fuel usage at idle, 300 SDL - Page 2 - PeachParts Mercedes-Benz Forum

#16 12-25-2007, 11:16 PM

Swift is cracking down big time on idle time. Mainly just because of fuel costs. They are even suspending drivers that have too much of it, some have had as much as 60-70% idle time on their engine. The trucks have timers that kill the engine after a specific time that they are out of gear and restart them when the coolant temperature gets cold or if voltage drops below 11v.

The drivers have been learning how to disable/bypass the timer by killing power to the unit or putting the shifter past the neutral switch and almost into gear. We have been installing tamper-proof fuses and connections in an attempt to thwart their efforts but they still find ways.

Very few of our trucks have APU's, mostly just the owner-operators. The new trucks (2007+) do come with a Webasto heater.

pawoSD · #17 12-26-2007, 09:18 AM

Quote:

Originally Posted by Skid Row Joe

Not exactly. All those famous MB diesel taxis overseas with all those miles on them, have gone through multiple engine blocks, and or overhauls.

However, the average for overhauls on the taxi engines seems to be around 550-650,000 miles. Which is a lot! Especially considering all the idling they do. However, now they shut the engine off every time they can, the taxi we used there turned his engine off at long lights, when sitting more than 30 seconds....etc. It was a W124....not sure which engine but it was a diesel....perhaps a 601 or 602? And a manual.

argus445 · #18 12-26-2007, 09:45 AM

well the combustion temp. would probaly go between 300-500 degrees after 5 minutes and about 1/2 of the fuel being injected would end up not being burned so i can only imagine what would happen i've read alot of books and most say 5-10 minutes max. after than u'd have to have some type of idle up device to keep the combustion temperatures up to burn the fuel.

#19 12-26-2007, 09:51 AM

Keep in mind that the amount of fuel injected at idle is as little as 1/5 of one drop of fuel per injection with an air/fuel ratio as high as 80:1. If your engine is in remotely reasonable condition there won't be any liquid fuel that can get into the crankcase, but there will be plenty of carbon to deposit.

Hatterasguy · #20 12-26-2007, 10:04 AM

Depends on how cold it is. -15 or colder, if you can't plug it in just leave it running overnight. But you need to let them sit for like 8+ hours to have starting problems, the first start of the day is the hardest once you get some heat in the engine they are fine.