BACKfiring - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 22 (permalink) Old Oct 13th, 01, 07:23 AM Thread Starter
 
Join Date: Sep 2001
Location: phila pa usa
Posts: 12
Angry

hi, i just did head gaskets on my 350 and now it back fires really bad through both the carb and the exhaust (its loud 'cause of the open headers) the timing is right (msd 6al) the valves are adjusted right but, the spark plugs all have a little bit of wetness on them and the part of the float bowl where the accelerator diaphram is housed(holley dbl pumper) is wet, would this cause my hard starting bad backfiring problem?
timemachiness is offline  
Sponsored Links
Advertisement
 
post #2 of 22 (permalink) Old Oct 15th, 01, 12:01 PM
Senior Tech
 
Join Date: May 2001
Location: Austin TX USA
Posts: 501
Post

Timeman...you have a vacuum leak...would be my guess.

Check...brake booster, vacuum advance diaphram (suck on the end of the hose...see if holds), carb gasket, and intake gaskets, and all the hoses and connections that suck vacuum from the carb or intake.

Get a vacuum guage...one for diagnostics...see if she holds a good steady vacuum...my guess is, probably not.

It's weird both carb and exhaust backfire...may indiacte multiple probs. Open headers won't help. Do you backfire under acceleratrion?..or decel? Tell me more.

Sleepy-69 is offline  
post #3 of 22 (permalink) Old Oct 15th, 01, 03:00 PM Thread Starter
 
Join Date: Sep 2001
Location: phila pa usa
Posts: 12
Post

uh, i dont have power brakes or any vacuum acceories for that matter, ill check the intake gaskets with either ether or a vacuum gage but this motor has low vacuum anyway, the headers are open so i could take them off to retorque the heads, and i have not driven it at all since it back fires. It wiil stay running with a sucky idle if i hold the gas down a little bit but the second i let off it will backfire and die, this is all while in park.(because i havent driven it) and i ahd none of these problem before i did the head gaskets so it is most likely something i have done.
timemachiness is offline  
 
post #4 of 22 (permalink) Old Oct 15th, 01, 05:07 PM
Senior Tech
Steven
 
Join Date: Jan 2001
Location: Raleigh, NC
Posts: 1,046
Post

In addition to checking for vacuum leak, re-check the distributor installation ( could be 180 deg off ) and check the plug wire order .
sdtsdt is offline  
post #5 of 22 (permalink) Old Oct 15th, 01, 08:43 PM
Senior Tech
 
Join Date: Jan 2001
Location: skiatook, ok
Posts: 3,692
Post

Sounds like the timing may be retarded quite a bit. Are you sure those valves are adjusted correctly?

------------------
375hp 78 Chevy truck
77 Chevy Nova
95 Chevy Lumina 3.4L
and building a 78 Nova
travis is offline  
post #6 of 22 (permalink) Old Oct 16th, 01, 12:32 PM Thread Starter
 
Join Date: Sep 2001
Location: phila pa usa
Posts: 12
Post

hmmm, i do have bad vision and i have the balacer marked at oppsite ends for valve adjusting so it could be 180 off, but would it still run? If the distributer is 180 off then the valves arent adjusted right.
timemachiness is offline  
post #7 of 22 (permalink) Old Oct 17th, 01, 05:14 AM
Senior Tech
 
Join Date: May 2001
Location: Austin TX USA
Posts: 501
Post

Let's drop the "180 off" solution to these problems. I've seen it posted many times. I don't know how stuff like this gets legs. If your timing was 180 degrees off, that means ignition would occur on the decompression stroke when the exhaust valve was wide open. If you can make an engine run with the rotor pointing 180 off, you have magical powers.
Sleepy-69 is offline  
post #8 of 22 (permalink) Old Oct 17th, 01, 02:41 PM
Senior Tech
Steven
 
