TCCS question
- Thread starter Josh Sulsberger
- Start date
I think we've got some laying around in a drawer at work, the kind that you can attach to a DMM, right?
Yeah, that is correct. Hold the thermocouple against the metal with a popsicle stick or some other thermal insulator that won't instantly melt or catch fire.
OK new data collected with thermocouple:
In 300F
Body 350F
Out 480F
That makes more sense...but good enough?
In 300F
Body 350F
Out 480F
That makes more sense...but good enough?
Hopefully this lesson will help those that think OBD level 2 is bad. All he would have had to do was watch the rear oxygen sensor.
I haven't monitored temps coming out, sorry. But if there was nothing wrong with the OBD 1 car on a 4 gas analyzer, then I would look at the cat.
I haven't monitored temps coming out, sorry. But if there was nothing wrong with the OBD 1 car on a 4 gas analyzer, then I would look at the cat.
Sorry if I mis-interpret you Nick, but given the data, you're thinking cat?
Again, thanks to all that have contributed.
Again, thanks to all that have contributed.
At fast idle, 30 to 100 degC rise would generally be considered normal. 200 degC rise suggests a rich mixture, and 500 degC rise indicates unburnt fuel.
You are at 180 degC, which is on the high side, and suggests a somewhat rich mixture. It also shows that your cat is working fine.
By the way, the MK3 California edition has a second O2 sensor after the cat.
Did you ever do the O2 sensor cross count test?
You are at 180 degC, which is on the high side, and suggests a somewhat rich mixture. It also shows that your cat is working fine.
By the way, the MK3 California edition has a second O2 sensor after the cat.
Did you ever do the O2 sensor cross count test?
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OBDII is great. I only wish these cars had it. Mode $06 alone would be worth it.
Josh: The cat seems to be working but I'd expect it to be hotter with all the HC going through it. It's doing something though because I doubt these engines put out 5 gr/mile CO ahead of the cat. 15 would be more typical. 3p: only N/As have a sub sensor.
Josh: The cat seems to be working but I'd expect it to be hotter with all the HC going through it. It's doing something though because I doubt these engines put out 5 gr/mile CO ahead of the cat. 15 would be more typical. 3p: only N/As have a sub sensor.
You could have more than one problem. The tough thing is high HC on acceleration. Well, that is normal. But since the car drives normal, I would not think you have a mechanical compression problem. That leaves the cat. Yes, you are rich.
Maybe a turbo guy can say wheter or not a turbo is capable of blowing off oil under load due to some defect.
Have you tried the stock $800 Toyota cat? Or however much it is?
Maybe a turbo guy can say wheter or not a turbo is capable of blowing off oil under load due to some defect.
Have you tried the stock $800 Toyota cat? Or however much it is?
He does have more than one problem but HC is not an indication of rich mixture unless the engine is in rich misfire and his CO is nowhere near bad enough to indicate that. As you pointed out he has decent combustion. The slightly elevated cat temp is likely due to HC although I'd expect it to be higher.
Another indication of decent combustion is he claims an average of 2.4 on Vf with the diag jumper in. That implies crosscounting at close to stoichiometric. It'd be nice to know the frequency though. Plus the signal shows slightly lean so why is the CO slightly high? Tough to tell with the stone age tools he's working with
Generally speaking, engine out HC for this engine should be around around 2.0 - 2.5 gr/mile, which is close to what he got on the test. That implies somewhat normal HC passing through a weakened cat. It's also why I don't suspect misfire. The bugger is CO being lower than typical engine out levels and a catalyst temp showing at least some oxidation is taking place.
Then again that's all under closed loop and his problem seems to be under open. Based on that and everything else I've read I'm going with you and betting on a weak oxidation bed. Without gas analysis changing the cat would be the only way to know. This is all theoretical though. It's tough to do this stuff on the internet, especially when I'm an ASM and not a IM240 guy. Even tougher when I look at the three analyzers I have sitting here
Another indication of decent combustion is he claims an average of 2.4 on Vf with the diag jumper in. That implies crosscounting at close to stoichiometric. It'd be nice to know the frequency though. Plus the signal shows slightly lean so why is the CO slightly high? Tough to tell with the stone age tools he's working with
Generally speaking, engine out HC for this engine should be around around 2.0 - 2.5 gr/mile, which is close to what he got on the test. That implies somewhat normal HC passing through a weakened cat. It's also why I don't suspect misfire. The bugger is CO being lower than typical engine out levels and a catalyst temp showing at least some oxidation is taking place.
