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Thread: ETA Rewiring

  1. #1
    Senior Member
    Join Date
    Dec 2014

    ETA Rewiring

    Well, after dealing with various running issues for longer than I want to admit, I finally rewired my ETA.


    Not difficult, just somewhat tedious. Recommended for the DIYer who can solder and is comfortable dismantling and reassembling his car.


    For the longest time, the car wouldn't rev past 1100 until fully warmed up. Then it would run fine the rest of the day. Eventually, it began to buck a little, even when warmed up. Finally, it wouldn't start. By then I had learned about eco wiring so on a whim, I manually moved the harness around while my wife tried to start the car. Eureka.

    I left the harness in its new position and the car continued to run for several months so I started looking for a replacement ETA. Finally found one at the dismantler but it had the eco wiring, too. So I practiced cutting open the harness on it.

    It was finally time to rewire mine so one weekend I commandeered the kitchen table and got to work. I cut open the connector, slit the outer sheath and got the 11 (now bare) wires exposed. I had read numerous posts about either splicing in new wires or completely replacing wires by unsoldering at the plug and at the ETA. After looking at the completely intact wires in front of me, I decided to just install shrink wrap tubing over them. I didn't want to make two splices on each wire and I didn't want to mess with trying to unsolder at the IC board and at the plug. It's a little cramped in there.

    The seven smaller gauge wires were twisted together in a spiral. An electronics-savvy friend told me this is intentional and that I should re-spiral that bundle after installing the shrink wrap. To do this I had to cut the other four wires first. I cut each one at a different length so I could be sure to solder the right wires back together.

    With the seven wires untwisted, I started cutting one wire at a time and slipping heat shrink on. i staggered the cuts so there wouldn't be a giant lump at one point in the harness. I used 3/32nd shrink wrap but I would recommend going smaller if you can. Even with removing the plastic filler rods from the harness, the outer sheath couldn't quite close all the way. Anyway, all seven small gauge wires were carefully cut and covered with shrink wrap, Then that single cut was soldered and a final piece of shrink wrap installed. Be sure to slip the final piece of wrap on the wire first, before soldering. It's so easy to forget this step, at least for me.

    I re-spiraled the seven before continuing the cut, wrap, solder process on the remaining four. I was able to slip the shrink wrap right up to the IC board in the ETA and right up to the connectors at the plug end. It's amazing to see how that eco insulation just falls off.

    I fit the 11 wires back into the original outer sheath and gave it a full-length wrap of 3M electrician's tape. There wasn't room to push the sheath back into the plug at the ETA so I squirted some Shoe Goo into the bundle of wires at the ETA. Not proud of that. Not overly pretty but it should keep out any moisture. The plug end didn't look too great, either. Some people are able to carefully cut apart the connector and then glue it back together. It didn't go that smoothly for me and I wound up just wrapping the end of the plug with electrician's tape. This means the plug is not locked into place with the little lever, as intended. I will probably try to fabricate some safety device to prevent its being accidentally pulled out.

    If you've never removed an ETA, prepare for some struggle. The rubber that holds the MAF to the ETA was rock hard on my car. I had to break it to remove the MAF. I removed the metal brake booster vacuum line from down beside the front of the ETA to get more clearance for the removal. I don't know if this is necessary. You must lift the front edge of the ETA first. Continue lifting and rotating upward until the ETA finally comes out. Lift the front but also lift the back a little. It's a pain but it does get easier with practice. The big rubber PCV line coming off the ETA was also rock hard. Best would be to replace all PCV lines at this time but I just replaced the one right at the ETA. I cut the hose
    at the plastic connector with a knife so I could remove it without damaging the connector.

    It's so rewarding to replace rock hard rubber with fresh, flexible parts. Be careful where you place the hose clamp on the PCV hose at the ETA. I had it in the wrong place and the ETA wouldn't sit flat on the manifold. I finally got that worked out after several R&Rs of the ETA. Then, the final bolt didn't feel right going into the manifold. So everything had to come out again. What a pain. I used a tap to clean up all four holes and used a wire brush to clean up the bolts. Be sure you drop one of the bolts down beside the CAN box so you can spend 30 minutes trying to retrieve it.

