hunting idle, stalling and not starting

[Bobboloo]

Thanks Super. I was just reading this post and thought the same thing. Verifing the ignition is always the best starting point.

I just wanted to throw a couple of things out there before you start to troubleshoot the ignition.

That electrical problems can be intermittant due to vibration and/or for thermal reasons.

Very often people tend to try to replace parts to fix a problem when there isn't a part problem. Quite often the problem is the flow of current through connectors. Particularly with older cars that have corrosion building up on the connectors. (your mention of the fuses made me think I should bring this up)

These points maybe a little premature but I just wanted to make you aware of this.

It's not a bad idea when you get an old car to go through it cleaning all the connectors you can. It tends to rid the car of little gremlins. Suddenly, the motor looses it's studder or the headlights are brighter and you don't have to change that turnsignal bulb after all.

Bobby

[47silver]

will get back to the basics over the weekend, no time with the holidays fast approaching,

i really appreciate the input from all of you and feel that even if i get one tidbit that helps it is well worth it, as i have not worked on cars in many years, in fact i wont work on my wifes or anyone elses car just the porsche, i must be a mechanic snob.

gary

[47silver]

first of all thanks for all of the ideas and suggestions, i feel as though they helped tremendously.

my son and i checked out the car today. we used the msd checkout to see if we had spark. we did. i adjusted the points and tried to start. no start. again we had spark to the spark plug. i used a new one at the end of a spark plug wire to check.

i removed an injector hose and we had fuel.

we sprayed in starting fluid and did not even get an attempt to start.

i checked distributor again and set up static timing.
we checked warm up regulator contacts. they were very corroded. we cleaned them but i only measured 40 some ohms across the contacts and i could not measure any voltage at the plug with the key on, this seems oddso i am going to check this further.

again we reset the points and checking for static timing the car would not attempt to fire even with starter fluid.

i finally gave in and pulled a plug and it was very black, i replace the right side plugs and tried to start the car. it started and ran on 3 cylinders. after i replaced all of the plugs the car immediately started and even idles. i would never believe that all six plugs could be so fouled that they would all fail at once but that is the only conclusion i can come up with.

i think the problem was that the points were closing as last week when i could not get the car running the point gap was non-existent. this caused the plugs to foul to the point of failure.
( i ordered the magnetic contacts from pelican the other day. i hate points.

i also suspect the wur may be too rich, due to a low 45 ohm reading on the contacts. i think that is is rich because i believe the wur works as follows:

outside air is drawn through the wur via the vacuum lines. it is very important to never plug them as this is the outside air component of the wur. the heater provides a constant wattage (12v x 400 = 480 watts. the heater warms the bimetal, however the colder the outside air is, the wider the temperature differential is between the heat created by the heater and the outside air temperature, so that the bimetal contracts and presses tighter against the fuel pressure port which increases fuel pressure.

as the outside air temperature increases, the heater can warm the bimetal so that they expand away from each other which pulls the bimetal away from the port causing the pressure to drop.
it is then imperative that the wur is working properly even in a warm environment because it is aways adjusting the pressure based on the temperature differential.

if the above is correct i think that by inserting anadjustable resistor in the power feed to the wur, that you could make an adjustable wur without having to remove or do any work on the wur. because if you reduce the current flowing to the heater the bimetal will close tighter against the pressure port which will enrichen the mixture. by lowering the resistance in line with the heater the heater will increase the temperature and cause the wur to lean out the mixture.

does that make sense
to me the wur is constantly in play adjusting the pressure based on outside air temperature, which makes it a critical component of the system.

can the wur be rebuilt? can you get the heater element?

thanks again

gary

[stormcrow]

Your warm up regulator (pressure regulator) actually increases pressure on the fuel distributor as it warms up creating a higher pressure on the air flow sensor to lean out the mixture.

When you first start the car, the pressure is low based upon outside temp. As the car warms up and the bi-metal strip heats up, it moves towards the top of the warm up regulator to reduce gas flow.

You need a rich mixture when the engine is cold. Black plugs indicate a rich mixture. You need to get a pressure gauge to toubleshoot your fuel pressure. This will help solve your starting problem.

Steve

"A Porsche does more then just go fast in a straight line"