1983 911 hard starting

[engrguy]

I hav a 83 911 sc. I let it sit all winter here in Michigan and when I went to start itit ws hard to say the least and took tons of cranking. WHen it started I coud hear the elec ful pump in the front running so I knew taht was OK. I figured it may have been the check valve so I got one and put it on. No joy it is still takes a bunch of cranking to get it started after sitting over night. Any suggestions? I can build HD's and American cars but know squat about these so any pics of the locationmight also help. I have a chiltons manual and also the 4 or 5 binder mech set but they don't tell alot about what to look for and where it would be located.

[brads911sc]

Did you have a full tank of gas and Stabil in the tank?

If not, drain all the gas. fill 1/4 the way with Chevron Premium, add a bottle to Techron.... Sounds like you have bad gas...

[engrguy]

Originally Posted by brads911sc

Did you have a full tank of gas and Stabil in the tank?

If not, drain all the gas. fill 1/4 the way with Chevron Premium, add a bottle to Techron.... Sounds like you have bad gas...

Gas is good and car drives good when it is running. If you drive it and then park it it generally starts right up if it has been run within 5 hours.

I checked the valve on the passanger side of engine (AAR Valve?) When it is cold it has a half moon when warm almost completely closed.



Can I jump electricity to the TTS to see if it is the CSV. As I cannot find the CSV. Everyone says it is behnd the throtle body but I cannot find it.

I also had someone tell me to remove the electrical plug form the Cold Start Valve to check that. Cannot locate the CSV.

Could it be the "cold start injector" If so where is that and how do I check it? What sends a signal to it to make this injection?

[Bob Kontak]

Sensor is in the middle of the picture. Drivers side chain housing.

[engrguy]

Originally Posted by Bob Kontak

Sensor is in the middle of the picture. Drivers side chain housing.

Bob
Thanks for the pic as that is the best way for me to locate the items. I located that one (thermo time switch). Can I send 12 volts through the non yellow wire to see if the cold start works?

Any pics of the Cold Start Valve by chance? This is the one that eludes me

[boyt911sc]

Originally Posted by engrguy

Bob
Thanks for the pic as that is the best way for me to locate the items. I located that one (thermo time switch). Can I send 12 volts through the non yellow wire to see if the cold start works?
Any pics of the Cold Start Valve by chance? This is the one that eludes me

engrguy,

Do you know that the non-yellow wire you are referring is a ground wire? Energizing that terminal with 12 volts would either cause a big spark or do nothing (open). The thermotime switch (TTS) works as a grounding switch for the cold start valve (CSV). It is open when the engine temperature is 113°F and above.

Below is the rear view of a '78SC engine. The the blue connector in the lower right of the picture is the CSV. Yours would look very similar to this.

There are several ways to test a CSV and I used the following procedures:
1). Check that it gets power (yellow wire) when the starter starts to crank.
2). That the CSV injects fuel when energized.

With the engine installed in the car, you need to access the CSV and dismount it. It is not convenient to remove the CSV but could be done with patience and some effort. Some home-made gadgets I used for checking a suspected CSV are shown below:

Just ask and you'll receive. HTH.

Tony

[engrguy]

Tony
Thank you so much for the pic as it helps a lot!

A porsche guy told me to unplug the CSV and it it started up then the CSV was the problem. Is this true?

[Scott R]

Do you have a pop off valve installed? If so 12v to the CSV and lift the sensor plate and look into the airbox. You'll know very quickly if the CSV is firing or not.

[engrguy]

Originally Posted by Scott R

Do you have a pop off valve installed? If so 12v to the CSV and lift the sensor plate and look into the airbox. You'll know very quickly if the CSV is firing or not.

I do have a pop off valve but do not know where the sensor plate that you are refering to. I have had others refere to this plate but do not know where it is. Do you have a pic by chance?

[ossiblue]

Originally Posted by engrguy

I do have a pop off valve but do not know where the sensor plate that you are refering to. I have had others refere to this plate but do not know where it is. Do you have a pic by chance?

The sensor plate is inside the air intake. Remove the air filter and look into the intake or stick your hand into the opening (palm facing up)--you will feel the sensor plate with your finger tips. Gently push up on the plate (with ignition "on") and you will activate the fuel pump and hear the injectors squeal.

[GaryR]

To continue this as I have a cold start issue on my 78 SC also;

After car sat for a couple days there is no pressure required in lifting the sensor plate, which i'm told means the injectors have bled down. Not sure of the consequences of this.

With engine cranking and a simple 12V tester on the TTS yellow wire/terminal - no power. I'm confused because I read on another thread "It is easy to test the TTS, just ground the yellow wire with a jumper and try a cold start. " Wouldn't this be sending a live wire (during cranking) to ground? Do you leave it connected to the TTS for this test?

