|
|
|
|
| Author |
|
|
Free minder
|
Cold start trick
Someone please explain this to me: Very often in cold weather, my car (78 911SC CIS) won`t start at all. The engine will crank, but not fire at all. However, I have found the trick to make it start: open the air box cover , and lift the cold start valve once, put the air box cover back on. Then I crank it and it starts. My question: what can be wrong with the CIS system? Is there a relay or something else that should make the cold start valve lift and does not do its job? Should the cold valve stay lifted for a while when the engine is cold?
Aurel |
||
12-16-2006, 09:17 AM
|
|
|
Registered
Join Date: May 2000
Location: Los Alamos, NM, USA
Posts: 6,044
|
"lift the cold start valve once" ?
The cold start valve or CSV is an rigidly mounted auxilliary fuel injector controlled by an electrical solenoid built into it. You are likely lifting the air metering plate which moves the plunger in the fuel distributor. You need to determine if the CSV is getting power while the engine is being cranked by the starter (which is the only time the CSV should be getting power.) |
||
|
12-16-2006, 10:32 AM
|
|
|
Designer King
Join Date: Mar 2004
Location: Toronto, ON Canada
Posts: 5,499
|
It's more likely your cold control pressure is too high, resulring in a too lean start condition, or your auxiliary air regulator isn't working properly, or your mixture is set too lean. Search WUR (warmup regulator) which controls the mixture, AAR, mixture setting and cold start problems for lots of info. This is a very common occurance as the weather changes to cold.
BTW do you have an airbox popoff valve?
__________________
Paul Yellow 77 Sunroof Coupe/cork interior; 3.2L SS '80 engine/10.3:1/No O2; Carrera Tensioners; 11 Blade Fan; Turbo tie rods; Bilstein B6; 28 tube Cooler; SSI, Dansk; MSD/Blaster; 16x7" Fuchs/205/50 Firestone Firehawk Indy 500s; PCA/UCR, MID9 Never leave well enough alone |
||
|
12-16-2006, 12:13 PM
|
|
|
Free minder
|
Quote:
Aurel |
||
|
12-16-2006, 12:20 PM
|
|
|
Free minder
|
OK, so when I lift the air metering plate, I release the air pressure in the CIS system, which makes the fuel-air mixture richer. Am I correct?
Aurel
__________________
1978 SC Targa, DC15 cams, 9.3:1 cr, backdated heat, sport exhaust https://1978sctarga.car.blog/ 2014 Cayenne platinum edition 2008 Benz C300 (wife’s) 2010 Honda Civic LX (daughter’s) |
||
|
12-16-2006, 12:24 PM
|
|
|
Registered
Join Date: Dec 2000
Location: philadelphia, pa
Posts: 594
|
Aurel,
By lifting the metering plate you are letting the injectors spray fuel into the intakes, thus priming the system. Crude, but will work in a pinch. Paul. |
||
|
12-16-2006, 12:28 PM
|
|
|
|
Registered
Join Date: Dec 1999
Location: TX USA
Posts: 9,804
|
Aurel,
The SC cold-start system was simplified from earlier CIS cars. There are only three components: starter solenoid, ThermoTime Switch, Cold-Start Solenoid/Valve, and the wires between them. 
__________________
Warren Hall, Jr. 1973 911S Targa ... 'Annie' 1968 340S Barracuda ... 'Rolling Thunder' |
||
|
12-16-2006, 12:51 PM
|
|
|
Registered
Join Date: Oct 2006
Location: MYR S.C.
Posts: 17,321
|
go with the cold start valve first. thats you are doing its job by lifting the plate. also check the TTS. it controls power to the CSV.
__________________
86 930 94kmiles [_  _] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ _] RUNNING: [__] NOT RUNNING:01 suburban 330K:: [_ _] RUNNING: [__] NOT RUNNING:RACE CAR:: sold |
||
|
12-20-2006, 05:27 AM
|
|
