Thermo time switch

[Observer]

1981 Fiat Spider

Ques: Is the Thermo time switch and Cold start switch the same thing?

Starts well and runs well. However, when I switch off for 30 minutes, the car won't start.

When the car does start there is a lot of smoke (and a strong smell of fuel) as if the injectors are flooded. My guess is the cold start sensor is faulty.

[divace73]

yes, the thermo switch (which is in in the middle between and slightky under your fuel injectors on the inlet manifold) controls the cold start injector.

Is it kicking over when you try to start?

[Observer]

yes, the thermo switch (which is in in the middle between and slightky under your fuel injectors on the inlet manifold) controls the cold start injector.

Is it kicking over when you try to start?

Yes its turning over, but it won't start and a strong smell of fuel is in the air. That is what led me to believe it was the switch.

[divace73]

Try the following

1. Get and Study Brad Artigue Fuel Injection document
2. unplug the cold start injector to see if you have the same problem (you car will be harder to start when cold without the cold start injector (I found out the hard way), so do this when the car is warm.
-------> If this solves your problem either your cold injector needs replacing or your thermo time switch needs replacing
------------------> check the volage at your cold start injector when cold and compare it to when warm, there should be 12v available when cold and 0 when warm (or at least a changed state), just check with Brad's document as I can't remember how the circuit is wired up.
-------------------------> If you do have the changed state this would suggest the cold start valve is not sealing when at a 0 state, you can alway pull out the injector and test it on a bench to be sure (I'd connect it to pressurised water instead of fuel for safety reasons, if working well, make sure it is complely dry prior to installing it back)

If you can also check the fuel pressure to ensure it is within spec,

I am assuming you do not have any obvious fuel leaks anywhere else, especially near the injectors.

Other chime in...

[Observer]

Try the following

1. Get and Study Brad Artigue Fuel Injection document
2. unplug the cold start injector to see if you have the same problem (you car will be harder to start when cold without the cold start injector (I found out the hard way), so do this when the car is warm.
-------> If this solves your problem either your cold injector needs replacing or your thermo time switch needs replacing
------------------> check the volage at your cold start injector when cold and compare it to when warm, there should be 12v available when cold and 0 when warm (or at least a changed state), just check with Brad's document as I can't remember how the circuit is wired up.
-------------------------> If you do have the changed state this would suggest the cold start valve is not sealing when at a 0 state, you can alway pull out the injector and test it on a bench to be sure (I'd connect it to pressurised water instead of fuel for safety reasons, if working well, make sure it is complely dry prior to installing it back)

If you can also check the fuel pressure to ensure it is within spec,

I am assuming you do not have any obvious fuel leaks anywhere else, especially near the injectors.

Other chime in...

Thanks so much. Will do!

[Observer]

No fuel leak.
Unplugged the Cold start injector and the car started right up.

Q: If I replace the Thermo Time Switch do I need to bleed the air out of the cooling system (radiator)

[rlux4]

You can tell if your thermo-time switch if working. Put a noid light on the connector for the cold start valve and start the engine, or crank it as the case may be. The noid light should get signal from the switch and come on for a few seconds. On my car when it's not cold the light goes out as soon as the engine starts. I'm waiting for winter to do it again and see how long it stays on in freezing temps.
If you don't have a noid light you can borrow one from an auto parts store that has the loaner program.
Ron

[divace73]

No fuel leak.
Unplugged the Cold start injector and the car started right up.

Q: If I replace the Thermo Time Switch do I need to bleed the air out of the cooling system (radiator)

Yes you would, it will let out coolant everywhere, It is advised to try and drop the coolant level lower than that point (in which case you may as well flush out the system with fresh coolant if it hasn't been done for a while.

When you unplugged the cold start injector, was the car warmed up or cold?

You may get by with it unplugged but will find it is more difficult to start when cold (that is what I have experienced anyway)

[Observer]

No fuel leak.
Unplugged the Cold start injector and the car started right up.

Q: If I replace the Thermo Time Switch do I need to bleed the air out of the cooling system (radiator)

Yes you would, it will let out coolant everywhere, It is advised to try and drop the coolant level lower than that point (in which case you may as well flush out the system with fresh coolant if it hasn't been done for a while.

When you unplugged the cold start injector, was the car warmed up or cold?

You may get by with it unplugged but will find it is more difficult to start when cold (that is what I have experienced anyway)

It was sitting for 40 minutes and would not start. So I unplugged & it started right up.

[bradartigue]

It was sitting for 40 minutes and would not start. So I unplugged & it started right up.

You can put a voltmeter on the wires to the cold start, if the thermo-time switch is bad then it will report power to that injector at all times (or never, but in your case, all times). Sounds like a dead ringer for it being bad.

On a cold motor not much water will flow out of the hole when removed, but it isn't fun to get to and sometimes you have to get the car jacked up and get your eyes on it (or a long wrench). Make sure you unplug the battery when servicing, you can easily get your hand and wrench fouling the starter connections (they are not fused) and shock the piss out of yourself.

[narfire]

Make sure you unplug the battery when servicing, you can easily get your hand and wrench fouling the starter connections (they are not fused) and shock the piss out of yourself.

I'll second that. I replaced mine or was putting the lead back on and did not disconect the battery. Caught my wedding ring on the starter leads and after the blinding spark and smoking flesh, I quickly pulled the ring off before the swelling started.

[divace73]

it think we have just learn 2 thing, disconnect the battery and no jewellery (even the wedding ring) whenever I do any electrical work I always remove any metallic jewellery (I only wear a wedding ring, sometimes my wife question me why I have my ring off (not knowing about the conductivity) so have to explain... and besides who am I going to chat up in my garage full of grease??

[76was124]

The noid light should get signal from the switch and come on for a few seconds. On my car when it's not cold the light goes out as soon as the engine starts. I'm waiting for winter to do it again and see how long it stays on in freezing temps.
Ron

As I recall the temp sensor fires the cold start injector for about 2 seconds on 70 degree day and only if temp sensor is under 90F. It heats up fast, so not sure if a cold day makes that a significant difference?

[4uall]

you sexy grease monkey you

[85redpini]

hi

sounds like the fuel pressure regulator, put a fuel pressure guage (for 40 60 psi) on the fuel rail, and see if the fuel pressure bleeds off in a few minutes.