Then again that's all under closed loop and his problem seems to be under open. Based on that and everything else I've read I'm going with you and betting on a weak oxidation bed. Without gas analysis changing the cat would be the only way to know. This is all theoretical though. It's tough to do this stuff on the internet, especially when I'm an ASM and not a IM240 guy. Even tougher when I look at the three analyzers I have sitting here
Yes, I misrepresnted HC. When acclerating, he should have more fuel, but not raw HC out the pipe.
I went and pulled an old IM240 for my 87. The limits were 4.0 gm/mile HC and 30.0 gm/mile for CO.
There may be nothing wrong with your car at all. Only your aftermarket cat.
There may be nothing wrong with your car at all. Only your aftermarket cat.
I'm thinking that my next move is to put the original cat back on and retake the exhaust temps. It should still be operational. If I see a big change, I'll retest. Otherwise, I guess it's time to pony up for a new one...
JJ-Did you want me to get a frequency on the Vf signal? I've got a o-scope at work...
Thanks for the help!
JJ-Did you want me to get a frequency on the Vf signal? I've got a o-scope at work...
Thanks for the help!
Nick: That IM240 stuff threw me for a bit. Not used to working with it. After this thread got started I had to spend a few hours at Colorado State's National Emissions Lab website to puzzle it out. I'm ok with it now.
When enhanced testing was mandated in Cali they tried to force the 240 on us but so many people bitched they backed down. The same thing is happening these days as the state prepares to ban R134a sales to the public. The trade off was lower cut points on the ASM. The irony is as far as I can tell this guy's car would probably pass in California. Makes it funny to see people whining so much about emissions standards there. As I said earlier I'll take an ASM loaded mode test over the IM240 any day.
Josh: Just be sure it's at least 8 times in 10 seconds. Your meter should be able to tell you that or simply time it. That said nothing beats a scope for looking at an O2 sensor. Transition time (< 100 ms), minimum and maximum amplitudes (> 800 mv and < 200 mv), noise, hash, ect. I don't think your problem is that though. Just look for 8 counts within 10 seconds when at 2500 rpm. Either use Vf with the diag jumper in and or look at the raw O2 sensor signal with the meter set to millivolts.
When enhanced testing was mandated in Cali they tried to force the 240 on us but so many people bitched they backed down. The same thing is happening these days as the state prepares to ban R134a sales to the public. The trade off was lower cut points on the ASM. The irony is as far as I can tell this guy's car would probably pass in California. Makes it funny to see people whining so much about emissions standards there. As I said earlier I'll take an ASM loaded mode test over the IM240 any day.
Josh: Just be sure it's at least 8 times in 10 seconds. Your meter should be able to tell you that or simply time it. That said nothing beats a scope for looking at an O2 sensor. Transition time (< 100 ms), minimum and maximum amplitudes (> 800 mv and < 200 mv), noise, hash, ect. I don't think your problem is that though. Just look for 8 counts within 10 seconds when at 2500 rpm. Either use Vf with the diag jumper in and or look at the raw O2 sensor signal with the meter set to millivolts.
He still has the stock downpipe with the OEM cat in it, so its even harder to comprehend how the RT cat would be so hard pressed to clean things up. But, I'll reserve judgement and wait for the test results using the old OEM cat.
I do have one other thought though, and that is maybe he has a small boost leak only evident under acceleration. If it were me I would go over the intake plumbing with an eye out for a small crack in a hose or loose clamp, especially that rubber pipe off the compressor going to the IC.
I do have one other thought though, and that is maybe he has a small boost leak only evident under acceleration. If it were me I would go over the intake plumbing with an eye out for a small crack in a hose or loose clamp, especially that rubber pipe off the compressor going to the IC.
Signals/samples look good.
