924Board.org

[Minus000]

Hi. Iv been progressing on getting some much needed mechanical maintence done. I have rebuilt or replaced most components in my CIS injection system but am still having a cold start problem. My car runs very smoothly when warm now and have just recently installed a new Fuel Accumualtor (40cc) and a new set of injectors. Over the last few weeks I also replaced : Injector Seals, Injector sockets, Fuel Pump, Fuel Pump Checkvalve, Fuel Filter, WUR, Aux Air. Valve and some Fuel Lines.

I highly suspect my ignition switch at this point but can not find a guide to testing operation. In the morning I crank the car and it does not starts with-in a number of seconds, it appears to be fine if not a slightly rich fuel mixture but dies as I release the starter to the running position by either dropping down to 100rpm for a second then dieing or simply stopping right there. I usually go through this cycle 2 to 3 times until the cars idle wanders slightly and then smooths out with the leaning fuel mixture.

With the replacement of my Fuel Accumulator just yesterday iv seen significant improvements in hot, semiwarm starting and initial starting from a cold engine. During hot starting , a twist of the key the car starts immideatly and climbs to 1000rpm in a second or two.

After I find a way to test the igintion switch my next job will be to diagnose all the cold start electronics to ensure they are starting and stopping as needed. Does anyone have any other recomendations?



The other job I need to do this weekend is install my new Bosch H4 Lens's and bulbs. The problem is after I switched my dashboard, my highbeam switch has been on the fritz. Has anyone else troubleshooted or diagnosed a high beam switch? Once started and headlights switched on they rise and lowbeams are illuminated but the highbeam switch can't be 'clicked' on. When reinstalling my steering column I forgot to place a small metal peice that goes between the ignition switch and the column, is this in anyway related? It didn't seem to affect anything at the time so I have not yet dissassembled and installed it. I know you can't turn on the highbeams without the key in the ignition so what controls that behavior? is it mechanical or electric?
As always, thanks for the good advice.

[Lizard]

if the start problem is only when cold it isnt your ign switch

I would be verifying that your thermo time switch is getting power, I think it runs off the fuel pump relay but someone posted it runs off the starter lead so bridge the fuel pump relay and check if nothing check while the car is being turned over
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3 928s,

[Smoothie]

The thermo time switch should keep the cold start valve running for up to about 10 seconds and it operates on its' own without having the ign switch in the start position.

Can you start it cold and keep it running by giving it some throttle?
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"..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

[924RACR]

I have successfully taken apart and fixed all the switches on the steering column; it's no big deal, they're pretty straightforward, and often corroded or otherwise junked up. I know the metal piece you're talking about, I think, and it's not related. I'd bet on corrosion in the headlight switch, or even perhaps a bad contact (contact spring bent, not making consistent connection). Shouldn't be hard for you to sort out.

As for the cold start, yes, sounds like the cold start valve is not operating properly. Reasons could be:
A) bad wiring to/between the cold start valve and thermo time switch (not getting power, no ground, or even loose contact pin on either switch)
B) bad thermo-time switch
C) bad cold start injector

When the engine's cold, and you turn on the ignition, you should have +12VDC applied to the cold start valve for a brief moment (you'll need a friend's help to measure this). The length of time depends on the temperature of the engine. I suspect you'll find this isn't happening, most likely due to a wiring issue somewhere.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype