Passat B5. 5
Karri Weston
My 2005 passat has issues starting in cold weather. Today it is -7. When this happened last year, I had to have it towed. I was told, sparkplugs, and other routine maintanance. I replaced the plugs, did the routine maintanance, and here I go again, not starting. I know it's cold out. The Toyota with 183000.0 miles on it starts no matter what the temp. Any suggestions? Does anyone know why the car won't start?
There are senors who read the engine temperature and another that reads the air temperature. Easiest proplem would be a damaged temperature sensor. If a sensor is damaged, the electronics think the engine and or air temperature is warm enough and does not preheat. But preheating is necessary, because its cold. A proper VW shop should be able to sort that out.
You may have a fuel problem such as moisture in the fuel. If you try to put a bottle of dry gas in your fuel tank you may be able to get the moisture out, which will sometime for ice crystals inside your fuel lines.
If all ok then check the HT leads to the spark plugs, check them for any damage or moisture; these leads carry high voltage to the plugs and if they short due to moisture etc then the plugs will not get the high voltage they need to spark.
There is also an air pump that holds vacuum while the car warms up which is located in the fender. My 1999 1.8t Passat had fuel line issues when the temp got that cold...it would actually leak until warmed up, I guess the crimp was bad or something.
if the engine doesnt starts, check the air filter, the distribution cap and rotator, the cables to the sparkplugs an the spark plugs. When you turn the key, but doesnt start, you should hear a low humming noise from the back of the car, that stops after 2-3 seconds. That was the main fuel pump, building up pressure in the fuel lines. If that was all ok, we have a litte problem.
If you have an engine with a central injection (SPI) in the throttle body, try the following steps. When you take out the air filter you can look into the throttle body if its messed with layer of a black oil-coal mixture, clean that throttle body. Your car has a cold-start-system, if the temperature is under a certain temperature an extra channel in the throttle body is opened up to have a richer mixture, wich helps to start at low temperatures. When this channel is closed by the oil-coal mixture you have issues.
A problem with the vacuum system could be found rather easy, when the engine is running. open a connection in the vacuum system and hear if the rev. changes, it should change, now close both ends, one after the other with you thumb, hear if something changes. Then put the connection back togehter then open the next one until you find a connection where the rev. doesnt change until you close the line with your thumb. An indicator for a working vacuum system is the small red pimpel on your thumb while closing the vacuum line.
If you have an engine with a injection valve for every cylinder (MPI) i would guess that the engine gets "false air" by a leak in the air intake system. The mass of air is meassured and the black box already calculated the matching ammount of fuel. If the engine gets more air, than calculated, by a leak in the air intake system, the mixture gets lean an the engine doesnt start well when its cold.
Start up the engine and buy a can of a.e. break-disk-cleaner, now spray, only 0,5 seconds per spray, the air intake in smal steps beginning from the air filter to the throttle body. Spray listen if you hear that the rev. goes higher, no next spot until you hear the rev go higher than you have found your leak.
The coolant temperature sensor is a common culprit for cold start problems. There could be other causes. If you can find someone who has a VCDS interface cable and a laptop with VCDS software (Ross-Tech), you can look into what's going on with the engine and make a more accurate diagnosis. It's better than buying and replacing parts based on guesswork.
Hey I have that Problem, In the am it has no problem turining on, but if I go and put gas, then to turn it on. It wont start I have to press on the gas paddle for a few times. I feel like im choking the car. any Ideas please email me
It seems that the 2001 -2005 VW passat was not built right in that respect, at least, and should be recalled to be fixed properly. I made a mistake and got a 2003 passat, have the same trouble, and may never buy VW again because of it and the fact that they ignored their mistakes and made all of us suffer as a result.
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