually my fans will come on and it will go back to about half. Is this normal?

[Lov'n'Da'Catera]

Okay here's what iv done so far and what i still have to do:


-Changed both electronic water pumps (the one on the pass fender and the one at the top of the driver side rad)

-Changed the water temp sensor at the back of the block and in the coolent jug (ohh and for everyones infromation i read up a few post about having to change the intire coolent jug, well it may be so if you plan on buying a new one but i went to the local yard and popped two right out of the jugs and replaced mine)

-Replaced my intire power wire from the battery all the way down to the starter and alternator

-Did an engine flush with new oil and a bottle of lucas oil stabilizer

-Cleaned my intire intake system including air sensor, maf, throttle body, valve cover and put in a new air filter

-Did a full coolent flush (question is it better to run normal green antifrezze?) a few ppl have said that GM's coolent (orange stuff) wears out the gaskets.

-Tommrow im doing the air pump that pumps air into my exhaust system (i think mine is shot)

And a couple questions:

I ended up getting two used cats off a catera with low mileage so when we took them off i just unbolted them off the headers and just after the cat.
So i need to know if they take gaskets for when i bolt them to my car?
I called a few places and nobody has anything coming up on there computers for exhaust gaskets.

Also there is this modual/sensor not exactly sure, i think it has something to do with air/vacume. It's located near the passenger strut right beside infront of the evap valve and is secured there by rubber hanger. It has a hose that goes to it coming from the fender and then has a plastic hose that comes off it and goes down toward the alternator well that hose is just hanging there not going to anything.
So what is that modual/sensor? And is that hose suppose to be attached somewhere? If so, where?

Sorry for the 100's of questions but im just trying to get this figured out and i havent yet recived my workshop manual for the car yet that i ordered.

Thanks in advance!

[dkinder]

If none of that works I would look closely at the MAF. I am so fed up with Bosch MAF's, they seem to be absolute garbage. They have failed on my Audi, Mercedes, and both of my Cateras. If yours was really gone south you'd know it because the car would run like crap and likely barely move when you got on the throttle but it's worth taking a look at still yet.

[ewill3rd]

I have to confess I haven't paid much attention to the exhaust on Catera, rarely do we have true dual systems on any of our cars.
There is typically a shared resonator or an H pipe. If it has true dual exhaust it changes the way the test is done actually, they would probe both pipes and the computer will measure them together. If it is true dual then it would be easy to tell which side there is a problem on.

I am really confused as to why you are doing all this stuff without even testing the car. You don't get arrested for failing the smog test, you just have to fix it.
I mean it is great that you are doing all these things to help keep your car running right but spending all this time and money because something "might" be broken seems awfully strange.

The AIR pump cannot be any sort of problem.
It only runs in open loop on a cold start and cannot cause a failed emissions test unless it is missing or a current code is set for it which would turn the MIL on.
AIR is in place to lower cold start HC emissions and pretty much for no other reason.
History codes are no problem, but if a code has the MIL turns on during the test it will fail if the code is current.

As far as I can tell we are trying to diagnose and fix a car that isn't broken yet which makes it really hard.