Ok, great. I know the shop was having a hard time because the car was giving itself so much fuel - appears this is still the situation. I have never seen raw fuel out a tail pipe.
How can I check fuel pressure? I have a fuel pressure gauge - for a schrader valve, I don't see a plug in anywhere.
Is there a way to test the cold-start valve?
Also, is their a way to test the throttle switch?
The air temp sensor - has some odd connections to it - seems as if someone has messed with it before. Are these expesive?
I'm going to peek around that other forum.
You really need an engine manual. It provides details on how to check all the sensors as well as ignition timing etc.
I have 4.5L V-8 engine in my '72 SL and have found that none of the mechanics know much about the D-Jet system. I had to learn about it myself and eliminate problems one at a time until car ran well.
One common problem, is the Auxiliary Air Valve. It sticks and causes high idle speed. If idle screw is screwed in to slow engine, the sometimes it will un-stick and this causes engine idle speed to drop off drastically, and you have to keep foot on pedal to prevent engine from cutting out. You can test AAV by squeezing the rubber tube that connects it to the idle screw assembly (if it is still flexible). Or remove the AAV and test in hot water. It should close when it gets up to about 200F. Thorough cleaning can get these valves working again.
You can test fuel pressure by teeing into the fuel tubing - either at back of engine or on line to cold start injector. Pressure should be in 28-30 psig range and should hold this pressure for some time. If it quickly drops off, this will tell you if cold start valve or injectors are leaking by.
The manual gives instructions on how to test the throttle switch.
You should also check the trigger points that fire the injectors (they are in bottom of distributor) - again manual describes how.
Check that points are set correctly (0.014", I think) and that distributor mechanical advance is working (Set at 30deg BTDC at 3000 rpm). Check also that vacuum retard has vacuum and works.
There is an engine manual on-line somewhere - someone may be able to point you to it. In have links somewhere, but have paper manuals, so never have used it. FOUND one but it may be for later model - the '73 models may have same engine?
Read the D-Jet write ups on the 116 forums here
and at *****************. If you Google for D-Jet or D-Jetronics, you will find more from Volvo, VW and Porsche sites - lot's of links on line including this one
and this one