Re: Absolutely disconnect the battery -- follow proper procedures to do this! -- before ...

I have a 2000 986 Boxster that had the top fail to open. (more questions on that later) I took a look in the trunk and pulled the liner back and wiggled connectors and checked for tightness of relays and then the car would only go to 2000 rpm. I pulled the liner again and all looked well and it would run normally. I put the liner back in again and it was back to only 2000 rpm. I have looked thru out the connectors and checked the wiring and I can see no loose connectors or broken wires. Any suggestions as to which connectors or wiring harness or relay that could be causing this problem.

BTW: there are not any check lights or warning lights displayed.

The ECU - Engine Control Unit, is located in the rear trunk, up high. I suspect in jiggling wires that you got a connector misaligned. Suggest exposing the ECU and firmly re-seating all connections.

Ill try that tomorrow. Thanks for the response.

Grant

gee-lenahan-at-gee-mail-dot-com

Will I need to disconnect the battery to pull the connectors on the ECU, or is it ok to reseat the connector plugs with the battery connected. Dont want to blow anything.

you fiddle with the ECU/DME connector plugs.

Also, be sure you discharge any static electricity you might have before you touch the connectors.

Afterwards be sure you follow the proper procedure to reconnect the battery.

Don't forget to obtain the radio code before you disconnect the battery.

After you reconnect the battery you have to (well should) reset the window limits and re-cal the E-GAS. The steps to do these things should be in the owners manual.

OK, I have reseated all the connectors to the ECU and the wiring harness to the left of it. The car is still only going to 2000 rpm. Do you guys have any other suggestions.

Yes, The CEL comes on when ignition does but goes out while it is runnng, I tried the E-gas cal, and I have re-seated all connectors on the ECU and the associated wiring harness. No luck as of yet

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gpbud
OK, I have reseated all the connectors to the ECU and the wiring harness to the left of it. The car is still only going to 2000 rpm. Do you guys have any other suggestions.

Could be a coincidence but the behavior appeared right after -- if I read your earlier post right -- you fiddled with the wiring. The problem might not be with a loose connector but with a broken wire.

But of course it may be related to something else. These kinds of problems can be hard to trace without the factory diagnostic computer and the know-how to use it.

The CEL is not on? If it is dark are you sure the LED works? Does the CEL come on when you turn the key but go dark when you turn the key to engine start and the engine begins to run?

The only other thing I can think of is the E-Gas is not working right and it has gone into limp mode in which case RPMs are limited. However, I would think the CEL would be on in this case but maybe not.

I seriously doubt an E-Gas calibration would help matters, but it doesn't cost anything but a minute or two of your time. The steps should be in the owners manual, but from memory (for my 2002 Boxster at any rate): With the key off and your foot off the gas pedal turn the key to the on position but not beyond. Wait 60 seconds. You can wait longer, a bit longer, but not any less (according to my info). Then turn the key off and wait at least 10 seconds. Done.

The E-Gas system is calibrated for the next time the engine is started.

Yes, The CEL lights when the ignition switch is turned on. After I start the engine it goes out and all seems normal until I try to rev the engine.

I tried the E-gas cal and unfortunately it didn't help.

As much as I hate to say it, yes it does seem like an open wiring issue. Even worse I cant get the top open to pull the deck lid to look into the engine bay. (convertible top not opening was the original problem)

Could an analyzer help me with some codes or do you think I am going to have to start replacing things to get this fixed.

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gpbud
Yes, The CEL lights when the ignition switch is turned on. After I start the engine it goes out and all seems normal until I try to rev the engine.

I tried the E-gas cal and unfortunately it didn't help.

As much as I hate to say it, yes it does seem like an open wiring issue. Even worse I cant get the top open to pull the deck lid to look into the engine bay. (convertible top not opening was the original problem)

Could an analyzer help me with some codes or do you think I am going to have to start replacing things to get this fixed.

In this case, where do you start?

Is the problem with the E-Gas system, the wiring harness, the DME or something else?

My WAG but not a very good one is it is with the wiring based on what you wrote in year first post:

pulled the liner back and wiggled connectors and checked for tightness of relays and then the car would only go to 2000 rpm. I pulled the liner again and all looked well and it would run normally. I put the liner back in again and it was back to only 2000 rpm.

It is probably not a bad connector but a broken wire in the harness and maybe more than one because there are a couple of seemingly unrelated problems: top and the engine failing to run over 2K.

Trouble is a harness is pretty tricky to repair so the usual solution is to fit a new one. This is almost assuredly expensive. And you want to be darn sure it will do the trick.

I'll toss this out but I really don't feel all that comfortable doing so: You might try enlisting the help of someone who on command can attempt to rev the engine above 2K and then removing the liner and gently manipulating various wires and such and seeing if this effects the engine any by having the helper rev the engine at various times. I really don't like this though for if in your manipulating the wiring a broken wire end pokes through the insulation into another wire it can ruin the DME and other things.

