Thread: Vapor lock
View Single Post
TDH888 TDH888 is offline
Registered User
Join Date: Jul 2009
Posts: 130
Originally Posted by 356-930 View Post
First, it helps to understand how the thermal time switch (TTS) works and how to work around it. It is indeed a switch. It has two wire lugs. One receives +12v and the other is wired directly to one side of the 7th injector which is located on the back of the intake manifold just below the throttle body. Both the TTS and the 7th injector receive their +12v supply from an auxiliary power terminal on the starter motor solenoid. This +12v power is applied to the auxillary terminal only when the ignition switch is turned to the start position.
If the engine is cold enough, the +12v applied to the TTS grounds the wire going to the 7th injector thus completing the circuit to the injector, it turns on and fuel flows. And, if an engine is cold and fails to start after cranking for 10 seconds +/-, the TTS open circuits and stays open for up to a minute. Until the TTS resets itself, +12v will not be applied to either the TTS or the 7th injector and fuel will not flow. Dropping power to the 7th injector is intended to prevent flooding during/with excess starter motor cranking and when engine is hot, the TTS is open circuited to prevent the 7th injector from turning on. No extra fuel should be needed when the engine is hot.
If one wants the 7th injector to fire and add fuel whether the engine is cold or hot, just tie the lug/wire going from the TTS to the 7th injector to ground.

Your hot start issue can be an accumulator issue, a WUR issue or a check valve in the front pump issue. Suggest to your mechanic to check the WUR pressure cold and after the engine is well warmed up. Then check system retention pressure to see that it stays in spec for 20-minutes. If not retaining pressure to spec, could be the accumulator or the check valve in the front fuel pump.

To assure yourself that vapor lock is not probable, get the engine warm to the point you have experienced the problem in the past and when you turn the car off, open the deck lid to reduce the effect of heat soak. See if it starts better after 20-minutes with ‘deck lid cooling,’
Thank you Cris. My mechanic had rule out vapor lock .Is the stock warm up regulator adjustable.?

Old 09-20-2009, 05:38 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)