My 72, 280 SEL with the Bosh Fuel Injection System was in storage for 10 years. It now has new plugs, distributor cap, rotor, wires and I sprayed electrical parts cleaner on the throttle position switch which cleared up the hunting on startup. Suddenly a miss started at all engine speeds. Pulled fuel rail and injectors not dripping with pressure on manifold and they appear on the surface to be ok. I think 2 cylinders on each side not firing properly, lots of black plug fouling on certain cylinders. Could the "trigger points" or "release contacts" in the lower part of the distributor be the problem. Do the "trigger points" only signal the injectors to open or do they also also play a part in the electrical spark? The fouled plugs make me think the injectors are being triggered properly and they are just not getting spark. I don't remember which ones on the left side are not firing but number 1 and 2 are not firing on the right side. I would apperciate any help.

You have a 280SEL 4.5 I presume...

The trigger points can get dirty and cause a lack of fuel, never an excess of it. The trigger point electrica signals are only used by the injectors. There is no connection to the igition.

There are 4 things to do before worrying about what's wrong...

- Replace the rubber hose from the back of the manifold to the pressure sensor on the wall, presuming you haven't done so already. Also look around for vacuum leaks.

- Loosen & retighten the ground connection to the injection wire harness. All of the injectors have separate grounds to one point by the battery. Make sure it's clean and tight.

- Make sure that your valve clearances are perfect. make sure that your ignition timing is perfect.

- Your last "prep" step is to get a pressure gauge and wire it in in place of the cold start valve. When you turn the key w/o starting the engine, that gauge should read 32psi. When you turn the key OFF, the presure should stay there for a while (hours). If not, you have a fault in the pressure regulator, pump or a fuel injector.

There are lots and lots of posts archived about the Djet system. Look for 4.5, djet, d-jet, jetronic, and/or EFI.

I send people of zip file that has some key information about the system. Send me an email and I will reply with the file as an attachment. It's over 1mb, so it can't go to a hotmail account.

-CTH

__________________
- cth350@gmail.com
http://www.111lakeside.com/

oh, and get the 108 service manual. There was a cheap one on ebay yesterday. You need BOTH the chassis manual and the 4.5 engine manual. Don't by the Haynes, get the real factory one.

The book is also available on CD.

-CTH

__________________
- cth350@gmail.com
http://www.111lakeside.com/

Thanks to CTH 350 for the info. I started to make some progress, but decided I needed a "Noid Light" set to check whether some of the injectors are getting a signal. I didn't know if they were still available. I found 2 different listings for "Noid Lights" on "mytoolstore.com". only $12.95 plus $5.73 shipping. Seems like a "must have" tool for those of us that don't have the Bosh box.

just so happens that I have the bosch box.

But, somebody else here pointed out that a basic dwell meter will work just fine. If you need to build a jumper to get your wires in there, any very good foriegn autoparts store has the small format bosch connectors to do the job.

-CTH

__________________
- cth350@gmail.com
http://www.111lakeside.com/