shadow27

hi guys, I was wandering if anyone could give me inputs on what you think might be causing my car to idle like this. Well my car starts up, but it makes constant *put* sounds when i rev. And it idles between 700-800 rpm and goes up and down and makes the car shake. I checked the map sensor and it seems to be connected alright and after the car warms up there's no smoke from the exhaust. Last time I checked, it was pulling about 14 mm/hg on the boost gauge at idle ~800rpm. oh the car has strong gas fumes.

black99

Your cam is too big and your carb is jetted too rich... lol

j/k



Seriously though, Does the car still have the air/smog pump on it?

shadow27

air/smog pump? dunno what that is. I still have the pre-cat and the cat if that's what you mean...

half past twelve

Mine does the same thing, but mine will fall all the way down to about 500, and the car will shake. I have noticed it mostly happeans on cold nights no matter if the car is warmed up or not...What could it be?

Street King

Check the dashpot and the throttle cable. I played with the dashpot and tightened the throttle cable and mine went away. It would drop idle to 400 rpms for like 2 secs and go back to normal rpms after I'd rev it. If you are missing your air pump which I doubt it, it just will idle lump like you got a wild cam =), I actually like it.

shadow27

i see... i'm just concerned about the puttering sound that my car is making though...i'm suspecting i might've blown a seal...

black99

Is it having this lumpy idle after you've "gotten into it"??? Just wondering because you jumped to wondering if it's a blown seal. It could be anything from a vacum line problem, or just bad plugs to a motor low on compression. It could be a ton of things, I doubt your motor's low on compression though from the sounds of it.

Is it a "put" coming out of your exhaust or more like a "knock" coming from your engine?

shadow27

well the reason i suspected the seal is blown is because yesterday I was waiting at a light with the engine not totally warmed up and the idle kinda dipped down to about 500 so i rev'd it up to about 2k to try to prevent it from drying. As I did that I thought I started hearing some sound of air blowing from the engine and it seemed like I had to press the gas pretty hard to get the car accelerating.

spurvo

You mean 14 inches mercury? At 800 rpm, I pull 17 to 19 inches, no porting, all systems go. Might have an intermittant vacuum leak (solenoid failing but not fully gone), but I'm just shooting in the dark. 14 inches seems really low to me, though...

shadow27

yeah my engine is pretty weak right now. I did a compression test a little while back and it wasn't pulling strong. I started it up today and after it's warmed up it doesn't make the put put sound...just when i rev it, you can hear it until it revs to about 3k. I was wandering could anyone tell me what the symptoms are for clogged pre-cat or failed air/smog pump?

PFSRX7

Could it be the O2 sensor?

MazdaMike

im getting the same **** but i idle from like 1200-1600 and i got no airpump, can i lower the isle a bit if i play with the air bypass valve

apneablue

Dunno, but that sounds like a boost leak to me...When you hear air hissing/blowing and you aren't getting any excitement on the butt dyno it usually means that there's a vac hose popped off, or maybe the y-pipe, or intercooler coupling hoses are cracked or not sealing well...

half past twelve

I am starting to notice that when I got on it after the idle will fall very low..to mabye 300-500rpms. Blown motor?

crazyrx7

If your boost gauge needle bouces around at 12-14 in at idle you either have a blown seal or you popped a vacuum line off. When I blew my motor the exhaust stunk worse than before, the idle was lumpy and my boost gauge needle bouced around at idle. Also do you have to really rev your engine at the light to get going? If thats the case its probably a blown seal. Just my opinion.

R.K.

half past twelve

O ****..


My car will idle around 18 vac but on cold nights after driven hard it will fall down to about 14. Or when the idle is going to **** and falling down to like 400 rpms i will goto like 12...doesnt sound good..