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Thread: Hesitation at 4k rpm after setting timing

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Posts: 1-7 of 7
2011-09-28 02:07:38
Hesitation at 4k rpm after setting timing
This is going to be a long read,this weekend I installed a new timing chain tensioner, at the same time I also re set the timing just to make sure it was on point. When I removed the old tensioner the timing skipped a bit so I had to reset it any way.I tried to turn the cams with a 1" wrench and the exhaust cam moved easily but the intake one was a little hard to move, thats when I broke loose all the cam caps,which were very hard to remove probably due to the fact that the person who originaly installed my cams did not torque them properly. Do you guys think that the cams being over tightened may have caused any damage? My valve train seems to be a little louder now that I torqued them to spec.
Well after that I set the timing I made sure the pulley was at the 2nd mark and piston 1 was at tdc,made sure the cam lobes on cylinder one were facing away from each other, intake cam at 10 o clock, exhaust at 12 and counted 20 dots in between both marks on the pulleys. After that I went driving around to check every thing out and I encountered a weird hesitation at about 4k rpm and an occasional intake backfire, it only happens at wot though the car drives fine otherwise and idles perfectly.
I do have one vacuum leak but I dont see how it would cause my problems, especially since it was present before i re set timing.My vacuum leak is coming from one of the gaskets on my intake manifold its missing a small piece, it happened when I installed my injectors .Im preparing the car for my turbo set up and Im just testing everything. The car is currently running on a jwt tune set up for turbo, 740cc injectors at 3 bar,z32 maf, and s4 cams.Do you guys think the injectors may be causing this problem since they are so big and I am still n/a?Or may it simply be the ecu adding fuel at that rpm because its set up that way because its tuned for a turbo? I did feel it a little bit before but it did get worse once I set timing. Here is a picture of how the cams are set.
2011-09-29 01:22:19
so 37 views and no one can tell me if my timing is correct atleast?
2011-09-29 01:30:15
looks pretty close, if anything the intake cam is one tooth too far back. I take that back, you're dead on 20 pins between them. Your tune has a lot to do with the hesitation at 4k because the ecu thinks that you are coming into boost at that point and I'm sure your maps are based on that. Do you have a wideband installed?
Last edited by nsusammyeb on 2011-09-29 at 01-34-11.
2011-09-29 02:14:18
thanks for the input I felt that the timing was correct, the hesitation was there before I re set it but it feels worse now the car practically skips from 4 kto 5k and then picks up again it sounds really bad and then in high gears under load if i wot it i get an intake backfire. I know the tune has an effect on it but Im just worried about driving the car like this because I have to daily it for a few weeks while I fix my other one. I currently dont have a wideband but I will definitely be purchasing one soon, I need to know whats going on with the car.
2011-09-29 02:23:01
i always thought the dark links lined up with the dots on the sprocket... then again, idk
2011-09-29 03:04:17
Have you checked your ignition timing to see if it's even close?

Originally Posted by ga16eats
i always thought the dark links lined up with the dots on the sprocket... then again, idk

There are three colored links on the chain. 1 for crank, 1 for intake, 1 for exhaust...throw them out...no one uses them. Put the motor at TDC, exhaust at 12, intake at 10, 20 pins between, and be done with it. I've had problems lining up the colored links because I slipped off of the crank before and have never had a problem doing it this way.
2011-09-30 00:31:45
i havent checked the ignition timing yet my friends timing gun that we were using actualy melted a wire on my header and stop working, Im going to take the car to work tommorow to check.
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