280SE 3.5 Problem mit dem Injektorimpulsstrom

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!