Ok, I got the water valve installed, coolant added and did the steps as mentioned.
Now the next set of questions.....
1. Why is the radiator fan constantly running? I ran the car up to 190 and i had the radiator cap off. I had to keep taking fluid out of the radiator because it kept wanting to overflow. Do I have a major air pocket maybe?
2. The car just seems like it is definitely getting hot. The air coming out of the exhaust pipe is REALLY hot. When I touch the tail pipe it is really hot. Air pocket again?
3. The TPS voltage is set at .542 volts and the WOT reading is 4.23 volts. Is this OK?
4. When I initially finished timing, it was idling back and forth at 600 to 700. Now it is idling at 1200. What is happening there?

I feel like I'm taking two steps forward and 4 steps backward.

 

I’d set the TPS voltage higher. I don’t think you want it below . 48 at any throttle opening. I thought the throttle response felt better that way. The idle wandering, mines doing it a little too, a little. I cleaned the Throttle body and replace the idle air control valve. Space back Capital. I thought the IAC was sticking but I have the same results for the new one. If you adjusted the mechanical throttle stop the computer may be trying to compensate. If he raised it with the screw set it back to 700 with the engine warm and about the computer control the idle speed. Also make sure the Butterflies are closing, they was some mention of sticking butterflies and you can lube the shaft, make sure the throttle cable is allowing the butterflies to close completely.

 

Duc, the tps is set at .542

 

Start via the process of elimination. You had the car running fine with idle properly set on 9/29 you wrote above, and from there the only thing that has changed is the installation of the water valve? I'd start there and figure out if something went wrong with that. Did you have the coolant level full and the system capped back then before installing that replacement valve? Are all of your hoses and electrical connections re-done properly after the change?

Remember when I wrote before that when you have the radiator cap off and the coolant is heating up, you need to add fluid until you've got some decent fill level near the top and then make sure to put the cap back on? If you have an engine hot, and you have the cap off too long, it will try to build pressure in the system and then eject that hot coolant from the radiator filler neck upon shutdown, sometimes forcefully. Your goal is to fill the car mostly full before the coolant gets too hot, then cap the radiator, shut down the motor, then allow the system to build pressure and eject excess coolant into the overflow container in the right front of the engine bay. If that hose is properly connected and the radiator cap is working, that hose will carry excess coolant down to the container and then suck it back in as it cools down.

Then, when everything is cooled off completely, you can open the radiator cap and see if you're full or not. If you need to add, then add, but do so at the radiator overflow container and let the engine suck that extra back in during the next cycle.

Don't worry about how hot the tailpipe or exhaust is. If your coolant temperature is at or near 190-228 degrees you're still within the very normal range for an engine that's sitting there without much airflow. Why is the fan on constantly? Figure that out later. Your TPS is fine if the base setting is .540-ish. WOT is not the problem yet. Focus on the first things first, then work the issue in steps.

 

So let me see if I can think straight here. One moment I am feeling good about what I've done and then the next I get so fed up with the damn thing.
When I got everything put back together, I did all the steps I needed to do but now I'm second guessing whether I did things right. Geeeeeeez, it is a bitch getting old.

1. I removed the radiator cap and left it off during the whole process but I did replace it before shutting the car off.
2. With the ignition key On and meter connected to top 2 wires on TPS I set the TPS voltage and turned key Off.
3. I reset system since the IAC was replaced as follows:
a. Jumped the A and B connectors on the ALDL
b. With IAC plugged in turned ignition key to On and confirmed there were no fuel leaks. The cooling fan came on and the check engine light started to flash.
c. After about 45 seconds with the ignition key on I unplugged the IAC valve connector and then shut car off and removed the ALDL jumper wire. (Should I have left the key on?)
d. With key Off I unplugged the ESC connector from distributor and loosened the distributor hold down bolt.
e. I turned the ignition key to On for a few seconds to prime fuel pump and start the engine and adjust the timing to 6 degrees. I was distracted by smoke coming from the wrap that I had on the EGR pipe going from manifold to exhaust and saw the leak from the water valve.
That's all she wrote....I'm done. I replaced the radiator cap and shut the car off before it even got to operating temp. My timing light did show rpms as 460.
f. I re-connected the IAC valve connector.
4. I re-connected the ESC connector and tightened distributor hold down bolt.
5. I disconnected battery quick disconnect to erase the code 42 from ECM.

So as you can see I did not get done what I wanted. So I walked away and locked the garage and said @### IT.

And here we are starting the four steps back part:

I drained most of the coolant out before disconnecting the valve from the heater core and once I got it connected again, I refilled the radiator as much as I could. The four hose connections are back as they were. There were no electrical connections involved.
I messed up by leaving the radiator cap off during the whole process until right before shutting it down which by that time the temp gauge read 190. Something did not seem right to me so I stopped. That fan running constantly had me worried.

And both times i never did perform the minimum air throttle plate adjustment procedure. Is this what you are talking about:

1. Ground diagnostic terminal, turn ignition on, but do not start engine.
2. Wait 45 seconds for IAC to fully seat, then with ignition still on disconnect IAC connector.
3. Disconnect the distributor set timing connector.
4. Start engine and allow engine to go into "Closed Loop".
5. Remove ground from diagnostic terminal.
6. Adjust idle speed to specifications using throttle stop screw.
7. Turn ignition off and reconnect IAC connector.
8. Adjust TPS voltage if necessary: With ignition "ON" adjust TPS sensor to correct voltage specification. Tighten screws, then recheck reading to insure adjustment has not changed.
9. Start engine and check for proper idle operation.

 

Disconnect your battery for a few minutes to reset everything in the ECM. Then start, make sure coolant is filled, then proceed with your engine timing set procedure (which should be at operating temperature BTW).

Yes, that is exactly what I'm talking about. Bottom nine steps must be done to set minimum air. TPS voltage set first, then minimum air procedure, then TPS voltage check. If you execute those nine steps you'll be setting correct TPS position, minimum air screw for idle speed (spec is 450-500 rpm), and the IAC valve positioning will be correct. Don't vary from that sequence; if you shut the ignition off at the wrong point you won't complete it successfully and your idle will hunt as the computer tries to correct for the issues.

 

Might be a dumb thing but did you know there's a lock that prevents removing the key unless the car is in reverse? Same thing for starting. I didn't know that for a while and would often leave it in first or neutral (with parking brake, obviously) and would have a hell of a time getting that key in/out. Any chance that might be it? I'm not sure if you have a manual or an auto but this would only apply to the manual obviously.

 

OK, here is another question

 

I have a quick disconnect on my battery and keep a tender connected to it at all times. Another habit I have been doing every night is with the tender always connected I disconnect the battery using the quick disconnect. Is this causing me any headaches as far as ECM needing to
re-learn everything every time I reconnect battery?
and
So I will....
With everything connected and plugged in, fill radiator as far as I can and this time put radiator cap on and start car and get it to up to temp?
Then shut it off and disconnect ESC connector and set timing?
Shut car off and reconnect ESC connector and disconnect battery quick disconnect to erase the code 42 from ECM.

and then.....

1. Ground diagnostic terminal, turn ignition on, but do not start engine.
2. Wait 45 seconds for IAC to fully seat, then with ignition still on disconnect IAC connector.
3. Disconnect the distributor set timing connector.
4. Start engine and allow engine to go into "Closed Loop".
5. Remove ground from diagnostic terminal.
6. Adjust idle speed to specifications using throttle stop screw.
7. Turn ignition off and reconnect IAC connector.
8. Adjust TPS voltage if necessary: With ignition "ON" adjust TPS sensor to correct voltage specification. Tighten screws, then recheck reading to insure adjustment has not changed.
9. Start engine and check for proper idle operation.

Is this correct?

 

When I started my 96 for the first time after rebuild I was having a heck of a time with the coolant overflowing from the reservoir. I ordered one of these from Amazon and I was able to get it fully filled.


It would heat up open and suck the coolant down then close and burp it out. With the funnel kit I started it with a little in the funnel. It heated up and pulled it in and I added until it was just full. Then quickly removed the funnel and put on the cap. That was a year ago and its been fine ever since. It uses the overflow tank like it should and runs 195-210 depending on the driving, traffic with AC is where it creeps up. Mine is an LT4 so it runs hotter but at 190 your not anywhere near too hot. Also since your sitting still for now having the fan on all the time is not hurting anything for now.

I would not keep disconnecting your battery. Leave the tender on it but leave it connected. That's just my thought on that one. From the looks of this thread I think you are close and you have a good understanding of the steps involved to get this thing correct. You will be a master throttle tech before this is all said and done.

Hope this helps.

 

Bfenty, I have the manual and it used to let me remove the key in reverse but not anymore.
Furias15x, I have one of those and tried it but I could not get it to seal...it leaked for me.
When I installed the thermostat I did drill one 1/8 inch hole in it as some suggest.
Today, I ran the car twice for 30 minutes each time and let it cool down and the radiator is full. Each time it would not go above 190 degrees but that fan is running constantly.

 

Oh and I do have the 190 tstat in it. When I got the car it always showed low coolant on the info panel...it no longer does that.

 

You don't still have the jumper connector in ALDL terminals A and B right? That will cause the fan to run....

 

no it is not

 

If its not going above 190 you're good there. I would move onto getting the idle corrected and worry about the fan issue later once your driving it.

 

That fan on constantly...could that be a relay?

 

METHOD 11. Ground diagnostic terminal, turn ignition on, but do not start engine.
2. Wait 45 seconds for IAC to fully seat, then with ignition still on disconnect IAC connector.
3. Disconnect the distributor set timing connector.
4. Start engine and allow engine to go into "Closed Loop".
5. Remove ground from diagnostic terminal.
6. Adjust idle speed to 450 using throttle stop screw.
7. Turn ignition off and reconnect IAC connector.
8. Adjust TPS voltage if necessary: With ignition "ON" adjust TPS sensor to correct voltage specification. Tighten screws, then recheck reading to insure adjustment has not changed.
9. Start engine and check for proper idle operation.


METHOD 2

How to
Adjust your Early C4 TPS and Idle Speed
by Lars Grimsrud


This tech paper will discuss the procedure for
correct adjustment of the Minimum Idle Speed and for adjustment of the
Throttle Position Switch (TPS) on the early C4 Corvette TPI systems.
These steps apply specifically to the 1985 model year, and in general to
other years.


General
Idle speed and off-idle throttle response
on the early TPI systems is determined by correct adjustment of the
minimum idle speed screw combined with a correct setting of the TPS.
I’ve seen many of these cars that have had their idle speed
“corrected” by well-intentioned mechanics and owners by simply
screwing the minimum idle speed screw in a few turns. This really messes
up the settings, and will not make your car perform properly. Doing a
correct setup of the TPS is one of the easiest ways to make your car feel
and respond better.
All specs and steps are taken directly from the Manual and this process is absolutely correct.

Procedure
There are two
electrical components on the TB that you will be working with: The TPS and
the Idle Air Control Valve (IAC).
You will also be playing with the diagnostic connector
under the dash. Remove the cover (if it’s still in place). Bend
your paper clip into a “U” shape. You will be playing with
the two top right hand terminals (“A” and “B”) in
the connector.
� First step is to set the minimum idle speed. If
nobody has messed with this on your car before, the set screw will be
covered by a pressed-in plug. It’s located on the driver’s
side of the TB. Remove this plug if it’s there.
� With the
IAC connected and the ignition “OFF,” stick the paper clip
into the diagnostic connector from “A” to “B.”
This grounds the diagnostic lead.
� Turn the ignition to the
“ON” position without starting the engine. Wait 30
seconds.
� Now, with the ignition still in the “ON”
position, disconnect the IAC connector at the IAC.
� Remove the paper
clip from the diagnostic connector.
� Start the engine and allow
it to reach normal operating temperature. The idle speed will probably be
really low, and you may have to coax the engine a bit with the gas pedal
to keep it running for a while.
� If your car is an automatic, set
the parking brake and put the transmission in “DRIVE.” If your
car is a manual, leave it in neutral.
� Adjust the idle speed
screw to obtain 400 rpm in drive or 450 in neutral.
� Shut off
the engine and re-connect the IAC.
That’s it for idle speed.


Now on to the TPS.
�
Turn the ignition to the “ON” position without starting the
engine.
� Loosen the TPS Torx adjustment screws.
� Set your
volt meter to a low scale DC volt setting that will accurately read less
than 1 volt.
� Measure the voltage between the two top TPS
wires.
� Adjust the TPS by rotating its position until you get a
reading of .54 volts.
� Tighten the Torx screws and recheck the
voltage. Re-adjust if necessary to make sure voltage is right at
.54.
� Turn the ignition “OFF.”
You are now in
perfect adjustment on idle speed and TPS output. Start the engine. It
may take a few seconds for the car to “catch on” to its new
settings.


Which one do I want to perform? One mentions removing the distributor set timing connector but the other makes no message of it?

 

I used Method 2 exactly. The one above it makes no mention of when to reconnect the EST wire ("distributor set timing connector"), so that lowers my faith in it also.

 

Been on break for a while and I am still wondering about that cooling fan running constantly. I removed all of the air conditioning lines and the ac compressor before I started this job and I have heard that the cooling fan gets switched on by the AC high (pressure) side and that if the switch plug is disconnected the fan will run continuously.
Is this correct?

Well earlier today I was doing a little looking around under the hood and I see that the hose for the AIR INJECTION EMISSIONS CONTROL VALVE SILENCER part # 14082474 was not connected. Would this have anything to do with an eratic idle?

Thanks