Question-------------------------
Followup To
Question -
Hi Ted. Problem concerns a 1984 Toyota Camry with 2S-E engine, auto trans, and about 140K
miles. Motor is very reluctant to start cold even though the cold start valve ohms out. Checking voltage across the cold start connector during cranking yields about 2v for a quarter of a second ( no load ), then nothing. I have already made sure that it is getting positive voltage from the cranking circuit, so the thermo- time switch is the likely culprit. Trouble is, I can't find complete specs on either the injector or the thermotime switch, making it difficult to complete testing ( I'm not going to buy a $200 component on a whim ). I could energize the injector by supplying a ground to the negative side but I don't if its a 12v or a 5v injector - the thermotime switch might have a built-in dropping resistor. The only specifications which my manual gives for the thermotime switch are for the heater terminal, not the injector terminal. With the thermotime switch disconnected, I'm reading about 40 ohms from injector terminal (on the switch) to ground, which means I'm simply reading the heater coil resistance and the device is probably bad. To make a long story short I could sure use 1. The operating voltage of the cold start injector and/or 2. The resistance spec for the thermotime switch injector terminal to ground (cold). Note that I am NOT looking for the resistance between the injector and heater coil terminals. Hope this information exists, thanks....Brady T.
Answer -
The cold start injector is operated with B+ 12 volts which comes from the ignition switch, when the key is in the start position a start signal is send to the ECU which grounds through the injector time switch to turn the cold start injector on when the engine is cold.
The factory manual states that to check the cold start time switch you make resistance checks, there are two terminals on the switch designated STJ and STA(stj is hooked to the cold start injector and sta is the starter signal)from the ECU.
The resistance specs are as follows:
Between the two terminals, below 86 degrees F, 20-40 ohms
Above 104 F, 40-60 ohms
From the STA terminal to ground 20-80 ohms( the sta terminal is the one on the right looking at the time switch with the square guide on the bottom and the small semi-circular guide strip on top in the middle. Hello again Ted. Thanks for the quick followup. Your identificaton of the sta/stj terminals certainly makes this easier since my wiring shematic doesn't show the designations. As I have indicated, my manual ( not a factory manual ) gives specifications for sta to stj, and sta to ground. What is really needed is a specification for stj to ground - looks like Toyota doesn't give that out. STJ is apparently responsible for connecting the cold start injector to ground, then disconnecting it after a few seconds of cranking. As a test, I could simply connect one side of the cold start injector to ground, but that would risk burning up the injector if it's not designed to run on 12v. ( An stj to ground spec would have let me know if there was a dropping resistor in the switch ). Does the factory manual give any sort of spec or procedure for testing the cold start valve which would shed some light on it's voltage rating? Thanks again...Brady T.
AnswerThe stj terminal of the cold statr injector is grounded through the cold start injector time switch which is a thermistor(changes resistance with temperature) There is no specification for stj to ground, I think your problem is with the cold start time switch.
If you want me to send you the illustration you do not need my email address just reply here and give me an email address so I can send it to you, I can not do it from this forum.
