924Board.org

[Mannghi]

HI! I'm trying to figure out why my 77 isn't starting.
It cranks and cranks but won't start.
Fresh gas, fresh battery. Distrib. rotor, cam, and oil pump pulley timing marks lined up, fuel pump working.
I haven't checked the injector output but the injectors and CSV are wet after trying to start. New cap, rotor, plug wires.
Not even getting a sputter.
I'm using Haynes to work through the ignition system and I am only getting about 9-10v from the starter solenoid to the .4ohm balllast resistor, same voltage at the solenoid terminal. Haynes tells me there should be battery voltage comming from the #16 terminal but its a few volts short of the 13v that I measured on the battery terminals.
So...
Would that cause a weak spark, and no start?
If someone could explain what function this +12v going to the ballast resistor and then on to #15 terminal on the coil has, well, then at least I'd be happy I learned something.

Pehaps the trouble lies elsewhere all together?

Thanks in advance!
_________________
The Stables:
1998 VW Beetle
1984 Porsche 944
1977 Porsche 924
1960 VW Karmann Ghia

[Paul]

The coil is designed to fire at the voltage that's available while the car is cranking, not after it starts. The ballast resistor is bypassed while starting. Once you let go of the key, the coil is fed from the ballast resistor to keep it near starting voltage.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[Paul]

Bring number one up to TDC (on its compression stroke) and make sure the rotor is pointing towards the wire you have going to #1's spark plug.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[flames]

Check that there is 12V, or there abouts getting to the coil while the key is in the start position.I found that mine wasn't, it would have power at the on position, but no power to the coil at start.
I ended up putting another relay in to supply 12V power to the coil while cranking, and it solved my problems.
_________________
'78 924
Carrera? Body Kit
Bright Yellow

[ideola]

also make sure you have the plug wires on in the correct order (1-3-4-2, clockwise) after double checking that the rotor points to one with the cam/crank @ TDC.
_________________
erstwhile owner of just about every 924 variant ever made

[Smoothie]

-And be using the correct cam timing mark. The correct one is on the back of the cam sprocket, a dot or circle located at a "valley" between two teeth.
_________________
"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[Paul]

Well if we are using the shotgun approach:

Check for spark.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[Mannghi]

Thanks for the advice!
Smoothie- I may have the wrong timing mark on the cam, I used the dot on the front of the gear to line up. Didn't know about the mark on the back.
Thanks!
_________________
The Stables:
1998 VW Beetle
1984 Porsche 944
1977 Porsche 924
1960 VW Karmann Ghia

[Paul]

After you retime the cam, you will have to pull distributor and reinstall it so that number one lines up.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[Mannghi]

Thanks!
Re-timed the cam, using the mark on the back, and got it started up!

It wouldn't idle without giving it throttle, and I couldn't get it started again once I shut it off.

I'm guilty of indiscriminately adjusting the air bypass screw on the throttle body and the CO adjustment on the fuel dist.
Does any one know what a good "default" setting for both these might be?

Thanks again, it was sweet to hear it run, if only for a little bit.
_________________
The Stables:
1998 VW Beetle
1984 Porsche 944
1977 Porsche 924
1960 VW Karmann Ghia

[Smoothie]

[Mannghi]

Smoothie- Thanks for your advice about getting the a:f mix in the ballpark.

I set it full counterclockwise (lean), and went clockwise until I heard fuel rushing in the lines, I could kind of see them twitch as they pressurized. Then worked in full turns clockwise until it started with my foot on the gas pedal. Worked it clockwise in full turns until it started without my foot on the gas, and then turned it counterclockwise in 1/2 and then 1/4 turns until it stopped backfiring.

Also, closed the air bypass in the throttle body.

Apparently, I had the mix way too rich. Now its time to change that gassy oil!

Thanks again!
_________________
The Stables:
1998 VW Beetle
1984 Porsche 944
1977 Porsche 924
1960 VW Karmann Ghia

[Buwani 931]

[Smoothie]

Yeah, this isn't making sense -

[Mannghi]

Yea, that throttle lever stop is way out of whack.
I'm sure it was being used to adjust the idle.

"set from the factory" heh heh.

Thanks again!
_________________
The Stables:
1998 VW Beetle
1984 Porsche 944
1977 Porsche 924
1960 VW Karmann Ghia