Hi CO on 3.0 CSI. Help please.

Hello Dr D-jet,

Meet the new member with an old problem.

I have fallen my recent MOT (ITV) here in Spain with my E9 because of 8% CO.
After searching around and checking and tuning everything I could bring it down to 4.5 % and that's it.

My check list was as follows:
1- air tem sensor (within tolerance)
2- coolant temp sensor (new one with a bit better tolerance than the old one)
3 - MPS sensor (absolutely ok according electrical and pressure tests.) I tried broken one and I couldn't notice dramatic changes in CO by the way.
4- injectors (a set of NOS I bought recently)
5- fuel pressure regulator (2 bar. Tried to low to 1.8 bar just for experiment  - no changes)
6- throttle sensor (0 Om closed, infinity after small pushing, 10 fluctuations 0-infinity after, so looks ok)
7- Ignition timing (checked and according to BLUE BOOK)
8- dwell angle (37)
9- spark plugs (new set of BOSCH W7DC)
10- valve clearance (checked and according to BLUE BOOK)
11- all wires and plugs between sensors and ECU (tested with multimeter and ok)
12- potentiometer on ECU (was in the middle when CO 8% was registered and in max anticlockwise now with CO 4.5%. So it seems like it works but maybe not as it should work. I'm not sure).
13- compression test (10.5-11.5)

After all these done should I still looking for some critical point I could missed? Or should I try another ECU (0 280 001 007) + MPS (0280 100 030)?
If yes please help me with a trusted source for these parts (you know prices and I have bad experience with a "NEW" MPS already).

Any help would be appreciated because I can't complete my car registration without this MOT (ITV) test.

Hope for your answer,

Regards,

Yury.







 

Hi Yury,

such a high CO normally comes from

1. MAP sensor
2. Engine temp sensor
3. Cold start valve
4. Vacuum leakage on manifold
5. ECU in rare cases, but then it tends to be higher CO

Hi Volker,
Thanks for your answer.

1. MAP SENSOR. I have 2, both tested for resistance and pressure.
2. ENGINE TEMP SENSOR. I have 2 the used one and the new one installed at the moment. Both tested for resistance. Both in tolerance. I tried to swap them and CO is changing about 1% depend on sensor installed.
3. COLD START VALVE. I made CO test with valve disconnected and hose plugged. No difference.
4. VACUUM LIKAGE ON MANIFOLD. I have 19 inHG at idle.

All wires from sensors to ECU are checked.
I tried to study your technical section before asking for help here first.
What exactly should I do first? It seems like I can't determine where exactly the problem is.

Could you help please?

Can anybody help?

Hi Yury,
19 inHg means about -0,35 Bar to us. I think, you should have a higher vacuum.
Do a search for vacuum leaks...

At first I would remove the hose towards the MPS, seal the support and try to apply a higher vacuum towards the MPS using a vacuum pump.
This is experimental - see what happens to the CO.

Regards
Norbert

Thanks you nordfisch,

It sounds interesting and I will try to play with it but I try to convert inHG to Bar and 19 inHG = 0,64 Bar according Google converter.

But nevertheless it't a good idea to confirm that MPS reacts on vacuum meaning.

Thanks a lot.

Oh yes, Yury -
I don't know why I got the difference to '1' as result when I searched for the Bar-conversion.

Are you sure the injectors you bought are genuine Bosch ones? Do they wear the Bosch-sign or just the number 0 280 150 036 like the chinese fake-ones do?

Regards
Norbert

Hi Yuri,

are your 2 MAP sensor trustable? So old ones, untouched and from 70s ? They should have a 3 digit no on top right rivet with a "2" or "3" in middle. I also do not understand what new MAP sensor has failed.
 
Otherwise it seems that you have swapped everything already and tested wiring harness as well.

 

here are injectors installed

 

Yes I have 2 in the middle.

Hi Yury,
the injectors are genuine Bosch ones and the MPS seems to be trustable... I have only one idea left now:
Does the vacuum reach the MPS?
Are the bore in the manifold and the hose free, can you hear the membrane inside the MPS work when you pull vacuum?.

Regards
Norbert

Thank you so much for your help!!! I appreciate it! Will check tomorrow.
What do you think about trigger points? May they cause over fuelling?
Mine look considerably worn. Found some private listing for the new ones.

Thanks again

nordfisch wrote:

can you hear the membrane inside the MPS work when you pull vacuum?.
 

Hi Norbert,
while I fully agree that one should now check whether MAP sensor sees manifold vacuum, I am sorry to disagree on noise from diaphragm. No you should not hear it. If you hear it jump instead of moving smoothly, something is wrong. In the beginning I had bought diaphragms from a USA source and they behaved like that. It also meant that they jumped like "Knackfrosch" - a children toy making a sound - from one postition to the other extreme position without smoothe movement in between.

Hi Yury,
it is reported trigger-points can bounce in a stadium between mostly and totally worn just before they fail completely.
Maybe this is true... and would produce extra injection pulses.

You can control and readjust the points using a tool I develloped some years ago.
Contact me via PM - I could send you the drawing needed to produce the tool on a lathe or send you the ready-produced tool.

Regards
Norbert

edit: Send a good photo of the trigger points and we can see the status in most cases or measure the gap between the two cams. If the gap is more than about 23,7 mm they are really worn. 

One more question if possible while I'm waiting for my new trigger points.

I have a Bosch transistor ignition kit exactly the same like one listed here : www.ebay.co.uk/itm/234950792901 . It has hall-effect sensor instead of breaker and capacitor.
I tried to install it as a kind of upgrade for my ignition system.

Everything but I met one unexpected problem.

I put my engine to TDC, made all alignments, found 1st cyl position, even checked a spark on a 1st cyl by moving distributor body.

I run the engine after without a problem and set the timing approximately first to get same vacuum value I had before with contact breaker.

Everything is running smoothly BUT when I'm trying to connect vacuum line back to distributor the engine is stalling immediately.

I know that on CSI we don't have vacuum advance for distributor, it's retard. So i tried add more advance with vacuum disconnected to compensate it. Without success.

More to say I couldn't find timing position that allows to connect vacuum line. Engine stalls and I can't start it with vacuum connected.

With vacuum disconnected and plugged everything is fine.

Any thoughts would be appreciated.

Hi Yury,
I think this is an electrical problem.
Did you check the spark when you apply the vacuum?

Might be the ground wire that is part of the breaker-bottom-plate is broken or misses and the electronic unit looses the ground it needs when the plate moves.

Regards
Norbert

Hi Yury.

yes you have a 10° retard on this distributor. Adjustment is done as follows:

• at 2500 rpm without vacuum connected (1700 rpm after 10-1975) with ignition light
• Must flash at 22° advance and there should be a small ball in fly wheel to indicate correct position

 
Do you mean this wire marked with the arrows? If yep I cut it according this manual. Should i keep it?
Thanks a lot!

Yes, correct wire - but it has to be intact.
Don't cut it away!

Regards
Norbert