back to the infamous rich Djet operation

[Graham]

Originally Posted by jdhill

Statically all your cross contact ohm readings for the TPS, the MPS the trigger points, air and water temp senders. I use a Fluke digital meter for those, the little radio shack analog is just to see the trigger points are working when turning the engine over (needle deflection) I then plug the injectors into the scope and check for voltage peak and pulse duration while the engine is running also proper ops. of the MPS. I already had a dual trace Tektronics to check each individual injector pulse at the engine but you could certainaly add a BNC connector to the box and get a probe for that. I should add that I have a permanently mounted fuel pressure gauge and wideband O2
gauge in the center console (where the ash tray was),they are essential. I removed the old test plug the Benz folks used for their test box but ran a lead from the triggering impulse sender to my box as the scope can read frequency (RPM) and the sender is much more accurate than the coil. An indispensible site for me when setting all this up and using it is members.rennlist.com/pbanders/. Brad has done more research on the D-jet
than most. He even has pictures of what a good scope trace looks like. Being self employed there are too many liability issues for me to get into making these but would be happy to show you the layout. It is butt simple.

You are one of the few, mainly only one?, that I know of with a d-jet who has also installed a wideband AFR gauge. I agree that it is the only way to go in order to get the MPS and ECU adjusted properly. The tailpipe ones I tried were hopeless.

Where did you install the sensor? Any pics of the displays? (mine below)

It would be nice to have a d-jet tester (you appear to have made your own!), but most checks can be done with a DVM. But I would like to have a scope that could check injector and other signals. Where do I find one for less than an arm and a leg? Any recommendations?

Have you checked the trigger point output on a scope? It would be great to be able to see the difference that rubbing block wear makes.

Any info on that butt simple layout would be great!

[meltedpanda]

ditto on the butt simple layout!!

[jdhill]

Sensor bung was installed in the X crossover pipe I had installed in the new exhaust system. I'll have to jack up the car to get a pic.
The scope came from JEY tech. and costs around $55. Check out their site, I know the have a distributor in Canada.
As you can see from the pics, I can't show you the gauge layout right now, as wer'e installing a new interior with custom center console. Gauges will be put back where the ashtray was, same as yours. Nice job by the way. I went with Glow Shift digitals, I just like the simplicity.
Have not tried to track the rubbing block wear. One of my first priorities when the interior is finished is to install the LH-2 and get rid of trigger points.
The box as you can see is just 3, 8 pos., single deck, non-locking rotary switches wired to a D-sub female connector with 20ga. wire. The center contact is wired to a banana plug jack for access. You need 3, 8 pos. switches instead of 2, 12's to have access to pins 8 and 10 for testing.
The dial markings were computor printed on colored paper to match the plug colors that I had.
A 25 conductor cable was spliced into the ECU harness with a parallel splice connector which makes it permanent. More to come.

[jdhill]

If you looked at Brad's site you know he used scrap P.C. boards and connectors that he had making it truly portable. Not an option for me.
Let me know if you have any questions. Forgot to add, a d-sub 25 pin male connector was added to the spliced in cable and plugs into the box. You can make it as long as you wish. Again everything is available from Mouser or any electronic supply place except for the scope. Obviously the box is homemade plywood and plastic, anything will work.

[meltedpanda]

you guys amaze me, I am stressing about making a plug for a set of trigger points -- thanks for the info!

[Graham]

Originally Posted by meltedpanda

you guys amaze me, I am stressing about making a plug for a set of trigger points -- thanks for the info!

Just a thought Ron - Have you tested your MPS to make sure it holds vacuum. Apparently cracked diaphragm will cause rich running.

Also check the vac hose from the manifold to the MPS. I recall mine being slightly loose at MPS end. I cut off a short piece and, I think, added a hose clamp (should replace whole line, but end behind engine is hard to get at ) But, if your car idles at 15-19 inHg, you MPS is probably not leaking. But easy enough to check with a Mityvac.

Then there are the temp sensors. There is a method in manual for checking resistance. They can both affect mixture. Might be worthwhile cleaning the probe and making sure wiring is good.

Above just in case you run out of things to do

[meltedpanda]

great minds think alike all checked Graham, and all good, MPS is suspect also , along with TP. HAve a knowm good one on its way and will bench test once here. Still working on trying to find a female plug for the new TP's

[350SL4spd]

This may sound crazy right now, but I'm actually looking forward to having these problems in the next couple of weeks.

Should finally have the fuel system back into my 350SL over the weekend/early next week. Then we get to see what else died in the 3yrs it's been sitting...

[rowdie]

MP, is this what you need?

[meltedpanda]

does that say 9626 on the bottom? IF so YES!!
and with the wires is even better!

[meltedpanda]

Originally Posted by 350SL4spd

This may sound crazy right now, but I'm actually looking forward to having these problems in the next couple of weeks.

Should finally have the fuel system back into my 350SL over the weekend/early next week. Then we get to see what else died in the 3yrs it's been sitting...

does not sound crazy , it is crazy , at least that is what I am trying to figure this out I think there is medicine we can take - hahaha

[rowdie]

9626 it is. PM sent. Generic MB plug. Don't know what it was plugged into on the old '72.

[meltedpanda]

awesome !!!, you have saved the day!

[RadioTek]

MP,

How are you going to do your connections to the new plug? If you are going to just solder the wires together from the 'new' plug to the old ones, you might want to look around for weatherproof heat-shrink tubing. It's a bit thicker than the usual stuff, and it's lined with something resembling hot glue. When you apply heat to it to shrink the tubing, the glue melts and provides a weatherproof seal. Just the thing for an engine bay.

You might have to check around for it, looking at the larger electrical/electronics supplies. Possibly a good automotive supply.

Good luck,
Scott

[meltedpanda]

working on the ideas now , thanks for the tip!