Author Topic: starts great cold, but won't start hot (Read 2271 times)

Dr. Diesel · « **on:** January 12, 2005, 09:22:06 am »

a little tidbit for your troubleshooting files.

Freshly overhauled MF engine, new injectors. Started great cold, drove fine. Shut it off hot and try to start it 2-20 mins later, no go.

Injection and cam timing was good, compression was 490 across all four, no evidence of fuel drainback. Fuel shutoff solenoid was changed with a known good unit. (even though it wasn't really a suspect)

Changed the pump to a known good one, and the problem disappeared.

QuickTD · « **Reply #1 on:** January 12, 2005, 10:18:44 am »

The pump head/rotor was probably worn. When the engine was hot the fuel viscosity was low and it was leaking past the injection pump head/rotor interface fast enough that the pump could not develop enough pressure to open an injector. This only happens at cranking speeds, at running speeds there isn't enough time for significant leakage so the engine runs fine. When the engine is cold the fuel viscosity is high, head rotor leakage is reduced and it starts fine.

Dr. Diesel · « **Reply #2 on:** January 12, 2005, 11:01:35 am »

I figured it had to be something like that... In an odd way, it was a refreshing change of pace, having a diesel not start cuz it was hot! :roll: :lol:

MacGyver · « **Reply #3 on:** January 12, 2005, 12:13:07 pm »

DD, how many miles on the suspect pump?

In retrospect, my previous 87TD did the same thing years ago, QuickTD suggested the same thing, and I'm certain he was right.
I had 370k km on the car. Didn't have an easy life either...

Dr. Diesel · « **Reply #4 on:** January 13, 2005, 07:11:37 am »

unknown history on the suspect pump. likely a little over 300,000km