280SE 3.5 Problem mit dem Injektorimpulsstrom

Hallo,
Ich habe w108 280SE 3.5 und ein Problem mit dem Pulsieren des Einspritzventils.

Ich denke, der Impulsstrom des Einspritzventils nimmt ab.

Wenn ich einen der elektrischen Stecker des Einspritzventils entferne, steigt die Leerlaufdrehzahl und die Motordrehzahl wird sehr gleichmäßig. Wenn ich jedoch die Steckdose des Einspritzventils 1. zurück stecke, verringert sich die Leerlaufdrehzahl. Wie Einspritzventil arbeitet nicht oder arbeitet gegenüber.

Denn wenn ich die elektrischen Stecker jedes Injektors einzeln (außer Injektor 1) entferne, verringert sich die Leerlaufdrehzahl um etwa 100 U / min. Welches ist normal, denke ich.

Was kann das Problem sein. Ich weiß, dass Injektoren als 2-Gruppe pulsieren. 1-5, 2-6, 3-7 und 4-8. Wenn ich mich nicht irre.

Vielen Dank

Hallo Unbekannter,

wäre schön, wenn Du uns Deinen Vornamen verraten würdest. If German is too difficult for you, we can also switch to English.

Bist Du sicher, dass Du am Zyl. 1 die Leitung des Einspritzventils und nicht die des Luft Temperaturfühlers aufgesteckt hast?

Jazzenco81 schrieb: r.
Ich weiß, dass Injektoren als 2-Gruppe pulsieren. 1-5, 2-6, 3-7 und 4-8. Wenn ich mich nicht irre.

Hallo,
fast richtig.
Es sind die Einspritzgruppen:
Gruppe 1: 1 + 5
Gruppe 2: 4 + 8
Gruppe 3: 6 + 3
Gruppe 4: 7 + 2
Viele Grüße,
Recardo

Hello Mr. Volker
First of all thank you very much for reply. Sorry, I forgot to write my name. My name is Kutluhan. You are right switching to English is better for me).
My problem is I recently bought 8 pcs of new fuel injectors (yellow) for my m116.980 3.5 engine. After installing all. I operted car and noticed that engine shakes little bit like individual cylinders are nit working.
So I checked each ignition cable,supressor plugs and spark plugs. All ok.than I stared checking injectors individually by removing electric plugs while engine running at idle speed. So, When removing each injector electric plug, I noticed that idle speed decreases around 100 rpm. This is same for all 7 injectors. But when I remove electric plug of injector 1. Idle speed increases! instead decreasing and engine runs smoother by 7 cylinder I guess all other cylinder gives more fuel to compensate missing 1 injector.

I just don't understand the reason why cutting electric of one injector increases idle speed.
I measure the resistance of fuel injectors, so all are 2 ohms.My old ones were 2.4Ohms. Do you think the problem can be more current consumption due to .4ohm difference by each injector.?But all in all injectors works as 2 group at each pulse. I hope injector driver transistors are not loaded so much by 2 ohm injectors so pulse get weaker?
I got confused.

Thank you very much in advance .

Best Regards,
Kutluhan Kutlu

Hi,
the wiring towards injector 1 has to be green (and brown).

Zum Injektor 1 gehören die Kabelfarben grün und braun.

Gruß
Norbert

Hallo Herr. Recardo,
Vielen Dank für die Korrektur.)
Freundliche Grüße
Kutluhan Kutlu

Merhaba Kutluhan Bey,

new yellow injectors are hard to find and I have recently seen strange copies with 0280150034 mark from China. Are you sure you got the right injectors from Bosch? A wrong impedance of an injector could create problems on cyl. 5 as well. Or you have accidentially swapped air temp sensor connector and cyl. 1 injector connector. I have seen that before as well.

Her sey iyi olacak . Bu hatayi buĺacagiz .

Merhaba Voker Bey)
Thank you very much for writting in Turkish and support. I keep following checking your site for a long time and you prepared perfect references about Djetronic and Kjetronic as well.

