Need help

[blacksupra]

This morning my supra started at the 3rd time but after 3 hours the supra didn't want to start at all. It just happend when the car is cold. What do you guys think ?
starter, cold start injector or ignition.
The spark plugs are new.

 

[socc924]

it would depend on what it is doing. Does it crank over at all? The cold start injector usually doesnt stop it from starting at all. If its bad it just causes the engine to crank over a few times before starting. I would guess either the battery from the cold or a bad starter/starter connection.

 

[Nick M]

More info.

 

[blacksupra]

Yes, it cranks. Today it started fine. I've noticed the car is way too rich cuz it pops a lot between shifts.

 

[MDCmotorsports]

Check your coolant and coolant sensors....

 

[theDon]

just a guess - plug gap? .031? You said they were new, is your problem as new as your plugs?

or maybe bad CSI sensor, mine was bad and I ran rich until I got a new sensor.

 

[jetjock]

CSI sensor? Do you mean the cold start injector time switch? If so I see no possible failure mode of that part using the stock wiring that can cause the engine to run rich. The cold start injector itself yes, but not the sensor. Can you elaborate?

 

[peachtits]

well mine does the exact same thing... and ive changed wires and it started right up when i put the wires in and then the next day i had trouble starting it.. it would just crank and never fire.. and my friend who also has an mk3 and knows the 7m engine inside and out said that prolly theres oil between the wires and the plug and the oil takes spark away from the wire so you have to change the valve cover screws to bolts and then tighten the things that go right down the middle of the valve covers and change the plugs... and ill be trying that this weekend and ill let you know of the turn out

 

[theDon]

I'm assuming here the CSI sensor tells the CSI when to fire. The sensor is in the thermo housing. Mine was actually cracked at the top so it never told the CSI that the engine was warm so it kept adding fuel. So I ran rich, especially at WOT - black smoke. New CSI sensor and walaa everything was fixed.

Not sure if this is related to your start up issue becuase your car would still start with a bad CSI sensor and bad CSI. But this could explain your richness. Maybe you flooded your car temporarily?

More than likely, as Peach was saying, something probably happened when you changed plugs. Hard to tell, need more information I guess

 

[jetjock]

Well, the cold start injector Thermal Time Switch (what you're calling the CSI sensor) and the CSI itself can only receive power during cranking. Releasing the key from the start position kills the entire circuit. If the power to it somehow became stuck on the starter would also be stuck on. You'd know if that happened. Doesn't make sense.

The cold start injector TTS operates on both temperature and time. Above a certain temp it won't fire the CSI at all and below a certain temp it fires the CSI for small amount of time (say about 4-8 seconds) or until the key is released, whichever occurs first. Even if cranking is continued the TTS will shut of the CSI after it times out. So you see, since all power to the circuit is removed when the key is released, the TTS couldn't have been the source of your problem even if it was "stuck on" internally..

I suppose it could have been a short in the wiring but if that's true you still have it and the new TTS is simply shutting off after timeout. Either way the root cause of the problem is still there and being masked. If you're happy than great but the solution used to resolve the problem doesn't make technical sense.

Now if you're talking about the coolant sensor for the EFI that's a different story and would explain everything. The TTS sticks straight up in the thermo housing while the EFI coolant sensor is horizontal.