Alright, the fuel distributor plunger ain't leaking, where's the gas going??
 

89 M103..... I disconnected the injector lines, separated the fuel dist from the air chamber, bridged terminals 7 & 8 on the fuel fump relay socket with my multimeter and it read 7.8 amps to start with and fell to 7.2 in thirty seconds. The wires on the multimeter started getting quite warm. But, there was NO gas leaking from the plunger in the fuel distributor. When I manually depressed the pressurized plunger, gas flowed through ALL the injector lines at the same rate. So, WHERE is all this gas coming from that's puddling in my intake???:confused:

By the way, I had a pressure guage plumbed into the cold start injector port, which I assume would be considered upper chamber pressure. As long as the fuel pump is running it read 5.5 bar and 2.5 bar after the pump is switched off. In a previous test it held 2.5 bar for over 72 hours. Injector lines #4 and #6 had slight fuel drips at fuel system pressure but stopped dripping at rest pressure.

TTT. Come on, somebody has an answer to this. Where are the techs???? Yall wake up out there!!!!

Cold Start valve leaking?

Peter

Is it in the air chamber, if so check the EHA it may be leaking. By the way you can order the seals seperately so try those before the eha itself.
m

As I said, the cold start port on the fuel distributor was connected to the pressure guage, so that isn't the problem. The EHA is not leaking externally and checks out fine within the electronic test procedure in the W124 CD. Now, is it possible that the EHA could be leaking internally, thus raising the upper chamber pressure and still check out ok with current draw, which is within spec?

Did you have the injectors connected? If not, there was probably not enough back pressure in the injector lines to duplicate actual running conditions. The plunger seal is ONLY designed to function when the plunger is seated. Since the injectors come out easily, it would be easy to redo the test with them connected, and a side benefit would be a check of the spray pattern.

Steve

yes the current assumes that the system is fine and not leaking, it would not know if it was.
m

How is the default setting for the EHA determined? In other words when the system is in open loop, what does the EHA revert to and how can that fuel flow be measured ?

cap'n, While I am no expert. I believe that if the system is open the EHA will sit at 0mA and not fluctuate. When closed the current will vary whether it needs a rich or lean mixture depending on the requirements of the cis brain (ECU). Now measureing it I can not help you I am afraid, have to pass you to steve.
m

Here's my thought path. A certain amount of fuel is passing through this 'controlled leak' (EHA) for tweaking the air/fuel ratio. So can it get 'stuck' allowing the maximum amount to 'leak' through at all times? I'm seeing a lot more posts on the different forums lately concerning increased fuel useage.
If the KEIII system can run in limp mode fairly well without electronic assistence, then why would it suddenly start gulping fuel? We all read Freestyler's horror story. I'd like to see a lot of people not have to use the

radiator cap principle to get a solution.

Cap'n,
Has your gas mileage gone up recently. If it was stuck open the car would be running very rich and the reading at the EHA would reflect the computer trying to lean out even if it was stuck open, the system would try an lean it. So check your EHA readings. Also your emission gases would be pretty bad too.
thanks
m

Is it possible for enough fuel to pass through the EHA to send the gas mileage to 10 MPG?

Check The EHA ..Remove it and Inspect it for cracks and Leaking o/rings 2 ..I Have replaced a Few for this problem

Also remove the Plunger at the Fuel distributor and Inspect it for Wear/Scuffs..I Have Seen them stick..and Give the same problem...leaking Injectors..loss of Fuel pressure

Thanks Mark. There are no external leaks on or around the EHA. I have replaced the plunger seal and the the plunger looked brand new, no scuffs or anything. It also moves freely in the housing. So, back to the question, can that much fuel pass through the EHA.