IC piping yielded some potential problems:
Some type of oxidation building up on the union between the two turbo discharge to IC pipes. Cleaned it up best I could, but there was lots between the rubber and the pipe, don't really know if it was airtight or not.
Also found that Suspension Techinques Sway bar doesn't touch standing still, but must get friendly with the rubber from union to IC. It was missing powdercoat and pipe was missing some rubber (down to cords.)
I'm installing the OEM cat, but I have a question about orientation.
There is a triangle cast in the body, is it an arrow for flow direction? Does it matter on this type of cat?
Thanks guys!
Josh
IC piping yielded some potential problems:
Some type of oxidation building up on the union between the two turbo discharge to IC pipes. Cleaned it up best I could, but there was lots between the rubber and the pipe, don't really know if it was airtight or not.
Also found that Suspension Techinques Sway bar doesn't touch standing still, but must get friendly with the rubber from union to IC. It was missing powdercoat and pipe was missing some rubber (down to cords.)
I'm installing the OEM cat, but I have a question about orientation.
There is a triangle cast in the body, is it an arrow for flow direction? Does it matter on this type of cat?
Thanks guys!
Josh
Found a pic on SM of some dude's whole exhaust, so based it off that.
Seems to me that boost builds a little quicker and drops off a little slower, so maybe there was a little leak.
I'm thinking it's retest time. Will post results good or bad sometime this week!
Thanks and wish me luck!
Seems to me that boost builds a little quicker and drops off a little slower, so maybe there was a little leak.
I'm thinking it's retest time. Will post results good or bad sometime this week!
Thanks and wish me luck!
:burnout: :burnout:
Results are in...
Thanks to all that contributed to getting my Supra back on the road (legally!)
Your input was appreciated and valuable!!!
VIP report only provides measurements when a vehicle fails any portion of the test, so I have no idea what my readings were this time, just that they were below the threshold.
The other thing that irritates me is we don't know for sure what fixed the problem...
For any members that may be facing a similar problem, I will list the things that changed between test #1 and test #2:
Adjusted TPS
Adjusted timing
Ran a bottle of Techron through the fuel system
Soaked pistons with Berryman B-12
Replaced Random Technology 3" cat with 1988 vintage OEM unit
Reinforced damaged rubber IC pipe connecting union and IC *note pipe did not seem to leak, but had been being rubbed by sway bar
Removed oxidation forming between union and rubber IC pipes running between compressor outlet and IC
Results are in...
Thanks to all that contributed to getting my Supra back on the road (legally!)
Your input was appreciated and valuable!!!
VIP report only provides measurements when a vehicle fails any portion of the test, so I have no idea what my readings were this time, just that they were below the threshold.
The other thing that irritates me is we don't know for sure what fixed the problem...
For any members that may be facing a similar problem, I will list the things that changed between test #1 and test #2:
Adjusted TPS
Adjusted timing
Ran a bottle of Techron through the fuel system
Soaked pistons with Berryman B-12
Replaced Random Technology 3" cat with 1988 vintage OEM unit
Reinforced damaged rubber IC pipe connecting union and IC *note pipe did not seem to leak, but had been being rubbed by sway bar
Removed oxidation forming between union and rubber IC pipes running between compressor outlet and IC
Attachments
Glad it all worked out although I don't understand why the NOx and CO are now much higher. Anyway, thanks for letting us know.
While everything you did helped from the evidence you presented the main culprit was a dead cat. Keep the EFI system running right at all times or it'll kill that one too. They aren't cheap you know. The scary part is without an engine out test it's tough to know how much of a beating it's taking even now. The CO results between the fail and pass tests are weird but as I said the IM 240 is new to me.
I've seen the sway bar do that on a few cars. Sometimes it'll rub right through the hose.
While everything you did helped from the evidence you presented the main culprit was a dead cat. Keep the EFI system running right at all times or it'll kill that one too. They aren't cheap you know. The scary part is without an engine out test it's tough to know how much of a beating it's taking even now. The CO results between the fail and pass tests are weird but as I said the IM 240 is new to me.
I've seen the sway bar do that on a few cars. Sometimes it'll rub right through the hose.