New problem bad backfire??

**FBracing1222** · 03-18-2010, 12:38 PM

Well got my car running finally and a new prob has arrived. Now under WOT it backfires really bad(like a 12 guage going off) and the engine shuts down. It will then start right back up. It drives fine when driving regularly. It is also not just when drivig we did it in nutural and it backfired and died. So what's up now any ideas?? Thank you

**bills98ta** · 03-18-2010, 02:29 PM

I had that with a rebuilt motor... Had reluctor ring damage... Could be the crank sensor too. New Motor ???

**FBracing1222** · 03-18-2010, 06:44 PM

Not a new motor but it hadent started since dec til Sunday. But I did put a new crank pos sensor in it to try an fix the old prob. Could it be tat I need to take it to get a relearn?

**bills98ta** · 03-18-2010, 07:14 PM

The relearn might do it.

**FBracing1222** · 03-19-2010, 11:44 AM

Bump any1 else??

**Cutlass** · 03-19-2010, 07:46 PM

relearn crank position sensor and let us know its fixed.

**FBracing1222** · 03-19-2010, 08:55 PM

The only prob is I don't want to test it haha, cus a new fast would run me a lil bit of change haha.

**bills98ta** · 03-20-2010, 03:27 AM

It will sure beat fixing the reluctor ring on the crank !!! I'm good at that now !!! LOL

**FBracing1222** · 03-23-2010, 04:39 PM

So I was looking at the vacume lines on my engine. I found that the one going to the back of the engine by the intake manifold wasn't on very well. I barely tugged it and it fell right off. So I put it back on all the way and turned my car on. I revved it to 6 grand and it was fine. So I'm hoping and thinking that was the problem. What u guys think?

**Conflict** · 03-23-2010, 04:57 PM

sounds like thats it, my lose vacuum line made my car misfire, if you mean the one by the throttle plate then we had the exact same part fail on two different types of motors

**cammed goat** · 03-23-2010, 05:15 PM

Drive the car, enjoy and keep us posted.

**FBracing1222** · 03-27-2010, 09:14 PM

Sooo bad news. That was indeed NOT it. It did it again tonight. I am at my wits end with this car right now. Fix a problem and another arives. Idk what to do next. Any suggestions?? I'm thnkin push it in street, let it get hit and collect insurance money? Haha ok maybe not just yet.

**Cutlass** · 03-28-2010, 03:53 AM

Is the backfire through the intake manifold or is it out the tailpipe?

**FBracing1222** · 03-28-2010, 11:18 AM

Intake. I changed the plugs I had delcos in and went to tr55 hope that might of Been it.

**FBracing1222** · 03-29-2010, 11:04 PM

Bump

**DaddySS** · 03-30-2010, 12:04 AM

Do you have access to a tuner who can scan it and look at the signals? The only thing I can suggest without more info about what is really happening is to make sure everything is clean and tight, verify all your grounds, etc.

**Spaz** · 03-30-2010, 04:32 AM

i know my brothers impala did this when we accidentaly switched plug wires... i'm pretty sure it's near impossible to do that on a ls1...

but it sounds spark related to me...

**FBracing1222** · 03-30-2010, 09:48 AM

Unfort no scanner other than drivng 4 2 hrs. And Im with u on the spark thing but there deff right haha. That's y I changed my plugs hoping they were it.

**Spaz** · 03-30-2010, 10:09 AM

Originally Posted by FBracing1222

Unfort no scanner other than drivng 4 2 hrs. And Im with u on the spark thing but there deff right haha. That's y I changed my plugs hoping they were it.

i got an idea... check your plug wires for slices/melting... the spark could be arching on to your manifold/header and letting the fuel pass through unignited...

**FBracing1222** · 03-30-2010, 02:25 PM

Well the wires have less than 2000 miles on them so I didn't change them with the plugs Sunday. But I did check all of them over and all looked to be in tip top shape.