View Full Version : Backfiring issues

01-20-12, 04:15 PM
Well let me first say that I need a new radiator cap because it is not holding pressure. So I was stuck in the snow and in the process of trying to get unstuck I smelled coolant which I attributed to the radiator cap releasing steam. Then my light came on telling me to idle transaxle because it was hot. So I shut it off and let it sit for a while. Then as I was trying to get unstuck my car began to backfire with a horrible smell. and now idles rough. What could this mean? The car is a 1999 Cadillac Deville 8 cylinder 4.6 liter.:worship:Please help!!!

01-20-12, 04:36 PM
Pull your diagnostic trouble codes from the car's built-in code scanner/memory. Use the sticky post ^^^ "How to pull codes". Study for which DIC readout control procedure you need to use.

01-20-12, 04:51 PM
And post the definitions!

01-20-12, 09:18 PM
I would diagnose the engine and trans overheating problem before worrying about anything else.

How do you know that the cap is bad and not holding pressure?

johnny kannapo
01-21-12, 04:16 AM
You can get the codes right off the dash board DIC without tools, write them down. There is a procedure using the heater control buttons.
Go to- "Reading OBDII codes" at this link-http://myweb.accessus.net/~090/dtcobd2.html
Then navigate that site & find the list of codes & definitions & post them back here for more help.

I hope you laid off when the warning messages lit up....you might be ok.
At some point the engine should have gone into limp mode and that may cause the poor running condition.

You now know this is about as destructive a thing you can do to a transmission. That alone is a possible $3000 repair.
If you over heated the transmission it's a cinch to figure the engine over heated and the radiator cap is not likely the reason.

It's possible the radiator fans are inoperative.

I hate to say it but it sounds like you tortured the engine & transmission in a barbaric fashion and something major in the engine may have given out.
I could be wrong, I wasn't there.

01-21-12, 08:09 AM
Sounds like the engine overheated and it went to camel mode - you might find P1258 history. Were you just mashing the throttle to get it unstuck?

Mark D
01-26-12, 04:53 PM
Stuck in the snow, eh? Well, your air intake is just behind the left headlight and takes it air from down low. That crappy running could also be snow ingested into the system. I have a friend who's daughter was driving his STS and drove through deep water. Engine ingested water enough to destroy it. Water doesn't compress. He had to get a new engine. Snow wouldn't be quite so bad, but sure can raise hell with drivability.
Mark D.