72 280se 4.5 warm start problem - Benzworld.org

roadrosen · 05-01-2007, 08:55 PM

starts great cold. starts great hot.....but wait 15 or 20 minutes on a hot day after shutting down and it turns over perfectly and then shuts down. as it cools completely it ill start and idle roughly and stall. finally it will be fine. thoughts for the trenches?

roadrosen · 05-02-2007, 12:36 PM

thanks

nedredbeard · 05-02-2007, 01:26 PM

i have the same exact car and the same exact problem and i know that it has to do with the temp. of course the engine gets hotter after its shut off. i usually have to baby the idle along until it cools down, or it will stall just like yours. if the temp gets any hotter than 180 or so it will run rough. maybe your aux. fan isn't operating properly. i was thinking of wiring my aux. fan so that it runs with the key out of the ignition until it gets to 175.

roadrosen · 05-02-2007, 01:52 PM

correct. a thermostaically controlled fan would probably do the trick. great

desertpagoda · 05-02-2007, 06:41 PM

Quote:

Originally Posted by roadrosen

starts great cold. starts great hot.....but wait 15 or 20 minutes on a hot day after shutting down and it turns over perfectly and then shuts down. as it cools completely it ill start and idle roughly and stall. finally it will be fine. thoughts for the trenches?

Two words: VAPOR LOCK, the current fuel must have a lower vapor point and the cars cant cope. New pumps, custom added fuel accumulators, fresh check valves,after run fans all help a little. But not enough. I have at least 30 towed in each of the last several summers and all of them run great when they get off the tow truck after cooling down for1-2 hours. Then act up again when good and hot. If anyone has solved this let us now! Keith

nedredbeard · 05-02-2007, 08:46 PM

roadrosen, do your door locks operate properly?

roadrosen · 05-04-2007, 03:38 PM

locks do not operate automatically. vacuum leak.

roadrosen · 05-04-2007, 03:42 PM

after searching the web some have suggested thatthe early injected cars have a problem with the fuel evaporating in the lines so spraying some cool water on injector lines can help or turning the key a few time to move cooler ful in. check this link

http://mercedesshop.com/shopforum/showthread.php?t=5904

it will be hot here in ci this weekend and i'll test the proposition.

comments?

frank220-450 · 05-06-2007, 08:00 PM

That kind of problem would definitely get me twisted. I tend to go with the incoming fuel temp after the car has reached operating temp as being the likely culprit. Their should be a an in line air exchange cooler available through a performance parts company that could be plumbed in with relative ease that should alleviate the condition. Good luck, frank220-450.

wbain · 05-06-2007, 08:34 PM

Perhaps a combination of check valve(s), fuel pressure regulator leakage and bad solder joints in the fuel pump relay.