78 SC Been Sitting too long - need help

jbrubaker001 · jbrubaker001's Garage

During this storm season on the east coast I have not been able to get to the 911 for about a month. I finally obtained access this weekend to take her out on a nice warm up ride but the car would not start up.

This is a relatively new ride to me and it has been a while since I worked on a CIS system. The car ran perfect prior to now. The starter does turn over and there is some combustion upon initial start up but that goes away withh continuous attemtps. I think this is a fuel issue rather than spark.

Any quick ideas I may want to try?

Thanks in advance,

John

kodioneill · kodioneill's Garage

Most likely since it ran before I would say cold control pressure. Could be many things but after a long cold soak I would guess it's cold control pressure. Obtain a fuel pressure gauge and check pressures.

jbrubaker001 · jbrubaker001's Garage

I must add the vehicle has been garaged for this period. What do you mean by "cold control pressure"?

scottrx7tt · 03-01-2010, 06:53 AM

i would make sure the fuel pump is working. I have had that issue with mine, and i ended up having a bad connection at the fuseblock for the fuel pump. I would try to start it, and it would attempt to fire, but die immediately. that sounds like what you are describing.

ossiblue · 03-01-2010, 06:53 AM

It does sound like a fuel issue as you get an initial firing of the engine. Possibly, you have a weak fuel pump or bad check valve or your WUR isn't within specs for cold start.

Try this: Remove the fuel pump relay and jumper the terminals (I think it's 30 and 86 but I don't have a car with the relay so wait for an expert to confirm) so the fuel pump will run with just the ignition turned on. Turn on the ignition and listen for the pump. Remove the air cleaner and lift the plate in the throttle body, very gently--you should hear the squeal of the injectors (do this only for about 5 seconds.) Now try to start the car. If it starts and runs, then your fuel lines were empty and you need to follow up with some other tests--pressure tests to determine fuel pump pressure and cold/warm controlled pressures, and residual pressure.

If the above gets your car running and it seems to be o.k. I'd suggest you try to start the car again after a couple of days, just to see if the problem returns. If it does, then further investigation can help pinpoint the cause. If the car starts but runs lousy, then the fuel delivery is a likely cause--low volume from a bad pump, for example.

Let us know what you find.

Gunter · Gunter's Garage

Even easier:
Don't remove the pump relay.
Remove the airfilter and cover.
Turn ignition ON.
Reach into the airbox and gently lift the Air Sensor Plate for only 2-3 seconds.
The injectors should squeal loudly.

That confirms the pump is running and fuel is getting to the injectors.

Let us know if that worked.

If it didn't work, jumper the pump relay terminal 30 and 87a to see if the pump gets power. Bentley 240-11.

Do you have the Bentley SC Repair Manual?

vash · vash's Garage

do what gunter said.

OP; you dont think rodents ate something important, do you?

jbrubaker001 · jbrubaker001's Garage

Thanks to everyone for the quick and useful responses. I will check this stuff out tonight and send an update.

PS - I will check on the rodent scene...good one!

jbrubaker001 · jbrubaker001's Garage

Ok - I completed steps per Gunter and determined that I do have pressure per the squealing. I know this is a bit unscientific but once I determined the pressure was there I replaced the air filter/cover and noticed a humming sound from the engine bay w/ the ignition on. The sound was coming from the blower motor so got back in the car, pushed both levers down and the sound goes out. I then turn the ignition and the car starts right up. Don't know why this would cause the car to start. Thoughts on this?

Two other items:
1) In addition, I tweaked the fuel/air ratio earlier in this process in hopes that it would make a difference. I haven't really noticed any but is there a quick way to make sure I haven't moved too rich/lean?
2) Once the car did start up, there was quite a bit of white smoke and nice fresh oil mist spit out. This did go away after about 3-5 minutes. The car does have a few miles on it and no rebuild so I am not surprised. Any thoughts on this one?

Thanks for everyone's help,

John

mholbrook38 · mholbrook38's Garage

SC's definately don't like sitting. I recommend you check your battery, level of water in the battery and what the voltage is when it is running and when it is just sitting. That fan in the engine compartment is controlled by the levers between the seats. Heat comes from that 3 speed fan. Could be too much draw causing some problem but I wonder about the battery. If you do have to leave it for a period of time, put a trickle charger on it to keep the battery up.

Run some Lubromoly fuel system cleaner through the car for a while. I would buy about 3-4 bottles and run a bottle every time you fill the tank. It took my car about 3000 miles of driving before it really came alive completely. It is a different car now than it was after we got her running following a long sleep.

Hang in there, get a Bentley and read that and study the posts on this forum. You'll be fine.

gsmith660 · 03-02-2010, 03:34 AM

I would wager that cycling the sensor plate like that cleared a vapor lock or primed the system you said that you heard a hum from the blower did you hear the whine from the CDI if not then you might have an intermittant failure of the bosch CD unit.

gsmith660 · 03-02-2010, 03:41 AM

A month is not a long sleep, I leave mine in storage for months during the winter. I just went out after 2 1/2 months and it balked but started when it had CIS I would pull the spade connector in the engine bay to make the fuel pump run all the time and let it run like that to flush fresh fuel through the system then would crank periodically until it started but didn't take long.

Gunter · Gunter's Garage

Quote:

Originally Posted by jbrubaker001

Ok - I completed steps per Gunter and determined that I do have pressure per the squealing. I know this is a bit unscientific but once I determined the pressure was there I replaced the air filter/cover and noticed a humming sound from the engine bay w/ the ignition on. The sound was coming from the blower motor so got back in the car, pushed both levers down and the sound goes out. I then turn the ignition and the car starts right up. Don't know why this would cause the car to start. Thoughts on this?

Two other items:
1) In addition, I tweaked the fuel/air ratio earlier in this process in hopes that it would make a difference. I haven't really noticed any but is there a quick way to make sure I haven't moved too rich/lean?

With the engine really hot, insert the 3mm Allen key into the mix adjust screw. Gently turn a little cw (rich) until the idle sputters. Then turn ccw (lean) about 1/2 turn until the idle again sputters. Now turn cw to the middle of the 2 settings. Do all this gently without pressing down on the Allen key. Don't leave the key in when revving. You may need to tweek the idle RPM with the large slotted screw on the TB.

2) Once the car did start up, there was quite a bit of white smoke and nice fresh oil mist spit out. This did go away after about 3-5 minutes. The car does have a few miles on it and no rebuild so I am not surprised. Any thoughts on this one?

No problem, normal moisture in the HE and muffler blowing out

Thanks for everyone's help,

John

You're in business, enjoy.

kodioneill · kodioneill's Garage

As you lift the plate you inject fuel in the cylinders, like a choke. It will happen again (not starting cold )and you can lift the plate to inject fuel but you'll still have a cold starting problem. You should check your cold pressure to ensure a proper cold start.