backfire

videogypse · 08-27-2003, 03:23 AM

My 1976 911 Targa backfired out the exhaust and stopped running. It turns over but won't start. I assume the timing chain jumped.

Is it possible nothing bent if it only jumped one tooth? Or do I just start ripping the thing apart?

dd74 · 08-27-2003, 08:31 AM

Are you sure it's not the pop off valve? Do you have a pop off valve?

Check under your airbox - the pop off looks like a toilet plunger. It might just need re-seating, which you can do by hand.

Cheaper than "ripping the thing apart."

Hopefully you have one of these valves. Otherwise, you might've blown your airbox.

Jim Sims · 08-27-2003, 09:03 AM

I agree, likely either an unseated "pop off" valve or a blown air box ($$). I would check the point dwell too as a good "thump" sometimes loosens the points if not they were not properly tightened. Good luck. Jim

Wayne 962 · Wayne 962's Garage

Do a bunch of research on this site and here (http://www.101projects.com) before you start tearing stuff apart. Sounds like you might have blown your CIS airbox, or at best, blew a hose and you now have a vacuum leak...

-Wayne

Wayne 962 · Wayne 962's Garage

Oh, and you can't knock out your timing with a backfire - the timing is controlled by a beefy metal chain.

-Wayne

videogypse · 08-27-2003, 07:48 PM

It has a pop off valve. It also backfired out the exhaust so it wouldn't be likely to blowup the air box that way. BTW I didn't mean the timing got knocked out with the backfire I ment the backfire may have been the result of a jumped timing chain. EG the plug fires while the ehxhaust vale is open.

Also, I just did a compression test and the right bank is low. So... when I get to pull the covers next week (I'll be out of town till Wed.) can I expect to find the timming out? If I do, is it possible it didn't break/bend anything?

Wayne 962 · Wayne 962's Garage

I think you're barking up the wrong tree with the backfire and timing. I'm going to move this back to the regular forum, unless this is a recently rebuilt engine?

-Wayne

hoosierdaddy · 08-28-2003, 12:47 AM

I had a set of points do this to me ( 77s ) about a month ago . I replaced them and the car has run fine since and by the way the points were only about a month old.
Jim