why do i have to reset ecu once a week

[maduer2]

i have a 91 talon tsi awd auto tranny, it has the following done to it..
turbo back exhaust, cat removed, ported 14b turbo, boost controller set 15psi, 450 injectors, k@n air filter, hacked mas,dejon tool 3in intake, ported 2g exhaust manifold, new plugs wires and o2 sensor...
my problem is that sometimes(alot) when i floor it from a stop the boost goes up and the car rolls out very slow, and once it shifts into second ill let off the gas and get right back on it and the car will take off..the car never acts up when im already moving 30mph or more.only from a stop and if i reset the ecu once a week it will only act up every now and then and as the week goes by it progressivlly get worse meaning it will act up almost every time i floor it from a stop....thanks to any one that can help with this stubborn problem...Eric

 

[turboholic]

-Is there any check engine light?

 

[Enigma_Man]

It sounds very much to me like a case of phantom knock/real knock.

Try turning the boost down to 12 psi or so, 15 on the 450's is a _little_ much, though you might be okay.

In my car (until recently) first and second gear were the worst for phantom knock. I have a logger, and the knocksum would just snap right to 43 (the max). The car would lose all timing, and feel so sloooow. If I let off the gas, and then right back on, the phantom knock usually wouldn't happen, and the car would shoot off like a rocket again.

My phantom knock was the worst when there was not much load on the engine (first and second, or free revving), and/or if the RPMs were below 2700 or so.

If you have a logger, watch the whole thing, to see what's going on. If not, try some of that restore stuff in your next oil change (it helped me). Also, try turning down the boost a tad to see if that helps.

Resetting the ECU every week might be just enough of a air/fuel ratio change to make it run better, until the car starts adjusting itself, and actually adjusts itself into a bad spot.

-Jesse

 

[maduer2]

okay, the car still does it sometimes with the boost at 12 or lower..is there any way to get rid of this problem....also no check engine light...thanks for your help

 

[splattj]

It sounds like the ECU is tracking too much knock all right. After the knocksum gets large enough the timing will be pulled back and the car will fell sluggish. If it just started happening you may have gotten a tank of bad gas. Just make sure you have 91+ octane in there and keep the boost reasonable with a proper boost gauge. The stock one is junk. If you've done that and the problem persists, check the knock sensor on the back of the block. If the black resin in the sensor is sticky and comes off on your hands or if there's no more resin left the sensor is probably in need of replacing and falsely sending knock signal to the ECU. Good luck.

 

[maduer2]

Originally posted by splattj
It sounds like the ECU is tracking too much knock all right. After the knocksum gets large enough the timing will be pulled back and the car will fell sluggish. If it just started happening you may have gotten a tank of bad gas. Just make sure you have 91+ octane in there and keep the boost reasonable with a proper boost gauge. The stock one is junk. If you've done that and the problem persists, check the knock sensor on the back of the block. If the black resin in the sensor is sticky and comes off on your hands or if there's no more resin left the sensor is probably in need of replacing and falsely sending knock signal to the ECU. Good luck.

hey thanks alot ill check the knock sensor out....anyone got a ballpark price on a knock sensor.....thanks again to all who responded