Author Topic: backfiring on crank  (Read 3242 times)

Offline Pescados666

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backfiring on crank
« on: August 21, 2013, 02:51:14 am »
I just did a tuneup with new fuel filter (PO converted it to an inline filter and electric pump) and also changed dist. cap and plugs+wires.  Now when I turn her over it backfires out the exhaust.  I noticed the new fuel filter isn't completely full of fuel either.  Would this be caused by a lack of fuel [pressure] or possibly an issue with the firing order?

Thanks!
1985 Chevy C10 Suburban w/ 350 sbc and 700r4

Offline Irish_Alley

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Re: backfiring on crank
« Reply #1 on: August 21, 2013, 03:46:36 am »
firing order/timing. take all the wires off and start again #1 should be about at 5 o'clock the fuel might be just because the engine isnt running fast/long enough yet
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline Pescados666

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Re: backfiring on crank
« Reply #2 on: August 21, 2013, 07:01:40 pm »
I checked the firing order and everything is plugged up right.  The fuel pump doesn't seem to be doing anything either.
1985 Chevy C10 Suburban w/ 350 sbc and 700r4

Offline Irish_Alley

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Re: backfiring on crank
« Reply #3 on: August 21, 2013, 11:20:01 pm »
to test the fuel you can spray some sort of starting fluid/ carb cleaner into the carb. if you can keep it running off the fluid then its a pump problem. but being it ran before you touched it your problem is probably what you touched or near what you touched. verify your getting spark, either spark plug grounded out or timing light.
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline Pescados666

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Re: backfiring on crank
« Reply #4 on: August 28, 2013, 02:16:44 pm »
ok, had some free time today and found out the fuel pump is working fine, but she still doesn't want to start. 
My dad too is leaning towards spark, but also have a bit of gas dripping out onto the air intake it seems. I have a feeling that I should rebuild/find another qjet soon (the carb body has a chip or two by a vacuum line and the fuel filter is epoxied shut, so I wouldn't be surprised), but I don't think that would cause my problems.
1985 Chevy C10 Suburban w/ 350 sbc and 700r4

Offline Pescados666

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Re: backfiring on crank
« Reply #5 on: August 28, 2013, 04:00:15 pm »
Finally she breathes!
It was the firing order after all. I originally followed the picture in the chilton and assumed the holes for bolts would line up with mine. 
To fix it my dad had me remove #1 plug and feel when it was at the top of compression and then remove the dist. cap and go from there. 

I definitely will be rebuilding the carb soon though as I suspect it will always be a problem in it's current condition, and dripping fuel onto the engine is never safe.
1985 Chevy C10 Suburban w/ 350 sbc and 700r4

Offline Irish_Alley

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Re: backfiring on crank
« Reply #6 on: August 28, 2013, 11:01:36 pm »
glad you got it fixed. not saying you are but done be ashamed of a simple mistake, we all make them. but its when you can say "hey i screwed up, but i found where. " this isnt a mistake its a learning processes. you dont know coffee is hot till you touch it
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline Fairlane514

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Re: backfiring on crank
« Reply #7 on: August 28, 2013, 11:32:49 pm »
"you dont know coffee is hot till you touch it"

Same thing goes for a woman.

Offline Irish_Alley

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Re: backfiring on crank
« Reply #8 on: August 29, 2013, 12:12:31 am »
but you dont touch them with out them saying yes lol or you will get touched in the face with a open hand
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes