possible locations for a vacuum leak?
 

Hey guys,

Here's my scenario. Monday morning did my regular commute to work. When I got off the highway the car started idling roughly with the clutch pushed in cruising up to a stop light. When stopped idles fine, when under load idles fine, when I have the clutched pushed in in gear or with the stick in neutral the tach starts jumping up and down when it drops under 1k Rpms.

I have a ram air intake, cat less mid pipe, HKS legamax exhaust, SR pulleys.
I have taken out the MAF and cleaned it and the temp sensor with CRC maf sensor cleaner. I took the cone off the intake and blew compressed air through it from the inside out. I have re-set the ecu to try and get it to learn new fueling (the high temps here have gone from high 80's to mid 60's in about a day!) Still does it! I have ordered an OEM intake from Maz Mart should be here by friday.

I have checked all the hoses attached to the TB and the accordion in front of that. What other locations should I check for a vacuum leak? I had the PCM read and was showing a code "System running lean." Oh ya and it only does it when the car warms up all the way (I'm guessing because the idle doesn't dip below 1000 until it warms up all the way?)

Any other ideas/suggestions?
Thanks in advance guys

So...........I can't really tell from your post, but do you have an aftermarket intake itself and/or have removed the VFAD? If so, then you should have a cap on the vacuum port(if you will)on the lower part of the throttle body. I'll see if I can find a pick, but sometimes those caps will get loose or cracked. Just a guess........I'll see if I can find a pic of where it is.



https://www.rx8club.com/attachment.p...1&d=1239247531

Vacuum system diagram.
Jon316G has some good posts about troubleshooting the solenoids, check valves etc.
https://www.rx8club.com/attachment.p...1&d=1274140084

Thanks for the reply guys. Vfad is still attached. Can I cap all those lines one at a time in dark brews picture for testing? SSV only kicks open at higher rpm as well as vfad, what about the VDI? If the VDI only kicks on at high rpm could I just cap those lines one at a time at the TB or will the Pcm freak out?

Thanks again guys and DB that picture is clutch!

The one you should leave active is the system that leads to the air pump until the engine is warm.
After that you can cap any of them for your idle test and make no diff to the other valves.
Basically you have only two places on the UIM to cap for your test; One to VFAD and one to the solenoids. Both are easy to find because they have one way check valves for the vacuum accumulators.
BTW, VFAD is always on vacuum until high RPM where it shuts off.... and the VFAD opens

There is also a purge valve on the UIM near the TB

A vacuum hand pump is a great tool as well.

The pic was colorized by Jon316G I believe.

Update: Cleaned the filter thoroughly and pulled the accordion( what is the actual part name?) and intake. Cleaned all the parts and inspected for cracks, then reinstalled everything. Started the car up and it idled like crap, and the CEL lit up. Took a cruise to pep boys for vac caps and they didn't have any WTF? When I got back in my car and started it again the light was still on, but it ran like a charm? Idles with the clutch pushed in never dipped below 1000.

Called the local rotary specialist to take my car in have the code read and compression tested. When I got in the car to go over there the CEL was not on and the car ran great?

Maybe Cleaning the filter again did the trick? Or maybe it's just temporarily fixed?

The tech read my code and said it was the same "system running lean" code we got on monday. He cleared it to see if the second airfilter cleaning did the trick. Went ahead and got my compression tested since I was already there and it was super low he said.

between 5.1 - 5.7 on all faces of both rotors at 258 and 273 rpms, so I guess I'll be looking for some more OEM parts and take the beast into the dealership.

Thanks for the help guys!

You could try a seafoam treatment to see if carbon is responsible for your low compression.
There's a DIY on the forum and several posts about performing this procedure.

Thanks Dark, I ordered some Mazda zoom-zoom cleaner with my oem intake should be here today actually! Hopefully that gets the compression up.

neutral position switch.

but what do i know. :)

you dont mention miles.

beers :beer:

update: Car is idling well. Zoom-Zoom cleaner produced a lot of smoke (at least 5 people in the industrial complex where I work looked down the building to make sure it wasn't on fire! hahahah), but no noticeable power difference :( Engine response feels the same at 50% and 100% in 4th 5th and 6th gear. Almost 0 acceleration in 6th. 1-3 still accelerate well.

60k swoope, 2004, august 03 build date

checked neutral switch after your post and followed the post I think made by jon 316 about testing neutral and reverse.

if you push the clutch in an the idle problem goes away. it is the neu pos switch..

beers :beer:

Hey I got a similar problem. Last Saturday I'm pulling out of the parking lot and as I start to depress the clutch my foot slips off it after about an inch or so. The peddle flipped back (not that hard) and I heard a snap sound. After that I noticed that whenever I'm stopped and I depress clutch and then shift into gear, the idle starts to jump over and over again. It's different from Tampa1stRotor because the idle only jumps once I've shifted into gear, not just when clutch is depressed.

Think it's the neutral switch too?

What about the two nipples on the exhaust side of the engine one of mine fell off after doing a de-carb and was giving me a vaccum leak code

Got an update to my problem. Tonight got a CEL. Whipped out the code reader and it said I got a P0704 - Clutch switch input ckt malfunction. I checked the clutch switch and sure enough it seems like it broke. The poky thing doesn't come out anymore. So I'll have to replace it.