emissions ugh.

[mattcosta7]

just got back from the inspection shop, and failed my HC emissions by .25. I need to replace my cat, and see this as a time to do an exhaust system revamping.

the problem is budget, so I need to try and remedy the emissions issue before I can worry about anything flow related. down the line ild like to get the bic downpipe with divorced wastegate, hook it into a testpipe and a 3'' exhaust, but right now I need to pass emissions

so after much time off topic, which cat can I get at cost that will allow me the best chance at passing emissions in new york .8hc. my levels of nox and such were far from failing. the car is an 87 turbo model

HC: 1.05, limit .80
CO: 9.35 limit 15.00
NOx: .58 limit 2.00

 

[Ckanderson]

HC is unburned fuel I used to know this stuff, but i have forgotten it. someone else will step in here with the answer as to what part needs to be replaced...

 

[3p141592654]

Post up the numbers and we can help. Otherwise, forget it. And don't replace your cat, there's lots of other cheaper reasons to fail that need to be ruled out first.

 

[tte]

Check your oxygen sensor and the wiring.
For the last smog check one of my oxygen sensor's wire on the connector was loose and broke off which caused me to fail. Fixed it and I passed.

If you are really stretched for money at the moment, you could drive till your tank is almost empty. Half an hour before your smog fill it with 1-2 gallon methanol. After you pass fill your tank with gasoline to help dilute the methanol.

Methanol is not good for the rubber components of your fuel system like seals etc...but I think running it for like less than an hour you would be okay.

I passed my smog years back with methanol and lots of hot rodders do that to pass smog.

Cheers,
Roy

 

[mattcosta7]

on hc I got a 1.15 passing is .8. I forget the other measures but ill post after work

 

[mattcosta7]

alright, i got the actual numbers infront of me now.

HC: 1.05, limit .80
CO: 9.35 limit 15.00
NOx: .58 limit 2.00
all measured in gpm

The gas station I brought it to for inspection tells me that they think it's the second cat in the exhaust, and that I should replace it, hoping that it brings the levels down to passing, otherwise they want to me replace both cats.

I don't trust them to do anything except inspections, and as such am not leaving the car to them for this. I rather do the work myself, especially something like a bolt on exhaust.

I havent had time to look at anything yet, as I've been in school and work all day, but tomorrow I plan to spend a good chunk of time under and around my car trying to get her to pass. Hopefully it's just a sensor or some other wiring issue. At worst, replacement cats. The exhaust system on the car dates back to 1987, so it might just be past its prime. Hopefully, it can give me another 2 months of use with a passed inspection. I am strapped until my college expenses are reimbursed by my fathers union, so I really need just a temporary fix, as I plan to replace the entire exhaust system once that reimbursement check comes

 

[Poodles]

don't worry about replacing the first cat, it's not necessary (cold startups maybe..)

I passed with a DDP and stock main cat...

check your timing, check/change your plugs, and change the O2 sensor...

 

[suprabad]

Also, make sure the car is really warmed up. I've seen people who unplugged their electric fans to get the car a little hotter than it would normally run, just to burn up the hydrocarbons.

Don't overheat it though.

 

[3p141592654]

Please post your oxygen reading too, then we can try to figure out your A/F ratio.

We are assuming you have no ECU codes set, so please confirm that. Also, as mentioned timing needs to be at 10 deg in diag mode.

Also, you will want to do a few simple tests.
First, hopefully you have access to a voltmeter, so let us know Vf voltage at 2500 rpm, and at idle.

Second, perform the O2 sensor cross counting test described here.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=119

Also, please comment on any unusual engine performance, rough idle, stalling, hesitation, fast idle, etc.

 

[mattcosta7]

the sheet i got doesnt list my 02. I will chck ecu codes tomorrow. I had no time to even take a real look at her today due to my hectic school/work scheduele. Tomorrow, however, has me home after 2, with a lift, a sheet of cardboard, and pages of information to look through.

the engine is running very well as far as i can tell. There is a small coolant leak i need to find, and other than that no issue. Idle is around 7-800 rpm, no stalling, no hesitation, gas mileage is around 24-26 highway, 18-20 city. i'll check the timing and such tomorrow as well. Go through the full service manual tuneup procedure, and see what comes up

 

[3p141592654]

That's too bad. The O2 reading would be helpful. The good news is that your car is running closed loop, and the A/F ratio is close to 14.7.