    The stuck bolts turned out to be a blessing in disguise because I had forgotten to test my ETA before installing. What a royal pain it would have been to go through all that work just to find out I had made some mistake on the wiring. So I plugged it in, turned the key on, and listened. At about 37 seconds, there was a 'click' and the throttle plate moved. I think this means it's okay so I proceeded.

    Another blessing in disguise: As I was struggling over the first installation of the ETA, I started thinking about removing the throttle linkage shaft. After you pop it off it's ball at the ETA, it drops down out of the way. But then it's IN the way as you reinstall the ETA. You have to hold it up out of the way while dropping the ETA onto the manifold. Well, this got me thinking that this really was the best time to clean and lube all the throttle linkage. I didn't want to, being interested in completing the project, but I forced myself. After disconnecting a couple things, you can remove three bolts that hold the linkage bracket to the manifold and remove the whole thing. Oh, that circlip that holds the transmission cable to the bracket? Make sure if you drop it, that it goes all the way to the floor. But don't count on being able to retrieve it with your extending magnet. It's non-magnetic. It was rewarding to clean all the goop out of each ball and socket and get fresh lube in there. I usually use SLS fluid but only had ATF on hand. Be careful with the circlips and springs and make careful mental or photographic note of how everything goes back together.

    Install the ETA by tilting and inserting the back edge first. You kind of need to hold the back up off the manifold as you feed it down and in. I used the PCV hose for help keeping the rear slightly up. It will drop down in there but just barely. I snugged the ETA bolts down to 9NM. Be sure to position the rubber MAF connector correctly so the MAF is facing the right way. I installed the two large hose clamps in opposite directions because I felt I could get easier access for tightening them. Be sure to use a flexible 1/4" driver with a 7mm socket. You will HATE this part of the job otherwise.

    My Shoe Goo had fractured after all the harness manipulation so after reattaching the clamp at the fuel rail to stabilize the harness, I applied another coat where the harness enters the ETA. Should be good now.

    I was simultaneously replacing the air pump so after that was installed and the belt put back on, I fired up the car. I don't think it has ever started so authoritatively! What a huge relief. An extended test drive says I'm back in business.

    So, it's not a huge job, just has a number of steps. I'm very glad it's done but would not hesitate to do it again.

    eta 10.jpg eta 11.jpg eta 6.jpg

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  3. #2
    E500E Guru nocfn's Avatar
    Join Date
    Jan 2014
    Kingwood TX

    Re: ETA Rewiring

    Nice work Mike, and good reference write up!
    1994 E500
    249/275 - 8F19 or 8F32 or 8320

    1991 560 SEC
    2014 E350 Cab 799/264

  4. The Following User Says Thank You to nocfn For This Useful Post:

    luckymike (10-10-2017)

  5. #3
    E500E Guru a777fan's Avatar
    Join Date
    Aug 2017
    Seattle, WA

    Re: ETA Rewiring

    Good stuff! I plan on attempting something like this with a spare ETA i picked up. Did you replace all wires and connectors, or just the wires themselves? I might have missed it, but did you post pics of what the original harness looked like inside?

    Sent from my iPhone using Tapatalk

  6. #4
    .036 Hoonigan™
    E500E Boffin
    gsxr's Avatar
    Join Date
    Dec 2008
    Boise, ID, USA

    Re: ETA Rewiring

    Quote Originally Posted by a777fan View Post
    Good stuff! I plan on attempting something like this with a spare ETA i picked up. Did you replace all wires and connectors, or just the wires themselves? I might have missed it, but did you post pics of what the original harness looked like inside?
    He did something a little different... rather than replace the wires, he re-insulated each with thin heat shrink tube. Nifty idea.

  7. The Following User Says Thank You to gsxr For This Useful Post:

    a777fan (10-10-2017)

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