93 explorer sport vacuum leak question

[xplorernewb]

Is there a way to test the upper intake manifold? Ive checked every line and they hold vacuum but when i blow into the hose connected to the nipple below the throttle body, i can feel pressure loss. Is that a sign of a bad gasket somewhere in the tb or intake?

 

[natenkiki2004]

Are you taking the little hose off the throttle body and blowing into it or are you taking off the hose at the charcoal canister that goes to the throttle body and blowing into it? Basically, which direction are you blowing? There's no real way to test the upper intake manifold since the IAC creates a big hole in it, plus if there's an intake valve open, you'll leak through that. A smoke machine makes pretty good work of finding leaks.

 

[2stroke]

Or since us common folk don't want to buy a smoke machine, blowing cigar smoke in works wonders for cheap.

 

[FR-425]

What makes you so sure you have a vacuum leak?

 

[xplorernewb]

Im taking off the hose from the canister and blowing into the throttle body. Had iac port and throttle body blocked off. I think its a vacuum leak because theres a high idle and goes pop pop pop when i coast to a stop in gear. Probably running lean i think. Would a bad cat cause high idle, or would the lean condition cause a bad cat? Or would the o2 sensors being bad cause the cats to go bad, adding pressure and causing high idle? Probably dumb questions but im stumped.

 

[2stroke]

You won't get anywhere with all these threads open and no real direction. Start with the throttle body. Don't worry about anything else now.

 

[OneofMany]

you can use WD40 to spray around the intake or any other suspected vacuum leaks, When the idle changes you have hit gold. You can also use a stethoscope moving the hose around to listen for leaks. But like others said, you have so many threads open it is getting confusing and maybe contradictory. consolidate.

 

[natenkiki2004]

If you're blowing into the throttle body with the intake and IAC closed off, I'd still imagine there's a leak into one of the cylinders. One of the intake valves would have to be open. I've never heard of anyone doing this test. Like OneofMany suggested, you can use a spray to find the leak around the intake (if there is one). ScannerDanner on YouTube advocates a pop bottle filled with water and a push-pin hole in the cap to squirt around the engine.

Start with basics. A high idle is almost always a vacuum leak. Can you borrow a vacuum gauge?

 

[swshawaii]

Did you check for trouble codes? Flashing CEL not needed to have stored codes.

How To: Pull Trouble Codes on a 1st Gen Explorer (paperclip method)
http://www.explorerforum.com/forums/showthread.php?t=255962

EEC-IV 2 and 3 digit trouble codes
http://www.explorerforum.com/forums/showthread.php?t=160035

 

[xplorernewb]

I apologize for starting other threads, but i didn't know what else to do and really didn't know where else to look. I did fix it though. Bad tps. This bad one was a replacement for the old bad one. The 2 gave 2 different symptoms and the 2nd one just happened to have failed when i actually did have a vacuum leak. Anyway, if theres a way to delete these unnecessary threads, please do. Wasn't trying to be a nuisance thanks for all the help anyhow, and i did learn quite a bit from the experience.