Does The car have any Stored codes..? Check Engine lite on?Do You Have Pressure Gauges on the Engine?Checked with the EHA Unplugged?...Or how about a Blocked/plugged return line?But the Fuel pressure would be Sky High!Is This Only When Warm?
Yes the EHA can Pass enough fuel to make a mess
As It Will Damage the O2 Sensor and Load up the cat

EHA can leak a large amount of fuel certainly enough to be cause your milage to go to 10 mpg.
m

Thanks yall.
Mark, there are no stored codes in the 89 W124. The fuel pressure is good and the return line is open. Problem is constant, EHA plugged/unplugged, cold/warm and when in open/closed loop. I just replaced the fuel pressure regulator because it was leaking at the vent tube.

Cap'n

Did you solve your bad mileage problem after swapping out the fuel pressure regulator?

Or rather, did you solve the problem at all?

Cheers.:)

I thought it was going to solve it as the gas mileage seemed to improve the next trip out. But if it got any better it quickly went back to being at least as bad. My regulator was leaking only a slight amout of gas into the tubing. I recall M.B. Doc saying that he lost an engine begause of this once. So apparently they can leak a lot worse than mine was. I have the injectors out of mine right now awaiting replacements. I'll try to post some pics soon of the fuel distributor flow test I did. I just got back from vacation and haven't got 'caught up' yet.

I am having the same problem as you.

Bad mpg (from 420km per tank to 260km) and smokin'!

Problem consistent cold/hot, eha on/off.

Can get a smooth idle but smoking really bad.

If I lean the mixture, smokin' less but idle really crappy (of course).

Also, while checking the fuel pressure regulator (read in a post somewhere that if it leaks fuel it's history), pulled off "vac" hose and broke it!

There is fuel leaking from the regulator anyway and I will replace the "vac" line and breather hoses as they're crappy anyway.

You changed your regulator and it didn't help at all?

I was also looking to do this but it's a 200 dollar part so I want to do some tests before I swap it out.

I have access to my kid brother's 190e (identical year/model) which is currently in good running condition (powerful at 21% duty cycle but lower mpg - 380km per tank) and will swap the part to see if it makes a difference (I doubt it).

I have recently posted my problem and I'm also closely following yours.

I was recently recommended to another Merc techie and hope this guy (he'll be the 3rd) can sort this out for me.Else, I'm on my own!:D

Best of luck, and I'll inform you as soon as there is a breakthru'.:)

I got lucky and found a used regulator for $100. The new regulator will come with the rubber tubing intalled. The white tubing is plain nylon vacuum tubing. Inconsistent fuel pressure can cause fuel management problems but I think my problem lies elsewhere. At any rate, if the regulator is leaking ANY gas then it needs replacement.

Arrrggghhhh!!!!:D

Fuel pressure regulator
 

Do you know specifically how the regulator goes bad?

Everyone seems to point out that if it is leaking fuel, it is bad.But I'm interested to know what's going on with the regulator when it leaks fuel.

And the problems it can cause when it is bad.

Anyone?

If it is leaking fuel, it is certainly bad, and should be replaced before it gets worse. BUT, a leaking regulator may cause no other problems. Performance problems would relate to its inability to maintain the correct fuel pressure, which must be tested with a pressure gauge. If fuel is truly leaking out the vent port, then why not replace it anyway, and if that does not solve the running rich issue, then at least you fixed the leak and have eliminated high primary fuel pressure as a likely problem too.

Steve

I guess that's next.

Tomorrow morning, I will also check for leaky fuel injectors and check the fuel distributor for leaks.

This is frustrating me, but on the other hand, I'm really interested in getting to the root of this problem.:D

Cheers.

With the engine running, the injectors are fully 'on' almost all the time. Shutdown is only during some decel conditions, and with the engine off. So, leaky injectors are not going to cause your problem. Leaky injector seals will cause a lean-run condition.

Interested in what you find with the fuel distributor. Good luck!

Steve

Here is a contraption I rigged to test fuel flow. Injectors are removed and fuel distributor is separated from air chamber. After bridging terminals 7 & 8 on relay, I manually depressed the plunger. Fuel flowed freely from lines 1, 3 and 5 but was much less volume in 2, 4 and 6. I removed the fuel lines at the fuel ditributor and lightly depressed the plunger. Nasty fuel came out followed by clean. After reattaching the lines I got what appeared to be equal flow from all the lines. I haven't ordered new injectors yet so I may hook it all back up just for the hell of it to check spray patterns. Injectors aren't hard to replace so if I still need them it's no big deal.

