190 E Fuel injection failure

[Dan41]

Hi,

Thanks for all the previous advice I recieved. I have another problem that I could use some help with though. The fuel injection system seams to have failed. I can run the engine on fuel that I squirt into the inlet manifold manually, but as soon as it is burnt the engine stops. This came about when I tried to adjust what I thought is a idle/air bypass screw in the top of the throttle body. The engine stalled and I have not been able to get it running since. If someone has some advice that may help me with this problem, it would be greatly apreciated...

 

[eric242340]

Hi,

Thanks for all the previous advice I recieved. I have another problem that I could use some help with though. The fuel injection system seams to have failed. I can run the engine on fuel that I squirt into the inlet manifold manually, but as soon as it is burnt the engine stops. This came about when I tried to adjust what I thought is a idle/air bypass screw in the top of the throttle body. The engine stalled and I have not been able to get it running since. If someone has some advice that may help me with this problem, it would be greatly apreciated...

Whoops, youve overdone it. How many times did you turn the key and in which direction?

 

[television]

Hard to describe this, to start with you must re set the air flow plate (thats the bit that goes up and down) so the the edges are level with the narrow part in the neck of the venturi, and it is 1½ turns down on the screw. the car should start with the setting around there.
Do bear in mind that ½ a turn is enough to stop the engine.

On cars fitted with a Lambda you should turn the screw only a touch as it takes time for the Lambda to adjust the mixture.

When turning this screw, do not press down,turn one quarter of a turn at a time then wait,

I have had to get my local garage out of trouble with these.

Malcolm

 

[Dan41]

The original setting before I turned the screw was around the 1 1/2 turns in from where it stops unscrewing. I have turned it quite a bit in from here but have come back out and have been trying around 1 1/2 turns area to restart without any luck.

What is the procedure to reset the air flow plate?

Cheers

Dan

 

[television]

The original setting before I turned the screw was around the 1 1/2 turns in from where it stops unscrewing. I have turned it quite a bit in from here but have come back out and have been trying around 1 1/2 turns area to restart without any luck.

What is the procedure to reset the air flow plate?

Cheers

Dan

As I said Dan,the plate has to be level with the > -< V part of the venturi.

Malcolm

 

[Dan41]

Still no go.

Hi Malcolm,

I have tried your advice without any change. Just to note that Lambda is not fitted to my car. It is a 1992 2L engine if that makes any difference.

I am still a bit confused as to the setting of the air flow plate. I have read and am sure I understand the theory of this air flow system but the airflow plate remains above the center of the venturi and nothing that I can see or I have adjusted has moved it. I made a temporary modification to ensure that the valve plate is in the correct position then screwed 1 1/2 turns down from the all the way out position of the screw. Without luck.

Is there something I am doing wrong here, or am I looking in the wrong area...

I can still start the engine by spraying lots fuel into the throttle body and can keep it running at around 4500rpm. As I let off, the engine starts to die, but if I am quick enough I can usually keep it going at high revs.

I am just amazed that such a small adjustment of this screw has caused me so much grief.

Appreciate your diligent posting on this site...

Dan.

 

[television]

Dan its a matter of turning half a turn max at a time, you will come to the point where it will start.

The last one that I had was so hard , I took the whole top off and set it up,then put it back,I then got it to run, saying this tha garage tried this but did not manage.

Do not push down when adjusting.

give me your Email I will send you the auto data set up

malcolm

 

[Dan41]

Sounds like I just have to be a bit more patient. Will have another go at it on Wednesday. The Auto Data set up would be much aprreciated. My email is danielpersal@gmail.com

Thanks again,

Dan

 

[television]

I have sent you 2 that refer to the setting up.

malcolm

 

[Dan41]

Thanks Malcolm, I received the files that you sent and have spent some time going through the procedures without any luck so far.

I am now going to do some research into the operation of this type of injection system which will hopefully help to diognose this fault.

Will let you know how I go.

Regards,

DAn.

 

[Dan41]

After re-setting the the flow sensor and going through the tedious procedure of turning the mixture screw a bit at at time, there has been no change in the symptoms at all. ie. only runs on fuel manually squirted into the inlet manifold and seams to be no pressure at the injectors. Plenty of return pressure though.

Is there another component that may be causing this problem?

Regards,

Dan.

 

[mattkh]

I am now going to do some research into the operation of this type of injection system

Hi

What is the name of this type of injection system ?