About yellow injectors I have 4 new Bosch 034, 8 pcs 022' 8 pcs 034. Totally 16 cleaned yellow old bosch which have been cleaned by bosch service but has a flow rate around 120cc in 30sec. At 2 bar. Where the flow rate of new ones are 132,5 cc in 30sec. So there is a 12,5cc difference each injector at full throttle. I considered this as a power loss and bought 4 new yellow bosch and repaced old ones with new. So 4 new 4 old. Than as yiu mentioned i found one nanufacturer in china manufactured 034 ordered additional 8 pcs from him. I did not know that there will beimpedance difference iabout 4 ohm. This problem emerged after installing this injectors. However construction and flow pattern of this injectors are really good not bad, unlike classic bosch there is no nozzle at tip just 4 micro holes). But undoubly Bosch is the best.

Yes injector 5 I did not check but sure if i plug on 1 and plug off 5 it will be same. May be I should check signal and current consumption by oscilloscope?

Yardiminiz icin cok tesekkur ederim.

Kutluhan

Hi Mr. Norbert,
Thank you very much for reply and cable color information. I checked it's correct. Brown is ground and green main line.

Best Regards,
Kutluhan

Hi Kutluhan,

when I saw the chinese fakes with the Bosch no printed on them these days I already knew that I would soon run into trouble with them. They look so much like original ones, share the same part no. and are dirt cheap. Vendor prouldy presents that they also have a needle and not 3 holes. It will be difficult to see the difference. Unfortunately you have now proven that they are not working.

All 8 injectors must have the same flow as original ones and they must deviate with less than 10% at idle and at high rpm. I have once done some of my injectors and brought them down to 3% deviation by cleaning.

I would appreciate detail photos of original versus fake injectors here that might let us learn how to see the difference.

Hi Volker,
Sure, I send you pictures of chinese injectors. I will also send you Bosch when turned back home.

About my old orginal bosch injector ones before cleaning

At idle speed,
first 4 group was 12cc where other were 4 were 11cc.
Moderate speed;
first group 105cc, other were 4 were 106cc.
Full throttle,
first group 120cc, other were 4 were 117cc.

After cleaning;flow test at 2 bar in 30sec
At idle: All 12cc
Moderate speed: All 107cc
Full throttle: all 120cc

So what are nominal values, if 265cc in 1 min at 2 bar full throttle, so, in 30sec, 132,5cc full throttle, but where the mine max 120cc.

I also have new bosch 4pcs that I did not have flow test. But weirdly other 7 injectors looks like working good. However, to understand I will remove injector 5 electric plug when 1 is connected I guess it will be same.

Best Regards,
Kutluhan

Günaydin Kutluhan,

resimler icin cok tesekkür ederim!

Did you get your old original injectors cleaned and tested at an ASNU service? Even that costs more than these China fakes. If you are in real need of new yellow injectors, I am able to help, But I only do in case of emergency. My stock is limited.

Rica ederim Volker,
Yes I have cleaned 16 injectors At ASNU Ultrasonic injector device than they had a flow test in Bosch service. But I guess my old injectors worn down. However, if injectors worn(needle or valve) they should inject more fuel I'm mistaken?Runing more rich.

I may need 6 new Bosch injectors. I restored my car previous year, I had an complete restoration took 3 years my w108 3.5. I replaced all sensors wih new ones, temp, engine coolant, ignition control module, throttle switch, 1 new 012 MAP sensor with rivet version (I think late version) 2 used spare, one diaphram damaged.

Also one question, when I remove electric plug of air temp sensor, idle speed should decrease or increase?

Because, I have tried with 2 different MAP sensor, one acts differently than other, old version which has screws, removal of air temp sensor socket, decreases idle speed, where the new rivet one, decreases idle speed.Asking just for curiousity).

individual piston is 12,5Bar.But
I cant solve the exhaust smell at idle or warm up. Clean water(condensation when starting cold) no black soot. But Smells too much, No smoke at all .but hydrocarbon smell. Sometimes burning eyes. I always think the reason is injectors, I adjusted the throtte switch, idle speed like your instructions on your web site, I have new trigger points installed 0231302001 distributor and breaker gap adjusted as .35. İgnition timing at idle 0 degrees at TDC 800rpm.

