While driving, hitting brakes to come to a stop, idle drops, car dies.
 

Hi all,

Currently, my RX-7 is parked because every time I drive it, I have to heel-toe while braking just so that the car won't die. I've had a few discussions with my mechanic friends, and they suggested that it's possibly the brake booster, and that it has a leak.

I'm passing it by you guys, as it's really frustrating to drive in stop & go traffic (espescially here on Oahu...the traffic sucks!) right now. I'm literally worn out by the time I get to wherever I'm going, and it's to the point where I'm having to use my e-brake half the time to slow the car down to a stop. So the car has been parked for the moment.

The idle doesn't seem to drop when it's parked and I press the brakes. Only while driving. I currently have to fix a fuel leak, so I've been unable to do further testing, but I'm taking care of that today, and this is something I'd like to fix at the same time.

Any suggestions? I made sure the line with the check valve was in place, and that's good to go...so I'm not quite sure what the deal is.

Thanks all.

brake master cylinder vacuum leak?

I know the Factory Five Daytone Coupe that I rewired had the same symptoms, and this was the culprit.

is your ac on and the fan set at 2 or above? if so I have the same problem and just leave the ac on low and roll the window down.

I may be misunderstanding your symptoms, but it sounds like a clutch switch problem. Lots of threads on this - search for "clutch switch".

No A/C (that need to be fixed, too...lol!).

Thanks for the suggestions, I will check out the "clutch switch" thing and the brake master cylinder leak.

In the FAQ thread stickied in this forum, scroll down to the D section and follow the link for Dashpot

The dashpot keeps your revs from dropping too low too quickly from cruising speed down to a slow down speed. It is located near the throttle cable assembly in front of the intake manifold. You may need to adjust the dashpot to keep the revs up a little more.

All the other things mentioned above may be your problem as well.

Little update guys...

It was my dashpot for the most part. I still need to change out both the dashpot and my TPS is almost shot (the shell that the connector slips over is cracked and about to fall off).

Once I fixed the fuel leak, and got everything back together...I cranked the dashpot all the way in, and started her up. At first I was scared shitless because the car was idling at 2200RPMs...but it was just the PFC learning, and after about 15 minutes it settled down to idle at around 900.

I got it back on the road, and although the battery is bone dead dry, there was barely a burble, no backfires, and plenty of kick off the line. What's more, the car didn't die when I went to brake. It was pretty surreal...I've been so used to having to heel-toe every time I braked, that I felt really out of place not doing it when coming to a stop.

Great stuff! Hopefully, I can just enjoy the car for a bit now! Whew! Thanks for the help, everyone!

Do you have a PFC? Mine did this because the rmp that the injectors come in at when dropping to idle was too low.

Did'nt read above - Ignore me lol

No biggie. That's an interesting tidbit though. I didn't tune it, a shop owner from Japan did...lol.

any mechanic should know how to test a brake booster,
there are 3 methods.

1) with the car off, pump the brakes until the pedal is stiff,
turn the car on with your foot pushing down on the brakes,
it SHOULD push down smoothly then hit the bottom out point.

2) with the car on, pump your brakes and watch your idle for any ups and downs

3) I forget, and I don't have my book with me to check, lol. sorry.

(like I said, get a buddy who is a mechanic to do a test for you, it takes less than 10 minutes)

Great, thanks for the tip. I'm not a mechanic in real life, but I did stay at a Holiday Inn. :D

cheers man!, best of luck!!!

:lol: :lol: :lol: :lol: :lol: :lol: :lol:

NOW that there is funny... I don't care who you are....

Hey ArchangelX,

Good to hear you fixed your problem, yeah I know how messed up the traffic can be on Oahu, especially with an FD in crawling traffic!

Are you going to the Mazda meet at Pearl City tonight? I friend who developed a new software tuning application for the PFC will be there. I'll bring my FD and another friend is getting his FD tuned today, he'll be at the meet @ 7:30 PM.

Might be a good time to see how it came out and ask more questions.:icon_tup:

i was about to say the check valve in-line with the brake booster. oh well, glad you found the problem