Hot Start problem

bergerdon · Post by **bergerdon** » 20 Aug 2012, 22:02

1996 Volvo 850 GLT:
The car starts fine when cold. Turn the key and wallam starts and runs at idle just fine. After running for 5 minutes and turning off, then restart is a different story. It will run 5 seconds and die. This will continue for many times. I get tired of it, and hold the gas pedal down and hold the key on start and it will continue to start and die 3 or 4 times then run at full speed. I release the pedal and have to add throttle from time to time, till it smooths out. Then it will run at idle fine.
What could be causing this problem?
Don

Post by **jblackburn** » 21 Aug 2012, 11:45

This sounds like an engine coolant temp sensor that is flooding the engine with fuel when the motor is warm.

Test resistance on the sensor when it's warmed up.

COOLANT TEMPERATURE SENSOR RESISTANCE TABLE

Temperature - F ( C) Ohms
32 (0) .............................................. 7300
68 (20) ............................................. 2800
176 (80) ............................................. 300
212 (100) ............................................ 150

Post by **igel513** » 21 Aug 2012, 12:25

JB, could these values also be applicable to an '03 S60 T5 2.3

bergerdon · Post by **bergerdon** » 23 Aug 2012, 23:15

OK I installed a new temp sensor, no difference. But then a strange thing happened. I was putting a new air filter in and disconnected the MAF sensor. I forgot to hook it up and when I went to start the hot engine it started on first try. I then noticed I had forgotten to hook up the MAF sensor and when I did it killed the engine. So after trying both ways the engine starts fine without the MAF sensor hooked up. I ordered a new MAF sensor, am I on the right track or just spending money?

Don

Post by **jblackburn** » 24 Aug 2012, 07:05

I believe you're on the right track! MAF problem would definitely fit those symptoms.

Post by **patrioty3k** » 09 Dec 2012, 05:36

Just got back from vacation,got the flu,4-5 days downtime{sucked},now back and obviously my 95 850 turbo did not fix itself...i have fuel,spark,new battery...but could the temp sensor have anything to do about non start hot or cold jblackburn?also have flat tire now,but that's minor....

Post by **cn90** » 09 Dec 2012, 05:55

Bosch MAF only, nothing else!