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Username Post: 454 HO Back Fires and lo        (Topic#357554)
bluesea112 
Poster
Posts: 2

Reg: 08-06-19
08-06-19 08:32 PM - Post#2772591    

I have a '78 chevy 454 HO that I had rebuilt with a cam that gives me 590hp on the top end. I am running a Holley 850 4 barrel carburetor.

The engine runs great until it heats up. After it is good and warm I hit 3000 rpm and the engine backfires several times and loses all power. I can keep the engine at 2900 rpm and it is fine, but when I take it to 3000 it starts the series of backfires and rpm falls to idle speed. I also noticed that the headers are turning BRIGHT red and glowing while I am running the engine in the high 2000 rpm range.

Does anybody know what could be causing the engine to backfire and lose power like that and cause my headers to turn bright red?

Thanks, in advance, for your help!



 


IgnitionMan 
Valued Contributor
Posts: 3669

Reg: 04-15-05
08-06-19 09:20 PM - Post#2772593    
    In response to bluesea112

What specific ignition system?

Have you done a battery load test, and charging system check?



 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17390
grumpyvette
Age: 71
Loc: FLORIDA USA
Reg: 03-16-01
08-07-19 08:26 AM - Post#2772613    
    In response to IgnitionMan

sure sounds like your ignition advance curve , IGNITION CONTROL MODULE,or the fuel/air ratio FUEL PRESSURE REGULATOR OR FUEL PUMP, and fuel delivery system area areas that requires investigation/inspection

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


 
bobb 
Super Senior Member
Posts: 5464
bobb
Loc: paradise
Reg: 09-05-03
08-08-19 08:48 PM - Post#2772765    
    In response to bluesea112

im thinkin low fuel pressure. but thats just a gut feeling. any of the above mentioned could be the problem. gotta do the checklist, one by one.

70 L camino, grampa engine, g-force 5 spd, road rage suspension. Pray first before all else fails.


 


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