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Old 02-20-2018, 06:33 PM   #1
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Wiring Harness 2002 vs. 2003 Boxster S (Swap)

I need help and guidance, I have a 2002 Boxster S with intermix issue. Found a donor engine from a 2003 Boxster S with automatic tranny.

From the research, I would need a 7.8 DME with a modified 2002 engine harness? The two harness are very different from each other. I need from someone that has done this swap before?

The top is the 2003 has extra connector that seem to plug into another box and bottom is 2002, they all plug to one box.




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Old 02-20-2018, 06:50 PM   #2
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I addition, the intermix is bad deal. The previous owner left it seating since 2016, the oil did it damage on the water hoses. He also use the car for sometime before he discovered the issue, so the oil/water mix turn it to a batter like. I need some idea how to clean the radiators and water hoses. I may replace every single rubber lines. Looking for suggestion, other wise this is surprising enjoying car to work on. I might even rebuilt the old engine?
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Old 02-20-2018, 07:11 PM   #3
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The top is the 2003 has extra connector that seem to plug into another box and bottom is 2002, they all plug to one box.
The part of the question that I can answer is about the extra connector.
The Tiptronic cars have the transmission harness bundled together with the engine harness. There is a separate transmission module on the firewall next to the DME that the extra plug connects to on the Tiptronic cars.
Everything you need for the engine is there on the harness and the Tiptronic stuff can probably be un-bundled and cut out if you want to use that harness (not recommended).

The DME 7.2 vs DME 7.8 has been figured out by others, but I'd only be guessing.
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Old 02-20-2018, 08:10 PM   #4
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Quote:
Originally Posted by xr_guys View Post
I need help and guidance, I have a 2002 Boxster S with intermix issue. Found a donor engine from a 2003 Boxster S with automatic tranny.

From the research, I would need a 7.8 DME with a modified 2002 engine harness? The two harness are very different from each other. I need from someone that has done this swap before?

The top is the 2003 has extra connector that seem to plug into another box and bottom is 2002, they all plug to one box.


I thought the 2002 was a 7.8 DME

Did the 2002 have the dual VarioCam like the 2003?

If it did, try using the 2002 harness on the 2003 engine.

Or you could source a 2003 manual harness.

You could try the 2003 auto harness and leave the tip connector unhooked.

Mike
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Old 02-20-2018, 08:37 PM   #5
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Hi 78F350,

Thank you for your response, my suspicion is right that was the module for the tiptronic transmission.

It would be nice to reuse the 2003 harness since i already have everything prepared. I also have a 7.8 DME arriving this week. I still need the additional information where i could or could not reuse the 2003 harness with deleted automatic module?

In addition, the water mix issue is a big mess, the car was parked since 2016. Due to the oil on the water line almost all rubber hoses are damage from the oil. Also confirmed the cause of the heating. The radiators are obstructed with dirt and leaves, i urges everyone to inspect your radiators and clean them properly. You'll need to remove the front bumper and hydraulic radiators to proper clean out debris hidden in between. Unfortunately, the water hosing outside the bumper scheme is not sufficient.

On the donor engine. i found some water pump impeller debris inside the oil cooler. looks like the donor engine also suffer from water pump failure at some point. This issue of partial impeller getting lodge inside the engine is real. I opted to use metal version to avoid previous issue. I would rather have some gouges on my block than plastic debris stock somewhere inside my engine, just my opinion.

Thanks,
XR
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Old 02-20-2018, 08:51 PM   #6
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Hi Seningen,

According to another site and base on the Porsche part list, 02 and 03 has different DME. The 7.8 was introduce to Boxster starting 03, so 02 are still 7.2 DME.

My 02 engine has Variocam with single control line. The 03 engine with Variocam has two wires. I heard early Variocam have ON/OFF response like vtech. The newer version has infinite adjustment, not sure what year if that limited only to Variocam Plus.

I hope i can reuse the existing 03 harness, i'm willing to modify if needed. I just need the wiring mods. Hopefully someone has actually done it>?

Thanks,
XR
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Old 02-21-2018, 06:25 AM   #7
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I would compare the locations of the various electric components on the 03 to the 02. They might be the same. I put an 02 manual engine in my 01 Tip and it was just a matter of pulling the plenums off the top and switching the harness and some vacuum lines from one engine to the other. Switched the clutched alternator to the unclutched alternator, too. I ended up using the 01 throttle body and that part of the plenum system, too. On an 02 (which started life as an 00) everything lined up perfectly with the 01 components.

As far as the tiptronic connectors, on mine, there is a blue connector in the trunk that goes to a blue component. And two plugins for the transmission. & an extra vacuum switch for the other side of the trans. which is part of the engine part of the harness, I think.

Logically, I think, it would be easiest and best to use the harness that came with your car. Switch out any senders, sensors that are obviously different.
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Old 02-21-2018, 06:54 AM   #8
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The water pump is an item to preemptively replace at some interval of years and or miles. Most folks here will say to use only the OEM water pump with a composite impeller. I'm one of the heretics that went with the metal impeller water pump. The issue with the metal impeller, which you've pointed out, is that it will grind away the water pump cavity in the block if the bearing is worn to the point of the impeller contacting the block. Even a little wear can increase the cavity space to the point that the water pump no longer adequately pumps and circulates the coolant. My first water pump with a metal impeller started to fail and my temperature gauge light started blinking indicating I had a low coolant level condition. I was able to drive the car about 50 miles to get home. Then I had the car flatbed towed to my independent Porsche specialist. The bearing had started to leak, causing the low coolant condition, but it was not worn sufficiently to allow the impeller to come in contact with the block. Based on that I decided to again have a metal impeller water pump installed and I'll replace it proactively or the first sign of any coolant leakage around the bearing. The thing I don't like about the composite impeller is that it becomes brittle and cracks after some number of heating and cooling cycles. So you can have a chunk of impeller break off and get lodged in a cylinder head, which will cause a hot spot and ruin the engine. But I am very much in the minority on this opinion.

