911 2

Is there any way of checking the fuel pumps on the 964 3.3 turbo, also should the pumps buzz/prime when the ignition is turned on and where are they located please

Metal Guru

They won't turn on until the Turbo Control Unit gets a signal that the flywheel is spinning.
They can be triggered manually.

911 2

thanks, today the car would not start, started with easy start then stayed fine, drove fine, parked it in the garage, went back to it a few hours later and same problem, just turning but will not start, I am not using easy start again, hate the stuff

fritz k.

One is directly underneath the tank, at the front of the steering gear under a small tin cover. The second is in the right rear of the engine compartment, behind the power steering reservoir.

If terminals 30 and 87 are bridged at the fuel pump relay in the trunk, both pumps should run. To check the functionality system pressure at the WUR and the flow rate have to be measured.
Fritz

fritz k.

​​​​​​
Could be a number of causes, false air, thermo time switch, auxillary air valve, WUR, cold start valve, fuel pressure for example.
This should be looked at by someone who knows the CIS and is able to check and measure the components.

Fritz

911 2

Is there a good manual I can follow, Im sure I could check these with a little assistance including the functionality system pressure at the WUR and the flow rate.
Or if you have any pics where the WUR is located and what values I should be seeing

wicks

This is all very sensitive stuff - you should download and read workshop manual and troubleshooting section carefully before even looking for the WUR.

Once my car did what you describe above - and i took apart/inspected the WUR, did pressure checks, tested fuel pumps, all sorts of electrical stuff chasing the problem. I replaced every sensor on the engine, and there are a lot. Replaced the injectors. What ended up being the cause was that I overfilled the oil and it got up into the fuel head. So I rebuilt the fuel head on the kitchen counter which was clinically clean - and used numbers and tags and notes carefully to put all the parts back in exactly the same position - and actually was quite an intricate and fun project. The diaphragm was actually in terribly dry non-flexible state so this is a project people should probably do to get the most out of the CIS and keep flow correct and such to the cylinders.

You may have overfilled the oil without knowing. The gauge is misleading. Pull the air box remove the air flow plate and get a mirror down into the FD housing, see if there is oil film etc. You can also fiddle around with the lever to get a sense of the stickiness or "return rate" of the plunger which manages the flow through the fuel head. If you get into it note that these parts such as the plunger cannot have even the slightest score. Have to imagine you're working on a rocket engine or something.

911 2

last year i filled the engine oil after an oil change but it did not go into the engine straight away until started it sat near the top of the filler neck but oil level put in was to spec
yes i understand the cis is complex, i have a mercedes sec and that has the same set up cis system