95 302 backfires through intake
Thread Starter
|
Senior User
Joined: Dec 2006
Posts: 125
Likes: 0
95 302 backfires through intake
95 f150, 302, auto trans, backfires through the intake at 4000rpm under load while driving, it idles fine and runs good at lower rpm's, we have checked fuel pressure and for vacuum leaks both seem to be ok, any ideas what it could be,
Senior User
Joined: Dec 2009
Posts: 374
Likes: 0
From: Portsmouth, Va
Backfiring through the intake is usually over advanced ignition timing. Spark plug fires before the intake valve closes. Check ya timing 
I understand you checked for vacuum leaks but did you test manifold vacuum?
95 truck. Mass Air Flow sensor or Speed Density? If MAF test that as well.
I understand you checked for vacuum leaks but did you test manifold vacuum?
95 truck. Mass Air Flow sensor or Speed Density? If MAF test that as well.
Senior User
Joined: Dec 2009
Posts: 374
Likes: 0
From: Portsmouth, Va
I'm not familiar with 302s nor 4000RPMS haha. My godbrother has a 302, but no tach so I have no idea he revs his truck.
I shift my 300 at right around 2800 to 3K according to my semi-accurate tach.
I'm just wondering if either of those problems would rear their head at lower RPMs. Kinda easier to hear **** flying around at idle.
I shift my 300 at right around 2800 to 3K according to my semi-accurate tach.
I'm just wondering if either of those problems would rear their head at lower RPMs. Kinda easier to hear **** flying around at idle.
Postmaster
Joined: May 2008
Posts: 2,703
Likes: 3
From: La Vergne, TN
well for him to be hittin 4k RPMs hes got it wound out fully... I have 4.10 gears and E4OD and 255/70/15 tires and my truck shifts at 4500 RPM's.
and yeah theres a problem in the valve timing as in a valve spring or something along those lines..
and yeah theres a problem in the valve timing as in a valve spring or something along those lines..
Thread Starter
|
Senior User
Joined: Dec 2006
Posts: 125
Likes: 0
Well I posted to see what kind of replies I would get, to see if the info we were given could be correct, so from what we have gathered I think it is quite possibly a valve spring problem, we talked to a guy at work before I posted on here and he brought up possibly a broken inner valve spring or something wrong with the valve train, but I didn't want to show my cards and just see what else yall thought about the symptoms, I think he is goin to check the timing again and maybe try adjusting it again, we were just hoping for some better news than a valve spring problem, thanks for all the info and I will post back when we figure it out, again thanks for the info
Trending Topics
Thread Starter
|
Senior User
Joined: Dec 2006
Posts: 125
Likes: 0
update- replaced plugs and wires and readjusted timing again, all seems well for now, thanks for the help
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Thread
Thread Starter
Forum
Replies
Last Post
ColtonMullis
Small Block V8 (221, 260, 289, 5.0/302, 5.8/351W)
2
Jan 20, 2014 03:53 PM
jordanz03
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
36
Jun 29, 2013 05:21 PM
coleaclark
Small Block V8 (221, 260, 289, 5.0/302, 5.8/351W)
37
Apr 11, 2008 02:07 AM
JCM51
Fuel Injection, Carburetion & Fuel System
2
Sep 16, 2003 11:32 AM