If possible, Culd you please give me the price of an injector ?

Thank you very much.

Regards,
Kutluhan

Merhaba Kutluhan,

these injectors get clotted and rusty from non-usage. Then their spray gets bad or they even do not open any more. They might also start to leak. A price for 1 new yellow injector? More than what these 8 fake ones cost in China. So before getting a shock try to recover your old ones.

When you remove air temp sensor connector you make fuel mixture richer by roughly 20%. So car should run a bit too rich and idle should go slightly down. Engine temp sensor is much more sensitive. It triples fuel amount on your car.

All your MAP sensors should produce same result. Where did you find a new one and what date of make is it? It is stamped on upper right rivet or on back of housing in 3 digits. Their meaning is written as FD in chapter 3 or 4. Everything produced in 80s or later is to be mistrusted. Quality control at Bosch seems to have been absent then.

You should adjust your dwell with a dwell meter and check ignition timing at idle, 1500 and 3000rpm and also vacuum retard. And I recommend that you check exhaust via CO and HC.

If your car would be located in Istanbul I would even know someone with a 350 SLC there with whom you could exchange experience.

Jazzenco81 schrieb: About my old orginal bosch injector ones before cleaning

At idle speed,
first 4 group was 12cc where other were 4 were 11cc.
Moderate speed;
first group 105cc, other were 4 were 106cc.
Full throttle,
first group 120cc, other were 4 were 117cc.

After cleaning;flow test at 2 bar in 30sec
At idle: All 12cc
Moderate speed: All 107cc
Full throttle: all 120cc

So what are nominal values, if 265cc in 1 min at 2 bar full throttle, so, in 30sec, 132,5cc full throttle, but where the mine max 120cc.

Dear Kutluhan,

the test of the injectors is much easier. You need to measure only the so-called static or stationary flow.

This means:
Measure the volume of fuel after opening the injector at a fuel pressure of 2,0 bar continuously for 1 minute. Than the volume should be 265 cubic-cm.

In order to open the injector continuously apply the battery voltage (12 V) via a series resistor of about 6 Ohms/7 Watts.

Do not apply the full 12 V of the battery directly because this could demage the injector !!!

Regards,
Recardo

Merhaba Volker,
Thank you very much for reply. About injectors, I will recheck old ones.For leaks, flow rates etc again.

About MAP sensor. I will tell you production date. After I check today. Old MAP sensor(with screws) idle speed decreases when removing electric plug of air temp sensor. As the car gets richer. As you mentioned. As this car belongs to my father since 1977 he also says same in the past it was like that, however, when I find and buy new one(with rivets) sure produciton is late 90s. idle speed increases when remove electric plug of air temp sensor. That time it means car gets leaner instead richer. So MAP is mistuned or behaving differently.

If you would like I can send you new one which is on car to you, if you can check wll be very appreciated.
As I dont have CO and HC analyzer I dont see the gas ratio. Lamda, HC,NOX,CO etc.

I have dwell meter, I will recheck timing at idle(0 degrees) 1500 and 3000rpm and also vacuum retard.I will check.

Yes I'm located in Istanbul, İt will be very useful if you share details of w107 350slc friend details with me.

Dear Recardo,
Thank you very much for information. I will prepare test stand for an injector. I guess it operated with 3V. Will try to prepare circuit of resistors 6ohm 7W as you mentioned.

Best Regards,
Kutluhan

Hi Recardo,

especially when you have clotted or fake injectors, a static test is not enough. When I cleaned my injectors I did a dynamic test at a low rpm and duty cycle and a high rpm and duty cycle. Good fake injectors will fail such tests and will show good results only during static test.

RSADUT benim Istanbul arkadasim. Ona özel mesaji gönder. Biz bir sene önce Yesilköyde bulustuk. Ben eskiden Istanbulda oturuyordum ce calsiyordum. Ah Istanbul!

Kolay gelsin!

Hello,

but about 3 V directly should be also o.k..

Best regards,
Recardo

Hi,

I repeat: A dynamic test separates the original ones from the good fakes. In static test good fakes show proper behaviour. Only bad fakes show deviation in static test.