Problem Re-starts

starting
volkswagen

#1

I’ve got a 2000 VW Lupo 1.4 automatic (essentially a small version of a VW Polo, sold in Europe). It’s got 65000miles on it. The car starts up just fine the first time, summer or winter. If you shut off the motor after a short time, 5 or 10 minutes, restarting it can be a problem. If this happens a third time, starting will be even more difficult. If you drive for awhile restarting is no problem, the pattern starts over again. I’ve replaced the battery, plugs, gas filter, had the distributor looked at. Restarting became marginally better. Any suggestions welcome. Thanks!


#2
restarting it can be a problem

What do you mean by this? The engine doesn’t crank? The engine cranks but doesn’t start? Starts after a bunch of cranks with a sputter? Until it cools down? Until the 3rd try? Ever? Until you say a prayer?

Help us out a little bit by adding some description.


#3

The motor cranks but won’t start. If it sits for awhile, a few hours, then restarting is OK. If I start the car, then turn it off after only a few minutes, then try to re-start it, it takes longer to start. The third time, maybe not at all. Then I just have to let it sit.


#4

After a difficult restart - when it does finally start is there a puff of black smoke from the tailpipe?


#5

I would guess that you have an injector that is stuck open and the engine is flooded when you try to restart it. If left for an hour or two the excess fuel has a chance to evaporate and the engine starts with no problem.

If you are handy you can pull the plugs right after shut down and if one plug is wet…that is the bad injector.

Yosemite


#6

My guess, some sensor is getting hot and failing. But it revives itself when cooled off. Crank position sensors are known to do this, likewise for cam sensors, so those are something to check. If that’s the problem, the reason it won’t start is b/c there’s no spark at the spark plugs. It won’t spark if it thinks the crankshaft isn’t turning. So next time it happens, ask someone who knows how, to test for a healthy visual spark at a spark plug.

If the spark is ok, a fuel pressure check at the fuel rail when it won’t start is probably required.


#7

I like both Georges and Yosemite’s suggestions. It always seems as though when you are sure its an electrical problem it turns out to be fuel… and then its opposite. Its easier to check for a wet sparkplug so do that first. The electrical problem will likely take a scanner so you can watch if a signal drops out while cranking.


#8

Thank you all! I’ll check out your suggestions.


#9

Another thing to check if the above suggestions don’t pan out is the coolant temperature sensor and its wiring. If the engine computer isn’t getting the proper signal and thinks the engine is always cold, it will cause extra, unneeded fuel to be injected, which is like flooding the engine in the old days of carburetors.