Cool.:D

Learn something new here EVERYDAY!:D

I am thinking of lifting the distributor up with the fuel lines connected after a short engine run and see if there is any fuel dripping. If there is, I guess closer inspection is required.

another view

That's like bleeding the fuel lines of the distributor, isn't it?

Haasman does it with the engine on and cracking one line at a time.

Didn't have the guts to do it that way (dripping fuel/running engine)!:p

Cool setup!:D

It gave me a visual way of seeing what the flow was. If you had six different graduated containers you could measure actual volume of each line/injector over a given time period. As for mine, it was obvious that they were not flowing equally.

Cap'n

I push down on the air flow plate and I see a pool of fuel on the throttle butterfly valve.

I pull the accelerator cable to clear the pool of fuel.

Next, I push down on the air flow plate a couple of times (don't know if it matters).

I stop, catch a ciggie 20 metres away from the car, and when I look again, I see a pool of fuel on the throttle butterfly valve again.Is this normal?

I checked this against my friends 124, pushing a couple of times against the air flow plate and all...no pool!

Tried to get the fuel distributor off to check for a leak (with all the lines attached) but i couldn't get the cold start fuel line off to access the 3rd torx bolt!

Wanted to get the EHA off but after getting 2 of the torx bolts off, fuell started to spray from the EHA and I lost my nerve!:D

Tomorrow, I will get her to my friend's MB techie and see if we cna find the leak...if this pooling is not normal, of course.

If this pooling is normal, I am lost!:confused:

How's the progress on your car?

Was the EHA leaking fuel thru' or did you not manage to get confirmation on that?

The problem I have with Capt'n's test procedure is that with the injectors removed, pressure load on the outlet ports of the fuel distributor is about 0. A leak will likely not show itself in this test, where it would occur readily if the injectors were attached.

I'd say your fuel distributor plunger shaft is almost certainly the source of your pooling, and it is safe to say both that this is not normal, and the source of your smoking. There is a post here with pictures of 6 o-rings to the separate distribution chambers of the fuel distributor, if you can find it. I'll bet if you replaced those it would solve your problem. You'd need to find an appropriate material - ordinary Buna-N o-rings won't do it.

Steve

I have too much going on right now to even look at my car. But if you have a fuel puddle on the top of the throttle plate, visible when you push down the airflow plate, then I'm thinking that you may have a leak around the plunger seal on the bottom of the fuel distributor. Of course this is what I thought on mine too and replaced it only to find the problem was still there. The difference on mine was that the fuel was puddling under the throttle plate in the manifold. The only sure way to know is to unbolt the distributor, leaving the fuel supply lines connected, pressurize the system and see if you have a leak at the plunger. As far as the EHA goes, only a little fuel will leak from it when it is separated from the distributor. Make sure the gas cap on the tank is loosened to relieve it. And buy a good flare wrench to remove those fuel lines and don't risk rounding the fitting off!

Cap'n

I have read in other posts that some have had success stopping a fuel leak by changing out the fuel distributor O-ring (the one between the FD and the AFM).

Did you do yours?

Does this O-ring really seal off the FD from the AFM?Actually, I honestly can't imagine solving a leak by changing this O-ring.

But if it's a possibility, I wanna take a look at mine!:D

Your thoughts?:confused:

There is an o-ring between the AFM and the FD but it's purpose is to seal for vacuum. The fuel leak will come from the plunger seal in the center of the bottom of the FD. This is a tricky seal to change because you have to measure the static height of the plunger before removal so that you can put it back where it came from. I'd mke sure that the leak is coming from there before I changed it. I changed mine and it didn't help. See if this helps.http://www.peachparts.com/shopforum/showthread.php?threadid=53987&highlight=EHA