If I lift the sensor plate (ignition on) and shoot some fuel in when cold (sort of a manual CSV), starts right up.
I have to get under the car to check, but if the yellow wire isn't getting power at cranking maybe it simply came off the starter solenoid?

I'll look at a wiring diagram but i'm better at following instructions from someone that's been there..
I'm betting that the yellow wire popped off my starter solenoid during one of my "curb jumps" at Watkins Glen..

[boyt911sc]

Originally Posted by GaryR

To continue this as I have a cold start issue on my 78 SC also;

After car sat for a couple days there is no pressure required in lifting the sensor plate, which i'm told means the injectors have bled down. Not sure of the consequences of this.

With engine cranking and a simple 12V tester on the TTS yellow wire/terminal - no power. I'm confused because I read on another thread "It is easy to test the TTS, just ground the yellow wire with a jumper and try a cold start. " Wouldn't this be sending a live wire (during cranking) to ground? Do you leave it connected to the TTS for this test?

If I lift the sensor plate (ignition on) and shoot some fuel in when cold (sort of a manual CSV), starts right up.
I have to get under the car to check, but if the yellow wire isn't getting power at cranking maybe it simply came off the starter solenoid?

I'll look at a wiring diagram but i'm better at following instructions from someone that's been there..
I'm betting that the yellow wire popped off my starter solenoid during one of my "curb jumps" at Watkins Glen..

Gary,

The CSV is an electro-magnetic device that injects fuel when energized. The mist-like spray pattern is also affected by the fuel pressure. The 12-volt energy is coming from the yellow wire (ignition switch) during START mode. The circuit to energize the CSV is OPEN when the TTS (thermo-time Switch) is open. The brown wire of the TTS has to be grounded (closed) in order for the circuit to be complete. For the CSV to work, it got to be energized (TTS closed) and sufficient fuel pressure delivered.

You don't need to LIFT the sensor plate to test the CSV!!!!! It has nothing to do with the sensor plate position. Have the FP running by jumpering terminals #86A & #30 (FP relay) and pressurized fuel is available to CSV.

Grounding the YELLOW wire of the TTS during start mode will cause a short circuit!!!! SPARKS and busted fuse or some burned wiring could result to this ill conceived test procedure. I've read several posts with this suggestion in the past and tried to stay away from it. But something urged me to call the attention of people wanting to do the test.

The yellow wire from the starter solenoid supplies power directly to the CSV and TTS (heater) @ START mode. Test the yellow wire terminals at the starter for power during cranking. Hope this helps other members understand the basic operation of CSV and TTS in 911 cars.

Tony

[GaryR]

Originally Posted by boyt911sc

Gary,

The CSV is an electro-magnetic device that injects fuel when energized. The mist-like spray pattern is also affected by the fuel pressure. The 12-volt energy is coming from the yellow wire (ignition switch) during START mode. The circuit to energize the CSV is OPEN when the TTS (thermo-time Switch) is open. The brown wire of the TTS has to be grounded (closed) in order for the circuit to be complete. For the CSV to work, it got to be energized (TTS closed) and sufficient fuel pressure delivered.

You don't need to LIFT the sensor plate to test the CSV!!!!! It has nothing to do with the sensor plate position. Have the FP running by jumpering terminals #86A & #30 (FP relay) and pressurized fuel is available to CSV.

Grounding the YELLOW wire of the TTS during start mode will cause a short circuit!!!! SPARKS and busted fuse or some burned wiring could result to this ill conceived test procedure. I've read several posts with this suggestion in the past and tried to stay away from it. But something urged me to call the attention of people wanting to do the test.

The yellow wire from the starter solenoid supplies power directly to the CSV and TTS (heater) @ START mode. Test the yellow wire terminals at the starter for power during cranking. Hope this helps other members understand the basic operation of CSV and TTS in 911 cars.

Tony

Thanks Tony. The lifting of the sensor plate was to check for backpressure in the system, had nothing to do with checking the Cold Start system. Was just one more test my shop asked me to do. What does result from lifting the plate with the ignition on is fuel is injected which will allow the car to start cold with no functioning CSV. I fond the wiring diagram right after my initial post and since I am not getting 12v power during cranking in the yellow wire I *think* it boils down to a simple fix, the yellow wire must be broken or disconnected from the solenoid. As soon as I can get under the car i'll check that out, and I can make a short jumper to energize the CSV during cranking (or lift the sensor plate) to facilitate cold starting until then.

[engrguy]

Turns out it was the Fuel Accumulator.