fuel injection pump

[Johnpin]

Hi everyone. I need some help. After a two year restoration on my 1967 230SL and thousands of dollars spent I still have a problem with cold starts and I have been told by two mechanics that its the injector fuel pump which I have had serviced but not rebuilt. Anyone knows where and who does rebuilds or exchange's on injector pumps and should I look at updating the injector pump to a 280sl one as I am told they are a lot better.
Any help will be appreciated

Regards John

[Nicolas Aristodemou]

Hi John,

With all due respect to your mechanics, I would first look at all the cold start devices like cold start valve, thermo switch etc before going into the FI pump. They rarely go wrong unless somebody has been messing up with it....

[Benz Dr.]

You have to stick to a 230SL injection pump. Each engine has its own pump designed to work only with that system. What are your problems right now?

[Pawel66]

I would have thought if youe are right after restoration, it seems like a natural step to go through the Linkage Tour: https://www.sl113.org/wiki/Restricted/Linkage-tour

Or specifically engine starting aid (if this is your issue): https://www.sl113.org/wiki/Restricted/Engine-starting-aid-tour

That may prevent you from huge expenses and going in the wrong direction.

You need to be a Full Member to access some of those, but I am sure you will soon find this is the best investment in your car that you could make.

[ja17]

After checking all the starting aids, I would hook a temporary switch to the intake CSV. By experimenting with this you can help diagnose the problem.

[Desertpagoda]

exactly, next time you think it will struggle to start, bring the fuel pressure up, then hot up the cold start valve for 3-4 seconds and crank. if it starts look at the cold start system

[ctaylor738]

You should be glad your mechanics are not doctors recommending a heart replacement because of indigestion.

The 230SL has a cold start valve and a solenoid on the injection pump (moves the pump to full rich) to help with starting.  Both are controlled by relays.  The cold start relay needs ground from the thermo-time switch to work properly.

Suggest you join as a full member, download the color wiring diagram in the technical manual, and take it to the mechanics.  If they can't understand it, you need to find another mechanic.

CT

[Benz Dr.]

You should be glad your mechanics are not doctors recommending a heart replacement because of indigestion.

The 230SL has a cold start valve and a solenoid on the injection pump (moves the pump to full rich) to help with starting.  Both are controlled by relays.  The cold start relay needs ground from the thermo-time switch to work properly.

Suggest you join as a full member, download the color wiring diagram in the technical manual, and take it to the mechanics.  If they can't understand it, you need to find another mechanic.

CT

Well, that sure is good, simple, advise.