General Maintenance & Repairs - backfires in drive
10-30-2005, 10:37 PM
This problem started the other day. I only drive my car on weekends and to fire/ems calls. The car sat for a while due to the fact that it rained every weekend with about a 1/4 tank of gas. Well it finally stopped raining and I went and filled it up with gas (93 octane from hess which is where I usully get gas from) and now when I get on it it pulls pretty good through first and second but when it goes into third it starts backfiring through the exhaust. I'm wondering if it sitting in the rain and a couple of nights with 40 degree temp drops if condensation could cause this or is it something else. The car has been running rich since the header install so could it be a fouled plug. Also something else I feel I need to mention is that the other day the car went into learn mode without the battery going dead and every once in a while the radio clock only displays part of the numbers. Any ideas would be great b/c I don't know where to start.
BTW the car has 35,500 miles on it and the ses light is on but I haven't had the rear o2's deleted from the computer. I will try to run it by Advance and see if there are any new codes in it.
10-31-2005, 09:29 PM
ok now I am stuck. I ran the codes today and got the rear o2's and the egr codes. This makes sense b/c they are both in the bottem drawer of my tool box. Now where do I go???????
11-02-2005, 10:29 AM
Check your plugs, thats easy enough. I doubt it would make it backfire but worth a shot. Another thing is did you remove both EGR and AIR or just the EGR? I know that I had some backfires when I still had my EGR and AIR. When headers went on and AIR came off, backfires went away. After time it gets a bad check valve and causes backfires/running pig rich.
11-02-2005, 10:58 PM
Well I removed part of the air system. I didn't take off the piece on the back of the intake or the piece with the electrical plug. I'll try those tomorrow and see if it helps. By not removing those parts do you think it would cause it to backfire. Also can I just tape up the electrical plug?
BTW thanks for the link it was very helpful even if it don't fix this problem.
11-04-2005, 05:45 PM
Yeah, as long as the air system isnt hooked up to your headers, it doesnt really matter. As far as it to backfire, its a possibility, and I know that my problem went away when I got my headers w/out AIR & EGR You can read through that post and see exactly what to do to remove the system. I wish somebody else would give some input on the topic.
As for the electrical, you can remove everything connected to the AIR system, the pump is by the wheelwell area. I just left mine hanging in there because I wanted to get the car going after a long header install. It wouldnt hurt to tape it up.
Some other things to check, plug gap. I know that plugs can cause backfire, especially if they have the wrong gap.
Go ahead and search for backfire if you havent, I looked through like 3 pages and saw many different conditions for exhaust backfires and popping (none exactly like yours), but no reason to keep searching.
11-04-2005, 10:15 PM
Thanks I checked the plugs and they all looked good except for they had a green discolartion on them. Anyone what would cause this. Also now that the outside temp is back in the 60's to 70's it doesn't seem to be doing it any more. I also removed the rest of the air system. Could a vacuum leak on the hose that goes to it cause the problem. I put a screw in the line before but it didn't feel real tight so this time i put silicone on ti b/f I put it in.
11-05-2005, 11:41 AM
I have a feeling it was plugs all along now that you checked and said green. Usually plugs can tell you alot about how your engine is running. I cant think of a better way ot describe it than what this is:
Normally the white area of the porcelain has a chalky appearance. If you see the porcelain take on a shine then it is time to change the plugs because the glass that is in the porcelain has been melted and has glazed the surface. If the car has been running rich (due to lots of idling or incorrect fuel mixture) then it is possible to glaze the plugs and short them out during a run because of the sudden heating of the plug with the soot on the porcelain. This glazing appears to be a glossy coating on the porcelain with a splotches of color of greenish yellow or brown. These two different glazings will cause the plug to short out and misfire and raise ring lands or make a popping through the exhaust when going down the track.
As for using silicone to finish closing it up, good work. I think a combination of things maybe causing problems.
11-05-2005, 09:17 PM
Thanks for all your help. I hope this solves the problem. I now wish I had put the new plugs in while I had them out. Oh well I needed something to do at work tommorow anyway. Thanks for your help I was about to take it to the deralership and let them have a look at it, but I'll def try this first. They told me you had to lower the engine to change the back plug on the passenger side :eek2: so I really didn't want them touching it.
11-06-2005, 01:26 PM
Let me know if this works out for you. The back was is a PITA to change, but you don't have to drop the engine. I'd never really trust a stealership to work on my car. Hell I even work at one. :eyes:
I really think with the plugs change, and the AIR system completly blocked off, things should be better.
11-06-2005, 02:16 PM
I hope so I'm running a friend of mine Friday at the track and he's got me by a couple tenths but he sucks on the tree. So I hope this fixes it.
Well he had me by a couple of tenths b/f the verter, shift kit and ET streets. :devil:
11-12-2005, 12:05 AM
It turns out that it was one of two things. Probally the plugs I changed them and it didn't backfire (pop) any more. I also added 2 gals of 110 race fuel to it also. If I had to guess it was the plugs. Thanks again for all your help. I lost to the s10 but he sprayed a 150 shot on me. I guess he wanted to be sure he beat me.LOL
11-12-2005, 10:38 AM
Awesome, glad its fixed. I think it was a combination of both.