I recently got my latest fbody, a 93 Camaro 3.4L v6
shortly after getting it we had a very cold morning and it started idling high.
It idles around 1700 rpm in park, and 1100-1200 in gear.

I have an alldata subscription for it and read a gm tech bulletin saying for an intermittent high idle to disconnect the battery for 1 min to reset the ecu,
After doing this the engine idled normal when I started it up.

Next morning after the car sat over night the high idle came back.
I tried the procedure once again. reset ecu, car idled correctly, a couple hours latter still idled correctly, next morning high idle was back.

according to the tech bulletin, "The engine control system sensors are supplied a 5 volt reference signal to ensure properly scaled readings to the engine control module (ECM). If a large current draw flows through the circuit supplying the 5 volt reference, the input signals, as read by the ECM, will be skewed low. The ECM program will store an incorrectly low throttle position sensor signal as zero. If the reference voltage returns to normal, the ECM will interpret the resultant high throttle position sensor signal as an open throttle and idle air control steps (throttle follower) will be added accordingly, causing an increase in the engine rpm at idle."

All ac equipment has been gutted from the car, and I can not find any bare wires that would cause a short during the starting process that would cause the 5v signal for the iac, tps, map, and ac pressure switch to be skewed low

Does any one have an idea what the problem could be or what direction I need to go in resolving this issue?

 

have you flashed for codes or had the trouble codes read. each time you unhook the battery your clearing any trouble codes that may have been set.

 

I have tried pulling the codes, connecting pin a and b, on the connector and my ses light does not flash. I also tried jumping pins a and m just on the off chance it was like a 3rd gen and still nothing.
Is it possible my 93 is actually a 94?
I work at autozone and can honestly say we don't have a scan tool that works on odb1.
Any ideas what I can try to pull any codes there maybe?

used this as a refrence
http://shbox.com/1/dlc2.jpg

 

I believe you need an actual scanner. Jumping the pins wont work. If it is the same as my 94.

 

its a 93 so flashing should work. do the fans come on when key is turned on with a and b connected?

 

Easiest way to tell from a '93 and '94, short of looking at the vin, is the color of gauge face plates. '93 was the only year to get yellow. '94+ swapped to the better looking white.

Like Craby said, jumping pins A and B with a paper clip should turn the fans on and making the SES light flash, even if there aren't any stored codes it should flash once...pause...then flash twice, indicating a code 12 which is just saying the diagnostic system is working.

 

Its got the orange/yellow gauges.
A previous owner hard wired the fan so its always on. when I jump pins a and b the light just stays on, though if I pull the jump wire with ignition in on position the ses light flashes 1 time and I can hear what sounds like a relay click under the hood.

 

i wonder if the jumper for the fan is messin with the diagnostic circuits. might try unhooking the hot wire for the jump and see if that changes anything

 

removed the jump wire for fan, fan does not come on with just key in on position, turned ignition to off, put jumper on pins a and b, turned ignition to on position fan comes on, but ses light does not flash just stays illuminated.

no idea why fan is jumped now other than maybe to make car run cooler?
since the fan comes on with the pin's jumped, I'm assuming the fan circuit should be working correctly, I wonder if with the fan on all the time of the high idle could be because the engine isn't getting warm enough for the ecu to bring the idle down.

still doesnt explain the ses light not giving the codes or the default code of 12.

 

check all your fuses, under hood and the dash side boxes. air bag, gages, maybe the cig lighter, abs