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  #16  
Old 08-18-2003, 08:57 PM
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Join Date: Aug 2001
Location: Evansville, Indiana
Posts: 8,150
#2 is a ground, you can use any convenient ground (as in the engine block or manifold).

I guess not having the duty cycle meter connected due to having the wire pulled out would work very well.

I don't really want to know why anyone would pull the wires off the diagnostic plug.....

Peter
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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!
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  #17  
Old 08-19-2003, 11:22 AM
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Join Date: Apr 2002
Location: westchester, ny
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We did it

Chuck, the blue wire was the hot one. I cut off about 1/4-inch of the insulation to get a good, clean contact, I confirmed the O2 sensor with a 69.3% reading & was able to adjust the warm engine readings of apprx 65% to appx 50% with a very small turn of the screw. The car purred, with no shakes or missing feeling. And it was quick and smooth from a dead stop, I couldn't believe it was a 1988 300CE!! When done I separated all the wires from the blue one by putting them into a short piece of plastic tubing & then wrapped them all, including the blue, in electrical tape to keep them clean & away from everything else.

Thanks to both Chuck & Peter for your time & sharing so generously of your knowledge. The people like you who reply on this board make it such an unbelievable resource.

Now, on to the next problem...the neutral safety switch on the 87 300e ( to be posted soon)
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  #18  
Old 08-20-2003, 01:00 AM
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Location: westchester, ny
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swapping parts from a totaled 1991 300e

We had an accident with our 91 300E & the car has been declared a total loss. I also have a 87 300e & a 88 300ce. What parts from the 91 should I swap into the older cars, assuming the part numbers are the same, to try to prolong their lives & avoid future repairs? Thanks for your thoughts.
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  #19  
Old 08-21-2003, 05:44 AM
azhari
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I would definitely keep the Fuel Distributor, it's easy to remove and costs a bomb new or used.

My 2 cents.

Cheers.
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  #20  
Old 08-21-2003, 11:06 AM
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Location: westchester, ny
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Thanks for your reply; this was supposed to be a new thread but I guess I messed up.
Could you explain how to remove the fuel distrib; I've never done that . What about the starter, which I can't seem to find. Is that an easy DIY? Thanks
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  #21  
Old 08-21-2003, 11:46 AM
azhari
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Here you go...

Remove the air filter housing to gain access to the FD.

Fuel system has to be de-pressurised if it hasn't (if the car hasn't been run for awhile there will probably be no retained fuel pressure).Remove gas tank cap to be sure.

To remove the FD firstly involves removing the fuel line unions at the distributor itself - going to the injectors, fuel pressure regulator, cold start valve and fuel supply line.

You need to use open end spanners for each fuel line.

Expect a little fuel to spill out from these lines when you crack them open.

Unplug the wiring harness connected to the EHA valve (black box attached to the side of the FD).

Then you have to slacken and remove 3 Torx bolts which hold the FD down to the Air Flow Sensor.

The FD can be removed once the Torx bolts are out.

There is an O-ring seal between the FD and the Air Flow Sensor.

If you re-fit the FD, fit in a new O-ring seal.

I think it costs less than a dollar on the Fastlane.

You will save a bomb if you ever need to replace your FD.

One question - if the car is written off, can you salvage bits from it or do you have swap them part-for-part from your other cars?

Cheers.
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  #22  
Old 08-21-2003, 11:54 AM
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Location: westchester, ny
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Mostly, I'm swapping minor things, like steering wheel (on the 87 the srs light sometimes comes on, even thou I've cleaned the contact rings), with the older 87 & 88, but it so happens I have a suspect fuel distributor from a previously owned 300e, so I thought I would take out the good one & reinstall the suspect one, that way I way have a good spare. I'm really glad you confirmed my idea by recommending swapping the fd. Thanks again for the easy to understand removal directions.

BTW, do you know how to drain the gas tank, it has almost a full tank.

