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1991 E-class 60,005miles
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263 Posts
Discussion Starter #21
Well, here is the deal. I droped my car off to the Mechanic's and he had it for a couple days.. He couldn't figure it out either.. So, i gather if the Mechanic cant figure it out i dought i can.. Do you guys think that i need to get a new fuel distributor/eha? Or should i do what ps2cho said..
 

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1991 E-class 60,005miles
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263 Posts
Discussion Starter #22
Hey, i have a question.. What tools do i need to remove the EHA and the fuel distributor.. Im thinking of removeing my old eha and replaceing it with the newer one that i got from the ebay seller.. I saw some crazy pattern on the eha and i dont have a screwdriver that has anything close to that head pattern..
 

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300 CE 24V Sportline
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873 Posts
Torx, I think ...

I saw some crazy pattern on the eha and i dont have a screwdriver that has anything close to that head pattern..
Your tool shop should be able to supply Torx bits which, I think, is what secures the EHA.

Failing that, take a photo and ask your supplier.

RayH
 

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2008 E350 4M, 1988 300TE
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5,432 Posts
If you can't do anything yourself, find a new mechanic, sounds like this guy doesn't know what he is doing. Sorry, I correct myself, He doesn't know what he is doing.

Find a REAL mechanic that KNOWS these older MB's. If he doesn't have any parked outside his lot, forget it. Do some research, there are plenty of recommended shops on this and peachparts forums for whatever area you are in.
 

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'92 300 TE 124.090
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16 Posts
I've been having problems with the EHA valve on my 300TE non 4 matic. So far the green "O" rings have been replaced, no more fuel leaks. The new problem after over night, cold start doesn't happen, the engine won't take any throttle. Back to my mechanic making just 30 MPH, while warm he "tappes" the EHA and makes a few adjustments and it runs fine. This morning the engine wouldn't catch. I took off the air filter and "tapped" the EHA, the engine fired and no hesitation. Opinions why this EHA,and the original EHA sticks? Thanks
 

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W124 Moderator
86 190E 2.3L 16V, 2 95 320TE's, 02 S500
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12,648 Posts
Let's see..your mechanic taps the EHA and the car runs fine. You tap the EHA and the car runs fine. Seems the EHA is needing to be replaced.
 

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'95 E300 DIESEL, '91 600SEL, '92 600SEL
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16,920 Posts
Just a wild idea here, but have you tried REPLACING the EHA with a new Bosch unit??? No tapping, knocking, futzing around.
 

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'92 300 TE 124.090
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16 Posts
Thanks for your reply,

I'm wondering "if" the problem is Electrical?? up stream. The original EHA worked fine except for the cold/hot hard starts. It went to Hell after changing out the green "O" rings. I've read here and two other forums where it's mentioned that the EHA has an adjustment and others say NO.





btw: The recycled valve currently installed on my 300TE was from a running MB.
 

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Premium Member
'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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10,186 Posts
First of all as Robert stated, they are set from the factory ON the FD by flow checking. If you put a different EHA on your FD, you're just taking the chance that it will match your FD. Yes they are adjustable and should be checked. But to do that you have to check the upper and lower fuel pressures of the FD and adjust the EHA so that the differential spread is correct.....and folks even argue about what the difference should be.

The ethanol blended gas kills these little bastards over time....and when they start leaking from the seam(not the green O-rings), they're toast.

Kevin
 

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'92 300 TE 124.090
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16 Posts
Thanks for the reply Kevin, Simply removing the "original" EHA to replace the green "o" rings can screw up the original factory flow set-up?

Let me try to post what's happening here. My Tech replaced the green o rings to complete the last repairs. he called me to let me know he would drive my 300 TE to my house as I don't have transportation. 15 minutes he called back saying when he started the car to pick me up, he said the idle and throttle response turned to crap. He called again saying he tapped the EHA body and idle/throttle returned to normal. Two days later I experienced poor idle and weak throttle response. I limped to the garage and the tech again tapped my original EHA things cleared up, but he wanted to try a different EHA from another 300 TE, it ran perfect. Next day I started the car for a 25 mile trip, it started, ran perfect at hwy speeds and thru town traffic. I parked in my garage, the next morning the car wouldn't start(start,quit, ect) So! what's going on here? Sorry to be a pest,
 

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'95 E300 DIESEL, '91 600SEL, '92 600SEL
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...I parked in my garage, the next morning the car wouldn't start(start,quit, ect) So! what's going on here? Sorry to be a pest,
Now this is a different symptom that reeks of bad voltage regulator.

Easy to verify, with the engine idling at full operating temp turn on EVERYTHING that consumes electicity (high beams, fogs, max A/C, rear defrost, heated seats, etc, etc, etc.).

Measure battery voltage across the battery terminals using a simple meter. IF you see anything below 13.5Volt or above 14.5Volt, the regulator is shot. Most likely it will read low due to worn brushes.

Just get a new Bosch (only) regulator and install it inside the alternator, it is good preventive maintenance. Do NOT get suckered into "you need a new alternator" before verifying and replacing the regulator.

As I've always stated, every MB owner should keep a spare regulator in the trunk to prevent getting stranded as this pesky little regulator will do just that and usually always at the worst possible moment.
 

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'92 300 TE 124.090
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16 Posts
sbaert Forgot, I just had a load test done at Firestone where I bought the Inter-State heavy duty bat. I thought the bat was dead or a shorted cell. turns out it was the neutral safety lock out switch. I learned when the car doesn't light up, I the shift lever in neutral and bi-pass the switch. Another part needing replacement, but this EHA has taken priority.
 

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Outstanding Contributor
1988 300CE
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1,424 Posts
... I'm wondering "if" the problem is Electrical?? ...
There are several mechanical and electrical possible problems with the EHA:
- valve plate damaged or fatigued
- valve plate’s suspension worn
- valve plate misaligned
- spring on the valve plate (opposite of the adjustment screw) damaged
- insulate contact in the coil wire
- coil resistance changed
- dirt, …

... I've read here and two other forums where it's mentioned that the EHA has an adjustment and others say NO. ...
Yes the EHA can be hydraulicly adjusted. And it can also be done without checking the fuel pressure. However that should only be approached with sufficient patience and wariness. If there is interest for that, I can post corresponding instructions.
 

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'92 300 TE 124.090
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16 Posts
Load test on battery, alternator or both?
Both. There's power to the ignition, I know how I posted did sound like no bat. But the engine would catch for1/2 a second and never really start. I tapped the EHA the engine started and ran fine. I let it sit it wont start, some times it starts. overall this eha problem is intermittent. To my inexperienced brain, it sounds like an upstream electrical problem.

Thanks for all the help and opinions, I'm sure some one here will have a solution. Until I'm sure it's the EHA I don't wantto speend250-300 bucks.
 

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Premium Member
1993 300CE Cabriolet (mine) ; 1994 E320 Wagon (wife's) ; 1990 Benz 300E 2.6 (son's)
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6,851 Posts
tapping on the EHA causing it to run sounds to ME like one of those spring/valveplate thingies that H.D. discusses is sticking, hanging up.

the EHA adjustment, IIRC, its a screw that you can only access by removing the EHA, you have to do this whole fuel pressure test thing while checking the lambda duty cycle, and if the EHA is off according to the test flowchart, shut down, remove EHA, turn screw one way or the other, replace EHA, rinse, repeat.
 

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W124
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IIRC there is a brass screw that reveals the adjustment screw once its removed. In the infantile wisdom of the designers at Botsch the adjustment screw can only be accessed after the EHA is removed from the FD.
 
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