First N20 BACKFIRE.
Thread Starter
9 Second Club
iTrader: (34)
Joined: Mar 2005
Posts: 2,248
Likes: 0
From: SPRINGFIELD MISSOURI
First N20 BACKFIRE. PLEASE READ THE END OF THE POST LAST PAGE.......... NEED HELP.....Well made a new best time that I will post up later of a 10.14@129.31 with the air fuel @ 12.3 which was off. So I came back and richin it up some. Then made another pass and BOOM. here is the pics of the backfire dont know what happen yet this is on a 200 shot progressed staring a 60% off the line and progress to the 200 shot in 2.1 sec.
vid watch it. I guess the spark plugs ends come out of the exhaust?? any feedback let me know.
vid watch it. I guess the spark plugs ends come out of the exhaust?? any feedback let me know.
Last edited by dnkynrbk; Aug 24, 2008 at 10:29 PM.
12.3 was good should have left the fuel out. how much did you put back in? probably not the cause of the backfire though. did you pull plugs before the run? car will backfire if you run it on nipped plugs.
I would almost bet you took the plugs out the pass before and there reason for the backfire on the next pass. I has the same thing happen to me with my fathers car a couple months back.
this was the first pass after trying autolites and since went to TR7 which we have always used and never had another issue
this was the first pass after trying autolites and since went to TR7 which we have always used and never had another issue
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Thread Starter
9 Second Club
iTrader: (34)
Joined: Mar 2005
Posts: 2,248
Likes: 0
From: SPRINGFIELD MISSOURI
video is right under the plugs..
TR7 PLUG GAPPED AT 32
116 ON DEDICATED FUEL CELL
93 IN GAS TANK
The timing has been retarded I will have to check with my tunner on #
10 psi fuel pressure.
NX single stage 200 shot the jets sizes I will get you there for low pressure fuel.
I did not check or pull the plugs out on that pass of the 10.14.
Would the fuel pressure gauge on the fuel cell that reads what the fuel pressure is cause it. not the regulator.
Now my fuel pressure gauge is not working but if I tap it. It does work. Would something cause a block.
TR7 PLUG GAPPED AT 32
116 ON DEDICATED FUEL CELL
93 IN GAS TANK
The timing has been retarded I will have to check with my tunner on #
10 psi fuel pressure.
NX single stage 200 shot the jets sizes I will get you there for low pressure fuel.
I did not check or pull the plugs out on that pass of the 10.14.
Would the fuel pressure gauge on the fuel cell that reads what the fuel pressure is cause it. not the regulator.
Now my fuel pressure gauge is not working but if I tap it. It does work. Would something cause a block.
Just do a quickie compression test and that will tell ya if you have a cylinder or two out of whack, then move on to a cylinder leak down test if need be. High rpm lean back fire is my guess. if it nosed over on the prior pass from going lean, well then the stage is set for a backfire. why, could be a couple reasons, just because the log says 12.3 a/f does not mean that it saw 12.3 at highest load. Being leanish and having to much timing (speculation at this time) has set the stage for a hot spot on your compromised plug(s) and thus firing at the wrong time and getting up into your plenum igniting unburned fuel due to reversion. Now remember, this is just a speculated guess with the info put forth and not an absolute. Hopefully you didn't hurt anything. I have had the same thing happen and it took out about half of my cylinders, the rings I guess couldn't take the explosion, lol. Still put down some outrageous numbers with ½ the cylinders reading 100psi on the compression and the other ½ reading 210psi, lol. If we want to go fast, it is not cheap, and anyone whom has been there has paid the piper. keep us updated on what you find. 
Robert
Robert
Thread Starter
9 Second Club
iTrader: (34)
Joined: Mar 2005
Posts: 2,248
Likes: 0
From: SPRINGFIELD MISSOURI
well just put plugs in and took it to the store got on it a little bit and it started knocking from the drivers head like a rocker off or something making a fast knocking noise if you rev it up it knocks faster so i turned it off any ideas. Oil pressure is fine. I guess im going to pull the valve cover off and see what up. any other ideas.
Again, a cheap 5 dollar compression tester will tell a story and it could be a number of things at this point. Could be as bad as a bent rod, or busted piston and easy as a chunk of ring caught in valve seat, or something else. Time for diagnostics.
Robert
Robert
Well maybe. The problem being if it's a bent rod which hole will it be, or ring seal or what ever? My opinion is at least pin point the problem so you know what your looking for. A cylinder leak down test will tell you if it's a intake, exhaust, rings/cylinder, head issue. Just get each cylinder to have each valve closed and apply air, then you can hear the air coming out the exhaust pipe, the intake tract, the PCV or into the coolant to get an idea of what to look for up on disassembly. All I did for mine was to run a comp test, then i squirted oil into the cylinder and the compression came up indicating that the rings were no longer sealing properly. Now if that had not worked my next move would have been a leak down test. You can get a tester at Harbor freight for pretty cheap.
Robert
Robert