 

[Dan41]

This is a KE-jetronic injection system

 

[eric242340]

Hi Dan, yes this is a KE Jetronic system, you must get the plate to the correct position as Malcolm described. Once you have done this you will find a small black box on the side of the fuel distributor ( the distributor is the circular, alluminium device with the pipes coming from the top) this black box is conneted to two wires. It is held in position with two screws and this is the fuel pressure regulator. Ehen removed you will find it has a tiny brass screw, and this is the fuel pressure regulator adjuster. But if you try to adjust this, mark the origional position first, and only adjust quarter of a turn each time you remove it. Prior to this get someone to turn the engine whilst loosening each injector pipe and once fuel comes out of the pipe close the pipe whilst the engine is still cranking. This is how to bleed the system. However, as first stated, you must have the air flow plate in the correct position. Believe me many mechanics have failed on this system. So be patient.

 

[television]

Hi Dan, yes this is a KE Jetronic system, you must get the plate to the correct position as Malcolm described. Once you have done this you will find a small black box on the side of the fuel distributor ( the distributor is the circular, alluminium device with the pipes coming from the top) this black box is conneted to two wires. It is held in position with two screws and this is the fuel pressure regulator. Ehen removed you will find it has a tiny brass screw, and this is the fuel pressure regulator adjuster. But if you try to adjust this, mark the origional position first, and only adjust quarter of a turn each time you remove it. Prior to this get someone to turn the engine whilst loosening each injector pipe and once fuel comes out of the pipe close the pipe whilst the engine is still cranking. This is how to bleed the system. However, as first stated, you must have the air flow plate in the correct position. Believe me many mechanics have failed on this system. So be patient.

Do Not do anything like the above,or you will have two faults. Sealed boxes do not move so do not touch them.

I can understand how you feel trying to start the car now , The car was running before you altered the plate.

Malcolm

 

[Ultymate]

I've never ever had to bleed any of the "jetronic" systems whatsoever:!:

 

[eric242340]

I've never ever had to bleed any of the "jetronic" systems whatsoever:!:

If you havent had to bleed a jetronic system then im happy for you, but it does happen and you need to know how to do it when this happens. Look chaps, what im posting is reality and im begining to think you havent worked on these systems. This is old hat, as any Benz Mechanic will say. Jetronic may be history but its faults remain the same. Its like Malcolm posted HHT?

 

[television]

If you havent had to bleed a jetronic system then im happy for you, but it does happen and you need to know how to do it when this happens. Look chaps, what im posting is reality and im begining to think you havent worked on these systems. This is old hat, as any Benz Mechanic will say. Jetronic may be history but its faults remain the same. Its like Malcolm posted HHT?

Eric why dont you please stop posting these things, the guy had a perfectly running car until he touched the throttle plate.
Almost all of your last 6-7 postings have been way out.
Some people may not like the way that I react to your post, because of the authoritative way that you write. get one answer correct and people may start to believe you.

Malcolm

 

[Ultymate]

Here's a schematic of the airflow sensor and a paragraph about it's adjustment I've just got after a search which may help. Eric I still stick by what I said I've never had to bleed one and I can assure you I've worked on all the Bosch systems a lot even going back to the old mechanical two element systems used on the old SEB Mercs and then the inline six pumps on the old 230 250 and 280 SEs



The Airflow Sensor
The airflow sensor, in most cases, is located on the air filter housing and is responsible for measuring the amount of air entering the engine. The sensor housing is conical in shape, into which the airflow sensor plate is fitted. The airflow sensor plate lifts as the throttle is opened by the incoming air.
The amount of lift is proportional to the volume of air entering the engine. The shape and angle of the cone will determine this ratio.
A neutral plate position is normally level with the bottom of the cone, this is adjustable by bending a small clip / spring that acts as a stop at the bottom of the unit. The purpose of this spring is to allow the flap to move beyond its neutral position to allow excessive pressure to escape if the engine was to backfire, passing a large volume of air back into the air filter housing.
If the system did not have this facility the pressure could split or blow off the rubber air trunking. Any splits or ill fitting air hoses that allow unmonitored air into the engine require rectification.
As the airflow lifts the sensor plate this subsequencially lifts the control plunger - the higher the lift the greater the amount of fuel delivered to the injectors.

To adjust the fuel mixture a small 3 mm Allen screw is located within the airflow sensor; this alters the relationship between the sensor arm and the control plunger. Turning the screw clockwise enriches the mixture and vice-versa. It should be noted that the screw should be turned in very small increments and the Allen key should be removed before the engine speed is raised.

NOTE :- Failure to remove the Allen key, before starting the engine, can result in damage to the airflow sensing unit.

 

[eric242340]

Eric why dont you please stop posting these things, the guy had a perfectly running car until he touched the throttle plate.
Almost all of your last 6-7 postings have been way out.
Some people may not like the way that I react to your post, because of the authoritative way that you write. get one answer correct and people may start to believe you.

Malcolm

Malcom, the authoritative way in which I write? What about your postings, and ive not yet seen an anwer to HHT PS im not starting an argument please.