Rich
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  #23  
Old 08-23-2003, 06:44 PM
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duty cycle reading on 88 300ce

Chuck & Peter, I need your help again. Just had neutral safety switch replaced because car, 87 300e, had died. Tested for CO adjustments- got 90.5 fixed with key on, engine off. Disconnected O2 sensor & attached to a new one in the box. Same reading. With engine on, fluctuations on meter only between 90.1 & 90.8 & no meter changes as I adjusted the screw & the engine got lower in sound & smoother. Wires appeared connected in tester. Now what?
Thanks
Rich
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  #24  
Old 08-24-2003, 05:39 AM
azhari
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Draining gas tank

Rich

The only way I know of doing it (with reference to my trusty Haynes manual) is by siphoning off (or handpump) the fuel via the filler neck.

Cheers.
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  #25  
Old 08-24-2003, 10:43 AM
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Join Date: Apr 2000
Location: Falls Church, VA
Posts: 5,316
You are having your share of troubles.

The manual says "Current to EHA implausible." That is not one that I have seen. It sounds like the ECU is getting a set of inputs and is being asked to send a current level to the EHA that is out-of-bounds of it's program.

The only thing that I can think of is that either the decel micro switch or throttle position sensor are bad and they are sending signals that the ECU recognizes as inconsistent. Not being able to figure it out, it shuts down and sends out a constant 90%.

Wish I could help more, but the manual does not give a remedy for this one.

Maybe the techs have seen this one before and can help.
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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe
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  #26  
Old 08-24-2003, 01:26 PM
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Bad O2 sensor will give you a fixed 50% (open loop mode) signal on the #3 connector.

90.8 with key on, engine off, is a diganostic, indicating electronic problems, I suspect. Steve Brotherton will probably know, but it may be computer time (OUCH). If the computer is buggered, no way you are going to get the mixture set correctly without a CO meter, and you must get to the exhaust in front of the cat....

Can you check the EHA current? This will tell you if the system is working at all -- 0mA means there is no control current being produced.

Check the OVP relay if you haven't -- is you ABS or SRS light coming on and off while you dirve?

Also, check for a good ground for the fuel computer -- if it isn't grounded correctly, it isn't going to work worth diddly.

Peter
__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!
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  #27  
Old 08-25-2003, 12:13 AM
azhari
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Peter

Quote:
0mA means there is no control current being produced.
Curious, if there is 0mA EHA current when it's connected to the FD, should the OVP be checked first?
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  #28  
Old 08-25-2003, 07:45 PM
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Location: westchester, ny
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For what its worth, I disconnected the O2 sensor & tested the vehicle connector. At the pin in the square plastic side, it measured -.04mA with key off, and resistance of 11.2 ohms--I did the same resistance test on the 91 300e with the good sensor ( 70% duty cycle with key on, engine off), & got .74k ohms, obviously a different reading. Does this help identify the problem?

I have never tested at the EHA, so if you would be kind enough to explain where to place the probes & what setting I use on the DMM, I can do it. Also, which black box behind the battery is the computer? Is the ground near the negative on the battery? If the computer is bad, I could swap it for a good one from a 91 300e recently totaled (same for EHA, if that is advisable). Thanks for your continued help-the good news is that the 300ce I adjusted with your help runs just super.

BTW, on this same 87 300e I unplugged the instru cluster to swap the outside temp LCD & while pulling it out I seem to have disconnected a vacuum hose ( I hear the telltale hiss, which wasn't there before) , & I can't see or figure out where it goes. Do you know? Thanks
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  #29  
Old 08-25-2003, 09:53 PM
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Join Date: Aug 2001
Location: Evansville, Indiana
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The vacuum line goes to the "economy" guage in the cluster. Connects under the hood right next to the brake booster.

Peter
__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!
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  #30  
Old 08-25-2003, 10:34 PM
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Join Date: Apr 2000
Location: Falls Church, VA
Posts: 5,316
There are two connections on the EHA - power and ground. You can measure the current by pulling the connector off just a bit and using the mA setting on your Sears DMM. If you search on my recent posts, you will see the readings that I got and their interpretation by the experts.
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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe
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