NORTHERNSHARK

I having hot start problems on my 1980 928s euro, eng # M28/11. Under the rt rear wheel well is the accumulator and some other white round thing that is routed from the front of the car and then over the wheel well to some other small part behind the rear bumper and then back to the front of the car. I was hoping to find a check valve that may solve my hot start problem, not sure what these other parts are. My fuel pump doesn't have a check valve and it's not the long neck type. Car starts fine cold and hot unless it sit for 20-30 minutes after running. I also noticed after the car is shut off the return line to the fuel tank pulses fuel (took the line off to check).
Any help would be appreciated.
Thanks in advance.

dogleg

+1

Randy V

This is a common symptom of an older CIS fuel management system indicating leaking fuel injectors.

When the car sits after running, the injectors are under pressure and leak fuel into the cylinders.

The cylinder(s) are then flooded with fuel and will not fire if trying to start again within a couple hours. If left to sit for an extended period such as overnight, the fuel evaporates and the car starts normally.

I recommend sending the injectors to a place that specializes in servcing them, or for about the same money buying some new Ford injectors.

Bertrand Daoust

I don't know about your MY, but I had the very same problem with my '91 and the problem was a bad (leaky) fuel pressure regulator and a bad dampner(?).
Changed both and never had the problem again.
Good luck.

Randy V

Totally different fuel systems on the '80 and the '91.

dogleg

dont the ford injectors replace the newer electronic injectors?its the mercedes ones to replace the mechanical injectors that are going to be fitted to this CIS car

Randy V

Ah, quite right - good catch.

jpitman2

Have been through exactly this issue long ago. Step by step - get injectors checked for opening and spray, replace as indicated - the short brass MB units are reported to work fine. If there is still a problem, check the accumulator (if possible) , replace. I would fit a new check valve on the pump anyway - not much $. All these thing help keep CIS working as designed - have done them all in mine.
jp 83 Euro S at 53k

NORTHERNSHARK

Thanks for the reply(s), I think I may have the wrong fuel pump as it has no check valve.

Randy V

Well, that's a start but probably won't solve your hot no-start issue. You can buy a separate check-valve that screws into the end of the fuel pump, using an aluminum crush washer. The fuel line then screws into the end of the check-valve - with another crush washer.

The check-valve ensures that the fuel system from the pump to the injectors stays pressurized, meaning if you have leaky injectors they will still be the root cause.

LT Texan

I spent lots of money on my '78 trying to cure this. Thousands to mechanics (Porsche and independant) and no joy.

Then I bought a CIS fuel pressure test gauge from JC Whitney and the book "How to Tune nad Modify Bosch Fuel Injection" and discovered that my fuel system didn't hold rest pressure.

A couple tests later, I found that it was a failed check valve at the fuel pump.

A cheap and easy fix.

I could have floundered around and replaced lots of other more expensive things first....
fuel injectors
cold start injector
fuel distributor
warm up regulator