TCCS question

[Josh Sulsberger]

I had the car stored for the winter with the battery out.
Had to go through emissions before I could register this year, so took it over yesterday, after having it back on the road for approximately 150 miles.

Failed HC portion of emission test, @ 2.08 grams/mile (limit 0.8 gr/mile) so she is running rich. Here's the split of the exceedances:

Acceleration 60% contribution
Low cruise 11%
High cruise 0%
Deceleration 27%
Idle 0%

Anyways, on to the question. How long does it take the TCCS to re-learn? The acceleration runs during testing were pretty hard pulls, if I haven't had any during my street driving this year, would this be a problem?

 

[Nick M]

Why do you think it is rich? There is an emission trace for it, and HC isn't it.

Post the whole trace if you can.

 

[jetjock]

What the Nickmeister said. HC is not a valid indicator of mixture richness. The engine could be into lean misfire and generate high HC. Need the other gases, especially CO

 

[Josh Sulsberger]

Pics attached (no scanner...)

 

[Josh Sulsberger]

Looks like the printer output and vehicle speed aren't matched up good. Black and blue lines are shifted left around a quarter inch...

 

[Nick M]

Since the NOx and CO2 aren't too far off, you have decent combustion. I am guessing it drives normal? But yeah, your CO is high, despite what the comment section indicates. Your NOx being a little low also shows a richer mixture.

That leaves the question of why. Off road down pipe? If so, get the car at operating temps before testing. And test in the mid day heat, *if* you have an off road down pipe. Normally, the cat isn't the first thing you look at, but as I already said, you numbers for combustion aren't too far off. How did it drive anyway?

 

[Josh Sulsberger]

Thanks for the reply. It drives nice, nothing of note. I guess I should have stated most engine mods have been removed, except Greddy Profec which is turned off. I am running the stock downpipe and airbox for the test, but they had been in the garage attic until I reinstalled them when I got the car out this spring. I do have a Random Technologies high flow cat on as the primary...

The car was driven at operating temp to the facility, and I let it idle the whole time I was in line there (20 min)

 

[Nick M]

Are the valve covers still dry? Random cats have been pretty good from what I have read. Many other "high flow cats" aren't so hot.

So no Lex/550 or other A/F altering mods at all?

 

[Josh Sulsberger]

Could you please elaborate on the valve cover thing? I'm not sure what you are asking.

No Lex/550, I did replace the O2 sensor a while back with the one that MDC sells, but that shouldn't have altered the A/F... 3" cat back, but I don't think that matters.

 

[jetjock]

And people say California is tough. I'd rather deal with an ASM15/25 than the IM240 any day. Cali cutoff points are tighter but the IM240 is a lot more demanding.

I think he might be feeling oil is getting down into the plug wells but I'm not sure where he'd be going with that unless he's thinking misfire. I have much more experience dealing with PPM and % than grams/mile but CO does seem high. You might want to measure the O2 signal and see where the midpoint is. I wish they listed O2 on that report. The high HC could be misfire, worn rings, valve seals, even fuel dilution. Could be a bad EVAP system too. Does the engine use much oil? Was the oil new when the car was tested?

What's Vf doing? The thing is running a bit rich but if I'm interpreting that report right the worst case is 12% and that's only during open loop. That puts A/F down around 13. That's not low enough to be into rich misfire territory so it shouldn't be associated with the high HC. As Nick pointed out it's enough to suppress NOx though. So you have two problems. If I were you I'd deal with the richness first because it should be easier to resolve. How's the condition of the air filter?

 

[Nick M]

I wasn't thinking he had any misfire. Just excessive HC's from an external source, or the cats not operating. Yeah, his oxygen sensor may not work right, it could be lazy. And it will affect your A/F's. I know you said you just got it, but you never know.

