Tuning questions, car hesitates and part load stumble

Okay thank you for responses. I painted the flywheel marks, 7 teeth from the OT on crankshaft pulley is the ball and with it bang on the ball it hesitates and you hear in the exhaust a stutter/miss. With 15 degrees more timing the rpms pick up 100 and it smooths out, 25 degrees it picks up more rpms and at 30 starts to shake again. I wonder if cam timing is off or something internal? I will read the referenced d jet material and try to sort through step by step.
 
I’m a fan of free diagnostics....



run a mitey vacuum test on your Manifold Pressure Sensor.
Does it hold vacuum?

you may be hearing a lean miss -fire

turn up your fuel pressure to the injectors by pinching off the fuel return hose partially and briefly while listening for that stutter/miss.
 
Get that long screwdriver out and put it up to your ear. Tip on each injector to verify the click.
Ev-1 plug connectors were invented because of how bad early djet injector connectors were.
 
I had this exact problem with my 1973 CSi ten years ago.

We threw the Pertronix in the trash. Used traditional points & condenser & went with a 123 VRI-E Distributor which eliminates the equally expensive trigger points in the bottom of the CSi Bosch distributor.

The ultimate fix was rebuilding the MAP (Manifold Atmospheric Pressure) Sensor located at the back of the brake servo bracket.
 
Back at it today after reading through some the D jet material. It took 10 revolutions to start today, once it fires it runs perfect until the fast idle comes down, then the stumbles start and engine shakes at idle or steady rpms. Giving aggressive throttle smooths it out so I am pretty certain it is lean. Pinching the fuel return hose did not help, no change. Plugging various vacuum ports did not help (crankcase breather, brake booster hose). I will test the manifold pressure sensor next week as we did not have the mityvac on hand; the pressure sensor is mounted above the brake booster area?
Injectors tick equally. I have a new wiring harness from WN to do this fall when the engine comes out for total paint redo (engine bay included), I may upgrade to sealed connectors as later systems use with wire bales (injectors are the same).
All thoughts and tips appreciated! It really acts like an unmetered air leak but not finding one, very simple vacuum set up. I sprayed the injectors and no leaks, manifold gaskets are all new and no leaks. The engine was rebuilt by an old timer BMW mechanic, it went back to him lately for retorque of head bolts and tuning but he was unable to make it better and not interested in working anymore (cancer). He did a complete rebuild despite "nothing" was wrong as I am told, it was always maintained this car. Owner just wanted a fresh car. I keep getting more info on the car in bits.
Trying to wrap my head around some of the material on these is not easy, the translation makes it difficult reading on certain documents or very incomplete info, it tells what the device does but not how to verify function/test. I will keep rereading and try to understand the concepts presented, I have a basic sense of it but misunderstand how it adjusts mixture? The ecm has a dial adjustment somewhere? Owner is willing to send the car for dyno tuning and have it done thoroughly but want to sort through it first.
 
Go ahead and adjust the fuel pressure regulator.
Add 3 psi and see what happens.
alternatively - add 6 psi and see which plug doesn’t foul.

I offer a csi computer loaner program - let me know if you want it shipped out.

you will have to pump the mitt vac like crazy - don’t give up to early.!

how far is the idle screw out?

have you cleaned the innerds of your TPS?

With key on but not engine running- actuate the throttle linkage quickly.
do you hear the crickets?
 
Yes to the crickets, when diagnosing the dead fuel pump last month. Will adjust fuel pressure next week and see. The idle screw is behind and under throttle body? It seems to not do anything half turn/full turn. I have not touched the tps yet, wanted info first which the d jet file has. I only get to play on it weekends when the shop is closed.
 
Back at it with a clearer mind
sfdon I need to clarify the timing marks. At OT on the crankshaft damper and flywheel, the ball mark for timing is 7 teeth BEFORE (CCW) not after, if I push the car ahead from the OT marks in 4th gear nothing found. Please verify.
 
TO on dampener matches TO on flywheel
Always verify for Top Dead Center.
 

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Z mark appears in bellhousing opening when properly timed (7 teeth, 22*, 2000 rpm)
 

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adawil2002 said:
I had this exact problem with my 1973 CSi ten years ago.

We threw the Pertronix in the trash. Used traditional points & condenser & went with a 123 VRI-E Distributor which eliminates the equally expensive trigger points in the bottom of the CSi Bosch distributor.

The ultimate fix was rebuilding the MAP (Manifold Atmospheric Pressure) Sensor located at the back of the brake servo bracket.
Click to expand...
Adawil: I'm at my wit's end trying to figure what's wrong with my D-jet: rebuilt MAP, new injectors, coil, verified ECU OK, replaced fuel regulator, checked Cold start valve, nothing works---engine runs like it is stuck on full choke. Checked trigger points, seem OK, and yes very expensive.
Saw you went with 123 distributor, did you keep the rest of your D-jet? How Does the 123 talk to the ECU? Thanks for your help.
 
Yes I run a 123 Distributor. The CSi runs the 6-VRIE specifically designed to run like the injector points in the bottom of the Bosch distributor.

Could your timing be out? Too much either way?
 
bill said:
Adawil: I'm at my wit's end trying to figure what's wrong with my D-jet: rebuilt MAP, new injectors, coil, verified ECU OK, replaced fuel regulator, checked Cold start valve, nothing works---engine runs like it is stuck on full choke. Checked trigger points, seem OK, and yes very expensive.
Saw you went with 123 distributor, did you keep the rest of your D-jet? How Does the 123 talk to the ECU? Thanks for your help.
Click to expand...
Disconnect your cold start system...
 
Don shared the D-jet information already, but I used this info when doing my troubleshooting in the past.

http://www.vclassics.com/archive/efi.htm

The same but more or less as a summary.
As I have done almost everything in the past to solve my issue, I would do the following.

1. Basic checks, ground, battery, working alternator, coil(does it get hot during idle run?) timing, etc. (Not sure if that is correct already based on the discussion here?)
2. Do a leak/smoke check of the intake system.
3. With fuel pressure being ok,
be sure to check the injectors and your cold start injector outside the intake plenum, so that you actually see that they spray. You are mentioning that it starts quit late (10 turns) before it starts. Mine starts within 2 or 3 turns). Your cold start injector is suspicious to me.
Read my other post, the injectors can click but the needle can still be stuck into the injector housing. You can make them open with a hammer (ask me how i know) by knocking gentle on the needle.
4. Check the electrical components of the D-jet system like mentioned in the link. You can check them with a multimeter and a vacuum hand tool for the MAP.
5. You can play with the knob on the ECU, but besides a leaner/richer mixture it won’t change your symptoms I believe. Then at least you know that there is ‘a knob’ on the ECU!

It goes sometimes straight through what you already mentioned, but see this then as a brain dump ;)

A combination of this was in the end my issue with a difficult low rev running CSi engine.
 
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This happened to me. Stuttered or died on acceleration. It was typical of poor fuel pressure. Replaced pump, pressure regulator and tested everything. It did not improve.

The solution was to clean the distributor which was arcing across the terminals. I’d say it is worth a look for you.
 
So a few years down the road...car went to body shop in 2023 for a total restoration on the rotisserie. Power train removed. I pulled the intake manifold and surprise! The gasket on the last cylinder was torn/leaking even though it was new(ish). So that was the leak causing all these symptoms. No idea how they tore that gasket but it was clearly split.
Getting the car back together now and running this week, hopefully it is better. Thank you again for all the input and ideas.
You can never trust someone else's work, never assume it is right!
The entire engine bay was redone, hoses, clamps, gaskets, seals, all shiny new. Will be easy to set up now.
 
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