Good luck with your project!

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On the donor engine. i found some water pump impeller debris inside the oil cooler. looks like the donor engine also suffer from water pump failure at some point. This issue of partial impeller getting lodge inside the engine is real. I opted to use metal version to avoid previous issue. I would rather have some gouges on my block than plastic debris stock somewhere inside my engine, just my opinion.

Thanks,
XR
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Old 02-21-2018, 03:04 PM   #9
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Brian,

Initially I have the impression that we have plenty of historical documentation people posted the necessary info for others to use. I was surprise not much really to follow on the electrical except for taking the engine and transmission, ohh well.

Additional pictures where you can see the debris getting suck in between the two radiators. I believe (please someone confirm) the radiator fan air direction suck air from front to back. When the front radiator become clog with debris, the low pressure get created on the side forcing the debris the low-pressure side. Ones its inside (in-between) its not going away even water pressuring it (please donít do that!), just saying. With that much debris blocking the radiator no wonder why cracking cylinder head are common on this car. Then you find the intermix issue to late adding most cost to the actual recovery to get the car back.

I would encourage to please check yours now and set aside a weekend or less to this job.

Paul,
I understand others concern the metal impeller would cause if NOT found soon enough, but no large chunk of plastic that will get lodge inside the engine. Base on my experience, water pump bearing will induce some noise before it fail and since you have it just behind the driver you should hear this warning noise. Or more so just replace it every 40K? I also replace my thermostat to 160, this is not necessary if water cooling system are service regular. But since Iím going to drive this car for fun (hard spanking from time to time), just for added assurance. I think normal driving stock thermostat will do.

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Old 02-21-2018, 05:40 PM   #10
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FWIW when my water pump started to leak through the bearing, it didnít make any noise at all. OTOH, when the idler pulley tensioner for the serpentine had its bearing go, that made a racket but even that was only audible at idle with the window down.

The radiator and A/C condenser can be gently separated to clean the accumulated debris in between them without completely removing and disconnecting them. There are things on the side that can be undone.
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Old 02-21-2018, 05:50 PM   #11
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If your donor engine had previous water pump problems and you've found plastic parts of the impeller in the water system, don't use a water pump with metal impeller. This can cause fatal fails if there is a bigger part of plastic still in there. In case of a plastic impeller failure, you'll mostly find a lot plastic parts in the oil/water heat exchanger.

If there is no plastic or any other debree in the system i don't see any problems with metal impeller water pumps (use one myself). But these pumps needs to be changed preventive before they.

Are we talking about an 2002 (252 HP) and 2003 (260 HP) ROW engine or are we talking about US engines / harnesses?

Regards, Markus

Last edited by Smallblock454; 02-21-2018 at 06:15 PM.
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Old 02-22-2018, 10:37 AM   #12
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Smallblock454,

Yes we are talking about US Boxster S 2002 6 speed transplanting 2003 Boxster S engine that came from Tiptronic.

Mainly looking for additional information i need to reuse engine harness from 2003 (if i can?), or if i have to use the 2002 harness what else do i need to add to work with the 2003 engine.

I've research the entire internet to see if anyone have document an 02 to 03 conversion or post 7.8 DME conversion from 7.2 DME, nada!

XR
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Old 02-22-2018, 11:05 AM   #13
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https://www.pelicanparts.com/techarticles/Boxster_Tech/11-ENGINE-911_Engine_Swap/11-ENGINE-911_Engine_Swap.htm

it's all in the link above. the wiring in your 2002 is already set to take a 7.8 dme (as are the abs pump, gauge cluster, wheel speed sensors, hvac controller which also updated in 2002). you'll have to add/extend wires for the updated variocam (which is not variocam plus, fyi). given all that, no reason why you couldn't use the 2003 harness to avoid updating the cam controller wiring (i don't think so, but some harness connectors may have changed so you may have to do some splicing - you won't know until you get at the engine). also realise you shouldn't trust the internet - for something complicated like this you should do your homework, get wiring diagrams for the components in question, compare terminal assignments and wire colour codes to make sure. again, most of the required wiring info is in the link above.

finally, what 7.8 dme are you getting? if for a tip, you will have to recode.
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Old 02-23-2018, 06:01 AM   #14
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given all that, no reason why you couldn't use the 2003 harness to avoid updating the cam controller wiring.
The 2003 206 HP vario cam system is oil pressure driven. There are no electronic actuators like in the 2002 252 HP engine.

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finally, what 7.8 dme are you getting? if for a tip, you will have to recode.
Colors of cables and plug connectors differ in some details in ROW engines. No experience with US engines, but might be the same. So you have to check wiring diagrams and plug connectors.

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finally, what 7.8 dme are you getting? if for a tip, you will have to recode.
Yes, i can confirm that.
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Old 02-23-2018, 10:03 PM   #15
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King,

I'm getting part number 996.618.604.00, i think its for manual since its has 618 rather than 628 according to the Porsche online parts book. I'm assuming this is a 7.8 DME. May be i can just leave the Tiptronic DME cable hanging and not connected to anything, using the original wiring harness that came with the donor engine. The clutch switch should be part of another box feeding it to the DME which i already have?



454,

This is my Variocan from 02, single wire




Here is from 03 dual wire




Looks like the 03 is still electromechanical scheme.

XR
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Old 02-23-2018, 11:22 PM   #16
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clutch switch comes from front of car.

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