what if another cylinder is running lean. how is the 3rd still the hottest? I guess what I really wanna know is. why not tap above the flange so all the runners are read and not just one?

 

good question. i've always read that the 3rd is the best place to plumb it, but i never thought about your question. anyone know?

 

up

 

#3 Always is slightly leaner. As long as your fuel injectors are all flowing within the same spec etc, spark and everything is the same on all 4. #3 will always be hottest.

 

# 3 is the hottest. Has to do with firing order and it is between two cylinders that....well you get the point...

How do you know if cylinder #1 is running lean when you tap cylinder #3? You don't, unless you do the egt the best way and run one for each cylinder.

Probe for all with the same sensor...That would not do much if one cylinder was lean and another rich, it would balence itself out and in turn still blow up. Like i said the best way to do it is to run one for each cylinder. But like Tchleung said, if they are all working good, they will all read the same, But the real question is, how do you know they are all good for sure if you only probe one cylinder?

 

um. No one answered the question..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boostage &raquo;</TD></TR><TR><TD CLASS="quote">what if another cylinder is running lean. how is the 3rd still the hottest?</TD></TR></TABLE>

Who ever said the #3 cylinder is always hotter than the rest? UNDER NORMAL CONDITIONS ON ALL 4 CYLINDERS...#3 WILL BE THE HOTTEST ONE. Now if #1 is running lean then yes it will become the hotter cylinder. That is obvious.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boostage &raquo;</TD></TR><TR><TD CLASS="quote">I guess what I really wanna know is. why not tap above the flange so all the runners are read and not just one?</TD></TR></TABLE>

You can do this but how are you going to know if #1 cylinder is lean? Maybe #1 is so lean it's ready to melt, but the other 3 are rich enough to make the average reading across all 4 cylinders (where you decided to get your egt readings from) to seam normal. The end result....pooof. I'm not saying anything is wrong with reading from all 4 where they meet but honestly....If you have one egt gauge and only one cylinder has problems, you wont know unless that one cylinder has the egt probe in it. And by monitoring all 4 where they come together, yes it gives you a better overall reading but if one cylinder get lean...r u really going to catch it in time when it is mixing with 3 other perfectly fine cyinders? The temp climb will not be as drastic on you gauge as what the increase in temp really is...other wise know as a false reading. Does that make sence?

When you check tire pressure, do you only check one tire, asuming the other 3 are fine?
what about compression test, #1 seams fine, why check the other 3?
Why should monitoring egt's be any different?

This is my opionion on this and if anyone dissagrees that is fine.

 

what your saying is confusing, becuase on one hand it sounds like your saying. its better to have all 4 cylinders be read at the same time. then you sound lie your saying the opposite. where is yours tapped?

 

Makes the EGT probe seem useless...i'd rather keep a close eye on my wideband display

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turboteg2nv &raquo;</TD></TR><TR><TD CLASS="quote">Makes the EGT probe seem useless...i'd rather keep a close eye on my wideband display </TD></TR></TABLE>

thanks for answering my question..

 

Mine was tapped 3" from the flange on #3 cylinder. I used it to tell me roughly what the exhaust temp would be, and let me tell you i never looked at it. It was a B16a, 75 shot. I no longer have the car.

All i am saying is the way i feel about using an egt gauge is it should be used to monitor all 4 cylinders individually. You could use it either way you were talking about but it won't be nearly as effective as monitoring all 4 seperately.

 

If you have good injectors, or new injectors.. the chances of running lean in cylidners 1, 2, or 4 are alot less then running lean on cylinder 3 I would think. So as I said before, if youre fuel and everythnig is all fine. there's no real need to put it in where they all collect because number will generally always be the leanest. So. if you have it in the collected pipes... and your fuel system is running perfect on all 4 cylidners... and you know #3 is gonig to run hotter, how will you tell how hot it's running? you can't. I jsut think that when you put the pros/cons ona scale. putting it on #3 would be more ideal. If you're just slapping in some injectors you found on the ground coverd in dirt and then you tried to clean them. then maybe it'd be a good idea to put an EGT on all 4 or in the collector lol

 

why does #3 generally run the leanest?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tchleung &raquo;</TD></TR><TR><TD CLASS="quote">If you have good injectors, or new injectors.. the chances of running lean in cylidners 1, 2, or 4 are alot less then running lean on cylinder 3 I would think. So as I said before, if youre fuel and everythnig is all fine. there's no real need to put it in where they all collect because number will generally always be the leanest. So. if you have it in the collected pipes... and your fuel system is running perfect on all 4 cylidners... and you know #3 is gonig to run hotter, how will you tell how hot it's running? you can't. I jsut think that when you put the pros/cons ona scale. putting it on #3 would be more ideal. If you're just slapping in some injectors you found on the ground coverd in dirt and then you tried to clean them. then maybe it'd be a good idea to put an EGT on all 4 or in the collector lol</TD></TR></TABLE>


this is what I was looking for thanks. but now 80884 raised a new question. how long does a wideband last for?

 

up for some info

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adictionbass &raquo;</TD></TR><TR><TD CLASS="quote">why does #3 generally run the leanest?</TD></TR></TABLE>

because it is the hottest... usually the inner 2 cyl.'s run the hottest cause they are surrounded by heated metal on either side from the outer 2 cyl.'s.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boostage &raquo;</TD></TR><TR><TD CLASS="quote">


this is what I was looking for thanks. but now 80884 raised a new question. how long does a wideband last for?
</TD></TR></TABLE>

Huh? a wideband gives you an air/fuel read out. should last forever unless you run leaded gasoline and foul the sensor

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turboteg2nv &raquo;</TD></TR><TR><TD CLASS="quote">

Huh? a wideband gives you an air/fuel read out. should last forever unless you run leaded gasoline and foul the sensor </TD></TR></TABLE>

what I was asking is how long do the probes last.. sorry if I was clear

 

looks like they dont last long http://www.aempower.com/faq.asp?sid=36

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boostage &raquo;</TD></TR><TR><TD CLASS="quote">looks like they dont last long http://www.aempower.com/faq.asp?sid=36</TD></TR></TABLE>

...with leaded fuel.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adictionbass &raquo;</TD></TR><TR><TD CLASS="quote">why does #3 generally run the leanest?</TD></TR></TABLE>

It gets the most direct path of air flow, so it runs leaner than the rest..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM Ninja &raquo;</TD></TR><TR><TD CLASS="quote">

...with leaded fuel. </TD></TR></TABLE>


According to th honda tech archives. even on pump gas it last about 40k miles.. I will stick to my egt. its not like I need more anyway.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boostage &raquo;</TD></TR><TR><TD CLASS="quote">
even on pump gas it last about 40k miles.. .</TD></TR></TABLE>

40,000 Miles is pretty good lfie tiem IMO. and the wideband O2 sensors are not that expensive considering yodon't ahve to repalce them for 40,000.

 

you could always get this http://www.aircraftspruce.com/...t.php (e-4 model) if you want egt's for each cylinder