![]() |
Register or Log In To remove these advertisements. |
|
|
![]() |
|
Thread Tools | Display Modes |
![]() |
#1 |
Registered User
Join Date: May 2002
Location: Stockton, CA
Posts: 169
|
Engine problems -- slight backfire ...
I've got a mid-80's 350, Edelbrock Performer intake and HEI with 700r4.
Installed new Edelbrock 650cfm vacuum 2nd's and new spark plugs gapped @ .045's. While idled @ ~ 700 RPM, no problems -- but once I put into gear, I get backfire sputers on the passenger side AND I have no power out of engine --- used 2x the amount of gas today going to work !!!! ![]() VERY frustrated. I've followed Edelbrock carb tuning tips --- back out 2 full turns, turn in clockwise ( one side at a time ) till RPM drops and put back a 1/8 turn. BTW: timing's at 8 degrees. What am I doing wrong --- what else do I need to check ?
__________________
71 C/10 : 350 / 700r4 ; Ford 9" posi 3.50 with 31x10.5 rear tires, single drive shaft, C-notch, 2.5" drop spindles, keyless entry 71 Suburban 350/350 -- caddy tail lights, keyless entry, late model seats, billet Autometer instrument cluster 70 Ford Torino -- 351W (balanced & blueprinted ), C4, VDO gauges |
![]() |
![]() |
![]() |
#2 |
Registered User
Join Date: Mar 2002
Location: Bondurant, IA but in Worcester, MA for school
Posts: 767
|
Sounds like you might need to advance the timing a bit more. My 350s running at 13-14 degrees advance. I could b e wrong though.
HotRod
__________________
1970 Chevy C-20 350 V-8 Turbo 350 w/ shift kit Dana 60 w/ 4.10 gears AND Powr-Loc POSI New Additions: Summit Headers 135amp alternator Proform HEI Edelbrock 1406 600cfm carb Sunpro Tach Powr-Loc POSI Edelbrock Performer RPM Intake MSD 6A Ignition Box AIM: HotRod929 Visit My Site: http://1970chevy.netfirms.com/ |
![]() |
![]() |
![]() |
#3 |
Registered User
Join Date: Mar 2003
Location: Stillwater MN
Posts: 1,166
|
If the carb was only thing changed before the problem developed, I would look for a vacuum leak. Strongly suggest rechecking the plug wire location. Sounds like you may have crossed two.
__________________
69 GMC K10 ..some restoration required....still.. ![]() |
![]() |
![]() |
![]() |
#4 |
Registered User
Join Date: May 2002
Location: Stockton, CA
Posts: 169
|
vacuum advance
Well --- I removed the carb and blew air through the port vacuum inlet and installed a 1/2 riser.
Power has been restored to engine -- but still backfires on the passenger side, not at idle anymore, but during acceleration. Does that mean I too rich or too lean ? Thanks for all the guidance !
__________________
71 C/10 : 350 / 700r4 ; Ford 9" posi 3.50 with 31x10.5 rear tires, single drive shaft, C-notch, 2.5" drop spindles, keyless entry 71 Suburban 350/350 -- caddy tail lights, keyless entry, late model seats, billet Autometer instrument cluster 70 Ford Torino -- 351W (balanced & blueprinted ), C4, VDO gauges |
![]() |
![]() |
![]() |
#5 |
Registered User
Join Date: Apr 2003
Location: Edgewood New Mexico
Posts: 2,088
|
i think that means it is to rich but why is it only happening on one side
__________________
1990 subaru legcy (daily driver) 1987 Toyota 4runner (weekend toy) 1968 ![]() 1970 ![]() 1976 Dodge Dart 1963 Dodge Dart ![]() |
![]() |
![]() |
![]() |
#6 |
Mike
Join Date: Jan 2003
Location: west chester pa
Posts: 2,474
|
Check to make sure Your plug wires are in the right order and there is no crossfire.I would advance the timing a little.Mine with hei runs best at 12 btdc
__________________
70'c/10, 71 suburban4x4 402bb, 72suburban 4/6 drop, 72k/5 4x4 blazer 4" lift 35 tires |
![]() |
![]() |
![]() |
#7 |
Registered User
Join Date: Mar 2003
Location: Meansville, Georgia
Posts: 218
|
make sure you check the firing order and timing. i had the same thing happen to me and it caught my carb on fire!
__________________
68 SWB Stepside 72 Cheyenne 20 72 SWB Fleetside 72 Suburban 72 2wd Blazer |
![]() |
![]() |
![]() |
#8 |
Nothing fits but the oil
Join Date: Mar 2003
Location: Gaston, Indiana
Posts: 424
|
My guess is vaccum leak, check the manifold "T" fitting directly behind the carb, on the manifold. Sometimes if this is off it pulls additional air right into the right side causing backfires and sputters as you describe. You may also want to check the vaccum port on the rear of the carb itself to see if there needs anything connected or plugged off.
__________________
Land of the free Because of the brave |
![]() |
![]() |
![]() |
Bookmarks |
|
|