Matts Garage: Merc W123 fuel injector swap
Вставка
- Опубліковано 29 вер 2024
- My Barn Find Mercedes W123 230E still won't start, so Im taking a look at the fuel injectors to see if the petrol in them has turned to varnish.
This is also a long way round 'how to' on changing W123/Bosch CIS fuel injectors - Авто та транспорт
If the injectors go in/out easy the seals are hard and probably leaking air. Waste ofvtime even trying with 40 year old seals.
You need (depending on the model) about 3 bar of fuel pressure to open a K-Jet injector, anything less......he will squirt, but that want start your engine - that´s not a carb
Looking at his latest video I think you hit the nail on the head here. I also put the same comment under his latest video that the injectors need 45psi to operate.
Go back to basics - An engine needs -- Fuel, air and a spark.
Check you have a spark.
Check your air filer and pipes aren't blocked.
Then work from the back of the car to the front ---
Does the tank have fuel?
If yes is the pick up strainer blocked? - If yes clean, if no go to the net step.
Does the fuel pump work? - Remove it and run a bench test with an old battery. Connect the live and use the earth to complete the circuit to see if the pump spins. If it does re-fit to the car.
Is the fuel line intact?
Is the filter blocked at all?
Can you get fuel out of the line BEFORE the filter?
Can you get fuel out of the line AFTER the filter?
Is the fuel reaching the fuel rail?
Are the injectors firing? Take then out and spin the car over, you'll see fuel squirting out of the injectors. Messy but you won't spread much fuel around if you look for a mist or a squirt from each injector then quit turning the car over.
If all is good then you need to start looking at valves and compression.
Hope this helps :)
I THOUGHT I had all 3, brilliant spark, air filter off and can see the inlet and the plugs were wet after trying, so had assumed timing, BUT now I think there might not be enough pressure so Im ordering a filter tomorrow and will check the pump while Im under there
Even with low pressure or a pulse pressure the engine would try or at least cough but it's not even trying. I'd suspect it's the fuel pump and would take it off to spin it up and see what happens. Sometime the impeller can get crap on it and you get a failed fuel supply. My 7 Series did the same thing but once I took the pump out and span it up it cleared itself.
might be worth changing the filter at the same time, its next to the pump. also perhaps borrow a fuel pressure tester
The filter is definitely next, I should have done that first really!
mine was full of crud even though the car ran fine. and the pump looks bad but is ok: www.classicjalopy.com/2017/10/300se-poor-hot-starts/ at least on my 300SE there is a second tiny little filter where the fuel line connects to the fuel distributor. They have similar injection systems so your 230E may have this too. It can probably be cleaned, but from memory wasn't very expensive.
Its the little gold one taped to the side of the big fuel filter in the picture.
Keep it up! On my 82' 230E despite a rebuilt engine, I had to replace a faulty fuel pump relay. My Merc was giving the same symptoms but before buying a new relay I made sure that it was the culprit. I did this by removing the passenger kick panel, unbolting the relay housing and removed the relay. Then I bypassed terminals number 9 and 7 with a wire and ideally some terminals for security. Then I pushed the relay on top temporarily and it started. A common 230E fault.
So personally I would check out your relay first and change your fuel filter before the pump. Good luck!
Albert Braid thanks, a new filter was definitely next but I didn’t know about the relay, I’ll check that before I spring fur a pump!
Albert Braid The fuel pump relay is a common problem. Mine just failed on my 500 SEC. I used to have a 560 SEC and it’s fuel pump relay also failed. It’s great to have a spare handy.
If you open the air intake and spray some easy start in the circular chamber, if the timings somewhere near right and you have a spark, it will start and run until the easy start is used. That will prove whether you have a fuel distributor / injector issue.
It does that, runs well on spray, its the injection thats the problem
do a compression test and check the timing.
Try hitting the fuel pump under the back axel and use oven cleaner on the engine it works a treat
Im a fan of the hit it till it works method! A new filter arrives tomorrow so Ill see what state the pumps in then. Thats a good idea on the overs cleaner, although I still have half a gallon of Swafega to use up..
Did you check the condition of the Air Flow Meter Boot under the housing of Kjetronic?
I havnt taken the injection system off but it looks OK. I think its fuel delivery now
Try to add little fuel in k jetronic housing boot then tries to start engine if start then sure is fuel delivery if not maybe the boot rubber is cracked and not have a vacuum