So I was driving down the expressway just now, hit about 7500 rpm, and then pulled onto a side street. I noticed that when I pushed in the clutch, the revs would slowly rise up to about 2200. They never went above about 1500 before. Anytime the clutch was in or the car was in neutral, the revs would rise up like the AWS was engaged. A blip of the throttle would send the revs up and then they'd drop to about 1400, and rise right back up again. The car still pulled just as strong as ever, just now it wanted to rev to 2200 in neutral. I was thinking the AWS was acting up, or maybe I popped off a vacuum hose? Any ideas? Also, after shutting the car off and starting it again, revs went 1300, up to 1500, 1300, 1500, 1300, etc, fluctuating between the two.

 

im not sure but right now my car is doing the opposite. When the clutch is in, the rpm drops like crazy. and once I was going somewhere and the car just shut off while I was stopped on the red light. Im thinking the problem might be the vaccum holes or I might just need a rebuilt. I have to take it to the shop and get it checked up.

 

I'm guessing that it is a vacuum leak.

-Max

 

How weird, mine started doing the exact thing last night. Anyone help? At 2200-2300 in neutral and idle. When I gas it the rpms act naturally.

 

I hate to be redundant but,



Start looking for vacuum lines that have popped off

 

Where can I find most of the vacuum lines? Is there a thread that explains it?

 

Found it! I got lucky, it was right on the top on that little black box. (See first pic) However, after putting it back on, the car still had the same problem. I took another look, and realized that it had also split at the bottom of the hose as well as coming off the top. (Dead center 2nd pic) Is there somewhere (Mazda dealer?) that I can get a single replacement, or do I have to buy the whole kit from rx7store?

 

It's just a hose.. goto autozone and buy some. Or if you want to be fancy buy silicone hose.

 

Way to go! Don't you love easy fixes like that.

 

Damnit! While taking the ripped piece of the hose off of the lower nipple so I could go to Autozone and replace it, I noticed there was another vacuum nipple next to it that was also empty! I can't find where it goes either... does anyone know? It's the one in the center of this pic, kinda hard to see.

 

That nippe is only used on automatic tranny cars. It's unused and left empty on manuals. Just replace the broken one, and you should be good to go.

-Rob

 

Haha that's a relief. Thanks man.

 

those look like the original hoses!

i bet they are all going south and you will be cracking plenty

 

Haha yeah I probably did, I just replaced the broken one, but the problem didn't go away. The turbos both still work fine, seems to make full boost, it just has a funny idle. The weird thing is, the idle is affected by what's running on the car. With everything off, the idle is at 1600, and blips to 1700 about every two seconds. With the A/C on, it blips about once a second. With the lights switched to running lights or headlights, the idle rises to 2500 and stays steady. I think I'm gonna have to take it to Rick's Rotary lol.

 

Check your butterfly valves in your intake manifold to make sure they are not
getting stuck open. if they are just give them a cleaning and send her on the
way.

JP

 

it sounds like you should do a complete vaccum hose job and replace all the check valves. those look like the original hoses, and if they're starting to crack on you, they're all going to end up cracking sooner or later. it's not that expensive, just lots of labor.

 

Only take on the project if you are very patient and experienced though. It is a huge job and it does take a lot of skill to do it smoothly. It sounds like you have a vacuum leak somewhere.

 

Ok, I guess I'll buy the hose kit from rx7store.net, but where can I find check valves?

 

Here's the link for Dale Clarks Check valves


| VITON check valves, $20 for 4!

 

Talked to Rick on the phone today, he says it may be a piece of the OEM intake manifold gasket causing an air leak. Gonna take it in Friday, have it checked out, I'll update then.

 

Yeah Dale Clark is a great guy and the valves work great. They need a little modification though if you're using them with a stock hose. Let me know and I'll point ya in the right direction for some parts that will make it a direct fit for the stock hose

 

I have got the exact same problem on my car. It started yesterday! I'm scare to drive it until I fix it. Please keep us posted on what was the problem....Thanks.

 

Mine just did it that one time, hasn't done it since. Didn't see any bad/disconnected hoses. Guess it was a fluke.

 

Well, took it to Rick's Rotary Performance, diagnosis: piece of the intake manifold gasket ripped off, I now have a vacuum leak. Front rotor is running lean, and gas and air are escaping... Estimate: $1250, turbos and rats nest have to be removed. Can't afford it right now, should I just save for a while and do a rebuild?

 

holy crap. Ricks Rotary charges 1250 for replacement of the LIM gasket? Damn, I'm in the wrong business....

A bad LIM gasket does make sense based on your symptoms. The rats nest does not need to be removed for this job, but the turbos do. If you are somewhat mechanically inclined, you can do the work yourself. It's kind of time consuming, and will have you swearing every once in a while, but it's definitely doable. Would probably take just a couple of weekends of your time, and a few hundred bucks worth of parts (The gasket and any other odds and ends you may break during the process).