'83 SC won't start, baffled !
07-04-2015, 06:45 PM
#1
Burning Brakes
Thread Starter
'83 SC won't start, baffled !
I'm tried everything I know so searched the internet thoroughly and I'm stumped - maybe an expert here might be able to give me a hint !
Problem:
'83 SC, was running perfectly, yesterday was checking/setting idle speed and timing in prep for a CA smog test. Car was warmed up and idling, running great as it always has. Idle was 910, timing was perfect, 5 degrees BTDC with both vacuum lines detached and plugged from the vacuum valve on the distributor. I was just about to shut it down and go get it smogged when I thought I would check the timing one more time. So I disconnected the vacuum lines from the distributor, expecting the idle speed to change a bit, and wham!, engine starts to run like crap, idle goes down to 300-400rpm, tach starts bouncing erratically, and eventually if stalls. I cannot restart it. It cranks solidly, won't catch. If I put my foot to the floor on the gas pedal while cranking, it catches sometimes, but runs rough, about 300-400 rpm, won't go higher even at WOT and if I take foot off gas it stalls.
I can't figure out what triggered this. Certainly removing the vacuum line from the distributor was a coincidence. I've done this many times and it doesn't have any big effect, including earlier yesterday.
So here is what I have tried:
- Battery is charged and strong. Engine cranks vigorously.
- Tried with engine fully cold. No change
- Checked fuel pressures. Main pressure is 70 psi. Control pressure is 51 psi
at 80 degrees, hot engine (in spec).
- Fuel pump relay is good (pretty new). Tested with the relay jumped, and tested pressure during cranking (70 psi).
- Checked spark - pulled boot on cyl 1 and tested with a plug. Blue spark during cranking.
- CDI box whines when engergized (good).
- Airbox has no cracks. Backfire valve is installed and looks good.
- No visible vacuum leaks - all lines in places and connected.
- Replaced fuel filter with a new one - no change
- Pulled cyl 1 injector, ran into a glass jar during cranking. Some fuel coming out but seems like a very small quantity.
- bleeding the fuel pressure gauge lines, lots of fuel comes out. Looks like fuel delivery quantity in the system is good.
- removed distributor cap - new cap and rotor, all looks good inside.
So, seems to be a fuel issue, like something happened all of sudden yesterday while idling, possibly triggered by me pulling that vacuum line of the distributor that is resulting maybe in a low fuel delivery condition. Seems like a massive vacuum leak.
Any ideas of what to check next ? Bad gas ? a blockage in a fuel line or in the FD somewhere ? Maybe the distributor is faulty, timing way off ?
I am getting spark and some fuel - just not sure if enough of both at the right time...
Stumped... Thanks !!
Problem:
'83 SC, was running perfectly, yesterday was checking/setting idle speed and timing in prep for a CA smog test. Car was warmed up and idling, running great as it always has. Idle was 910, timing was perfect, 5 degrees BTDC with both vacuum lines detached and plugged from the vacuum valve on the distributor. I was just about to shut it down and go get it smogged when I thought I would check the timing one more time. So I disconnected the vacuum lines from the distributor, expecting the idle speed to change a bit, and wham!, engine starts to run like crap, idle goes down to 300-400rpm, tach starts bouncing erratically, and eventually if stalls. I cannot restart it. It cranks solidly, won't catch. If I put my foot to the floor on the gas pedal while cranking, it catches sometimes, but runs rough, about 300-400 rpm, won't go higher even at WOT and if I take foot off gas it stalls.
I can't figure out what triggered this. Certainly removing the vacuum line from the distributor was a coincidence. I've done this many times and it doesn't have any big effect, including earlier yesterday.
So here is what I have tried:
- Battery is charged and strong. Engine cranks vigorously.
- Tried with engine fully cold. No change
- Checked fuel pressures. Main pressure is 70 psi. Control pressure is 51 psi
at 80 degrees, hot engine (in spec).
- Fuel pump relay is good (pretty new). Tested with the relay jumped, and tested pressure during cranking (70 psi).
- Checked spark - pulled boot on cyl 1 and tested with a plug. Blue spark during cranking.
- CDI box whines when engergized (good).
- Airbox has no cracks. Backfire valve is installed and looks good.
- No visible vacuum leaks - all lines in places and connected.
- Replaced fuel filter with a new one - no change
- Pulled cyl 1 injector, ran into a glass jar during cranking. Some fuel coming out but seems like a very small quantity.
- bleeding the fuel pressure gauge lines, lots of fuel comes out. Looks like fuel delivery quantity in the system is good.
- removed distributor cap - new cap and rotor, all looks good inside.
So, seems to be a fuel issue, like something happened all of sudden yesterday while idling, possibly triggered by me pulling that vacuum line of the distributor that is resulting maybe in a low fuel delivery condition. Seems like a massive vacuum leak.
Any ideas of what to check next ? Bad gas ? a blockage in a fuel line or in the FD somewhere ? Maybe the distributor is faulty, timing way off ?
I am getting spark and some fuel - just not sure if enough of both at the right time...
Stumped... Thanks !!
07-06-2015, 04:36 PM
#3
Team Owner
does that distributor have 2 lines atached to it ? one to advance the timing and one retard it during cold starts or something ?
my 78 only has the one but i thought the later CIS cars had two.
id check that it again and make sure nothing is mixed up , as well as making sure the mechanical advance in the distributor is working and isnt "stuck"
my 78 only has the one but i thought the later CIS cars had two.
id check that it again and make sure nothing is mixed up , as well as making sure the mechanical advance in the distributor is working and isnt "stuck"