Join Date: Jan 2001
Location: Raleigh, NC
Posts: 1,046
Post

Sleepy, lighten up . Diagnosing cars probleams via internet is simply throwing out opinions and possibilities ( trying to be helpful ). I doubt that anyone is batting 1000 ... If you disagree with an opinion, give your opinion, ... give a technical explanation if you wish ... and go on ... Anyone who takes the time to answer a post is only trying to be helpful ... NO, I don't expect a car to run with the dist 180 deg off, but I can see some backfiring or popping occuring ... Someone had already posted a vacuum leak as a possibility ... our intent was to suggest other things that could possibly be wrong ... If we're wrong, ignore us or enlighten us, but don't criticize us ... Everyone here learns something from time to time ...
sdtsdt is offline  
post #9 of 22 (permalink) Old Oct 17th, 01, 03:48 PM
Senior Tech
Bob
 
Join Date: Dec 2000
Location: Ct.
Posts: 1,142
Post

I don't think an engine will run 180 off, but it sure as hell will backfire loud enough to change the color of your shorts in a hurry. From just yellow to brown.

------------------
Bob
Garnet Red 69/SS396/TH400/355 Posi
94 HD Dyna Wideglide
phel69 is offline  
post #10 of 22 (permalink) Old Oct 18th, 01, 04:50 AM
Senior Tech
 
Join Date: May 2001
Location: Austin TX USA
Posts: 501
Post

Sdtsdt my man...sorry for the post. Wasn't trying to step on your effort. You've always posted good stuff and I respect your comments.

But recently, I've read a dozen times "180 degree off" as reason for a poor running engine. Not just your post, but from many others. It's not possible an engine could run at all if the rotor were pointing in the exact opposite direction. The distribuor turns half as fast as the engine crank. Long story short, the plugs would fire on the decompression stroke, and not on the compression stroke.

Make sense? Still friends?
Sleepy-69 is offline  
post #11 of 22 (permalink) Old Oct 18th, 01, 05:33 AM
Senior Tech
Steven
 
Join Date: Jan 2001
Location: Raleigh, NC
Posts: 1,046
Post

Sleepy, No personal offense taken ... still friends ... I just don't want to discourage anyone from posting ... sometimes it is like being in school...If you never raise your hand, you don't know that you don't know until Test time ... I don't mind being corrected ...
sdtsdt is offline  
post #12 of 22 (permalink) Old Oct 18th, 01, 06:07 AM
DjD
Retired
Dennis
 
DjD's Avatar
 
Join Date: Apr 1999
Location: Fortuna, CA
Posts: 26,453
Garage
Post

Not trying to put this further off course but we should use the correct terms... I was taught...

"intake" (piston moving downward with intake valve open),

"compression" (piston moving upward with both valves closed), piston heading toward TDC...

"power" (piston moving downward) and

"exhaust" (piston moving upward with exhaust valve open)

are the 4 strokes.

Check that all your plug wires go to the correct plugs. And as Travis suggests, timing may be way retarded...

...Dennis
DjD is offline  
post #13 of 22 (permalink) Old Oct 18th, 01, 06:48 AM
Senior Tech
 
Join Date: May 2001
Location: Austin TX USA
Posts: 501
Post

Or,

1) suck,
2) squeeze,
3) boom,
4) fart

...the old school way learning...not currently taught, not politically correct, but easily remembered...as I have for 25 years.
Sleepy-69 is offline  
post #14 of 22 (permalink) Old Oct 20th, 01, 04:07 AM Thread Starter
 
Join Date: Sep 2001
Location: phila pa usa
Posts: 12
Smile

I've been working all week so i havent had chance to check anything out until this morning, i advaced the timing by about a 3/16th's of a turn and i starts and runs a whole lot better, but my timing light doesnt work now(i left it under the hood and we had a couple of rain storms and its super foggy out right now) but im confident that i was reading a scratch of something when i was setting the timing the first time and that the whole problem was timing all along. I would like to thank everybody for their help and all suggestions were appreciated and researched. Thank you.
timemachiness is offline  
post #15 of 22 (permalink) Old Oct 22nd, 01, 07:19 PM
Tech Team
 
Join Date: Aug 2001
Location: AZ....USA
Posts: 71
Post

Not trying to be arguemenative (is that a word) but I have seen a chevy run 180 off. So it is possible...runs like crap and backfires but possible.
SS67muscle is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome