A4 Won't Upshift at WOT/ Backfiring
07-18-2007, 03:52 PM
#1
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A4 Won't Upshift at WOT/ Backfiring Well I originally posted this in the LT1-LT4 section but haven't gotten many responses so I figured I'd at least try it here. The car is a 96 Z28.
Last month I got 3.73 gears put in along with a tune from madz28 programed for harder shifts. Well the car was running fine until the other week. At first I noticed that when I floored it, it seemed to always start in 2nd gear and wouldnt downshift to 1st.
Then later on that day when I decided to floor it on the highway, once i hit the upper rpm's the tranny wouldnt upshift and the car would just backfire. But whenever I would drive it normally it would upshift just fine, even at half throttle or more.
So I drove it around a few more times without ever flooring it and it drove around just fine. Then the other nite I had to give it a lil gas to get by something and it kinda did the backfire thing again but not as bad because I didnt exactly go WOT. After driving a few more seconds down the road the engine started to backfire quite loudly just at random times.
After it did that a few times I put the car in neutral and coasted off to the side of the road, but while doing that the car just died on me. I was able to start it right up and drive home fine. So what im asking is if anyone has any possible ideas what it could be, whether it be from the gears or the new pcm or any other possible problems? Thanks
Last month I got 3.73 gears put in along with a tune from madz28 programed for harder shifts. Well the car was running fine until the other week. At first I noticed that when I floored it, it seemed to always start in 2nd gear and wouldnt downshift to 1st.
Then later on that day when I decided to floor it on the highway, once i hit the upper rpm's the tranny wouldnt upshift and the car would just backfire. But whenever I would drive it normally it would upshift just fine, even at half throttle or more.
So I drove it around a few more times without ever flooring it and it drove around just fine. Then the other nite I had to give it a lil gas to get by something and it kinda did the backfire thing again but not as bad because I didnt exactly go WOT. After driving a few more seconds down the road the engine started to backfire quite loudly just at random times.
After it did that a few times I put the car in neutral and coasted off to the side of the road, but while doing that the car just died on me. I was able to start it right up and drive home fine. So what im asking is if anyone has any possible ideas what it could be, whether it be from the gears or the new pcm or any other possible problems? Thanks
07-18-2007, 04:28 PM
#3
do anything to your engine around the same time? mine did the samething but it was after i pulled my LS6 manifold off, i torqued the bolts down in the wrong order and i forgot to slide the clip back on the vacuum line to the brake booster . . . fixed everything and now my car drives better than ever
pretty much you have a detonation problem. have that pcm check also, might be telling the engine when to let fuel in at the wrong time
pretty much you have a detonation problem. have that pcm check also, might be telling the engine when to let fuel in at the wrong time
07-19-2007, 12:29 PM
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Originally Posted by King Nothing
do anything to your engine around the same time? mine did the samething but it was after i pulled my LS6 manifold off, i torqued the bolts down in the wrong order and i forgot to slide the clip back on the vacuum line to the brake booster . . . fixed everything and now my car drives better than ever
pretty much you have a detonation problem. have that pcm check also, might be telling the engine when to let fuel in at the wrong time
pretty much you have a detonation problem. have that pcm check also, might be telling the engine when to let fuel in at the wrong time
07-19-2007, 04:30 PM
#6
I will agree your looking at a tuning issue and likley its on the engine side , Many people do not realize the engine and trans sections are not stand alone many things in the engine running and even a problem with and engone componet can affect the trans and how it works I would look at the MAF as suspect myself
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07-21-2007, 12:11 AM
#7
I'm beginning to suspect my MAF as part of my shifting issue where it won't shift at WOT, is there anything I can do to test if it is the cause or not without getting a new one? I keep throwing 1133/1153 metering codes as well, but that seems to be O2 related.
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07-21-2007, 12:44 AM
#9
I'm thinking if I can't smooth this thing out after 3 tear downs in 5 months I'm going to take the leap and go for either a built unit or a 6 speed swap. The swap is sounding more and more attractive because I just plain don't trust automatics. I've owned 2 and they both had/have a ton of problems and make me wonder every time I get in if it will get to where I need to be.
07-21-2007, 12:49 AM
#10
Yes but the things that may affect your auto shift in the tuning are also affecting your performance in most cases a switch to a 6 spped is just covering the issue and you will be slower and trust me I read all forums those guys have there issues too
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07-21-2007, 01:17 AM
#11
Oh yeah, I'm not trying to cover the issues I have in other areas, I've got those in line to get fixed first but I get the feeling that the transmission is just beat. If it comes down to a new one, I may just head over to the T56 as it is my preference. Also, had a question for you. I saw on ebay you sell some remanufactured units, do you have any for LS1?
07-21-2007, 11:39 AM
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Originally Posted by performabuilt
I will agree your looking at a tuning issue and likley its on the engine side , Many people do not realize the engine and trans sections are not stand alone many things in the engine running and even a problem with and engone componet can affect the trans and how it works I would look at the MAF as suspect myself
I got the tune from madz28 so do you think I should just try and contact and discuss it with him?
07-21-2007, 01:24 PM
#14
Okay, I got under there today to look at something and noticed that the trans has been venting fluid out of the vent thing. The whole top is covered, along with the wiring harness and the pass side rear O2, it has even gotten into the exhaust pipe on the pass side. I know it was not over full, so what gives? I'm taking a shot in the dark but I'll guess it has to do with its not shifting.
07-21-2007, 02:14 PM
#15
Venting out the top is a sign of the trans overheating , You probably do have trans issues. As for ebay no we dont have LS1 units there but we do on our website, In fact we sell very very little on ebay as comparitive to all the backyard builders on there we are a bit high on the price in that forum. Hard to match the price of the guy in his backyard lol. But it is considered and excellent advertising source to get people to come to our website. In other words we use ebay as a wide audience comercial.
Oh and on the MAF one test is when the car is warm idling hit it with a small hammer not too hard jst to shock it and liste for a change in idle speed or characteristics. Also you might try cleaning it also. If the car stumbles when you hit it the MAF is bad and need to be replaced.
Oh and on the MAF one test is when the car is warm idling hit it with a small hammer not too hard jst to shock it and liste for a change in idle speed or characteristics. Also you might try cleaning it also. If the car stumbles when you hit it the MAF is bad and need to be replaced.
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07-21-2007, 09:09 PM
#16
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go to autozone and get some MAF cleaner. clean it off, let it dry and let us know if anything changes. sounds like your tune had the line pressure in the trans raised (a no-no in most people's opinion), and a dirty MAF may be causing your line pressure to increase even more. this could cause serious problems.
07-22-2007, 01:23 AM
#17
I cleaned the maf the other day, it still looks like new right now. However, once I changed my fuel filter today I dropped the codes I was pulling and shifting went back to normal. The filter was TERRIBLE (I have pics up in the general maint section) and I honestly don't know how fuel flowed thru it. I drove about 150 miles today and it shifts like a dream at WOT. I'm not sure how this all works out in the PCM, but as long as its good to go I'm happy.
