85 vette hunting for an Idle

[chris454]

recently I couldn't get the car to start at all. That was because the TPS was out of ADJ. TPS is the at the correct setting now . I think it was at .54 volts. Okay Know I found out that is the diagnostic terminal is grounded or that if a scan tool is hooked up the car runs in something like ACDL mode which means it advances the timing and the idle is at about 1000 rpm that's what it was doing until I took the scanner off. Ungrounded the diagnostic terminal rpms sink to about 500 but the car is searching for the correct idle about 500 rpms and will stall in the process of doing this also getting a little bit of backfiring.

I have check:
EGR solinoid 26 0hms
2 Air pump solinoids 26 Ohms
Canister Solinoid 26 Ohms
Injectors 23 Ohms
Fuel Presure within Specs. (I Think 42 PSI )
Check for a Pulse in the injectors with a Noid Light.

Is there A list anywhere that tells me all that is ECM Controlled?
Is there any way to tell if the ECM or the PROMS are bad is there a test for that ?

Thank you for any help

Today I have also checked the IAC valve resistance about 51 Ohms


Did a Compresion test and these are the results


#8 140 PSI # 7 140 PSI
#6 140 PSI # 5 140 PSI
#4 135 PSI # 3 140 PSI
#2 135 PSI # 1 140 PSI

Also I have a question about the compression test you take out all the spark plugs? and test each cylinder. and those are the readings I got above.
Know I took out the Nr. one spark plug and my compression gauge said I am only getting 90 PSI with all the other cylinders firing and the car running on 7 cylinders why would I have less compression with the car running?

Monday I go back to work and then I am going to try set the IAC thanks Grumpyvette.

 

[grumpyvette]

viewtopic.php?f=32&t=168&p=202#p202

viewtopic.php?f=55&t=1475&p=3325&hilit=testing+sensor#p3325

viewtopic.php?f=55&t=1475&p=3325#p3325

read thru this thread CAREFULLY

it sounds like the IAC is in need of adjustment or cleaning, but it can be several factors, you will want to isolate and verify every systems functioning correctly, before proceeding to the next test.
lets assume everything's in need of tweaking until checked
(1)pull the plugs and post VERY clear pictures with the cylinder locations labeled .
Id suggest swapping to new AC or NGK plugs gapped at .045 as a start point.
(2)measure the battery voltage with a multi meter both before starting and at idle
(3)measure EACH individual ignition wire OHMS, end to end and post results
(4) whats the BACK PRESSURE on the exhaust at idle and 3000rpm?
(5)VERIFY the firing order and IGNITION ADVANCE CURVE
(6)clean the throttle body and IAC, reset the TPS
(7)whats your fuel pressure at idle and at 3000rpm
what does each fuel injector read in resistance?
is the fuel pressure steady?
is there fuel in any vacuum lines?
(are you sure the timings correct and youve verified TDC on the dampers CORRECT?
(8) have you verified theres no vacuum leaks?
(9) have you recently adjusted valves? you should at least check them
(10) do you have an IR temp gun?, what does each header read next to the head?


what codes are still there?