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Just Bought a $3000 986, Let the Troubleshooting Begin (EVAP)


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Hi all, just wanted to introduce myself. I'm the proud new owner of a 99 Boxster (manual transmission) that needs a fair amount of work. 

 

Most immediately, there was a check engine light for EVAP, though sadly I didn't get a chance to write the code down before the previous owner reset it. It said something about a large leak in the system, so I'm reading threads on that until it pops up again and I can narrow it down.

The clutch is totally shot and slipping under normal loads, so I'll be doing that, as well as all the 'while you're in there' things.

I'll also be doing all filters and fluids since as the 10th owner, I have no idea what's been done and what hasn't.

 

As to be expected, there are some... unknowns... with the wiring. I've attached two pics of a plug found near the battery, besides looking like it could be plugged in somewhere, it looks like it could take a blade fuse. Any idea what this might be? I don't see anything within reach that looks like it's obviously missing a plug, and it appears to be well integrated into the harness, so it looks factory. 

 

Please post welcoming messages, snide comments, or helpful advice!

 

🙂

 

Thanks,

Chris

 

 

20211115_111856 1.jpg

20211115_111901 2.jpg

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Weird, okay I'm not worried about the alarm horn. The fuse is pulled for the regular horns, and I found out why when I plugged one in. There's a short. Likely it's the bracket behind the steering wheel, so I'll add that to the list.

 

Does anyone have a good diagram of the relay board? I've found a 2001 diagram online, but a lot of things must have changed, since the diagram only has a few slots filled in, whereas my board has a ton (and even one weird double wide relay that someone wired an external ground to :eek:)

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Thanks for the response, your site is a wonderful resource!

 

Yeah, that's what I'm talking about. That relay diagram doesn't seem to be anywhere near what my relays look like

 

Diagram:
https://fotohostingtv.ru/show.php/19314_knigaproavtoru08290509.jpg

 

Someone else's that looks closer to mine:

relay_horn.JPG

 

 

(Also, I haven't figured out how to add a signature here, so I should try to remember to include "99 Boxster" at the end of my posts)

Edited by Chris Henry
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Nice! I wish that this thing didn't need a clutch. I haven't driven it for a week or so just because how badly it slips at partial throttle. As I look at clutch parts (knowing that it probably needs a flywheel since I'm sure the surface is thrashed) and all the other 'while I'm in there parts' like the IMS, rear main seal, spark plug tubes, all fluids and filters, ugh this is going to add up.

 

So do I spend $2000 on refreshing this powerplant, and at the end still have a motor that's underpowered for the chassis, and still subject to blowing up at any time costing a phenomenal amount on a rebuild? (But sounds really nice)

 

Or do I keep that $2000, sell the motor in as-is condition (I see some m96.20s on ebay for $3k, so maybe $2k for this one, optimistically?) and plan a swap?

 

I bought this as a project car, so no worries if the work takes forever. I have very limited time, so even just refreshing the 2.5 it's going to be down a long while. For example, I won't even order the flywheel until I take it all apart and see what condition it's in, so months of down time is to be expected. But it's a fun hobby, and I need one of those.

 

I'd love someone to confirm or deny whether a K series and transmission would fit like they do in the MR2s. That would be ideal, as a turbo K24, or even a K20 (3/4 inch shorter) will make way more power than the 2.5 ever could without a full bottom end build. If the Honda transmissions could work, that would be ideal (plenty of them, cheap, lots of variety for gearing, and if I was a baller, even a sequential dog-box for $10k)

 

I don't even know the code for what the current transmission is, so I'll have to look it up to see what kind of power it can hold.

 

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  • Moderators

When contemplating a later model Porsche engine replacement on one of these cars, you need to take a lot of things into consideration, such as: The fuel systems changed year to year, some changes were minor, others not so much.  Later engines are nearly totally CAN Bus technology, the early cars had none; over the years, there have been multiple DME changes, some were significant, and trying to use the later engines can turn into and electronic and reprograming nightmare. 

 

I could go on, but I think you get the picture.  You need to understand just how much will need to be changed to make a possible swap work before you leap into a financial black hole......

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Yep, I hear you. In my opinion, for me, with this particular $3000 car, there are two options:

 

Tune up the M96.20, and enjoy the car as is. Which even with a slipping clutch, I can appreciate that this is an excellent driver's car. After all, without being able to accelerate out of a turn, you really need to manage and carry speed! 🙂 It's brilliant!

 

Or

 

Non-Porsche motor swap. Huge upfront cost, huge upfront headaches, potentially incredible payoffs (how much would a 400hp, 600hp, 800hp Porsche engine and swap cost?) If people are successfully putting LS motors in 911s, I'd like to find something that works in these mid engine cars. LS might be the answer, but it seems like overkill. A relatively high-strung/high-revving 4 or 6 cylinder seems like it's a better fit for this car than a grunty V8 to me.

 

Unfortunately, to answer my own question above, it does not look like a k series and matching transmission will likely fit as the motor is nearly on top of the axles of the Hondas, which work well in mid engine MR2s and NSXs, because there's definitely a significant offset between the high point of the Porsche engine and the axles (like a foot and a half). This would put a Honda motor (located by the transmission) through the area the top folds into, or even into the trunk. I'm fine with cutting and boxing the trunk, but it would hardly be practical for most people to follow a recipe where you need to run without a roof, or go with a hard top only.

 

Just thinking out loud here...

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That basically describes nearly every hobby that we've ever come up with as a species. 🙂

 

I'm still working on a pair of speakers that I probably have $500 and 100 hours into. I certainly could have worked another job and bought jaw-dropping speakers, but where's the fun in that? These will be mine, they will be unique, they will give me a sense of accomplishment and pride every time I listen to them or look at them. How much is that worth?

 

9 previous owners, a rolled back odometer, on a model that very few people care for, trim level that's least desired, slipping clutch, this was never going to be an investment.

 

Thanks for the feedback though. I'm just kicking ideas around for now.

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  • 2 weeks later...
On 12/2/2021 at 3:30 PM, JE 17 said:

You might consider exploring a VW 1.8T as mentioned in another forum. It appears to integrate more easily, and you stay in the corporate family at least.

 

 

Small displacement turbocharged engines come with their own drawbacks and considerations.

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  • 2 months later...
On 11/15/2021 at 3:44 PM, Chris Henry said:

Hi all, just wanted to introduce myself. I'm the proud new owner of a 99 Boxster (manual transmission) that needs a fair amount of work. 

 

Most immediately, there was a check engine light for EVAP, though sadly I didn't get a chance to write the code down before the previous owner reset it. It said something about a large leak in the system, so I'm reading threads on that until it pops up again and I can narrow it down.

The clutch is totally shot and slipping under normal loads, so I'll be doing that, as well as all the 'while you're in there' things.

I'll also be doing all filters and fluids since as the 10th owner, I have no idea what's been done and what hasn't.

 

As to be expected, there are some... unknowns... with the wiring. I've attached two pics of a plug found near the battery, besides looking like it could be plugged in somewhere, it looks like it could take a blade fuse. Any idea what this might be? I don't see anything within reach that looks like it's obviously missing a plug, and it appears to be well integrated into the harness, so it looks factory. 

 

Please post welcoming messages, snide comments, or helpful advice!

 

🙂

 

Thanks,

Chris

 

 

20211115_111856 1.jpg

20211115_111901 2.jpg

I am right behind you…. Pick my $3k 986  up a few weeks ago…… currently trying to make sense of the radio wiring that has been butchered.  I was able to determine that the door speakers are still connected to the amp but none of the others, they have been cut somewhere between the amp and speaker.  Fun times. Best of luck! 

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