Trying to get my idle dialed in, getting closer and closer. After figuring out I had a massive vac leak at the brake booster and replacing it, I did the basic tune-up. TPS, idle speed, idle mixture (idle mixture screw had no adhesive on it, so I figured PO had jacked with it at some point. Followed procedure in FSM. One last thing I can't figure out:

Car idles like a harley for roughly 90 seconds after a hot start. Then it suddenly starts idling fine. Is this the hot start assist? has anybody bypassed theirs and had it make the car idle better on hot starts?

Car is a 1988 non-turbo.

 

To make things short it sounds much like your problem is associated with the FPR and how it receives vacuum or not which then affects the fuel pressure. If you look in the FSM it details how the FPR works with respect to hot starts. See if the vacuum line to the FPR has the proper vacuum or not when it is supposed to.
On a hot start there should not be vacuum on the vacuum hose connected to the FPR for a period of close to 2 minutes. In doing so the fuel pressure is boosted and once vacuum returns to the hose the pressure drops. So, pull the hose off before a known hot start situation and check if there is no vacuum. If there is vacuum then that could be your problem (likely the fuel pressure regulator solenoid- the Orange one).

 

Well i checked it out today and found I have vacuum to the fpr during hot starts. So tomorrow when I have some more light I will go poking around with the multimeter and some jumper wires and figure out if it is the solenoid.

 

The solenoid has two wires to it. One wire is Black/White which should have close to 12 volts w/key to on, car not running, and also w/the car running. The second wire is Blue/Orange and this is the wire which activates it. You can start your car even when cold, pull the hose off of the FPR, and then place a ground on the Blue/Orange wire and see if this kills/stops the vacuum on the hose or not. If the vacuum is cut then the solenoid is operating properly. If this is so then either the ECU is not receiving a proper signal from the intake air temp sensor or there could be an issue w/the ECU. The wire which connects this temp sensor to the ECU is Green and runs to pin 2L of the ECU. When the engine is at full operating temp the Green wire should read about 1 to 2 volts.