Emissions help, idle test
- Thread starter The Dread Pirate Fisher
- Start date
Audio Man
New member
Re: Emissions help, idle test
To be perfectly honest, I drove up there, they looked at the vehicle and saw what was on it and replaced it. I didn't go looking for some performance, high flow, special blah blah blah converter. Just put back what was there essentially. Did that with both my trucks. Both my trucks passed. The thing is, I could have gone out and looked for a high flow Random Technologies converter or something but then what happens when I don't pass emissions again because it doesn't filter enough or something. Yea, I may have made it faster...maybe... but I couldn't have driven it because it won't pass still. What would be the point of doing that?
Most high flow cats it seems like were made for vehicles that don't have to pass the sniffer in the tail pipe. They are more there for newer OBDII vehicles that just have to not have a check engine light on so they can get away with it, especially with a tune. That's one of many reasons I just had them put back what was there. It worked.
It seems like everyone in their quest for more power...as we as gear heads do admittedly....we neglect the obvious thing that the truck was already quick and used to pass emissions when new and we tinker with stuff and tinker with stuff and then are confused when it either A is slower then it was before or B won't pass emissions, etc.
Just a thought..
To be perfectly honest, I drove up there, they looked at the vehicle and saw what was on it and replaced it. I didn't go looking for some performance, high flow, special blah blah blah converter. Just put back what was there essentially. Did that with both my trucks. Both my trucks passed. The thing is, I could have gone out and looked for a high flow Random Technologies converter or something but then what happens when I don't pass emissions again because it doesn't filter enough or something. Yea, I may have made it faster...maybe... but I couldn't have driven it because it won't pass still. What would be the point of doing that?
Most high flow cats it seems like were made for vehicles that don't have to pass the sniffer in the tail pipe. They are more there for newer OBDII vehicles that just have to not have a check engine light on so they can get away with it, especially with a tune. That's one of many reasons I just had them put back what was there. It worked.
It seems like everyone in their quest for more power...as we as gear heads do admittedly....we neglect the obvious thing that the truck was already quick and used to pass emissions when new and we tinker with stuff and tinker with stuff and then are confused when it either A is slower then it was before or B won't pass emissions, etc.
Just a thought..
It's just a six
Super Member
Re: Emissions help, idle test
I know, I was suggesting to use a smaller ID pipe, this way it will heat up faster & burn more of the unburned fuel.
Not suggesting for performance, just for passing smog.
When you use a larger cat, like say a 3" it will run cooler, most likely have a low CPI count & not burn the unburned fuel that well = not good for passing a smog test....:2cents:
I know, I was suggesting to use a smaller ID pipe, this way it will heat up faster & burn more of the unburned fuel.
Not suggesting for performance, just for passing smog.
When you use a larger cat, like say a 3" it will run cooler, most likely have a low CPI count & not burn the unburned fuel that well = not good for passing a smog test....:2cents:
The Dread Pirate Fisher
Donating Member
Re: Emissions help, idle test
Update:
So I pretty much went through the top end. Changed the vacuum lines, changed intake manifold gaskets( these were very poor)
, upper plenum gasket, all the throttle body gaskets, got the correct PCV's, changed the O2 sensor, put in stock injectors and rebuilt them, went back to a mechanical fan, built my own 2.5" mandrel down pipe, 3" transition to 3" magnaflow CAT, to 3" magnaflow muffler. Installed an AEM wideband.
Then I checked the timing, It was advanced 6* the distributed bolt was not very tight either. Set the timing back to 0. Idled perfect on first started up, no stalling when changing gears.
When in park, my best vacuum reading is 16-18. When driving and I left off the gas I can get 20. When in drive at idle it's 16-15. Fuel pressure 42.5 vacuum off.
Took it for its emissions, passed easily on idle and 2500rpm.
Update:
So I pretty much went through the top end. Changed the vacuum lines, changed intake manifold gaskets( these were very poor)
, upper plenum gasket, all the throttle body gaskets, got the correct PCV's, changed the O2 sensor, put in stock injectors and rebuilt them, went back to a mechanical fan, built my own 2.5" mandrel down pipe, 3" transition to 3" magnaflow CAT, to 3" magnaflow muffler. Installed an AEM wideband.
Then I checked the timing, It was advanced 6* the distributed bolt was not very tight either. Set the timing back to 0. Idled perfect on first started up, no stalling when changing gears.
When in park, my best vacuum reading is 16-18. When driving and I left off the gas I can get 20. When in drive at idle it's 16-15. Fuel pressure 42.5 vacuum off.
Took it for its emissions, passed easily on idle and 2500rpm.
It's just a six
Super Member
Re: Emissions help, idle test
That's cool, what were your A/F ratios @ idle & at 2500 RPM?
That's cool, what were your A/F ratios @ idle & at 2500 RPM?
ZavzTy547
Senior Member
Re: Emissions help, idle test
Here's an old school trick to pass emissions that worked for me. . . .
If you have an adjustable fuel pressure regulator, turn it down to about 25-30, this will lean the truck out at idle.
If the idle starts to miss or fluctuate or check engine light turns on, turn the FP up a little until the idle is steady and no check engine light is present. . .
You want to also keep an eye on the water temps, because leaning out your truck will raise the temps and the truck will overheat.
Of course, you will only do this right before you enter the booth - when your done, let the truck cool down, and turn the FP back to normal.
GZ
Here's an old school trick to pass emissions that worked for me. . . .
If you have an adjustable fuel pressure regulator, turn it down to about 25-30, this will lean the truck out at idle.
If the idle starts to miss or fluctuate or check engine light turns on, turn the FP up a little until the idle is steady and no check engine light is present. . .
You want to also keep an eye on the water temps, because leaning out your truck will raise the temps and the truck will overheat.
Of course, you will only do this right before you enter the booth - when your done, let the truck cool down, and turn the FP back to normal.
GZ
It's just a six
Super Member
Re: Emissions help, idle test
Thanks but the best thing that worked for me was to unplug the brown wire w/blue stripe .
(The timing wire)
I use code 59 now & have already made a chip for passing smog.
No more of the BS I had to go through just to pass a smog test.
Thanks but the best thing that worked for me was to unplug the brown wire w/blue stripe .
(The timing wire)
I use code 59 now & have already made a chip for passing smog.
No more of the BS I had to go through just to pass a smog test.
Last edited:
jaystcb
Sy 0902, 92Ty 0909
Re: Emissions help, idle test
DaveP was telling me about how to smog test a SyTy. There is a 2-stage Smog Test that most smog stations overlook on our vehicles. To pass at idle. You have to pre heat the cat at 2500rpm for 300 seconds or something like that. Maybe he will chime in on this post. I cant remember where he said he got the info from. But its DaveP
I would like a copy of it to shove down my SMOG guy throat.
DaveP was telling me about how to smog test a SyTy. There is a 2-stage Smog Test that most smog stations overlook on our vehicles. To pass at idle. You have to pre heat the cat at 2500rpm for 300 seconds or something like that. Maybe he will chime in on this post. I cant remember where he said he got the info from. But its DaveP
I would like a copy of it to shove down my SMOG guy throat.
syclone809
Member
Re: Emissions help, idle test
It should be common knowledge for the smog technician once you tell them it's awd, since most places have 2wd machines. The smog place I go, he charges $45-50, he will precheck the rpms before he charges you, that way you don't waste your money, and can put it towards the repairs to get it running right. He does the sniffer and gas cap test too.
DaveP was telling me about how to smog test a SyTy. There is a 2-stage Smog Test that most smog stations overlook on our vehicles. To pass at idle. You have to pre heat the cat at 2500rpm for 300 seconds or something like that. Maybe he will chime in on this post. I cant remember where he said he got the info from. But its DaveP
I would like a copy of it to shove down my SMOG guy throat.
It should be common knowledge for the smog technician once you tell them it's awd, since most places have 2wd machines. The smog place I go, he charges $45-50, he will precheck the rpms before he charges you, that way you don't waste your money, and can put it towards the repairs to get it running right. He does the sniffer and gas cap test too.