Proper Starting Technique/routine?

scotricker · 07-13-2009, 01:57 PM

I heard a little backfire today.. poof , way back there.. I thought that might not be a good thing. yes, I have a pop-off valve.

but it might be operator error.

When starting, I have tried no gas, just crank, some gas first, some gas later,
then oops, backfire today.

What works best for my 78?

back when I had my 73T, there was that throttle on the floor, but not on this one.

What seems to work best is, a few cranks, then off. then a second attempt, with a little tiny bit of gas. this is just for first start of the day. later it cranks right up.

SteveinTO · 07-13-2009, 02:06 PM

My '82 starts cold w/o any throttle, but I have to catch it immediately and work the foot throttle for about 20 seconds. Then it will settle to a low idle, & away we go.

Hot, it starts up w/o throttle and will idle at +-1000 immediately.

I think no throttle is what the handbook says.

scotricker · 07-13-2009, 02:10 PM

the handbook! what a concept. who'd a thunk

longhornchris04 · longhornchris04's Garage

Turn the key

Ok, sometimes when the car first starts the alternator warning light stays on. If so I'll rev the engine up to ~2k and it goes out, never comes back. Its hit or miss.

After that, its drive lightly untill the oil temp comes up to ~180. If its really cold out, I'll hold the revs at ~1200 with the throttle while I'm sitting at lights. Something is hinky with my WUR or AAR (or AAV, i get the two confused), so it cold starts great but runs too rich during warm-up.

When warm, turn key and she fires up every time. I haven't had a warm start issue since my before my last tune-up. Prior to that I'd have to rev it for 5-10 sec on a hot start before the idle would settle in (way rich on the start, I figured residual fuel in the intake).

ossiblue · 04:26 PM

Quote:

Originally Posted by scotricker

I heard a little backfire today.. poof , way back there.. I thought that might not be a good thing. yes, I have a pop-off valve.

but it might be operator error.

When starting, I have tried no gas, just crank, some gas first, some gas later,
then oops, backfire today.

What works best for my 78?

back when I had my 73T, there was that throttle on the floor, but not on this one.

What seems to work best is, a few cranks, then off. then a second attempt, with a little tiny bit of gas. this is just for first start of the day. later it cranks right up.

Sounds like you may have a Cold Start Valve/Thermo switch problem . Unlike your old 73 which activated the CSV with a micro switch attatched to the cable (along with a bit of throttle), you now have an "automatic" system in which the thermo time switch activates the CSV during cranking of a cold engine and throttle is increase by the Auxilary Air Regulator. The CSV should be injecting raw fuel into the intake which should immediately fire and since it doesn't fire, this may be the area of concern. It appears that the engine fires after enough revs that the fuel from the injectors is sufficient to begin the engine running. Check the voltages to the CSV and thermo time switch (only during cranking will there be voltage, I believe.)
You may also want to check to see if the Auxilary Air Regulator is operating--it should be open on a cold engine. You may also have an air leak which makes things a bit tricky.
If the system is in order, you should be able to turn the key to start, with no pressure on the gas pedal, and the engine should fire up and rev at high idle, and gradually settle down as the engine warms to proper idle speed.

scotricker · 07-13-2009, 07:18 PM

thanks LJ, that is very specific diagnosis advice. I will get out my Bentley manual and get to looking at those things.

Paulporsche · 01:02 PM

In addition to what LJ said, check your aux air valve (AAV). It supplies the engine w/ a little gulp of air during startup.

Also check your fuel pressures. It's very possible your cold control pressure is too high. This is a fn of the warmup regulator (WUR), and is very common. It seems to be the single most common cause of lean conditions/start and run problems w/ these cars.

And verify your mixture is correct. If it is too lean, for example, and someone has tried to smooth out the idle by adjusting the idle screw too far out, this will cause hard starting.

As others have said, make sure you have no vacuum leaks. They are very common on these cars, and are one of the typical causes for these symptoms.

Finally, make sure your ignition components are all working within spec.

The engine should just start up w/ a twist of the key. You can put the clutch in if you want to take some load off the starter, but that's all you should need to do. As someone mentioned, you should get a high idle (say about 2000) on a cold day, which should gradually reduce down to normal idle (about 950) over about 4 min or so.