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Old 01-15-2011, 07:37 AM   #743
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Originally Posted by zebra View Post
i have trouble believing this car would be in closed loop withing 1 minute of a cold start when it's 20* outside
Damn, you guys made me drag out all my notes and books from my classes I took

When a car is started, the computer is in open loop until certain criteria is met. The o2 sensors need to be heated to work properly, so this is the main reason there is a delay.

After the sensors are heated up, the car goes into closed loop and the O2 sensors make their corrections.

The computer will go back into open loop under a variety of conditions. Throttle Position (TP) is one way.

There are parameters in the computer that determine what the TP is for Open Loop, and other things.

When that TP is reached, and the car goes open loop, and richens up.


In closed loop fueling, the computer takes readings from the oxygen sensors which read +/- of 14.64 AFR (Stoich) and makes corrections for it. If your car is idling @ 13.5 AFR, the 02s can see this, and will know to pull out enough fuel to get back to stoich.

In open loop, the fueling is purely based off the MAF transfer function and the open loop fuel table. This table has to be calibrated any time you make MAF changes, and changes that affect the airflow of the MAF.

With that being said.....as long as the 02 sensors are warm, he's in the loop..given the fact they are heated, it's likely the car is in fact in closed loop.
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Old 01-15-2011, 07:50 AM   #744
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But he is running CAT Less. The sensors are not reading anything.
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Old 01-15-2011, 08:06 AM   #745
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But he is running CAT Less. The sensors are not reading anything.

That is incorrect....there are 2 sets of 02 sensors on the car, one set before the cats ( which will be in the collector of the header ) and one post cat ( in the cat or the off road pipe ).

The rear 02 sensor are disabled in the PCM so they don't throw codes...the front 2 are still sending info the PCM to determine A/F ratio.
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Old 01-15-2011, 09:08 AM   #746
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He told me he did not hook anything to the headers. Made it sound like the cables and sensors are just tied up on his car in a loop.
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Old 01-15-2011, 09:12 AM   #747
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He told me he did not hook anything to the headers. Made it sound like the cables and sensors are just tied up on his car in a loop.
He would have to have the collector 02 sensors or his car would be even more screwed up than it is now.
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Old 01-15-2011, 09:12 AM   #748
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Make Peace with Ted. Order CNC VMAX from Ted since Chris just bought one and buy a tune from Ted and be done with it. Ted could probably have you running today if you would listen to me. 300.00 from Ted and your tranny will be freaking tuned also. You should really quit being so pig headed at times.

Shit did i really just type that?
Sometimes when you buy stuff from ted, he will give you a free tune!!!!! Maybe give him a call and see what he has to get you going......kinda like buying a tune and getting a free toy!
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Old 01-15-2011, 09:21 AM   #749
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Before running much more, I'd check the oil. Make sure the oil doesn't smell like gas. Just to make sure it's not way overfueling and washing down the cylinders. You can get a rough idea if the stall is from rich or lean by blipping the throttle while its starting to die. If it chugs, revs real slow, and puffs out dark smoke.... way too rich. If it stumbles, hesitates, pops, revs quick, no dark smoke, no gas odor, then way too lean.

A few more run times (as long as it's not flooding the oil with gas) should be enough to set a code. If the oil is good, I'd give it a few more warm up runs, check the data and codes. If it's not setting codes, maybe it is just the tune. But normally it takes quite a significant mechanical change to a motor such as a big cam to not even be able to stay running on the stock tune. Fuel pressure should be fine if it idles good in open loop.

The O2 readings, short term fuel trim, when the problem is happening should tell the story.
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Old 01-15-2011, 09:52 AM   #750
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Quote:
Originally Posted by Scott@Bjorn3D View Post
He told me he did not hook anything to the headers. Made it sound like the cables and sensors are just tied up on his car in a loop.
If that's the case....he's got some serious issues on his hands.
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Old 01-15-2011, 10:12 AM   #751
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Quote:
Originally Posted by Scott@Bjorn3D View Post
Make Peace with Ted. Order CNC VMAX from Ted since Chris just bought one and buy a tune from Ted and be done with it. Ted could probably have you running today if you would listen to me. 300.00 from Ted and your tranny will be freaking tuned also. You should really quit being so pig headed at times.

Shit did i really just type that?
I don't need a VMAX. And no mail order tune will ever get the max efficiency as a dyno tune. It's not Ted. There is no need to 'make peace'. It's not Ted himself that makes me not buy a tune. It's just that I don't believe he can do what I need.

