45 is not low enough to need preheating or for problems w/fuel due to temp.
Slow start could be lousy fuel (low cetane, contaminants), though it would be unusual. Problem w/"unusual" is that when it happens to you, that's the problem you have. Under Diesel Injection
in the yellow pages there should be an authorized Stanadyne
dealer that will have Performance Formula
diesel additive. It improves fuel lubricity, cetane rating, removes water by dispersal... and increases fuel mileage ~3% when used in the dilution ratio recommended (based on tests reported on The Diesel Page
. Should be $5-8/bottle, is easy & the first thing I'd try.
Slow start could be other stuff also, but mostly related to fuel delivery. Diesel's don't have spark like a gasser; just squirt fuel into cylinder at point where compression (~19:1 in our case) then heats & ignites the fuel. So when a diesel won't run or runs poorly, it is almost always related to fuel delivery. W/today's EFI engines, diagnosis of those issues is a shop issue, though making certain all ground connections are bright & tight is one thing the DIY'er can do. Also, if you have scantool or Silverleaf access to computer Diagnostic Trouble Codes, the DTC can provide a data point for further inquiry here or on sites like Yahoo Diesel-RV Newsgroup
. You need a detailed mechanical background on your rig (engine, year, mileage, tranny, where you last & usually get fuel, maint. record, symptoms well described) to get good feedback, but posters include diesel tech's and tech groupies, among numerous diesel RV owners who may have had similar issues. You can also post your life story on IRV2 Motorhome Problems & Solutions
, and possibly some other sites. If nothing else, you will get theories and reports of repairs others have gotten.