Even if you uncover the area of the wiring that affects the engine you are still faced with what to do. Repair the wiring harness? Or replace? Repairs are real tricky. In some cases you can't just say pull the bad wire out of the loom and cut out the bad section and put in a new section. In some circuits solder can affect the electrical signal from the sensor. You can be leaping from the frying pan into the fire. Crimp connections can be used but these have be to very secure and then sealed against the elements.

Another problem is with the age of the car and the wiring as you work on the harness more wires break or aged and dry and brittle insulation cracks and well, this just gets uglier by the minute.

This is generally the point I advise someone to take the car to a knowledgeable tech well experienced in these things. He might have encountered this before and tell you my diagnosis -- well, my WAG masquerading as diagnosis -- is way off the mark (I can only hope) and the situation is not as dire as I make it out to be and there's a reasonably affordable fix.

I'm a newbie here but maybe your ECU went bad, maybe that should be tested? Have you checked your fuses for the top maybe one has blown.

Thank You to all of you for your input. I was hoping to pull the wiring harness and ohm it out. That's why I was going to pull the engine deck lid and look at connectors to pull. Trouble shooting with the wiring harness still in the car will be very difficult, but not impossible. Ill have the wifey help with the engine revs while I look at the wiring harness. Ill also check the connector pins on each plug.

As far as the ECU, I guess Ill have to find a shop that can test it. I am in Southlake, Tx. which is in the Dallas area. Does anyone know of an independent shop in the area that wouldn't charge an arm and a leg to look at my ECU.

I have looked at the fuses for the top and all are good. The problem with the top is that I go thru the routine, Car parked, E-Brake up and E-Brake light lit on the dash. I pull the latch and the windows open half way. I hit the switch and hear for a moment a noise in the rear as if it is going to open. It doesnt sound like motor noise, more of a coil being engaged or a good size relay kicking in. Then after a second its complete silence as the top stays in its closed state.

I know its off of the original topic but I kinda need to get the roof working in order to get easy access to the engine compartment. So if you guys have any ideas about the top not opening and how to repair it, please chime in.

Thanks again Guys.

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gpbud
Thank You to all of you for your input. I was hoping to pull the wiring harness and ohm it out. That's why I was going to pull the engine deck lid and look at connectors to pull. Trouble shooting with the wiring harness still in the car will be very difficult, but not impossible. Ill have the wifey help with the engine revs while I look at the wiring harness. Ill also check the connector pins on each plug.

As far as the ECU, I guess Ill have to find a shop that can test it. I am in Southlake, Tx. which is in the Dallas area. Does anyone know of an independent shop in the area that wouldn't charge an arm and a leg to look at my ECU.

I have looked at the fuses for the top and all are good. The problem with the top is that I go thru the routine, Car parked, E-Brake up and E-Brake light lit on the dash. I pull the latch and the windows open half way. I hit the switch and hear for a moment a noise in the rear as if it is going to open. It doesnt sound like motor noise, more of a coil being engaged or a good size relay kicking in. Then after a second its complete silence as the top stays in its closed state.

I know its off of the original topic but I kinda need to get the roof working in order to get easy access to the engine compartment. So if you guys have any ideas about the top not opening and how to repair it, please chime in.

Thanks again Guys.

I'm not ready to blame the ECU proper for any of the misbehavior you describe.

However, it is your call as to what you want to do and in what order.

As for testing the ECU your best bet is to have the car checked out, the ECU checked out, by a tech with access to a Porsche diagnostic computer. He can run a scan on the car's electronics and if there is an issue with the ECU or a suspected issue with the ECU he can do some preliminary investigation to eliminate the wiring.

If you want to have the thing checked out by another shop then check out the ads in Excellence or Panorama. I have seen a couple of ads in those mags offering ECU/DME repair services. I'm assuming you do not have a world renown ECU repair shop in your immediate vicinity of course. When you call try to get some over the phone diagnostics. I suspect you'll be told it doesn't sound like the the ECU is to blame for the symptoms.

If (big if) the ECU is deemed in need of repair you are still faced with the likelihood the harness is bad. If so then you could have a repeat performance after you install the repaired ECU.

My top trouble shooting expertise is very minimal, non-existent in fact. All I can offer is a WAG and my WAG is the behavior you describe is not a wiring/electrical problem but probably a mechanical problem. IIRC there some drive gear mechanism and that is where the noise is coming from.

You might find the info at this link informative:

[www.pelicanparts.com]

… swapping it out with another one from the same model and model year car.
If the issues persist with the other ECU then you know it's not the ECU.
If the issues are corrected with the other ECU then that was the problem.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

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Edited 1 time(s). Last edit at 08/24/2015 10:48PM by Pedro (Weston, FL). (view changes)

Here's how to manually open the top from the up position. It doesn't look fun, but good luck...

[www.renntech.org]

It's not unheard of to have a pin in a connector become unattached to the plug. It will look fine, but will not connect when plugged in to the mating part. Pull gently on each wire in the plug/socket and serif it pulls out. If it does, you have found a problem.

Ed B