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| How to replace the wiring loom with the engine in place |
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This is not an easy job at all! Although it's not technically complex, some of the
connectors are very hard to get to, and there are an awful lot of them too - so you'll
need to allow plenty of time to complete the job. Here, I am replacing the loom on a
1989 J-spec car, with a US LHD loom - the job would be a little easier using a RHD loom,
but they are almost identical (bar the price! a US loom is around half the price of a UK
sourced loom), the only difference is that the spur which goes to the ECU is longer, and
comes off the main loom in a slightly different location, due to the ECU being on the
other side of the car.
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| Required parts |
The loom part numbers vary by year and spec, so I've listed them all.
All the part numbers listed are for LHD looms - if you want to get a proper RHD loom
then you'll have to speak to Nissan UK - sorry. If someone would like to email me
the part numbers, I'll gladly add them here.
| Date |
Applied model |
Part number |
| 0289-0589 |
T/R. MT |
24011-30P00 |
| 0289-0589 |
T/R. AT |
24011-30P10 |
| 0589-0789 |
C. MT + T/R. MT |
24011-30P00 |
| 0589-0789 |
C. AT + T/R. MT |
24011-30P10 |
| 0789-0790 |
C.MT + T/R. VG30D.MT |
24011-30P00 |
| 0789-0790 |
C.AT + T/R. VG30D.AT |
24011-30P10 |
| 0789-0790 |
T/R. VG30DTT.MT |
24011-30P60 |
| 0789-0790 |
T/R. VG30DTT.AT |
24011-30P70 |
| 0790-0991 |
C.MT + T/R. VG30D.MT |
24011-30P01 |
| 0790-0991 |
C.AT + T/R. VG30D.AT |
24011-30P11 |
| 0790-0991 |
T/R. VG30DTT.MT |
24011-30P61 |
| 0790-0991 |
T/R. VG30DTT.AT |
24011-30P71 |
| 0991-0792 |
T/R. VG30D.MT |
24011-45P00 |
| 0991-0792 |
T/R. VG30D.AT |
24011-45P10 |
| 0991-0792 |
T/R. VG30DTT.MT |
24011-45P60 |
| 0991-0792 |
T/R. VG30DTT.AT |
24011-45P70 |
| 0792-0993 |
T/R. VG30D.MT |
24011-45P02 |
| 0792-0993 |
T/R. VG30D.AT |
24011-45P12 |
| 0792-0993 |
T/R. VG30DTT.MT |
24011-45P62 |
| 0792-0993 |
T/R. VG30DTT.AT |
24011-45P72 |
| 0993-0795 |
T/R. VG30D.MT +CV |
24011-48P01 |
| 0993-0795 |
T/R. VG30D.AT |
24011-48P11 |
| 0993-0994 |
T/R. VG30DTT.MT |
24011-48P61 |
| 0993-0994 |
T/R. VG30DTT.AT |
24011-48P71 |
| 0994-0795 |
T/R. VG30DTT.MT |
24011-51P61 |
| 0994-0795 |
T/R. VG30DTT.AT |
24011-51P71 |
| 0795- |
T/R. VG30D.MT +CV |
24011-54P01 |
| 0795- |
T/R. VG30D.AT |
24011-54P11 |
| 0795- |
T/R. VG30DTT.MT |
24011-54P61 |
| 0795- |
T/R. VG30DTT.AT |
24011-54P71 |
If you are using a LHD loom, then you'll also need some light guage automotive wire
(I'd get red & black personally), a soldering iron, solder, and electrical tape (if you
want to do a really neat job, then some heat shrink too), because there are one or two
connections which need lengthening to reach (the PRVR solenoid connector, for example).
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| Hints & Tips |
It's a good idea to clean each connector as you put the new loom in, since over the years
corrosion builds up, and you're only replacing one half of each connection.
My preferred method is to clean male connectors with a small strip of wet & dry, wrapped
over the end of a small screwdriver. Female connectors are harder - a tiny scraping device
is good though, perhaps a large pin or needle. I also spray each connector liberally with
contact cleaner before I put them together - including the new half (on the new loom), in
case there are any manufacturing residues present.
One word of warning, some connectors have a small rubber seal inside them (see below),
and when that seal gets wet from the contact cleaner, it sometimes "inflates" up to larger
than it's normal size, causing it to bulge (as in the picture below).
If that happens, the only thing you can do is wait for it to shrink back. Personally, I
removed the inner sleeve from the connector by pressing the small tangs in (see the second
picture, they are the two visible tangs in the centre of the connector), and then removing
the seal, bringing it indoors and putting it near a radiator overnight.
