I'm working on a 89 CRX si for a friend. This car is a future HC race car. We are slowly modifying it as he does HPDE's and gets his skills up to HC levels.

The problem I noticed what when we dynoed the car I noticed that cylinder #3 at the header was 40-60deg F hotter than the others .. it seemed the average temp was 260.. #3 was at 300+. If I'm correct this indicate that cylinder # 3 is running lean. I can't seem to figure out why tho.

This motor has 121K miles. Brand new cap and rotor. Injectors have been cleaned and balanced. Very recent valve adjustment.

Any idea's? anyone else run into this problem?

here is a pic, you can see the difference in the color of the header

 

maybe the injector is bad?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by d16rice &raquo;</TD></TR><TR><TD CLASS="quote">maybe the injector is bad?</TD></TR></TABLE>

If the injector is bad the cylinder would usually run cooler and when you hit it with an IR gun you'd see that that cylinder is dead. #3 is usually the cylinder that will run the hotest.
Mike

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by d16rice &raquo;</TD></TR><TR><TD CLASS="quote">maybe the injector is bad?</TD></TR></TABLE>

I had moved #2 and #3 injector and re-tested. The problem did not move. I then sent the injectors out to have them cleaned and balanced (sent to RC engineering). I'm confident that is not the problem..

I'm leaning towards a bad valve adjustment. I'm going to do a compression check later this week..

 

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

If the injector is bad the cylinder would usually run cooler and when you hit it with an IR gun you'd see that that cylinder is dead. #3 is usually the cylinder that will run the hotest.
Mike</TD></TR></TABLE>

Is this common on a D block only? my B18 has pretty even temps...