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high CO emission at every rpm level

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29 Mai 2022 10:58 #18032
von rsadut
high CO emission at evry rpm level wurde erstellt von rsadut
Hello Jetronic community,

Regards from Istanbul.
My 3,5 L D-Jet V8 MB engine is running on high CO. (116982)The value is around 5,60- 5,10 during idle with warm engine by adjusting the lever on the ecu.When the engine is revved up. (up to 4200 rpm) the CO drops to 4,8 only.I have checked the following:Air temp sensor cold 369 OhmEngine temp sensor 3,70 kOhm when cold and 372 Ohm when a little below degrees 80 C.I have checked the map sensor 99 and 367 (primary and secondary ).With the vacuum pump I have created vacuum up to 380 mm/Hg (ca. 0,5 bar) as per instructions on the web site. There is almost no drop in the manometer during 15 seconds.Do you have any suggestions? Kind Regards,Juan

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29 Mai 2022 11:47 #18033
von nordfisch Europe Opel Diplomat 2.8 E
nordfisch antwortete auf high CO emission at evry rpm level
Hi Juan,
what color are the injectors? Could you send a photo, they could be the wrong type.

The MAP sensor could be misadjusted.

Did you check the fuel pressure, the pressure after shutoff, too?

I think, those are the possible reasons for your probs.

Regards
Norbert

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29 Mai 2022 20:56 #18034
von Dr-DJet Europe Mercedes-Benz R107 450 SL, Mercedes-Benz W111 280 SE Cabrio
Dr-DJet antwortete auf high CO emission at evry rpm level
Hi Juan,

can you vary CO at idle by ECU rheostat ?

Such a high CO normally comes from
  • disconnected engine temp sensor
  • Detuned / vacuum leaking MAP sensor
  • Vacuum leakage on engine or vacuum hose to MAP sensor

Viele Schraubergrüße - best regards, Dr-DJet Volker
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30 Mai 2022 12:23 #18035
von rsadut
rsadut antwortete auf high CO emission at evry rpm level
Hi Nordfisch,

the injector color is yellow. I had found 'new old stock' a couple of years back and replaced the old ones with these.
before doing so I tried to have the injectors cleaned and measure the values of the old ones. My mechanic had a special device where injectors are attached and run for a period before starting with the cleaning. some of my old injectors were injecting more and some were injecting less fuel.
I had checked the fuel pressure which was at 2,1 bar. I never tried the pressure after shut-off. I could do that.
The MAP sensor was sent to Bosch device and returned after being adjusted.

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30 Mai 2022 12:47 #18036
von rsadut
rsadut antwortete auf high CO emission at every rpm level
Hi Dr. D-Jet,

First I have tried to adjust the CO level by using the ECU rheostat.
When the engine was warm around 90 C the measured CO value was at 5,60.
By using the rheostat the value was brought down to 5,10.

Afterward, we started to rev up the engine to detect the change in CO values. As I explained above it did not go down much (4,80)
- I measured the engine temp sensor first by disconnecting the connector on the engine value was at circa 350 ohms. (warm engine) later I reconnected the connector and measured at the 25 pin ECU connector. (23-12) this time value was 372.
-I checked the vacuum leak at the MAP sensor as I have mentioned I did not see any change in the value

- I still need to check the vacuum hose to the MAP sensor and vacuum leakage on the engine.

Since the beginning (it has been 10 years since I acquired the car and put it back on the street after a long restoration period) the wall where I park the car has been blackened with soot all the time. I suspect this is due to the rich mixture.

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30 Mai 2022 14:06 #18037
von Dr-DJet Europe Mercedes-Benz R107 450 SL, Mercedes-Benz W111 280 SE Cabrio
Dr-DJet antwortete auf high CO emission at every rpm level
Hi Juan,

an indication would be if your mechanic could connect a pressure gauge via a T-connector in the vacuum hose to MAP sensor. In idle you should see minimum 500 mBar vacuum.

