|
This afternoon I spent some time cleaning up the wiring harness after a PTU failure left me stranded this afternoon. One of the things I like the least about the harness is the fact that it travels along some really cumbersome routes and gets in the way as well as clutters up the engine bay. I picked up a couple bags of wireloom and two rolls of high quality *approved* 3M electrical tape. It was like $3.50 a roll, but the material is apparently designed of a high quality vinyl which is highly resistant to heat aging/hardening. I suspect the adhesive is also some of the best you can find, considering 3M has the finest chemical engineering junkies in the world. Objective 1: Remove old tape and old loom.
Obviously you will need to remove the two intake pipes, the hardpipe from the turbo, and the rubber turbo intake pipe. Be sure to plug up the open pipes with a rag or papertowel to avoid any debris getting into them. Deloom: This process is a little like figuring out a jigsaw puzzle as you obviously should find the end of the tape and begin unraveling it from there. Sometimes I couldn't find that point and I simply made a careful incision just to start one. The 12 year old tape and loom comes off in a crackly display similar to a weak 4th of july. Once all the loom and tape was removed I took a shop rag and sprayed a little brake cleaner on it to wipe the wires with to remove the old adhesive and make it 'cleaner' to handle. Objective 2: Reroute and reloom/retape the harness.
Here's where your imagination can get involved. The typical route the harness takes on the driver's side starting from the firewall is up and over the boost pipe from the turbo. Then it splits and one side goes towards the CAS, PTU, temp sensor, and the other part slides up under and around the fusebox and connects to two connectors up there which are clearly visible. 
Once you have the harness de-loomed, you can seperate the lines that go to the PTU, MAS, temp sensors on upper coolant pipe, CAS, and this harness/connectors at the fusebox, and the TPS. It helps to start at the beginning of the harness; the part coming from the firewall - and then work your way to the ends. You can loom and tape up about the first 10" of the harness from where it comes from behind the engine - all of these lines go forward as one bunch. Here's where that section will route to: 
This section runs just under the plenum all the way to the rubber 90^ pipe you see with the hoseclamps on both ends that you see in just about the center of the picture. The next section to do is the CAS and the temp sensors. I used the medium sized loom to wrap this up. In the typical configuration, the PTU harness is also part of this section of wire as the PTU is located BFE on the passenger side of the engine on the timing belt cover. Horrible place for it - hard to get to - it is an electronic piece and heat is definately in high levels where it is located in the stock form. Only loom together the CAS and temp sensors for as long as they need to in order to keep from kinking the CAS line when it is plugged in. There was only about 4" of loom I used to hold the temp sensor lines and CAS line on mine after the previous section. Be sure to wrap the tape beyond the loom itself and join it to the previous section so ensure it wont leak if moisture is present. The PTU and MAS lines can be done next. I found it really helps to have another pair of hands when looming/taping as they can hold it taught while you slip the loom on and wrap it with tape. The PTU has two sets of wires that go to it including the inductive timing pickup loop. Be sure to include the inductive loop with these two wires all in the same loom and wrap it with tape. Keep the MAS line seperate from the PTU lines to avoid any potential electrical interference. You will need to remove the bolts holding the boost pipes to the core support and also remove the radiator brackets. There is also a 10mm bolt holding the AC condenser in place on the driver's side - remove this as well. Once these are loose, you will have ample room to get the MAS and PTU wires routed through the core support and to the front of the car. Once they are routed, put the pipes, AC condenser, and radiator back into place while taking note that the wires are not getting pinched between anything. There are several paths the wires can take through this section - just follow the path of least resistance - the electricity will too. :) At this point you should mount the PTU on the centerpanel rail. There is already a hole with a 10mm nut on the backside - all you need is a 10mm bolt to hold it in through one hole of the PTU's heatsink. Connect up the harnesses to the PTU and MAS. Might also want to check the condition of the conductors and clean/dielectric grease them up to ensure they dont corrode down the road. 
Locating the PTU here is clean, easy to access, and doesn't expose it to high temps that it sees in the engine bay. AT this point the only wire left to deal with is the harness that goes up over the fusebox. Those connectors atop the fusebox are simply connected to a metal backing plate that is held in place under the fusebox via a 10mm bolt. Remove the bolt and this plate comes out. Remove the connectors from the plate and route these wires DOWN below the fusebox. Their mating ends are already down there. Loom and tape up this last section of wire and connect the harness connectors. The TPS connectors are the only connectors left to plug in - you should connect them up and take a look at how the wires want to run and get an idea of where the pipes will go. Now that the harness has new loom and tape on it, it will be much more flexible and moving it around for the pipes is much easier. The finished product looks as such..
 
The next section I will be redoing is along the back of the engine and on the passenger side. There are a good number of wires/loom/tape that are aged and cracking like all of this stuff was. There is also some rerouting that can be done there to also clean it up and make it less messy. Will be doing that doon and posting that as well.
Hope you all find this helpful.
[ ashleypowers.com ]
[ agpowers@bellsouth.net ] [ Zemulator Information Sheet ] Enthusiasts soon understand each other. --W. Irving.
Are you an enthusiast?
|
Engine bay cleanup: EFI harness, reroute. - 
