Lt1 idle
10-17-2010, 07:11 PM
#1
Teching In
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Lt1 idle My 95 Z28 has a idle issue, when I crank it (cold or hot) it goes straight to 1200 rpm and over a period of 5 seconds settles to it's preset 775, it also does this after i've been driving and put it in to park the idle goes back to 1200 then settles again after 5 seconds. I've sprayed brake clean around the hole intake and vacum sources with no luck, the engine shows 15 on the vacum gauge with hot cam. Replace tps and set to .670 closed and 4.65 open, also replaced iac but have not monitored it on scan tool. My a4 set up is a fresh stock bottom end with hot cam, ported heads and intake, mid-tube headers, 1.6 rr, stock throttle body, egr and air pump removed, 3" cat delete with magnaflow, 8.8 rearend, and madz28 tune. I have access to tunercat if I knew what table to adjust, any advice will be appreciated.
10-17-2010, 10:29 PM
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I've got the exact same problem it sounds like. Tried to test the IAC, but couldnt really get good contact with the pins.
might just change it when I get some extra cash.
here's the diagram if you want to give it a try. let me know if you get it fixed
http://shbox.com/1/iac2.jpg
might just change it when I get some extra cash.
here's the diagram if you want to give it a try. let me know if you get it fixed
http://shbox.com/1/iac2.jpg
10-21-2010, 07:06 PM
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First off, solomon is wonderful and is helping me with this problem. He recommended making sure throttle blades are closed and not setting against the stop before setting tps values, and he was rite mine was against the stop so I slightly bent tab and reset tps to .670closed, 4.69open and it has helped but not completely fixed yet. Put scanner in it today and my iac is at 47 @ idle when warmed up, i'll be data logging it and sending info to him for advice.
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10-23-2010, 05:55 PM
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I've just about got it smooth out, my iac has a count of 47-49 hot @idle. I removed my stock throttlebody and drilled out the existing hole @ the bottom center of butterflys, I went up 1 size @ a time eventually going up 4 sizes which gave me a count of 32 @ hot idle. My car is much better and my stop and starting almost has the manners of a stock car.