 

[Josh Sulsberger]

Some of the stuff you are asking I will have to check on.
Here's what I do know:
The engine does leak some oil, so I don't have a good idea about the amount that it actually uses vs. what it just drops on the ground. I did do the valve seal replacement two seasons ago. It doesn't smoke when I start it or get on it. I know this doesn't count as a real test, but I'm not getting any appreciable blowing out of the oil fill when I take the cap off with it running. The oil was changed right when I pulled it out of storage, so about 150 miles ago. The air filter is also new in the last few thousand miles or so. At the same time that I did the seal replacement, I changed the plugs and wires, and replaced the hardware for the valve covers with the allen head and lockwashers. I don't think that the valve covers are leaking, but I will double check. I may have made a mistake storing it with some gas in it (around a quarter tank), but I filled it full after I pulled it out and ran it down to around a half tank before the test, hoping to have good fuel running through it for the test.

On to what I don't know:
I don't know what Vf is doing. Should trying to get that data be my next step? I was kind of ignoring it since my "steady state" situations idle and cruise were looking pretty good...

I'm sensing that you guys don't think that the ECU reset has anything to do with this, right?

 

[Josh Sulsberger]

I've still got the old O2 sensor still sitting around...

 

[Josh Sulsberger]

Oooh, I just thought of something that might be related. I'm sorry that I didn't mention it earlier, but I just thought of it. A few days ago I had to give it a little gas to keep it going when I started it hot. Not floored or anything like that, but without a little throttle, it would quit at first...

 

[Nick M]

Pulling the EFI fuse doesn't fix or break cars. The IM 240 test will pick up stray HC's from leaks, wether it is oil or gas. That is what I was thinking about. One thing with that is you are only high during accel, which you are supposed to be anyway. Which is why I also asked about the cat.

 

[jetjock]

Nick: Ok, I get you now. Good point. With the rich mixture his O2 is no doubt down so the cat isn't getting enough for oxidation, especially during open loop. It's why I wanted to know O2. Either that or it's already been killed by the HC. Wish I knew PPM so I could make a better guess on engine out versus tailpipe. I'm not used to working with IM240 data.

Josh: How old is the cat? Got an infrared gun or some other method of measuring the inlet and outlet temperatures?

As for the O2 sensor well, that's a delicate subject. All I'll say is they're not created equal. The number and design of the flutes is important. Others will work but not as optimally as the one designed for the engine. I doubt that's your problem but it'd be nice to know what it's doing. You can look at it using Vf. The O2 sensor's sole job in life is to serve the catalyst and it'll only function at max efficiency if the sensor is controlling the exhaust stream to a very narrow range.

An ECU reset won't help. As Nick said people need to get over thinking it's a silver bullet.

 

[Josh Sulsberger]

The downpipe is the original (88) and the Random Tech was purchased brand new in summer of '03. I'm only putting on 3-4K miles a year, so lets say a max of 20K ago. I did have leaky valve seals a while back which I have since replaced...think the burning oil killed the cat(s)?

I've got an infrared thermometer max 518 deg. F...good enough?



When I check Vf can I just play with it in the driveway, or do I need under load data to verify how it's operating?

 

[Nick M]

According to the emission trace, your problem is when loaded.

 

[jetjock]

Jumper T and E in the diag block. Run the engine at 2500 rpm unloaded and measure between Vf and ground. Try and measure the average of the signal on DC volts and tell us what it is. If your meter has a Min/Max/Avg mode use it. If not use the analog display bars. If it doesn't have either you need to buy a better meter. After the engine gets good and hot at 2500 rpm get under there and shoot the front, middle, and rear portion of the cat with your IR. Tell us what you get.

Keep in mind this stuff can be tricky to find without the right tools and expertise. You may be better served by taking it to someone who has them. It's either that or you could be setting yourself up to go through the frustration of repeatably failing tests because you have no real accurate way of checking for progress. Nick: I want to see if he has an engine out or tailpipe out problem ie; if the cat's working. His Vf is going to show open loop under transient conditions anyway.

 

[figgie]

Josh

did you do the small maintanance items ESPECIALLY the spark plugs?

Reason I ask is that if the car has been sitting and the plugs were never changed before that. You might be getting a slight misfire on one of the cylinders which will make your HC go up at that point.

ninjaedit: lmao. Just saw the pictures and they also said the same thing about the missfire.

How are the connections to the CPS? Coilpack age? Spark plug condition? Ignition wires age?