Hey guys, I pulled off the manifolds & cleaned 5th/6th ports. While in there I replaced all vac lines. Starts fine, wont idle. Fairly smooth as long as I keep gas on it (not as smooth as before I decided to fix it). Far as I can tell all plugs and vac nipples accounted for. If I had swapped vac lines somewhere, would that cause this?
I'm thinking vacuum leak, thought I'd run it past you all. Any place in particular I should look?

 

Isn't there some kind of "Vacuum Resistor Pill" thing for the altitude sensor? Did you keep the old lines? You might find it & transplant it? of course that's just off the top of my warped head... :P

 

That is in the power booster hose, and i think thats only turbo models(?)

Did you use NEW gaskets on all the intake pieces? If not, you may as well start disassembly again.

 

Yes, new upper and lower intake gaskets. If it was a small leak I'd assume it would idle roughly, this one fires up at 3k like normal, when it drops it drops to zero.

 

Are you sure the AFM has a good connection, as well as the injectors (primarily the primaries and wired properly too). And a large vacuum leak would indeed cause the engine to cut out.

 

I didnt unplug the AFM, guess I could clean the connector. I did pull out the secondary injectors..should the grommets be very easy to remove? They seemed to be just sitting in there..not tight at all. Didn't touch the primaries.

Thanks for the suggestions!

 

The grommets you speak of would be a good place to search for a vacuum leak.

 

Both turbos and NAs have a restrictor pill in the vac line to the manifold pressure sensor.

 

Vacuum leak. Id pull all the manifolds again and start over.

 

I figured I'd have to pull em and do it all again. Question; I used 'the right stuff' on both sides of the new lower gasket, didn't use anything on the new upper. Do you guys always use a sealer?

 

I don't use sealant, I coat the gaskets with grease (wheel bearing)...that way they don't stick to the flanges.
I just disassembled a manifold I'd done about 4 years ago and the gaskets could've been reused.

 

Great idea on the grease..I'll do that upon reassembly. I just now took off the upper manifold, found a plug I cannot identify. Doesn't look like its ever been plugged in..but I could have overlooked it. It was laying just under the tstat housing next to the (I assume) temp sensor attached to the back of the housing.
Can you tell me what this might be?

 

That's the sensor lead for an auxiliary electric fan that some AC equipped cars got.
Just leave that unplugged.

 

Ah good thanks. Didn't see where it would plug in anyway.

Boy I'd be in way over my head if not for your guys and this forum!

 

Mazda seems to have used the fully optioned harness on most (but not all) of the cars, so you'll probably find unused plugs (often wrapped onto the harness) for things your car did not get.

If you haven't already, go to foxed.ca and download the factory service manual.
The included wiring diagrams allow you to find out what a plug is by checking wire color.

 

I did download it, printed several pages to help with vac lines, etc.
Thanks again!