TSI Failure

Just returned from getting my 94 Toyota Corolla inspected and the idle failed. The HC ppm reading was 288 and standard is 220. Do I need to bring this to the dealer or can I bring this to the local Pep Boys or Sears?

Any info would be greatly appreciated

There is absolutely no reason to take a 20 year old car to a dealer’s service department.
However, I would avoid places like Pep Boys and Sears (and other chain-run establishments) like the plague.

Any trained mechanic can work on a 20 year old Toyota, and a mechanic at an independent shop will more than likely do it with more competence and at a much lower cost than any of those “chain” shops.

All of that being said, high HC emissions are usually the result of lax maintenance. So, replacing spark plugs and air filters that are over-aged will frequently do the trick. Sometimes it is necessary to do additional work, such as replacing spark plug wires, or adjusting the ignition timing (if it is actually adjustable on your engine), or cleaning the EGR valve, but none of that requires a visit to a dealership.

However, it is also possible that excessive engine wear is the cause of your high HC emissions, and if this turns out to be the case, then you would probably be better-off getting a newer car, rather than spending the money to overhaul that 20 year old engine.

Just for the sake of discussion…
How many miles are on the odometer?
When were the spark plugs last replaced?
How often do you change the oil?
How much oil do you need to add between oil changes?

I have to add this caveat for service on a 20 year old Corolla. We have a few really good places in this area I would not hesitate taking my Toys to for service of his type. But, if you are just not sure, it’s a crap shoot and some independents are no better in price and worse in service if they don’t know what they are doing. I have had some independents try to jerk me around for labor trying to find a problem then a higher priced per hour dealership could in a shorter time. It was then cheaper from a dealer. So, you really don’t know without references. Safe and expensive from a dealer or reasonable and effective from an independent but only if you know which ones. Good independents of long standing customer satisfaction are definitely the way to go for Your problem…just make sure you knw exactly who they are.

The car was previously owned by a woman who barely drove it. Before we purchased the car it sat for quite some time because the previous owner passed.

On to your questions:

  1. How many miles are on the odometer? - 81,000
  2. When were the spark plugs last replaced? - Over 3 years - Never changed them from time of purchase
  3. How often do you change the oil? Every 3,000 We did have the oil changed immediately upon purchase.
  4. How much oil do you need to add between oil changes? Never needed to.

Based on what you told us, I doubt if excessive engine wear is the problem, and that should be good news for you.

More than likely, you just need to bring the car up to date with its maintenance.
Take a look in the Owner’s Manual for the Toyota Maintenance Schedule.
Find the maintenance lists for 60k miles, 90k miles, & 120k miles, and have EVERYTHING on those lists done.

I am including maintenance up to 120k miles because maintenance is done on the basis of odometer mileage OR elapsed time–whichever comes first. On a 20 year old car with low odometer mileage, the elapsed time factor overrides the odometer mileage factor, so maintaining it as if it has 120k miles is realistic.

Simply bringing the car up to date with maintenance should–hopefully–correct the emissions problem, and it will also improve the gas mileage and the drivability of the car.

Failing a smog check because of high HC is generally caused by a slight mis-fire. Unburned fuel is escaping the tailpipe. Does your engine idle smoothly or is there a little skip or unevenness when idling? Was the car completely warmed up when you had it tested? Many things can cause this problem so listing them all here does not really accomplish anything. A good mechanic should be able to quickly isolate the problem and fix it. A much better plan than just throwing a basket full of expensive parts at it and hoping for the best…

If it’s been 3 years, I’d plan on swapping out the spark plugs, checking the condition of the plugs for anything amiss. And, I’d also change out the O2 sensor. Make sure you get a Denso brand. Toyota’s are fickle. Unless this car is California emissions, there should be only one. 1994 is still OBD-I. I’d be surprised if it fails again after that.

Here is a link to a discussion I started when I was trying to get my 1993 Caprice to pass the NJ emissions test.

Driving a good distance (40-50 miles) the day before, making sure the car was fully warmed up before going to the inspection station, and not waiting in line for any length of time seemed to do the trick.

Good luck,

Ed B.

Thank you all for your detailed responses. I am taking each one into consideration. edb1961 - I did have to drive 15 miles and most of that ride is down a 65 mph road and I sat in line for about 30 minutes. I would think that would be enough time for a warm up. VDCdriver - I don’t have an owners manual but will try to find one on line. I am going to start with the plugs and wires because they don’t look in good shape at all. Again Thank you all for your responses. I will keep you all posted with my outcome.

Have a great weeken

Coincidentally, my 92 Corolla recently failed an emissions test for high HC’s. In Calif the limit is 130, mine was 140 on the first try. It recently passed with 127, after I did a bunch of stuff. Here’s the thread, may be of some help. I concur w/the above, start with bringing all the routine engine maintenance suggested in the owner’s manual up to date. It would be interesting to me to find out what works for you, so post back. Best of luck.


VDC has given excellent advice, as he always does, as have the other respondents. Follow his advice and you can expect many years of good service out of the vehicle.

I would suggest looking for a reputable independently owned and operated shop rather than Sears or Pep Boys. Sears has had problems in the past that have even caused class action civil suits, and while the Pep Boys in my area seems good, their reputation, as is the reputation of most franchise operations, is spotty.