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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: achevy1978 on October 11, 2013, 09:05:12 pm

Title: quadrajet running rich
Post by: achevy1978 on October 11, 2013, 09:05:12 pm

i had a quadrajet rebuilt  and it seemed to run fine then all of a sudden its stataed to run rich and hard to .
i took it all apart it looked ok put it back together and it idles rich.....i have a holly hi volume holley fuel pump
that i think runs at 7.5 lbs. is that to much pressure??

thanks

Title: Re: quadrajet running rich
Post by: Captkaos on October 15, 2013, 04:55:45 pm

have you adjusted it?  Most Qjets need 5lbs of pressure.

Title: Re: quadrajet running rich
Post by: Stewart G Griffin on October 22, 2013, 12:03:57 am

What year is your truck?

Capt., believe it or not, The service manual for my 83 calls for 7lbs of fuel pressure for the quadrajet.

Title: Re: quadrajet running rich
Post by: achevy1978 on October 22, 2013, 08:55:24 pm

78 with a 454
thanks

Title: Re: quadrajet running rich
Post by: Stewart G Griffin on October 26, 2013, 11:12:52 pm

So, my service manual on pg. 6C-25 calls for all small blocks without vapor return line 7.5 to 9 lbs.

All small blocks with vapor return line 5.5 to 7 lbs.

Big block 7.5 to 9 lbs.

inline 6 4.5 to 6 lbs.

But mine is an 83.

My first question is what is the vapor return line?

i guess time to get a fuel gauge and service manual for 78's?

Title: Re: quadrajet running rich
Post by: Stewart G Griffin on October 27, 2013, 08:58:59 am

i meant fuel pressure gauge.

Title: Re: quadrajet running rich
Post by: Boone83K10 on October 27, 2013, 11:09:25 am

Quote from: Stewart G Griffin on October 26, 2013, 11:12:52 pm

So, my service manual on pg. 6C-25 calls for all small blocks without vapor return line 7.5 to 9 lbs.

All small blocks with vapor return line 5.5 to 7 lbs.

Big block 7.5 to 9 lbs.

inline 6 4.5 to 6 lbs.

But mine is an 83.

My first question is what is the vapor return line?

i guess time to get a fuel gauge and service manual for 78's?

there is a line from the fuel tank to the charcoal canister. that is the vapor return line.