Annoying Cold Idle Problem, Revisited

[jj421]

Not sure if anyone here remembers when I last posted about my cold idle issue. Needless to say, it hasn't been fixed. I've been able to tolerate it the past few months, but now it's getting ridiculous. I've started taking auto tech classes, and my class starts at 7 am, so I have to deal with it every morning.... Please read everything carefully. Car is my '90 Loyale, EA82 N/A.

 

The problem I have is when the car is cold, it doesn't want to idle. I start it up and have to rev it at 2000-3000 RPM for ~5 minutes before I can get it to idle at 500 or so. It's good enough to get going, so I leave. However, EVERY time I push in the clutch (or put it in neutral), the RPMs fall so fast that the engine stalls. When changing gears, this isn't a problem. But if I'm coming to a stop, I must heel-toe and feather the gas to keep it from stalling.

 

Then, randomly, it'll idle normally. Just like if someone flipped a switch, it'll idle fine. It used to take 5 minutes or so before this happened, but now it takes up to 30 minutes!!! My school is about 30 minutes away, and sometimes I can go most of the trip there before it idles normally. Funny thing is, if I've been driving for 10 minutes or so, turn off the car, then turn it back on, it'll idle fine. For example, if I stop and get gas before school, it'll idle normally when I start it back up. The few minutes it takes to fill the tank is enough for the car to decide to idle.

 

I know what you're thinking, it's the IACV or the CTS. I've replaced the CTS twice and the IACV twice. I've cleaned the IACV a few times, but it didn't help. The only part I've noticed that had a difference was the water pump.   I swapped my longblock and it came with a new water pump on it. That water pump failed in 400 miles, but during that time, I never had an idle problem. I put my old water pump on and I soon saw the idle issue again. I've never heard of a water pump causing an idle issue, have you?

 

Here are some of the things I've noticed:

 

• The issue doesn't seem to be related to weather much. It'll have more problems idling during the winter, but I still notice it during the summer.
• The issue doesn't seem to be related to how long the car has been sitting. I mean, if it's only been sitting for less than 3 hours, then it'll probably idle. But I've had it idle fine after sitting for 8 hours, and I've had it not idle at all after sitting for 4 hours.
• The issue doesn't seem to be related to coolant temperature. The temp gauge will reach it's normal range in a few minutes, but as stated before, sometimes it'll take 30 minutes before the car will idle. However, I believe once the temp gauge reads normal, I can turn the car off, sit for a minute, turn it back on, and it'll idle fine.

In the video posted below, I took off the IACV hose with the engine running. Made no difference. Disconnected the CTS. No difference. Disconnected the IACV (electrically). No difference. I'll try the tests again with the engine warm, if that's when I'm supposed to do it.

 

My CEL is on, but I believe it's for the purge and EGR solenoids, if I remember correctly. Been a while since I've checked; I'll check again.

 

Anyways, any ideas? Please feel free to ask questions to help with diagnosis. Feel free to tell me any tests to do, and I'll do them (assuming I have the tools for it). When I posted this before, someone stated something about testing a pin on the connector on the ECU. I never got confirmation on what pin and what numbers I should be getting. I'm just kinda stumped as to what it could be, especially since the two most probable causes are not likely to be the problem. My gut feeling says it's an electrical problem, but I don't know where exactly to start with that. I really want to test and diagnose this, rather than doing the "shotgun" method to fixing it: throwing parts at the car hoping one will fix it.

 

Here is the video that kinda shows the cold start. Before you say anything, the oil pressure gauge reads low; always has. And I did adjust my belts after the video.

 

http://youtu.be/KwjWYgybeLc