Fuel System Tester

[85911]

I am in the process of purchasing a fuel system pressure tester and want to make sure I get the right tool.

I have an '85 Carrera, so it has the DME- Motronic fuel injection system. (When I look in my parts catalogue, which is for an '86, it lists parts for an L-Jetronic I, II, and III system, and a K-Jetronic I,II, and III system. From simply looking at the pictures, it looks like a have the L-Jetronic. Is there a more definitive way to determine if I have an L or K system?)

This is not a CIS system, correct?

If correct, then I do not need the pressure tester that has a "T" with a shut off valve and 2 separate hoses with connectors branching out from the "T", correct?

I simply need a gauge with a bleeder and a single hose with a 12 mm X 1.5 pitch connector (without a shut off valve).

Interestingly, on page 240-2 of the Fuel Injection section in the Bentley Manual (for a 1984-1989) under special tools, it shows a fuel pressure gauge with the "T" and the 2 hoses. Later on in that section on page 240-7, it shows a gauge with a single hose (I think) hooked up to the connection at the end of the rail. On page 240-6 in the narrative on checking fuel pressure, it only says to connect the gauge to the fuel rail (singular).

Thanks.

[kuehl]

For normally aspirated (not a 930 turbo) engine staring 1984, yes, not a CIS system.

Pressure testing is done a the LH fuel rail over cylinder 1. There is a hex head cap on a short port on the rail. Remove the cap (carefully) and there is a round steel ball which together with the cap provides seal.





For testing Pressure (discussed in the shop manual sections 240 and 201), use a gauge attached to a hose, the hose fitting mating up with the fuel rail port.

[85911]

Kuehl: Thank you for your reply.

Do you know how I can tell if I have an L-Jetronic or a K-Jetronic system?

Thanks again.

[boyt911sc]

Originally Posted by 85911

Kuehl: Thank you for your reply.

Do you know how I can tell if I have an L-Jetronic or a K-Jetronic system?

Thanks again.

'84~'89 Carrera 3.2 engines use the air flow meter system (L-Jetronic) commonly known as Motronic system. While '73.5~'83 engines use the continuous injection system (K-Jetronic) commonly known as CIS.

Going back to your inquiry about the fuel pressure gauge illustrated in the Bentley Manual, the book shows a typical fuel injection gauge kit with a shut-off valve and a pressure bleeder. Which we commonly referred as CIS pressure gauge in this form. This is actually a fuel injection pressure tester with metric fittings (12-mm X 1.5 pitch thread).





Take a closer look at the above pictures. I was using the typical fuel injection pressure gauge to measure the fuel pressure produced by the fuel regulator at the fuel rail. The shut-off valve must be CLOSED when you use this pressure tester in a Carrera 3.2 or Motronic (L-Jetronic). This is the same fuel injection pressure gauge illustrated in the Bentley Manual. More versatile than a single hose pressure gauge.

Tony

[85911]

Tony: Thanks for the clarification. That's what I was looking for.

I have found what looks like a good, 100 psi fuel pressure tester, but has fittings for GM and Ford. The tester is $32.95 and make by OTC.

The only item I need is a 7/16 in. X 20 to a M12 X 1.5 adapter.

Thanks.