spdweb.net

I recently installed a stainless header on my car. I noticed after a few hundred miles that the #2 cylinder pipe did not get rain-bowed like the others. This made me wonder so I put an IR thermometer on the pipes and sure enough #2 is about 150 - 200 degrees cooler then the rest.

I checked the plugs, they all look fine, no visible difference on the #2 plug as if it were running rich. I also swapped the #3 and #2 injector with the same result. Engine runs smooth at idle.. no miss on the #2 cylinder. Running a multi spark CD ignition so spark is not the problem.. hence.. no miss fire. Anyone have any theorys?

At idle within 20 seconds of WOT
#1 1248
#2 1101
#3 1246
#4 1243

Archidictus

That's a badass question and awesome research. I wish I could help you out, but you already covered all the bases I would have, so all I can do is bump this very interesting question and hope someone else has a clue.

Tad

hmmm.. wierd.
wouldn't bother me personally..
but whatever.

do a compression test is my advice!

btw, how'd you hook up a thermometer to each individual runner?


Modified by Tad at 5:59 PM 11/30/2004

sleepingEg8

I second the compression test. Low compression=low cylinder pressure= lower temp. check this out for some good reading.


quoted:

"Fundamentals of EGT

The basic ingredients of combustion are fuel, air (oxygen), compression, ignition, and timing. The measurement of exhaust gas temperature (EGT) is really an indication of the harmony of interaction of these ingredients. A slight change in any of these five factors will result in noticeable changes in EGT"

http://www.insightavionics.com/pages/gemguide.html

spooncivic1

bent valve or something?

spdweb.net

Yeah a compression check is next.. though I doubt seriously that's the problem. The engine is running fine and lacks no power so it's more of a curiosity thing. I have never seen anything like it that wasn't easily diagnosed as fuel delivery.

hondainspired

well if they were all staggered like 100-150 apart from each other i could almost see that.. but that number two is really low and its the only one low...

jlacoy82

Whats the internal cooling look like? Anything different around the #2 cylinder than the others?

spdweb.net

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jlacoy82 &raquo;</TD></TR><TR><TD CLASS="quote">Whats the internal cooling look like? Anything different around the #2 cylinder than the others?</TD></TR></TABLE>
Yeah I was looking for a schematic of the internal coolant chambers in the head but I cant seem to find one.. I hardly think that would affect the EGT that much though. I don't know.. I am the type of person that will wrack my brain because its something weird.

Thanks to everyone for all the fast responses BTW.

jlacoy82

I dont know if that could even be a factor, the exhaust gasses are in there for such a short period of time, I really dont see the coolant sucking up 100-200 degrees MORE from one cylinder than another. Try swapping injectors to another cylinder and see if the injector from that cylinder is running "cold"??

Redline96LX

i suggest seafoam?
it could be carbon buildup causing lower exhaust flow.
Check your EGR. check your intake manifold. could be too much exhaust gas recirculation givin it a low temp

MugenHonda

ssautochrome headers
i know a lot of people hate this header, but when i had a 4-1 on my mpfi swapped ef it made a difference in the top end
you could automatically feel it after the change
bump for cheap headers that make a difference

dirtyturtle

could be an early warning of the headgasket going...
also try moving the injectors around a bit.. see if ones not working at par...

ABK

it could be so much **** that you don't want to even get into it. The easiest way to really determine what COULD be the problem with it is to throw it on the ignition scope. But it could be anything from to small of the gap on the spark plug (bad spark plug wire), to a carbon deposits in other cylinders. I don't even wonna get into it.

I would just do a leakdown and compression test. Maybe hook up a scope to it if you got access to it. And the difference is not that huge anyways. I wouldn't worry about it.

How did you take the measurments anyways.

DohcSide

just wondering is the header screwed in all the way? or anything like that?

spdweb.net

Bump for compression check results.
Got some uneven results in this for sure though it still doesn't explain why the #2 is running cooler. Checked the temp with an inferred thermometer for those who ask.

D16y7 96,000 miles

#1 - 200
#2 - 195
#3 - 159
#4 - 175

Not low compression though it is quite uneven.. should be around 185 for this motor. It's in the valves though.. a shot of oil in each cyl. and they only come up 5 psi. each.

BLA.. Work work.. its always something. Might be the perfect time for a y8 head swap.

FizzGiGG

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by spdweb.net &raquo;</TD></TR><TR><TD CLASS="quote">Might be the perfect time for a y8 head swap. </TD></TR></TABLE>

Or a Z6 head swap, better high RPM flow.

spdweb.net

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

Or a Z6 head swap, better high RPM flow.</TD></TR></TABLE>

Yeah.. I am already running a Z6 intake mani on it. BLA.. I should have never ran the compression test!! Now it's bothering me UGH. No signs of a bad head gasket either, water or oil. Ran some seafoam through it with the same results.. thought it might knock out some carbon and take down the high numbers but the engine is squeeky clean.

FizzGiGG

I've heard rumor around the net about the SSAutochrome headers being major piles of doo doo. They do look nice, but crack easily.

I'm wondering if you have some kind of defect in the header gasket surface, maybe it's not getting the same amount of seating pressure as the other runners.

Get yerself a new kasket and pop that thing off so you can run a straight edge on it.

Just a suggestion though.

BTW - Do you accept IM's? I tried but you haven't responded.

RCautoworks

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by allmotorbret &raquo;</TD></TR><TR><TD CLASS="quote">could be an early warning of the headgasket going...
</TD></TR></TABLE>

How so ? Unless coolant is entering inside the chamber but I think you would notice white smoke

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Redline96LX &raquo;</TD></TR><TR><TD CLASS="quote">i suggest seafoam?
</TD></TR></TABLE>

Why not just spray some water in the tb ? Its safer then seafoam.

Anyways try switching the spark plugs and wires see if that makes a difference, then try switching injectors around. I know you said there was no misfire but you could have a weak spark.