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Discussion Starter · #1 ·
Hello,
I posted this a few months back, but with the cold weather the car never gets hot. Now, when hot and when just started, the idle will just go up and down and usually flatten out. But in traffic last week with the temp gauge redlined, at a light it started the syndrome, and when I tried to drive off the engine got no gas. It eventually cooled down and was OK.
I attempted to clean out the idle air control, but apparently that wasn't the cause or I didn't clean it well enough.
Any suggestions?
Thanks.
 

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Discussion Starter · #2 ·
Now, more info. This syndrome has only occurred when the air temp is above 85°F. The engine eventually loses the ability to take gas. It holds a fairly steady idle. I can not rev the engine. Eventually, and I open the hood to hasten the cooling process, the engine starts normally.
Which sensors/components are affected by high temps? Is there an air temperature sensor? I'd like to spray with an electronic parts cooler to isolate the cooling process.
 

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Discussion Starter · #3 ·
I have a '94 CSE. At the risk of appearing obtuse, I can not see the MAF sensor. Where is it on this car?
A friend of mine said that an early symptom of failure in these is what I described occurring with hot ambient air temps. It also appears the car is running rich as I have black deposits at the tailpipe.
 

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You probably need a new thermostat from your description. Or, possibly your radiator is partially clogged, more likely the thermostat.

There are two temperature sensors affected by underhood and engine temperatures: for coolant on the back of the cylinder head between intakes for cylinders 2 & 3 and for compressed air on the top of the air tube from the compressor outlet to the throttle body. The one that sends a signal to the temperature gauge does not input to the ECU.

That air temperature sensor often fails but when it does you should get a CEL. Ditto for the air mass sensor. On Trionic cars at some point (not sure when) SAAB switched from a MAF to an absolute barometric pressure sensor. This latter sensor is a small black platform bolted to the false firewall (bulkhead) just to the left of the dipstick, looking in from the font of the car i.e passenger side for lhd cars. This has a black vacuum hose running from the sensor to the intake plenum downstream of the throttle plate and an electrical connector to feed the signal to the ECU.

Also suspect might be your FPR on the end of the fuel injection rail: the vacuum hose sometimes cracks and the internal diaphragm sometimes leaks both of which would enrich the fuel incorrectly. A failing FPR would not likely throw a CEL code.
 

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Discussion Starter · #5 ·
The radiator is "new," installed last fall. Maybe the thermostat is bad, but in the course of investigating I discovered the hose at the bottom of the overflow bottle had failed and I was leaking coolant. For some reason there was no warning light. Now with the proper level of coolant and operation of the fans, the temp gauge is fine.
I shall check on the FPR, etc, and I think I'm still in search of a reason why the car is dying when the weather gets hot.
 

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Discussion Starter · #6 ·
Superaero you are right I believe. The car does not have a MAF sensor according to the Haynes book.
 

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Discussion Starter · #7 ·
I changed the vacuum lines at the FPR, MAP sensor, and valve cover to throttle body.
Now, and since the operation of the info box is intermittent, I did not see it until this morning, the CHECK ENGINE light is on. Is there any way to retrieve codes on this car?
 

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Generic code readers are available for OBDII problems. They are pretty economical. SAAB uses their own proprietary code reader which can be found at any SAAB dealer (if there are any SAAB dealers left!). The code would indicate a failed component. From your description I am betting the air temperature sender is failing.
 

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Discussion Starter · #10 ·
Thanks for all of your help. Regarding the codes, this site
http://www.saab9000.com/procedures/powertrain/diagnosis/faultcodes.php
tells how to bring them up with the trionic system which my car has. Unfortunately, since the CHECK ENGINE light operates intermittently, I can't just run the test. I'm leaning toward the temp sensor, too.
Yesterday I ordered the air temp sensor from Parts Geek, and it will be delivered today.
But this AM I jiggled the rheostat for the IP lights and the CEL came on. Two flashes: MAP sensor. Oh, well.
 
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