eratic idle after cam install???
eratic idle after cam install??? just installed the t2 (232/234 595/598 on a 112 lsa) cam and a set of 30lb injectors on my 98 a4 and since then the car has an eratic idle not the idle i'm supose to have with a cam. the car seems to idle fine sometimes and other times the idle will shoot down to almost stalling then shoot back up to almost 1500 and it will continue doing this til it finally does stall. if i give it alittle gas just to keep it alive it will eventually idle steady. i took it to my tuner and beside his a/f meter being down he said he thinks i have a vaccum leak but checked all vaccum lines and manifold but nothing plus wouldn't a vaccum leak stay constant? anyone ever have this problem i'm kinda stumped on this, is this just a tuneing issue with this cam or what?
well i dont think you would have a vacume leak because they will actually help out the idle of large cams. My guess is that it is extremely rich at idle. Large cams want alot less fuel and more spark at idle, and with you adding larger fuel injectors thats just addin more fuel down low. Its probably running pig rich, which will cause horrible idle. Tim
I have the torquer v 3 cam, and I am experiencing the same thing. I talked to my tuner and he told me to try and adjust the screw for the throttle body, and if that doesn't help, I could send the computer to him, and he could add some air into the idle for me. When I got the cam installed, I had a dyno tune at the same time. I just have not gotten around to adjusting the screw.
Sounds like a 98 car problem we see alot. The 98's are a complete bitch to idle,expecially with a A4 big Cam setup.The computer can't keep up.Takes alot of tuning time to get it right.Of course a few 98's have no problem.
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I just installed a simular cam in my block 2 weeks ago (234/238 ish), and I definetly got the same idle issue as you described.
The idle will hunt a bit at 1st start-up for about 10-15 seconds. I need to give it a little gas during that time to keep it from dropping too low & stalling out, after that, it idles alright.
I have not been tuned yet.
My dyno session is setup for Tues, the 17th at New Era Performance.
I cant wait to get the car re-tuned, and the weather around here to break for the summer!
The idle will hunt a bit at 1st start-up for about 10-15 seconds. I need to give it a little gas during that time to keep it from dropping too low & stalling out, after that, it idles alright.
I have not been tuned yet.
My dyno session is setup for Tues, the 17th at New Era Performance.
I cant wait to get the car re-tuned, and the weather around here to break for the summer!
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If you want to know if your problem is fuel tuning you need access to a scanner or computer that will interface your OBDII computer. You will need to look at your fuel trims at idle. If they aren't close to 0 + or - about 10, then your computer is fighting to correct your fuel. If you are running rich, your trims will be negative numbers meaning the computer is pulling out fuel. Also, watch your front 02's and make sure they are swinging between high and low voltages. This will help indicate that they are reading properly. Did you degree the cam when you installed it? I always do. It is worth the time to make sure they ground it properly and sucks not knowing if that is your problem.
well as many of you described the car is running pig rich enough to burn my eyes when behind the car. and i did really notice the idle get funny once i put the 30lbers in i guess its just a tuneing issue. and blownbluez06 i didn't degree the cam but i did slap the same cam in my buddies car (also a 98) and he had no issues til last night when we put in his 42lbers. i think it is just running too rich considering i changed my plugs the other day and they were all fouled out. thanks for the info guys.
well brought the car down for a tune again and my tuner found the problem. its a bad maf bought a new one and the car has a little bit of trouble idleing on start up but once it gets its idle it holds it. hopefully by next week or the week after i'll have my new numbers.
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just for extra info!!!
One factor that is easy to miss, is that larger cams / lopey cam will cause the pcm to think the car is misfiring. The lope of the cam causes the cam position sensor to think a misfire is happening, causing the PCM to act erratic in trying to fix it. It causes your car to go into limp mode and dump in more fuel.
Its behaving just like when a tps (throttle position sensor) goes out!
One factor that is easy to miss, is that larger cams / lopey cam will cause the pcm to think the car is misfiring. The lope of the cam causes the cam position sensor to think a misfire is happening, causing the PCM to act erratic in trying to fix it. It causes your car to go into limp mode and dump in more fuel.
Its behaving just like when a tps (throttle position sensor) goes out!