Let us know on the items I mentioned previously.

 

[mattcosta7]

I did the diagnostic today, and it seesm to be saying 22. I may be wrong, but thats what i am interpretting the engine blinking to mean. it looks like 2 long pause two, long pause 2.

I dont know if i have the appropriate tools to do the o2 sensor test. I have a multimeter, but i'm not sure how to/if i can set it to be any good with the 02 sensor test. Either that, or my sensor is dead, and that's why i get no fluctuation.

 

[mattcosta7]

on second check, i made a mistake and forgot to connect te1 and e1 while measuring e1 and v1. worked perfectly, so it's not the o2 sensor causing the issue. Could the water temp sensor cause an increase in HC in my exhaust, or is this narrowing the culprit to the cat more and more?

 

[mattcosta7]

im not entirely positive how to use the multi to measure voltage of Vf, but i assumed it set to the same as for the o2 cross test, and it seems that the needle points to 6volts at idle and 4 at 2500 rpms. I might be reading this incorrectly though, as there are several measurements and settings, so i may have the wrong one.

 

[mattcosta7]

ttt, tomorrow is the end of my 10 day inspection grace period, so i may end up having to replace the cat, otherwise driving it will have to stop for the time being, sadly

 

[3p141592654]

Okay, I'm confused.

1) Did you get a code 22? If so, that needs to be fixed. To get a code 22 the sensor has to be really screwed up (short or open). Driveability when cold with a code 22 will not be good as the ECU ignores the sensor and assumes a warm engine.

To check codes you connect TE1 to E1 with a wire jumper. The MIL light will flash rapidly if no codes set.

All the following tests must be done on a fully warmed up engine.

2) With TE1 and E1 jumpered, measure VF1 with engine at 2500 rpm and should see alternating 0 and 5 volts with at least 8 crossings in 10 seconds. It sounds like that is what you got, but please confirm.

NOTE: If you have TE1 and E1 jumpered then 5V at idle means you have a code set. Don't confuse that with the next test.

3) With TE1 and E1 *NOT* jumpered, measure VF1 at idle and at 2500 rpm. Should be between 1.25 and 3.75 V (ideally it should be 2.5V).

If it is 6V (actually more like 5V) at idle then you have identified a problem. The ECU is adding extra fuel to try to bring the engine back to stoichiometric. Typically this would be an air leak somewhere after the AFM.

By the way, I assume you checked timing and the plugs look good with correct gap. Also, listen at the exhaust at idle. There should be no intermittent miss or lumpiness.

 

[foreverpsycotic]

ive got a stock DP and am in southern CT if you want to use it. ill charge you $20. when you bring it back ill refund $15 of it.

 

[mattcosta7]

I don't have a timing light, but was told by the inspection station that the timing and plugs were fine. Plugs look fine to me as well.

I get the 0 to 5 jump while te1 and e1 are jumpered, by putting red to vf1 and black to e1. more than 8 jumps.

When i remove the njumpr to measure VF1 at idle, i am getting a measure that sits at 4, jumps to 4.25, and back to 3, then to 4 again, pauses at 4 and continues on this trend. At 2500 rpm, the measure is approx 3.

So we are to assume this means that it's an air leak after the air flow meter, right? This means my o2 sensor is fine, and that my cat is probably not the cause of my emissions. Now how to find the cause of the leak and fix it?

 

[mattcosta7]

ive got a stock DP and am in southern CT if you want to use it. ill charge you $20. when you bring it back ill refund $15 of it.

I've got the stock downpipe on the car. Right now the stock exhaust is runing, and not passing with the measures ive listed. thanks for the thought though

 

[3p141592654]

So no code 22, right?

Well 3-4 V could be normal (i.e. 2.5 - 3.75V) but its still worth checking.

Is it a turbo?

To check for an air leak start by looking for tears in rubber pipes, loose clamps and so on. Its more likely to be an issue with the turbo because of all the extra plumbing.

If you can't find it visually, then you can sniff around the intake system with propane. Hitting the leak will cause the engine speed to change. I wouldn't do that test without good ventilation and a fire extinguisher handy.

It would also be a good idea to verify that the EGR valve is working properly and not leaking at idle.