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1982 928S
 
georges 928S's Avatar
 
Join Date: Oct 2010
Location: Las Vegas, NV
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RE: cold start problem

Hi Guys, back in summer took my car to firestone tire shop in vegas and they
steem cleaned the motor and bottom, did a nice job. i dont know if this is related
to that, but since it takes longer to start. this morning i tried to starting it. it took
a very long time to start , like 60 cranks or more, i even tried giving it gas and
it wont help. colder the weather longer it takes to start. Thanks Ed.


Last edited by georges 928S; 11-03-2011 at 05:19 PM.. Reason: missed a word.
Old 11-03-2011, 05:16 PM
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How is your AAV? There is a write up on how to test it. How are your Injectors? Just throwing stuff out there.
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1981 Porsche 928 "Euro" Auto Gunsmoke Metallic Flat - Black Interior
1983 Porsche 928S "US" Auto Light Bronze (Copper) Metallic - Brown Interior **SOLD**
Old 11-03-2011, 06:12 PM
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You have a LOT of connectors to open up and clean ahead of you. Lots of times the shop SAYS steam clean, but its some version of a hot water or even cold water wash.
Old 11-03-2011, 07:18 PM
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'79 928 Euro 5 Speed
 
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I had a similar issue with mine. On cold days, took forever to start. Turned out to be the thermotime switch for the cold start valve was bad. Cold start valve should inject gas while the starter is cranking when the temperature falls below a certain value. Since mine was dead, the cold start valve never fired. You can unplug the thermotime switch and ground one of the two wires of the connector (should be a brown one)and it will cause the injector to fire every time the starter turns. If it fires up right away, you have your answer.
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Old 11-03-2011, 07:43 PM
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1982 928S
 
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RE: cold start

Hi Leo, my injectors were send to (witchhunter) and cleaned, new hoses,new
injector conections or (plugs), by the way whats AAV mean and were is located.

rupesy, thanks ,iam thinking thermo switch also, but i dont know were its located.

pictures will help. thanks Ed.
Old 11-03-2011, 08:16 PM
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rupesy suggestion sounds more right than mine. I'm also not sure where the Thermo Switch is. Location Pic on Engine?
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1983 Porsche 928S "US" Auto Light Bronze (Copper) Metallic - Brown Interior **SOLD**
Old 11-03-2011, 08:23 PM
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Crazy, I know I'm getting old. I actually asked a Thermo Time Question earlier this year.

Thermo-Time Switch Questions?
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1981 Porsche 928 "Euro" Auto Gunsmoke Metallic Flat - Black Interior
1983 Porsche 928S "US" Auto Light Bronze (Copper) Metallic - Brown Interior **SOLD**
Old 11-03-2011, 08:29 PM
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1978 928 - 9288200072
 
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Here is a picture of where the Thermo Time Switch is:

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Old 11-03-2011, 10:45 PM
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1982 928S
 
georges 928S's Avatar
 
Join Date: Oct 2010
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Thermo switch

Thanks vandenham, and Leo for the picture , i will order part and let you know
asap. thanks again. Ed.
Old 11-03-2011, 10:54 PM
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1978 928 - 9288200072
 
Join Date: Jul 2008
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Ed - there is a test you can do on the switch to check it before you spend money on a new one. The switch may be working correctly, but the cold start valve is faulty. You might be buying the wrong part to fix the problem.



I have a cold start problem with mine also so am going through the same issues as you.

Rick
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1978 928 - 5 speed - no sunroof - Copper Brown Metallic - Cork Interior
1979 924 - 5 speed - sunroof - Red - Light Brown Interior (sons)
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Old 11-03-2011, 11:03 PM
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928: Serial Enabler
 
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Just buy a new thermotime. Key no-start or difficult-start root cause.
They go bad.

Certain sensors on these cars should be replaced "wholesale" just because they are old.
(O2, thermotime, water temp, Temp II, radiator temp) to name a few. Then all key relays and all fuses. Just part of the refresh game. I stock a set of these things, and a timing belt/ pump kit just in case I stumble on another car to drag home. They all need it.