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I would tend to agree. Do what's needed to get a tune from somebody as reputable as Janetty. Then after your other mods ( don't worry, there'll be more!!!) you can send him your logs, and he can adjust accordingly.
I don't like sendign stuff and not knowing when I'm gonna get taken care of. The thought of sendign an emial, waiting to hear back, sending another, waiting again, to get 'close' to a good tune is not appealing at all. I don't even know how to do the data logs.

Quote:
Originally Posted by Scott@Bjorn3D View Post
He told me he did not hook anything to the headers. Made it sound like the cables and sensors are just tied up on his car in a loop.
You got me mixed up with someone else.

All of my sensors are plugged in.

Quote:
Originally Posted by Huggerorange73 View Post
That is incorrect....there are 2 sets of 02 sensors on the car, one set before the cats ( which will be in the collector of the header ) and one post cat ( in the cat or the off road pipe ).

The rear 02 sensor are disabled in the PCM so they don't throw codes...the front 2 are still sending info the PCM to determine A/F ratio.
I totaly forgot about that. So it could explain too why even the stock tune is messing up.

Quote:
Originally Posted by Russell James View Post
Before running much more, I'd check the oil. Make sure the oil doesn't smell like gas. Just to make sure it's not way overfueling and washing down the cylinders. You can get a rough idea if the stall is from rich or lean by blipping the throttle while its starting to die. If it chugs, revs real slow, and puffs out dark smoke.... way too rich. If it stumbles, hesitates, pops, revs quick, no dark smoke, no gas odor, then way too lean.

A few more run times (as long as it's not flooding the oil with gas) should be enough to set a code. If the oil is good, I'd give it a few more warm up runs, check the data and codes. If it's not setting codes, maybe it is just the tune. But normally it takes quite a significant mechanical change to a motor such as a big cam to not even be able to stay running on the stock tune. Fuel pressure should be fine if it idles good in open loop.

The O2 readings, short term fuel trim, when the problem is happening should tell the story.


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Originally Posted by Huggerorange73 View Post
If that's the case....he's got some serious issues on his hands.
Everythings plugged in.
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Old 01-15-2011, 11:24 AM   #752
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One quick check you can do to make sure all the pcv stuff is hooked up right... While it is idling relatively stable, take the oil cap off real quick. The engine should falter slightly and a small drop in rpm. Stick it back on and it should stabilize. It is very slight but noticeable. If there is absolutely no change when popping the oil cap on and off at idle, something in the PCV is not right or vacuum leak somewhere.
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Old 01-15-2011, 11:30 AM   #753
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Quote:
Originally Posted by Russell James View Post
One quick check you can do to make sure all the pcv stuff is hooked up right... While it is idling relatively stable, take the oil cap off real quick. The engine should falter slightly and a small drop in rpm. Stick it back on and it should stabilize. It is very slight but noticeable. If there is absolutely no change when popping the oil cap on and off at idle, something in the PCV is not right or vacuum leak somewhere.
I'll try it.
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Old 01-15-2011, 11:42 AM   #754
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Originally Posted by Huggerorange73 View Post
My guess is it's coming into closed loop at that point...at that time, it's taking info from all the sensors to make it's call on fuel & spark.
Quote:
Originally Posted by Huggerorange73 View Post
When a car is started, the computer is in open loop until certain criteria is met. The o2 sensors need to be heated to work properly, so this is the main reason there is a delay.

After the sensors are heated up, the car goes into closed loop and the O2 sensors make their corrections.

The computer will go back into open loop under a variety of conditions. Throttle Position (TP) is one way.

There are parameters in the computer that determine what the TP is for Open Loop, and other things.

When that TP is reached, and the car goes open loop, and richens up.


In closed loop fueling, the computer takes readings from the oxygen sensors which read +/- of 14.64 AFR (Stoich) and makes corrections for it. If your car is idling @ 13.5 AFR, the 02s can see this, and will know to pull out enough fuel to get back to stoich.

In open loop, the fueling is purely based off the MAF transfer function and the open loop fuel table. This table has to be calibrated any time you make MAF changes, and changes that affect the airflow of the MAF.

With that being said.....as long as the 02 sensors are warm, he's in the loop..given the fact they are heated, it's likely the car is in fact in closed loop.


I believe if left at idle the time is an 88 sec delay which coincides w/ shutdown in the video...
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Old 01-15-2011, 08:12 PM   #755
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Mighty quiet in here. I can hear crickets.
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Old 01-15-2011, 08:15 PM   #756
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Mighty quiet in here. I can hear crickets.
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