Viele Schraubergrüße - best regards, Dr-DJet Volker
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03 Jun 2022 12:44 #18067
von rsadut
rsadut antwortete auf high CO emission at every rpm level
Hi, Jetronic community.
Two days ago, I went down to the garage to take the car to the mechanic to check the vacuum levels of the engine.
The engine started but the engine speed did not go up as it should.
I pushed the gas pedal the engine started to vibrate as If some pistons were missing.
Later the engine speed leveled at around 1200-1300 rpm and ran normally.
After about 100 m. I had to stop. at a red light. The engine started to choke. I shifted to neutral and tried to regulate the engine speed by giving more gas. The shaking started again. Finally, the engine died.
As the engine was still cold, I turned the idle screw slightly anti-clockwise in order to have a higher idle when I restart the engine. I was able to fire up the engine again but there was erratic behavior. All of a sudden, the rpm went up and ran very smoothly. I opened the hood and took the air filter away and started to play with the engine temp sensor and distributor cables as I thought it could be an electrical problem. In my first attempt doing this improved the engine speed but later I could not see the effect of playing with the cables anymore.
May I have your comments?

Kind regards,
Juan

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04 Jun 2022 07:29 #18070
von Dr-DJet Europe Mercedes-Benz R107 450 SL, Mercedes-Benz W111 280 SE Cabrio
Dr-DJet antwortete auf high CO emission at every rpm level
Hi Juan,

this jumping effect sounds liike an electrical problem. It would be good if you could locate it further.

Viele Schraubergrüße - best regards, Dr-DJet Volker
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04 Jun 2022 14:43 #18071
von rsadut
rsadut antwortete auf high CO emission at every rpm level
Hi again ,

I have tried to start the car again this morning.
when the engine is cold the engine speed is around 1800 rpm and gradually drops to adjusted idle speed of 900 rpm. Once the engine reaches its operating temperature (above 80 C) the idle drops and the engine dies. there is no way to run the engine when it is warm.
I tried to measure the engine temp sensor (on the manifold) around 40 C the value was 1,257 kOhm
why would the engine die when it is warm?

KR,
Juan

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04 Jun 2022 23:47 #18077
von nordfisch Europe Opel Diplomat 2.8 E
nordfisch antwortete auf high CO emission at every rpm level
Hi Juan,
did you check the connection of the sensor towards the ECU?
As Volker wrote before, the ECU sees an engine temperature below zero when the connection is faulty and enriches the mixture so much that the engine dies.

Regards
Norbert

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05 Jun 2022 13:59 #18082
von rsadut
rsadut antwortete auf high CO emission at every rpm level
Hi Norbert,

Thank you for your support. When I bought the car the cable harness was in a very bad shape. So I had it redone by ordering parts here and there. I used it for 10 years. Last year with Jetronic support I got the drawings for cable harness and produced two more sets.
Before connecting I check the wiring. I have also had the ecu checked before installation.
As far as the engine temp sensor is concerned I check the values on the sensor itself and remotely at the end of the 25 pin connector. The values match the original chart. To be on the safe side I have ordered 0280140014. The air temp sensor was purchased new at MB 6 years ago.
There is definitely a rich mixture problem because everytime I go back home from a ride I smell the gasoline on my garments. Recently I checked the CO emissions the values were between 5,6 and 5,1 (after adjustment of the ecu-rheostat. ) no way to bring it down. I tried to check the -twice by Bosch readjusted- MAP sensor leakage at 0,5 bar the values did not change so I think it is working fine.
Last thing to be checked is vacuum leaks on other parts of the engine but I cannot mive the car more than 200 meters as the engine dies when it is warmed up.

Kind Regards
Juan

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05 Jun 2022 15:15 #18085
von Dr-DJet Europe Mercedes-Benz R107 450 SL, Mercedes-Benz W111 280 SE Cabrio
Dr-DJet antwortete auf high CO emission at every rpm level
Hi Juan,

havin returned from a K-Jetronic workshop I can only repeat what makes a mixture extremely rich:
  1. Engine temp sensor
  2. MAP sensor
  3. Injectors leaking
  4. Wiring problems and interference on trigger contacts
  5. ECU
  6. full-load switch in throttle switch
All other parts have minor contribution.

Viele Schraubergrüße - best regards, Dr-DJet Volker
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