Backfired/now won't start w/out pouring gas in carb - Chevelle Tech
Engine General Engine Discussion.

 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 6 (permalink) Old Apr 3rd, 07, 2:25 PM Thread Starter
Tech Team
Mike
 
Join Date: Mar 1999
Location: McDonough, GA
Posts: 305
Cool Backfired/now won't start w/out pouring gas in carb

Well, I went to crank up the beast last weekend for a quick spin while the weather was nice, and as I was starting the engine it tried to crank over but would not start after a few seconds, so right when I took my hand off the key so the starter would stop, the engine BACKFIRED. (It sounded like it went out back through the exhaust.) After that, the engine would not start unless I poured gas into the carb. Once I poured gas in the carb, it ran great. I let it heat up to 195 degrees and I took it out for a healthy romp on a country back road. Got back home, turned the engine off, waited about a minute, and then no start...... poured some gas in carb, and she purred.

Could the backfire have damaged my carb?? Somehow it is no longer getting fuel in the bowls at startup. I did some searches on "backfire" and most said something about the power valve possible being blown, but I can't see how that would affect starting the engine. And I also don't see how the timing could be off either. Like I said, once I pour some gas directly into the carb, it starts and runs fine.

Thoughts?

ACES# 8456
Peach State Chevelles #366
1971 Malibu - [email protected] with mild 350 (Vortec heads, Performer intake, 600 Holley, 268H Comp cam, MSD 6A, TCI 2400 Breakaway, 3.73 w/Eaton posi)

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

2003 Chevy Trailblazer LT EXT

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
71boo is offline  
Sponsored Links
Advertisement
 
post #2 of 6 (permalink) Old Apr 3rd, 07, 2:29 PM Thread Starter
Tech Team
Mike
 
Join Date: Mar 1999
Location: McDonough, GA
Posts: 305
Re: Backfired/now won't start w/out pouring gas in carb

Forgot to add, when I went under the hood, I removed the air cleaner, and manually pushed the accelerator pump, I peeked down in the carb and I did NOT see/hear/smell any gas squirting out. Normally, even if I can't see the squirt, I can hear the little "tssst tssst" when I pump the gas.

ACES# 8456
Peach State Chevelles #366
1971 Malibu - [email protected] with mild 350 (Vortec heads, Performer intake, 600 Holley, 268H Comp cam, MSD 6A, TCI 2400 Breakaway, 3.73 w/Eaton posi)

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

2003 Chevy Trailblazer LT EXT

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
71boo is offline  
post #3 of 6 (permalink) Old Apr 3rd, 07, 3:19 PM
Tech Team
Scott
 
Join Date: Jun 2006
Location: LI New York
Posts: 50
Re: Backfired/now won't start w/out pouring gas in carb

I am not an expert on carbs by any means however if the acc. pump is not working it will be hard to start and pouring gas down the carb would be doing the work of the acc. pump. It is possable you have dirt or varnish in the pump causing a blockage. I dont think the power valve would casue that issue I have blown mine out many times on my old carb and had no starting issues. I am sure someone with a better grip on carbs will chime in soon.

Scott

1970 Chevelle
454 4 speed
Team Chevelle #3871
mfd560 is offline  
 
post #4 of 6 (permalink) Old Apr 3rd, 07, 3:23 PM
Tech Team
David
 
Join Date: Feb 2007
Location: Centennial, CO USA
Posts: 95
Send a message via MSN to dkpeppard
Re: Backfired/now won't start w/out pouring gas in carb

Quote:
Originally Posted by 71boo View Post
Forgot to add, when I went under the hood, I removed the air cleaner, and manually pushed the accelerator pump, I peeked down in the carb and I did NOT see/hear/smell any gas squirting out. Normally, even if I can't see the squirt, I can hear the little "tssst tssst" when I pump the gas.
Whether it is the full problem or not, it is definitely an issue to not see or hear gas from the accelerator pump when you pump the gas.

The backfire could have just been a misfire since the car has been sitting due to old gas in the carb.. Normally, it is the backfire through the carb itself that causes the power valve in Holley's to blow out, but this was rectified by Holly in all their designs back in the laste 80's or 90's (help me out here Holley folks).

No matter how long you crank it 9not exceeding 60 seconds), the car won't start on its own now?

It is possible the fuel bowls are empty due to low fuel pressure, which would also make your accelerator pump not discharge. Can you unhook the fuel line, crank the engine and see if fuel is pumping out?

1967 Chevelle, SS Clone, 396, 4 speed, 12 bolt posi
Centennial, CO USA
Team Chevelle Member #3713

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Member #122

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
dkpeppard is offline  
post #5 of 6 (permalink) Old Apr 3rd, 07, 5:22 PM
Tech Team
Jim
 
Join Date: Apr 2004
Location: Michigan
Posts: 858
Re: Backfired/now won't start w/out pouring gas in carb

I'm waiting for the right person to chime in cuz I had kinda the same problem, after my car sat for a couple days I would have to pour gas into the carb. 2 fuel pumps and two different carbs. I even removed my gas cap to see if there was a vacuum created in the tank. Good luck on her.

1969 hard top
1966 hard top
1969 SS hard top
1969 SS Convertible

"The day you think you know everything there is to know is the day you start learning"
NOTHINBUT69s is offline  
post #6 of 6 (permalink) Old Apr 3rd, 07, 5:29 PM
Tech Team
Eric
 
Join Date: Feb 2007
Location: Mi
Posts: 136
Re: Backfired/now won't start w/out pouring gas in carb

could be something as easy as a pluged fuel filter. but the gas we have now days can actually gum up your carb. you need to pull it apart and get good carb cleaner and spray in in every hole in the metering blocks and carb base. check the fuel line while cranking the motor over to make sure the fuel is getting to the carb. if you pour gas down carb and it starts the carb starts pulling the cfm and draws fuel in. just trying to start the car does not draw the cfm as it does running. I hope this helps. I clean my carbs out every year after storage. just to ensure everything is clean and running correct.
blown68bbc is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle 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, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in









Old Thread Warning
This Thread is more than 4634 days old. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
If you still feel it is necessary to make a new reply, you can still do so though.

Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
Expanded "Basics of Basics" Inverted welding MARTINSR Body Shop 13 Dec 17th, 05 3:59 PM
Rebuilt Carb, now car won't start gUmBaLL68Malibu 2004 18 Jan 20th, 04 9:08 PM
Idleing prob with UD 288/296F10 and 950HP C.W.Mellow 2003 18 Nov 25th, 03 3:59 PM
oversized carb and single-plane intake bowtie455 2003 10 Nov 19th, 03 5:27 AM
does jetting affect idle quality (switched 750DP to 950HP)? 19_chevelle_71 2003 11 Nov 9th, 03 9:18 AM

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