I am under the impression that... When you pump the brakes rapidly your RPM's should gradually go up 300 to 700 RPM's and slowly drop back down to normal. Well this is the impression I got from searching and from my mechanic. Also, in my girlfriends GS-R, when you pump the brakes the RPM's will go up a little and then come back to normal, nice and smooth. So here is my problem...

When I pump the brakes rapidly the RPM's climb to about 1500 then drop very rapidly all the way to basically zero, however the car doesn't die. If you continue pumping the breaks the idle will climb to 1500 RPM's and drop to zero over and over, until you stop pumping the breaks. I thought that this was a brake boster related vacuum leak, however I changed my brake booster and brake master and it didn't this problem. Now I think it's just a general vacuum leak, am I correct? And why wouldn't replacing the booster and master fix this problem?

Another reason I believe it's a vacuum leak is because sometimes my idle will surge. Most of the time it will sit at a constant 700 RPM's but when it surges (mostly when really hot or cold) it will basically drop to zero then come back up to 700 then back to zero and so on. I have read through everything trying to figure this out with no avail.

Help would be greatly appreciated!

 

you should have a check valve on the line running to the booster. valve cold be missing or bad, depending on modifications, if not, could be a defective seal in the booster

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">you should have a check valve on the line running to the booster. valve cold be missing or bad, depending on modifications, if not, could be a defective seal in the booster</TD></TR></TABLE>

I replaced the booster and brake master two weeks ago. Didn't solve the problem.

Do you have a picture of what the check valve looks like? It's probably there, I just don't know where to look.

More help would be greatly appreciated.

 

its just a little round thingy spliced into the booster hose, should be the only break in the line going to the booster

 

Thanks. BUMP

What does it mean that my idle climbs then rapidly dies when I pump the breaks? That isn't natural, what does this suggest? Vacuum leaking right? I believe that this is the root of my problem. I could care less about the runability right now.

 

BUMP for Answers

 

BUMP

 

the booster uses vacuum to increase apply pressure, once you open the booster a certain amount air pressure is allowed in. if your check valve is inoperable or missing, that air makes its way to the manifold, decreasing vacuum, raising RPM just like a vacuum leak.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by techer &raquo;</TD></TR><TR><TD CLASS="quote">... decreasing vacuum, raising RPM just like a vacuum leak.</TD></TR></TABLE>It's supposed to do that. That's why it raises idle a couple hundred.

But if the pedal pushrod is adjusted wrong, or the hydraulic system has air in it, it'll let in a lot more air than normal.

 

The check valve works correctly, however when I removed it, and blew threw it, there was a small amount of water inside the valve. What does the mean?

And the entire brake system has been bled and the push rod is adjusted properly.

More help will be greatly appreciated.

 

BUMP for some much needed help.

 

BUMP for some much needed answers, come on guys

 

Maybe this will help, I know you Tech peeps can help me out...



Why does my idle drop when I pump the brakes? Could it be the IAC valve? Where the hell is it, do H22 not have a idle air control valve?

 

Try tightening your fast idle valve located underneath the TB, try tightning the idle screw on top of the TB and cleaning the IACV with carb cleaner or brake cleaner.

 

BUMP cause I still need some help.

 

Where the hell is the IACV? Look at the diagram, I don't believe that I have one.

 

BUMPage

 

Pumping breaks... idle drop???

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">if you pump your brakes, and your idle goes up and drop and so on, it is working properly.</TD></TR></TABLE>

How do you figure? I have pumped the breaks on a few Civics and Integra recently, just to see how they react as compared to my car. NONE of them act the same as my car, basically when you pump the breaks on every Honda but mine, the idle will slowly rise to about 1500 RPMs and HOLD THERE until you stop pumping. Then when you stop pumping, it will SLOWLY fall back down to 700-800. When I pump the breaks my idle will rise to about 1500 RPMs and then immediately DROP like a rock to 0, then back up to 1500 RPMs then DROP like a rock back to zero, OVER AND OVER. This process will continue until I stop pumping the breaks. This cannot be right, what could be happening???

Where is the Idle Air Control Valve (IACV) on the H22? If you could, I would really appreciate it if you scanned the Helms page for me. PLEASE

 

Well I took of the brake booster check valve off today and blew out a small amount of water that was sitting inside. I was just checking if it was working properly too. Now my idle only drops to the proper idle level (700 RPMs) so I am not worried anymore. What a wierd problem.

I fixed the sporatic idle at hot temps too, it was a small coolant leak in my upper radiator hose that I couldn't see. The clamp wasn't quite tight enough. Damn, H22's are sensitive as hell to coolant issues. So everything seems to be resolved.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slim9300 &raquo;</TD></TR><TR><TD CLASS="quote">


Where is the Idle Air Control Valve (IACV) on the H22? If you could, I would really appreciate it if you scanned the Helms page for me. PLEASE </TD></TR></TABLE>

its right under the tb.