Not starting when warmed up????

[bkj_90_300D]

Hi all,
Here's my problem:

90 300D 2.5 Turbo 102000 miles

Have had this car couple of years now. During the summer months have been having intermittent problem. When the outside temperature gets up to say 80+ degrees F and the car has just been driven and is up to temperature (80 to 100+ C) and has sat parked and off for a few minutes (5 minutes and up) While still hot from running she won't restart. The manner which it doesn't start is as though starving/no fuel. In the process of trying to determine the cause.

Some recent related and unrelated work performed :
new fuel filters
new glow plugs
new remanufactured injectors
new return hoses (injector to injector)
checked and cleaned in tank prefilter
new fuel lines to 2 injectors
Good charge on battery


My sense is as though the injector pump (IP) is losing it when warmed up or there is some sort of vapor/vacuum being induced w/i the fuel system. As I said it acts as thought the system is attempting to prime when this occurs. I had the opportunity last year during one occurence to remove the return hose at the spin on fuel filter and this appeared to help me get started.

The good and bad news is that it is intermittent and it is occuring at lower temperatures and more often.

Currently we are getting into the weather where this is going to happen all the time. I am still troubleshooting and experimenting in search of the culprit. I have a sinking feeling the IP is to blame however not looking forward to the repair bill jusst to have this bear tested let alone repaired. My feeling is if this was the case it would be occuring frequently and worse on cold start. However at a cold start not a problem, starts beautifully and sounds like running water in a brook.

To anyone having experience or recomendations on what to do here, your input would is greatly appreciated in advance.

Thanks
BKJ

[pawoSD]

I think another forum member had this problem recently, it was traced to a vacuum issue holding vacuum on the shut-off valve on the IP when an attempt to restart it was made shortly after the car was shut off...normally the vacuum to the shut off valve should vent out when the ignition is placed back to run....or just by itself after a little while of sitting, I think something can go wrong that causes this to not happen. I'd suspect this though....a good way to test it is to run the car till its hot, shut it off, try to restart, if it won't, go under the hood and disconnect the vac line to the shutoff, then try to start it, if it starts, there's the problem.