Check also for vac leaks if you haven't lately. Hidden cracks on intake hoses for instance.
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Old 11-04-2011, 04:10 AM
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Quote:
Originally Posted by Landseer View Post
... just in case I stumble on another car to drag home.
Such dangerous words in my Dictionary
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1981 Porsche 928 "Euro" Auto Gunsmoke Metallic Flat - Black Interior
1983 Porsche 928S "US" Auto Light Bronze (Copper) Metallic - Brown Interior **SOLD**
Old 11-04-2011, 05:11 AM
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1978 928 - 9288200072
 
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Thanks Landseer - that is useful information. As a 928 newbie I didn't know these common failure points. I just went through the same thing on my son's 924 and found the thermo-time switch was the problem.
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1978 928 - 5 speed - no sunroof - Copper Brown Metallic - Cork Interior
1979 924 - 5 speed - sunroof - Red - Light Brown Interior (sons)
2005 BMW X5 4.4 - 6 speed auto - Grey/Green - Light Beige Interior
Old 11-04-2011, 06:35 AM
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FYI - the Temp II switch goes for ~ $45 and the Temp Time Switch goes for ~ $90 ... I would test them before purchasing new!
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1982 Porsche 928 Auto Black on Black - Competition Package
Old 11-04-2011, 11:25 AM
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1982 928S
 
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Question RE: cold start

OK Guys, i checked my thermo temp switch this morning, and the readings were
as follows. G and ground = 00.6 W and ground = 32.5 ohms

G and W together= 32 ohms
according to this test W and ground should been 00.0 ohms, does this mean my
thermo time switch is bad and has to be replaced. Thanks. Ed.
Old 11-05-2011, 02:10 PM
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928: Serial Enabler
 
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Yes.
Replace Temp II also.
They both are notorious.
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Old 11-05-2011, 05:39 PM
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1982 928S
 
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RE: cold start

Hi Landser, can you give me location of tepm II and a picture will help too.

Thanks. Ed.
Old 11-05-2011, 06:53 PM
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928: Serial Enabler
 
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Temp II is item 8




Temp II is running vertical into the water bridge, positioned pretty much in the center of the engine, close to the oil fill canister that has the yellow screw cap. Its identified by one of the blue arrows on picture. (Car shown is the "stan shaw" 1984 automatic car my daughter drives)






Thermo Time ( as you already know ) screws in horizontally, and is located as shown, lower on front of engine, other blue arrow on picture.

Temp I, not shown, is integral to the "barn door" AFC or air flow control assembly.

OK?


General information:
For those that have the Moorehouse CD set and haven't spent quality time exploring it yet, you would find this stuff described in the first year that Porsche shifted the 928 USA car to the L-jetronic electronic fuel injection system. That year is 1980, so this description would be in the 1980 Service Information document. Those documents are done for every year of the 928. Even though 80, 81, 82, 83, and 84 USA all used this system, it is only described in the 1980 document. That's the way those documents work. Porsche expectation is any new technician reads ALL of the documents --- they cover the new stuff only once by exception. Any new document is an add-on.

For newbies, the reason some guys can spout all these tech details ad-infinitum is simple: they read the documents that aren't part of the WSM's. Easy as that. No brain surgery. If you like the hobby, read.

So, that said, you can just imagine the incredible motherload of information that was covered in the 1978 service info document! Diagrams of engine oiling, power steering rack circuit, etc --- lots of stuff that didn't change in basic form for the entire run of the series. Brother Vandenham would definitely want to key-in on that first year document to determine what features / sensors support his mechanical fuel injection / spark engine management system, CIS, which probably doesn't have temp II.

That's why I keep telling you guys how important the Moorehouse CD set is. The WSMs that are available on the internet don't include much of this type of information, especially not with the diagrams and explanations. No affiliation of course except trying to help folks keep these freaking cars alive.
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Last edited by Landseer; 11-06-2011 at 07:32 AM..
Old 11-06-2011, 07:15 AM
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1982 928S
 
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RE: therm time switch

Hey guys, looking to buy a thermo time switch, 928 intl dont have one, roger dont have it in stock. is there any place you guys know to get one. thanks ED.
Old 11-07-2011, 10:52 AM
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How about right here on Pelican?

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1983 Porsche 928S "US" Auto Light Bronze (Copper) Metallic - Brown Interior **SOLD**
Old 11-07-2011, 12:12 PM
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