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-   -   runs bad at idle (http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/132811-runs-bad-idle.html)

scrambled2k3 10-23-2003 12:40 PM

runs bad at idle
 
the car hasn't been started in about 2 1/2 years and i just bought it. It had a bad fuel pump and i replaced it. I got the car to start and run, but it just lopes in the lower RPM range and won't idle. it shuts off when you take your foot off the gas. I had it running for about 20 minutes to see if it was bad gas or something, and i noticed alot of smoke entering the cab of the car from beneath the floor. So i looked under the car and the cat was glowing red hot. I immediately shut the car off and have no clue what could cause it. can somebody help?

Tishabet 10-23-2003 12:46 PM

Cat going red hot means you need a new cat, the one you've got is fouled up. Not sure is a cat can get so fouled up that it would effect your idle though......doesn't seem likely to me.

scrambled2k3 10-23-2003 12:48 PM

is that causing the idle to run choppy?? and the response time to be horrible?

Techmonkey 10-23-2003 12:55 PM

was there exhaust coming from the tail pipe??
The CAT may be clogged.

scrambled2k3 10-23-2003 12:56 PM

yeah...it was pretty smokey and black...but exhaust was coming out!!!

Dark Skies 10-23-2003 12:58 PM

Could just be a poor engine to firewall ground - even good clean looking earths can prove to be wanked. Try putting a booster cable across the neg terminal of the battery and the firewall earth to see if the idling picks up.

Roger Hall 10-23-2003 04:34 PM

I would agree with removing or replacing the cat. Also you might want to replace the O2 sensor and have the fuel mixture set.

SoCal Driver 10-23-2003 06:20 PM

Better check for a rats nest in the exhaust.

You did change the timing belt before starting it.

scrambled2k3 10-23-2003 06:25 PM

no i didn't change the timing belt, but i will look at it

SoCal Driver 10-23-2003 06:34 PM

Quote:

Originally posted by scrambled2k3
no i didn't change the timing belt, but i will look at it
Car sat for 2 1/2 years. Change it now.

Or the CAT will not be the only thing that is glowing red.

Remember a new too tight timing belt is better than an old ready to break timing belt. You can get it adjusted later. Same for the balance shaft belt.

scrambled2k3 10-24-2003 10:02 AM

how can i check the vacuum to my fuel regulator?

scrambled2k3 10-24-2003 10:35 AM

the car has been garage kept those past 2 1/2 years...it hasn't been exposed to any weather...are you sure the timing belt is the reason? cause it looks good to me!

SoCal Driver 10-24-2003 12:59 PM

The timing belt is secondary to your problem. If you have not turned the engine over during the storage the bends in the timing belt as it goes around the pulleys take a "set". That is the belting strands will move inside of the rubber and tend to stay in a bend when the engine is run again. This causes heat build up as the bends are straightened and possible premature failure of the timing and balance belts.

..P 10-24-2003 01:14 PM

Birds, mice, insects can get in a car sitting that long. In addition, when you start up, a motor sitting that long is going to probably smoke a bit while it burns off dried oil and varnish, etc., that was in the system, including some of the old gas that has almost turned to varnish. It will smoke. WHen this smoke goes to the cat, the cat gets hot trying to burn it up.

You might try again a couple times watching the cat closely. If it continues to get hot like that, you do need a new one. Beware, the factory cat for a 944 is $1500, but if you do a Google for "catalytic converter" you can find one for the 944 for around $150. I'm running one right now, it makes the car sound a bit better, passes the smog test, and saved me a bunch of money. It's not stainless steel like the stock unit, but hey, for the price it's a deal.

good luck, P

Nashville

scrambled2k3 10-25-2003 07:40 PM

i'm not a complete idiot...but just so you guys know, it was the spark plug wires! The guy i bought the car from said he changed the plugs and the wires before he parked it, so the whole time i'm thinking that its a sensor, or something not very obvious. Pistons 1 and 4 weren't firing and i removed both of their spark plug wires and the engine never changed sounds...and i know its not the distributor cap or rotor cause the dist. is firing fine!! now i have to pay that outrageous price for plug wires! can somebody tell me why their so expensive???

scrambled2k3 10-25-2003 07:59 PM

i checked that too...their in the right order and their on correctly...i even found an old set of spark plug wired and rigged them so they would fit the car...and it ran ALOT better...but still not perfect...cause the wires i put on their worked, but they were old!

porscheguy1 10-25-2003 08:24 PM

cat glowing hot red means toooooo much unburnt fuel entering it you probably melted down the center of it . mazda rx7 style .

scrambled2k3 10-26-2003 05:21 AM

the plugs are brand new...i just bought them the other day!

Tishabet 10-26-2003 06:55 AM

Are the plugs gapped correctly? Are they (duh) the correct plugs/temp/etc for the engine you're using? Are you sure they're firing at all? You can test the spark by using another plug plugged into the spark plug wire and holding the threads to the body of your engine (like the manifold) while the engine is running or cranking over.....you should be getting bright blue spark. If not, look at the plug wires, and possibly the coil, which you can test using a multimeter. Also, as someone said before, what do the plugs look like in the cylinders that aren't firing? Do they look fouled up, etc? Although with the very limited time the engine has been run, the look of the plugs may not be a trustworthy indication.....

SoCal Driver 10-26-2003 07:53 AM

I can't believe that you could run an engine on just two cylinders and not know it.


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