Cold start vs hot start; or old start vs fresh start

[micbrody]

I have 81 FI. Previous owner made many changes to ignition start. He had secondary switch to directly energize starter (because of bad contact on ignition switch); bypassed fuel pump electrical to always be on in key run position (bypassing afm and double relay).
Car would still have some starting issues.
I checked key to ignition coil to distributor to spark plugs. Added extra ground. This greatly helped start car. I then reversed the fuel pump wiring to factory original; repaired double relay; opened up afm and cleaned contacts.
Though not 100% repeatable, there seems to be a trend I have noticed:
1) if I go to start car after it has been sitting for a day or two, it starts immediately, with no need to hit accelerator to keep engine running.
2) if I go to start car an hour later, it takes longer cranking; and frequently needs me to hit gas just after ignition engages. If I don't hit gas, it either slowly chugs for 5-10 seconds and then obtains good rpms; or it dies out immediately.

In either scenario, once it is fully running, it runs great. Very smooth.
I did check cold ignition injector, and the temperature probe and timer to cold start injector. They all work. (Disconnected and saw the spray of fuel; also separately with volt meter measured voltage to injector during start sequence)
Any suggestions?

[azruss]

Go into Brad's FI tuning guide. Set the throttle body sensor, idle stop, and idle air.

[micbrody]

Thanks for quick response. I was thinking of adjusting those things; but didn't yet because I would think the car would not run smoothly when warmed up if those were out of wack; and car car runs great 10-30 seconds after it does start. can those things negatively affect just the starting of engine?

[76was124]

Easy quick test on the throttle position switch is with the engine off, do you hear a click when you first move the throttle off the idle stop screw? You should, but doing the whole procedure aIn Brad's manual would be a good thing to do if you haven't yet.

[wizard124]

I will make some assumptions based upon what you have told us of your problem by reading between the lines.......

1) Car runs well when fully warmed up...yes?
2) Car starts well when fully cold......yes?
3) Car starts well when fully warmed up....yes?
4) Problem starting when semi-warm. As in sitting for an hour?.......yes?

Does the car smell rich when you have this starting issue? Maybe, the cold start circuit is sending too much fuel in this luke warm situation. Opening up the throttle plate is leaning out the mixture for combustion?

The TTS (thermo time switch) is a grounding switch. It provides the ground for the Cold Start Valve. This circuit only works with the key in Start. There is an internal heating coil within the TTS. This heater warms the bi-mettalic arm of the switch, which opens the switch, breaking the ground contact, and turns off the CSV. This is why the manuals say the CSV will not operate for more than 10 seconds.

I think either the heater coil is bad or the grounding switch does not open. Cold day, you crank the engine and it fires right up. You return the key to the RUN position . This turns off the CSV before the TTS has had a chance to open (less than10 seconds). Semi-warm engine, you crank but the TTS stays closed and the CSV delivers too much fuel. When the engine is hot, either the extra fuel still burns easily and you quickly return the key to RUN. Or, the contact has opened because the block is still hot.

Test the heater coil resistance. There are 2 contacts on the TTS. One is the POS side of the heater coil. The other is the GND which connects to the CSV. With the engine cold, one contact should read 0 when the other ohm meter probe is grounded (this indicates the internal contact is closed). The other contact should read a low value when the other probe is grounded (this indiates the coil's resistance). If one of the contacts reads an open circuit value then the internal coil is bad.

[micbrody]

Thanks for reply. Your description is what my suspicion was. I did check the voltage going to
Cold start injector and it did show voltage at ignition; not sure if I cranked it long enough to see voltage stop via timing switch. I will check voltage again (I will disconnect voltage to fuel
Pump so car does not start; and crank. Based on temperature , I should see voltage to cold start valve for a few seconds, and then no voltage. Does that sound like a plan?

[micbrody]

So I removed the fuse for fuel pump; I put a voltmeter on the leads to the CSI. It was probably 50-60 degrees in garage and car was not run for 24 hours. I turned key to start and voltmeter read 3.5 volts for about 8-10 seconds, and then dropped to 0.15 volts.
I then replaced fuel pump fuse; started car (it took many seconds) and voltmeter showed same readings for 8-10 seconds. I ran car for 5-10 minutes. Shut it off. Started car (it started a little quicker...seems to be random); voltmeter showed 3.5 volts for 1-2 seconds and then went to 0.15 volts.
I think this means that the TTS is definitely working. not sure what the voltage is suppose to be. But previous week, when I removed CSI, I saw it spray.

So as I am writing this, a few questions:
1) what should voltage be to CSI?
2) I think I should remove CSI again and see if it actually shuts off. Maybe it's stuck in "on" position. Today, it was warm, and car to 4-5 seconds to crank
3) Can auxillary air valve cause this issue?
4) where exactly is the TTS? Do I have to get under car to access it?