D-Jet hot start on 1973 W108 280SE 4.5 USA import - fuel pressure bleeding off?

Started by kev_a_chatswood, 21-06-2026 06:18 PM. 22 replies. 618 views.

21-06-2026 06:18 PM

kev_a_chatswood Member

Join Date: Feb 2018
Location: Chatswood NSW
Posts: 79
Car: 1973 W108 280SE 4.5 USA import

1973 W108 280SE 4.5 USA import, ex California. Bosch D-Jet. Cold start fine, runs fine warm, but hot-restart within 20 minutes of shutdown gives a 4-5 second crank before catching. Once it catches, runs fine.

Is it fuel pressure bleeding off? vapour lock near the pump? or leaking injector?

21-06-2026 07:42 PM

Vasilios_Billy

Lifetime Benzer

Join Date: Mar 2008
Location: Campbelltown NSW
Posts: 2,031
Club: M.A.L.A.K.A.S.
Car: 2020 AMG GT C

Kev.. D-Jet not carb. check rail pressure after shutdown. if it drops quick look at pump check valve, leaking injector or regulator return. clamp return for a minute and you will know. dont touch trigger points till you know pressure.

21-06-2026 09:18 PM

kev_a_chatswood Member

Join Date: Feb 2018
Location: Chatswood NSW
Posts: 79
Car: 1973 W108 280SE 4.5 USA import

Billy your right.. I wrote Solex cos my last one was a 280S. will test rail pressure tomrrow.

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