Help!!! 390 won't start after header install
Thread Starter
|
New User
Joined: Nov 2011
Posts: 5
Likes: 0
From: Ronald, WA
Help!!! 390 won't start after header install
Hello. New to the forum. Installed headers the other day. Had to jack up the motor to get them in. Truck started, but my tach was bouncing around, and the motor was popping out the exhaust. Now it won't start. Has new HEI dist, wires, plugs. Ran great before the header install / jacking up the motor. Feel pretty dumb at this point. Am thinking that the motor is not grounded, and is affecting the dizzy. Please help, this is my daily driver, and it is snowing. Can't get to work without help.
Fleet Mechanic
Joined: May 2001
Posts: 1,396
Likes: 4
From: Cupertino
Welcome in, Buddy.
This is a headscratcher since obviously there is no connection between exhaust manifolds and ignition. You have disturbed something.
The tach counts pulses in the primary and the fact that it is bouncing up and down suggests some primary misfire. I would start by double checking the 12v. connections to coil, distributor, switch to see if you have jerked anything loose in moving that engine around. Check and tighten the ground strap from engine to firewall. Let us know what you find.
This is a headscratcher since obviously there is no connection between exhaust manifolds and ignition. You have disturbed something.
The tach counts pulses in the primary and the fact that it is bouncing up and down suggests some primary misfire. I would start by double checking the 12v. connections to coil, distributor, switch to see if you have jerked anything loose in moving that engine around. Check and tighten the ground strap from engine to firewall. Let us know what you find.
Thread Starter
|
New User
Joined: Nov 2011
Posts: 5
Likes: 0
From: Ronald, WA
Thanks for the welcome. Nice to have a reply. Getting 12v to the distributor. Checked engine grounds with a volt meter and they are fine. Getting spark to the plugs. Getting fuel to the carb. Motor has been gone through and has always started. Spark, good compression, fuel, should make some kind of noise. Don't understand how the timing could be off, but it is the next thing that i'll check. Pulling hair out.
Fleet Mechanic
Joined: May 2001
Posts: 1,396
Likes: 4
From: Cupertino
You have a tach. When you are cranking does it move up to 200 rpm or so? Indicates the primary is functioning. Have you looked at all slide connections that might have been disrupted when you jacked the motor? Distributor connector? Could you have knocked the distributor loose? Timing?
Calm down. You have fuel and spark. Flooded?
Charge the battery up full, open the throttle full, crank it for ten seconds to clear its throat. Wait ten minutes, give it choke and it will fire.
Calm down. You have fuel and spark. Flooded?
Charge the battery up full, open the throttle full, crank it for ten seconds to clear its throat. Wait ten minutes, give it choke and it will fire.
Fleet Mechanic
Joined: May 2001
Posts: 1,396
Likes: 4
From: Cupertino
Added thought:
You may be flooded and may have wet the plugs. Do what I said above and if it doesn't work pull the plugs and dry them off with a bernzo torch. You obviously know what you are doing.
This is one of the situations where the old guys wish that we were hunching over the fenders to get you started.
Semper Fi
You may be flooded and may have wet the plugs. Do what I said above and if it doesn't work pull the plugs and dry them off with a bernzo torch. You obviously know what you are doing.
This is one of the situations where the old guys wish that we were hunching over the fenders to get you started.
Semper Fi
Thread Starter
|
New User
Joined: Nov 2011
Posts: 5
Likes: 0
From: Ronald, WA
Thanks for the advice. I got it started. Ran it down the road. Was smiling ear to ear, got it home, turned it off, and it wouldn't start. The only thing i did was move the dizzy a bit, checked the number 1 plug wire to make sure it was seated, took off the distributor cap for the millionth time, put it back on, got in the truck and it fired right up and ran strong. Drove it for a while, ran fine. Shut it off, and now it won't start again. Plugs were always dry, so i know it was never flooded. It should run, i just don't get it. Not much hair left. Thanks for the help.
Trending Topics
Posting Guru
Joined: Mar 2006
Posts: 1,182
Likes: 1
when you say that it won't start- what are the symptoms?
slow cranking, no cranking, good crank but no fire, etc.
slow cranking, no cranking, good crank but no fire, etc.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
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
Logistics Pro
Joined: Jan 2011
Posts: 4,762
Likes: 54
From: Antelope Valley ,CA
check your wires to dizzy , sometimes they are old and cracked , 12v could be jumping out of crack before it gets to dizzy , or you just have corroded connections , if in doubt just hack it off and run a new wire . at this point it's worth a try.
Thread Starter
|
New User
Joined: Nov 2011
Posts: 5
Likes: 0
From: Ronald, WA
Appreciate the help guys. To answer rusty68- the motor turn over fine. It gets spark to the plugs. The timing hasn't been changed. Ran great, came home, shut off, now won't light off. The dizzy is a new pro comp HEI unit. I am starting to think that it might somehow be my ignition switch? I am getting 12v to the dizzy, but maybe i am not while i am turning the motor over due to an old switch? Sooo frusterating. The truck runs great, it just won't start anymore. I have spark, fuel, compression. What the heck?
Thread Starter
|
New User
Joined: Nov 2011
Posts: 5
Likes: 0
From: Ronald, WA
Problem Solved
I finally got it. It was the ground strap under the coil on the HEI. The coil wasn't grounding thru the strap becaseu of a screw that came loose. What a PITA. Seems stupid now, but it had me on the ropes. Thanks to all that tried to help. I will try to return the favor if i can. Take care. 70sportcustom.
Thread
Thread Starter
Forum
Replies
Last Post
Purplepills
1961 - 1966 F-100 & Larger F-Series Trucks
33
Aug 31, 2015 09:51 AM
Nathane
General Automotive Discussion
1
Oct 22, 2007 11:21 AM
john1972f25
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
6
Dec 28, 2002 09:07 PM
