lbfd48

Its a 99ls1 single turbo. It ran great for about a week after getting it tuned. Just today, a loud popping is coming out of the exhaust, when I let off of the gas. Has anyone had this problem before? Could it be a bad coil?

Thanks

cbr600rx7

iTrader: (12)

Do you have a A/F meter? Is there blackish smoke coming from the exhaust? Is the car filling a little more slugish or boging? Any codes?

theblur98ss

iTrader: (71)

Does it seem to do it more when you go from full throttle to coasting? I had a motor doing that and it was from leaky valve seals.

elias_799

iTrader: (8)

can you get us a video of this popping ?

is it a loud bang or just a pop ?

lbfd48

No codes, and it does it after wot and just crusin. I don't notice any smoke. For example I was crusin at 2200 rpms, let off the gas and it popped 3 or so times like a gun fire. It does any time you let off the gas while driving.

bongva

iTrader: (7)

plugs? it happened to my brothers supra, and it was his plugs that were bad

cbr600rx7

iTrader: (12)

What is you exhaust system like from the turbo back?

lbfd48

Plugs are tr6 with less than 200 miles, but I will prob get new one. My down pipe is 3in to 3.5in straight pipe that turns down at the rear end, but like I said it was fine for a whole week so idk.

Keep the ideas coming, ill try them all.

Thanks

black98ws6ta

iTrader: (77)

Do you have a wideband? Does it feel like it runs normal at WOT?

ls1 1990 VN

Unburnt fuel igniting, mine does it

lbfd48

Yes, it has widebands, and Yes, it also feels normal at wot. I just dont understand why it just started, I mean the popping is stupid loud, and everyone looks likes its a drive-by. Its prob not good 4 the turbo.

cbr600rx7

iTrader: (12)

What is your wideband reading? I have not had the issue on a LSX car but i did on my old TSI talon. After a small turbo upgrade to a 16G, FMIC, and a AFC the car was running good. About a week later for what ever reason the car stared acting up just driving around normal. When you came off the gas it would pop and even some times during normal driving or under load. It was of course running crazy rich. A quick tune and the car was fine.

Also have you had any change in weather?

lbfd48

I dont know what the wideband is reading or how to check it lol. The weather is about the same. When I get off work friday night im changing the plugs. I did take one of them out and it was mostly white.

cbr600rx7

iTrader: (12)

Your wideband will tell you if you are running rich or not. What kind of wideband are you running? Also who dyno tuned the car after the turbo.

lbfd48

The widebands were in it when I bought the motor from my friends wrecked ws6, so idk what kind they are, but they have a red sleeve over the wires. It was tuned by engine power systems out of Baton Rouge.