dnkynrbk

iTrader: (34)

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.

ShiznityZ28

iTrader: (11)

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.

LS1 SPEED

iTrader: (22)

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

BAKED

iTrader: (14)

I'd do a leak down just to make sure you didn't burn a valve or **** up a valve seat when the tip of the plug went through.

dnkynrbk

iTrader: (34)

Im going to try and do a leakdown test. Is there another way besides a leakdown test. Or is that the only way to test the valve

BAKED

iTrader: (14)

It's the best way. You can just chuck air up into the cylinder and listen for air blowing but if it is a very small leak you may not hear it.

ATVracr

iTrader: (5)

Post up the details of your tune up.

Plugs
Fuel
Timing
What jets
fuel pressure

camscam02

iTrader: (21)

makes sense because on the other pass you posted a vid up it died up top and thats where i bet you burnt up those plugs and why it only trapped 129

Beaflag VonRathburg

iTrader: (176)

Maybe it's because I'm at work, but I don't see a link for the video.

dnkynrbk

iTrader: (34)

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.

dnkynrbk

iTrader: (34)

Would nipping the plugs like that make me lose mph on the top end?

dnkynrbk

iTrader: (34)

Yea on my pass you can hear it falling off.

ShiznityZ28

iTrader: (11)

Yes. and alot of times it can still run and idle just fine if it nips them but has no burnt the trode off.

dnkynrbk

iTrader: (34)

Going to put new plugs in today and see what happens. Im going to do a leakdown test too.

Robert56

iTrader: (2)

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

dnkynrbk

iTrader: (34)

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.

dnkynrbk

iTrader: (34)

pulled the valve cover off all rockers look good and the springs and valve looks good any ideas

Robert56

iTrader: (2)

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

dnkynrbk

iTrader: (34)

if i pull the head off that would probally tell a betters story right

Robert56

iTrader: (2)

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