My 92 RS Camaro 5.0 engine is hard to start when cold. Cranks for a long time (30 seconds) then starts but runs really rough and smells like raw gas. Idle speed after starting is about 1100 RPM. I can hear fuel pump run before starting engine. Is the computer thinking engine is not cold? Maybe a bad coolant temp sensor?

 

The fuel pump runs to build pressure in the system before it is started. Your Injection system uses pressure and a nozzle that opens and closes to put fuel in the motor. Without the pressure it wouldn't be atomized and it wouldn't start worth a crap, if not at all.

It could be a bad CTS but I doubt it. Check it with a scan tool if you can. Maybe it's a weak ignition system that it's not getting enough spark. If it starts fine after it's been warmed up check your rotor and cap maybe they're slightly corroded not giving adequate spark. The idle speed will be high because of the programming in your PROM.

With a low Coolant Temp, it will idle higher to warm up and so it doesn't stall. As soon as it gets to temperature it should idle beautifully. If it does idle nicely, I REALLY doubt it's a coolant temp sensor.

 

 

Cold starting could be a variety of things, I'm just making guesses here. Could be too thick of oil, dirty injectors, not enough voltage to fuel pump to build enough pressure, bad ignition, low voltage somewhere in the system, or even it's just that dang cold and no vehicle likes to start that easy.

I do know it has to be some sort of problem or something not up to par even if it's just a badly gapped spark plug. Because my 1990 RS 305 TBI cranks slow at 10 below and takes about 5 maybe 6 good turns of the motor to start, but as soon as it's warm it'll start no problem. As long as it starts within the first 10 seconds or so you shouldn't worry too much.

I helped swap a 350 crate motor into my brothers original 305 TBI and it's just a cold blooded motor. It cranks slow and starts and idles worse than my car. I guess if you upgraded your ignition system it could be spark plug gaps not set correctly, initial timing a little off, even a bad starter. The only true way to find out is to go through and set everything to stock form. This includes but is not limited to, Spark Advance, Fuel pressure, and spark plug gap.

By no means am I a certified mechanic. I just go through the car and make sure everything is set to what it should be. See what is required to do what it is supposed to do and check those systems. The list I suggested just gives an idea where to start or look. You could have slipped when gapping a spark plug or they're old and never been changed. I hope this helps because I've been ranting for a while.

 

If its wery cold a little "wild dragster" start is normal.
When cold you just need to give gas pretty quick.

 

Could be too little base timing, faulty pump, bad CTS telling the engine its colder then it really is. Should start somewhat OK when cold. The older systems where never that great, but they usually gave resonable cold starts.

 

Bought and installed a new coolant temperature sensor. Fired and and idled better than it has in a long time. Thanks for the ideas,

 

I have a car, it starts fine everymorning. EXCEPT when it rains. Then
Iam out there ages trying to start.

 

Rain on distributer cap, design problem. Cover the cap to keep it dry

 

I also am having problems with cold starting. I can prime it and it will fire right up. Plenty of power thru the whole rpm range. I've rebuilt the fuel pressure regulator, replaced the fuel filter. Just got a code 32 and replaced the map sensor. Fuel pump relay is bypassed so it is not the fuel pump ( I know about the possible dangers ). No other codes. Been having trouble with the new distributer cap tightening down. Gave it a complete tune up. Plugs, wires, cap, and rotor.

 

im having the same problem, hard to start when cold on my 88 tbc with a 305, when start up when its warm fires right up, and mine idles great and running so rich I can see the fumes coming frm my tail pipes

 

Yours sounds a bit like an O2 sensor, as far as it running rich, plus maybe a faulty temperature sending unit. Mine are all new and I've tested them all. Have you looked at the injectors instead of the exhaust? Problem still exists here.