erniejenso

I have replaced the gasket for the front valve cover with no problem I have remove the intake with no problem. Laying on top of the rear valve cover is the entire engine wiring harness. After removing the bolts from both side, there is not enough movement in the harness to remove the rear valve cover. I see no mention of this problem on others doing this job. The plastic harness cover is brittle and I see no way to get it out of the way. Pulling up on the harness will dislodge wires going below. There is not enough room to push the harness out of the way between the engine and the firewall unless I break the harness apart or lift the engine.. This all seems like a serious problem. It is hard to believe that Lexus placed the harness right on top of the valve cover making it look like engine removal is the only solution. Is the1996 Lexus ES300 unique?
Help please!

synrgy350

In order to move the wire harness up and away from the valve cover, you need to remove a bolt on the timing cover side of the harness, as well as two bolts on the other side, near the thermostat. Follow this picture tutorial, it got me through the first time I had to change the rear valve cover gasket. I can now do it in under an hour!

http://www.wjowsa.com/carstuff/toyot...lve-cover-job/

-Lawrence

erniejenso

Thank you for the reply. I removed the bolt on the timing cover side and the two bolts on the other side. This will allow me to lift the harness up about 2 inches. There are wires leaving the harness on the bottom and going down to maybe the converter that prevents raising the harness far enough to get access. I will have to get under the car and see where these wires go and remove them. I was hoping that the harness would unplug at one end. I am really afraid to pull up very hard as all the plastic is brittle from the heat that a car see in Southern California. It seems that I would need to lift the harness three or four inches and then push it to the back against the firewall. I am afraid to pull so hard that I might break a wire at the terminal and not even know it until I try to run the car. I wonder if the harness in the ES300 is the same as the Camery. This harness is really stout and very brittle I am worried about getting the gasket in there properly if I can't get the harness up at least a few more inches.

synrgy350

What I did was pull the harness high enough to place on top of the EGR pipe that is next to the valve cover. By resting the harness on top of the pipe, I was able to get enough clearance to get the cover off. The harness has some slack, just don't pull it too hard.

erniejenso

I put in new plugs and put it back together for another day. I was happy that the car didn't have any problems afterwards. I don't remember a defeat like this before in my car repairing days. I just couldn't get the harness to rise more than about two inches. After removing the three bolts, I tried pulling on each side, being careful to not pull too hard on the center because of the wires going straight down to I think the converter. I figured if I could get the two ends to rise a couple of inches, I could then remove the wires that went straight down by going under the car and then slip the valve cover around the harness. I puller pretty hard and found very little movement.
Thank you very much for the information.

tomf

Did you replace the rear valve cover gasket? Or did you just give up?

I know it's difficult to remove the rear valve cover. I also have a 95 Camry. It has the same difficulty with the wiring harness. On my 99 ES, once I did not get the gasket seated correctly. When I took it out for a test drive I had oil spraying out. In order to get the gasket seated correctly, I positioned the cover in position and then used my sense of touch to ensure it was in place. I also used a mirror to check the position.

erniejenso

II just gave up for now.

msekanha

i would unplug bank 2 air/fuel sensor, that may be the reason why you can't move the harness. You also don't want to rip the wires out of the sensor, as I did.

Restored

I did two things:

First, I unplugged the rear o2 sensor (When fishing the o2 sensor out to reconnect it, just make sure that you have a 3 ft grabber to reach it.), and second, I clipped the wire running down to the power steering pump (it's a ***** to pull out otherwise).

By doing that, it becomes very easy to reposition the wiring harness out of the way. Now I'm not stupid here; I made sure that I soldered (< 65w gun), heatshrunk it, and spliced an extra 4" of automotive grade 16ga wire to lengthen the connection so the harness would be more mobile later.

***Put in the gasket set following the fsm (make absolutely certain that the spark plug tubes are seated properly), Carefully button her back up while being extra gentle with the old brittle heat damaged plastics, and make sure to REPLACE every connector you can to prevent one becoming damaged while driving (ebay search "supra coil connector", and "Fuel Injector Connector Lexus").

Surculus

not sure if it's much help or not but this is a decent video on the entire process on the dual TB 1MZ. He sort of flips the harness out of the way quite cleanly.

The video is of a RX300 but same engine so should be similar.