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click the pictures for a larger version
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| Procedure |
- When I did this, I had the upper inlet manifold off the car already, but you will
at least need to remove the boost hoses. Remove anything else 'easily' removable too,
it'll save you time in the long run. Take the centre plate off the inlet manifold too
so that you can get at the injector connectors. (Fig. 1)
- The first loom spur I removed was the connection to the MAS. You'll need to remove
the centre panel between the headlights, and split the airbox (you need the top off
to be able to get your hand in to the new connector), unplug the MAS connector, and
withdraw it - it'll be a tight squeeze out past the intercooler pipes. (Fig. 2)
- Now unbolt the relay box - the loom is attached to it's lower mounting bolt (Fig. 3),
and tease the loom upward. There is an earth wire that screws to the chassis underneath
the inlet pipe - the screw is inaccessible, so cut the earth, and we'll use a different
earthing point later (Fig. 4)
- Unplug the PTU, temperature sensor and CAS connectors, and then withdraw that part
of the loom from the front of the engine, pulling it under the hard turbo inlet pipe -
it's a very tight fit, so you'll have to pull quite hard. There are now four connectors,
which on my car were crammed down under the inlet pipe - they connect the EGI loom to the
fuse/relay box, and also connect to the magnetic clutch for the A/C compressor. Try to
unplug the A/C clutch first (one pin, small connector), then if you are lucky you'll be
able to pull all of them up to easily undo them - if not, you just have to struggle. They
aren't actually attached to anything, just very tight.
- You should now be able to bend a large part of the old loom toward the back of the
engine bay. At this point, I started to feed the new loom in - starting with the MAS section.
You might need to tie some wire around the MAS connector to be able to pull it through into
the airbox area, it's a very tight fit. Then feed the PTU/CAS section of loom under the
hard inlet pipe, and across the front of the engine (Fig. 5), making sure that you secure the section
of loom to the cambelt covers, and that the CAS connector comes up the back of the
section of loom, so that it will not foul the fan. (Fig. 6 & 7)
- If you have your plenum on, you'll need to work your way back down the side of the engine
removing the connectors that you come across - there will be two for the TPS (Throttle Position
Sensor), one for the wastegate solenoid, and one hard to see one on the PRVR solenoid just in
front of the battery, attached to the inner wing (Fig 8). Bend that section of loom back
as far as you can.
- You can now attach the new connectors down the passenger side of the engine, starting with
the three connectors that are by the relay box, and the magnetic clutch connector for the A/C
compressor (Fig 9). If you are using an LHD spec wiring loom, then you may well need to
extend the PRVR solenoid connector by splicing in some wire extensions so that it reaches the
solenoid.
- You will have a "spare" earth connector down by the relay box spur of the loom now. Originally
this was attached to the bolt point that is inaccessible with the engine in place, so I put the
terminal in between the two metal halves of the P shaped retainer that bolts the wiring loom to the
lower relay box fixing point, and bolted that back up (Fig 10).
- If you are working with the inlet manifold still on, then you'll need to start working your way
around all of the connectors that are in that area now - O2 sensors, VTC solenoids (if your car is
a TT), air regulator assy are all in the back right corner, then coil packs & injectors (the injector
connectors are quite hard to get to - you'll need a small screwdriver to prise the metal tangs out),
and finally drivers side O2 sensor and VTC solenoid, not forgetting the two solenoids (AIV & EGR I
believe) underneath the stock boost sensor in the extreme rear left corner of the engine bay.
Once all those are disconnected, you can withdraw the wiring loom - you'll need to unplug it from the
ECU in the passenger footwell - I'll assume you know how to do that.
If you are lucky, you'll be able to pull the ECU plug out through the hole in the firewall (you have
to remove the clear plastic cover from the connector to make it small enough), but if your loom is
like mine was (i.e. well cooked), the easiest thing to do is cut through all the loom wires, and then
take the loom out in two halves - an inside half, and an outside half (Fig 11 is the outside
half).
- Now work toward the rear of the car down the passenger side, reconnecting the connectors as you
work your way down. If you are using an LHD loom, then you'll need to splice into the PRVR solenoid
wiring to extend it, the US loom seems to be far too short to reach for some reason, unless you prefer
to move the solenoid closer to the loom, which is what I did (Fig 12).
At the rear right of the inlet manifold there are a couple of earths that need reconnecting, as well
as the other connectors.
- Once you've finished the passenger side, it's best to switch to the drivers side, and reconnect
the solenoid connections first, then work back toward the centre of the car (O2's, VTC solenoid, coilpacks
etc), and you should end up with just the ECU connection left over.
Now comes the hard part..
- You'll need to take the clear plastic cover off the back of the ECU connector, then feed it through
the bulkhead any way you can basically. You might want to pry on the plate of metal that sits just behind
the bulkhead hole to make access easier, and thats it - you're finished.
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Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
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