Emissions

[xxiiac]

Hey everybody, was wondering if you guys might be able to help me troubleshoot an emissions problem?

My 94 LS has 120000 miles on it. I have to pass emissions to get it registered. I failed my first test, said that my HC (hydrocarbons I believe) were too high (114 and 75 is passing). Prior to this I had changed my valve cover gasket and when I put everything back together I accidentally pinched one of my spark plug wires under a plastic cover. This caused the wire to be exposed and it was shorting against other metal in the engine compartment. I noticed I had a problem when all of a sudden I had no power when I was driving. I found the short and fixed that issue. However, when it had no power I believe it was running only on 4 cylinders. I think this means that the bank that went down was having gas go through it but not being ignited. Would this unburnt gas travel down to my catalytic converters and clog them up? I've noticed that when I get out of the car and I put my legs to the ground, it feels warm from under the door area. I've also noticed a slightly burnt smell after I park it in the garage.

Do you guys think I've ruined my catalytic converters? Is there a way to see if I did? Any thoughts/ideas would be appreciated....

[billydpowell]

I would have to try driving fast freeway speeds (80) for about an hour to try and burn them out

[xxiiac]

Alright, I tried burning them out, don't think that is the problem. I ran it at around 80mph for over an hour. Also was punching it alot (slowing to 40 then gunning it to 80). Then I had the emissions test. Worse than the first time. The mechanic at the shop said that the reason the hydrocarbons were so high was due to unburnt fuel. He said too much fuel was going through the system and not being burned????? Is there a way to adjust the fuel injectors? Does anyone have an idea?

[curiousB]

Alright, I tried burning them out, don't think that is the problem. I ran it at around 80mph for over an hour. Also was punching it alot (slowing to 40 then gunning it to 80). Then I had the emissions test. Worse than the first time. The mechanic at the shop said that the reason the hydrocarbons were so high was due to unburnt fuel. He said too much fuel was going through the system and not being burned????? Is there a way to adjust the fuel injectors? Does anyone have an idea?

I had a car (a dodge not a Lexus) fail several years ago for similar reasons. In the end one injector was stuck partially open so was always passing some fuel. At lower RPMs this was enough to fail the test. Unfortunately with your Lexus's fuel rail design its not possible to take one out at a time to check them so you are looking at a fair bit of work to get at the injectors.

Maybe before you spend a lot of time and $$$ you run a couple tanks with a high quality injector cleaner in the fuel and see if that cleans any gummed up aspects of the injectors. Granted this is a guess but its easy to try if you have some time to work at this.

Was your fail at low or higher RPMs?

[93ls400walt]

have you checked for any cell codes? I have read that the erg being somewhat clogged can cause this failure also. If you were running on 4 clys. It may be a bad coil. The driver side coil seems to go out most often.

[lexfourcam]

i agree check the egr pipe and make sure its not cracked because that's the exhaust gas recirculation pipe. All the unburnt gas is recirculated back into the motor. It connects to the exhaust manifold, turn your car on and listen for a leak...

[xxiiac]

Thanks guys for your replies. After I failed the first test I ran fuel system cleaner through two tanks of gas. I also used a can of seafoam to burn everything out of the system. Last time I checked the codes I got nothing. I am going to check the egr pipe and see if that is leaking. Checking the injectors seems like a bigger job than I have time to diagnose. As far as the coil, if it was bad would those cylinders still function? Will let you know what I find out. Thanks again.

[xxiiac]

I think I may of found out what is causing it. I started the car and listened for a leak, after a moment I heard one. I then saw a line disconnected. I put my finger over it and there was suction. I think it is an EVAP line and according to the manual it says that plays into the hydrocarbons. That is probably why it's testing high in HC's. Back for the free emissions re-test tomorrow. Hope this did it......thanks everyone for the responses, will let you know how it turns out.

[xxiiac]

Found the problems....according to the Toyota shop. I took it in for a diagonostics although I check the computer and there were no codes. I explained the shop my problem and they said I needed a smoke test done. Once it was done, they said I needed: 2 cats, 4 o2 sensors, distributor cap and rotor (2 caps), and PCV valve....all for the small price of $5k. I guess you know what I said to that. I started to check prices online for this stuff and have a couple of questions about the job:

-Can I get away with using the cheaper ($100ish) cats?

-Can I trust an aftermarket (cheaper) o2 sensor?

-How difficult is it to replace the cats and o2 sensors?

-Has anyone heard of shops "re-stacking" the cats and does this work?

Looks like with aftermarket parts I could get away with everything for about $500 (1/10th) of the Toyota quote. I am not a "gear head", but have done minor jobs (valve cover gasket, pwr steering pump, CV joints, ect). Would changing the cats and 02 sensors fall in this category of difficulty? I've looked at the manual and it doesn't appear to be too difficult.......thanks in advance for any resonses

[VBdenny]

I'm pretty happy we don't have emissions tests here in Virginina (NOVA does). I'd go to an Autozone or Advance before I needed testing, borrow their OBDII (for free) and clear all the codes.

[xxiiac]

That's the issue, the computer isn't throwing any codes at all. I'm relying on the diagnosis from the smoke test that Toyota did on it. Looks like I can get away with buying 2 cats and 4 o2 sensors for about #350 from Ebay. The b***h of the job will be doing it myself. I've seen that the bolts are tough to get loose as well as the 02 sensors. Anyone out there done this, any tips????

[VBdenny]

That is more than I would get into unless I had a shop and a lift since it is pretty tough "on your back" work. Not sure what state you are in but I would try registering it in another state. The ticket (in the unlikely event you are ever caught) would be a whole lot less that the repairs. A 1994 car is pretty old and shouldn't be subject to modern emissions testing.