a4 hesitation

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Apr 10, 2011 | 05:18 PM

Go On 3

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a4 hesitation

i just recently purchased this car last summer knowing it needed alot of tlc, so over winter i put in new plugs, msd wires, msd coil, longtubes, lt4 knock module, new acdelco o2 sensors, deleted smog, egr,and air,

Idle sounds great when in park but when i took the car for a short drive today(openheader) it was hesitating real bad on light throttle, it had this issue on cold startup last year but the issue seems alot worse now.. i have a actron scanner and checked o2 reading(800range) and tps at 0% and wot@100%, how do i check the iac? what reading should i be seeing?? only codes present were for egr and smog

cam226/230 , i know it needs a tune horribly... im going for a dyno tune in 3 weeks so im trying to sort everything out

Last edited by Go On 3; Apr 10, 2011 at 05:25 PM.

Apr 10, 2011 | 05:28 PM

Gojira94

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O2 values indicate it's obviously pig rich on both banks. Get that tune, even a mail order will help a lot. I'd imagine the IAC counts are going to be pretty low, trying to stay open as far as it can to try to let more air in for all that fuel it's dumping...

Apr 10, 2011 | 05:35 PM

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i was told it has 30lb injectors so thats why its so rich, i have stock injectors that i plan on throwing in when i drive it to get tuned, do u think the hesitation is something i could try to fix(bad sensor) or you think its in the tune?

Apr 10, 2011 | 05:45 PM

Gojira94

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You could put the stock injectors back in now- they probably wouldn't hit 80% of their duty cycle until around 5200-5500, even with that cam. You could almost get away with stock injectors. And if they're Ford red tops, remember they're more like 32# at 43 psi...

And I'd think there'll be little to fix after the tune.

Apr 10, 2011 | 05:48 PM

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ok, ill put the stock ones in tomorrow morning, and yes they are the redtops, thanks for the info

Apr 10, 2011 | 08:42 PM

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ok i put the stock injectors in tonight but cant start it because the neighbors will have a cow, i dont think the injectors are the main problem since it had the 30lb injectors last summer and ran fine, anything else i can look at?

Apr 11, 2011 | 08:43 AM

Gojira94

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So, did you start it up this morning? Untuned with 30#ers is going to wash the rings pretty fast. I'd change the oil to fresh before driving it to the tuner, even with the 24#ers in. A change of plugs is almost a guaranteed necessity. That may be a lot of your driveability issue by itself. But it's not going to fix itself, even if you got away with driving on the 30s for a bit. I ran the car in my sig for a total of about 25-30 minutes (1st startup, some idling, one quick horrible trip down the street). I had to change the plugs and oil for my tuner, just from that little amount of running time.

You may find your O2s have gotten lazy from fouling as well. With the tune done and new plugs, they may get hot enough to clean up somewhat, but I'd keep an eye on their voltage numbers with a scanner. They can be flaky and not give you a DTC until they go low enough on voltage for long enough to set a code. Meanwhile you're scratching your head over stumbling/ hesitation due to unbalanced BLMs/ rich condition on one or both banks. Been there...