How to diagnose and resolve engine issues using Durametric.

[jb92563]

Originally Posted by Reebuck1

Maybe the DME hit it's learning time set and brought the car back to the original programing. Not sure of the time frames for each or all the adjustments. Have had problems that were corrected during an extended test drive as the computer learns and adjusts the cars program.

I'll try putting some miles on it and see what happens. My new Triple A card just arrived, it must be a sign from the Porsche Gods to just go for it!

[Melb boy]

Hi Guys
I just came across this and thought,are these fly by wire gas pedals,ie: No throttle cable,if so maybe it's something to do with the operation of that,connection,wear etc as it is in a position that gets dirty and used all the time,and just thinking that there are mods available to plug into electronic gas pedals to increase response so maybe that's a possibility

[wawa]

Hi

I dont have my 986 anymore, sold it for a brand new 981. But related to the egaz, my mechanic had change the tb to check for faulty egaz, but no change. But your problem really look like mine. You have done about everything
Il had try. I really hope you'll find out whats wrong.

Later

Wawa

[jb92563]

I did take apart the Throttle plate actuator and spray electronic contact cleaner on the wipers and there was no change.

I think I'll take the car for a spin tonight and go get some fresh fuel.

I can start driving it to work and see if the situation improves with the new battery and the computer relearning after resetting everything.

As I mentioned I was idling in the driveway looking at the Durametric data on the laptop when suddenly it started running consistent again. Perhaps the DME made a correction?

If it was the egas I would think that the problem would be consistent and not wandering idle and then suddently steady again.

However, problems do love to hide right under your nose in the most unexpected places and often the last thing you think it could be is precisely what it is.

[jb92563]

Update -

So since the last time the car shut down it was running perfectly.

I startup and everything runs perfect still, so I go to the gas station and fill the tank.

Upon restarting, it quickly stalls and then I try again and it starts but now its running horrible again with the wandering idle and hessitation when accelerating and just coasting along. No check engine lights and probably the same codes as before but I will check tonight.

I get a block from home at a light and it stalls.

My first attempt to restart and I get nothing when I turn the key, no clicks or starter turning...nothing.
Then I take a breath, wait a couple seconds and try again and it starts and runs perfectly again all the way home.

WTF is going on I'm in the pulling hair out realm now....damm F$%#@!*&^%$#%)%##

Any suggestions, I'm running out of ideas, or do I just give up and take it to an Indie at this point and hope they can figure it out?
Anyone know of an excellent shop that does Boxster work in my area?

Is my computer going bad? Is there a way to test it?

[jb92563]

Trying to apply logic which never seems to work with car problems like this:

The Facts:
Car runs perfectly at times and then suddenly it runs like crap with wandering idle, hesitation on acceleration, stalling at idle.
It seems that after it stalls and restarts it could go either way running good or crap again.

No Engine light is triggered.
Codes thrown are; P0102 MAF Low Input (connections/supply?),
P0507 Idle Speed too high (Wandering idle?).
P1571 Immobilizer - Open Circuit / No Signal

Since its my second new MAF I think I can rule out a faulty MAF as the source of the problem,

A faulty ground on the MAF or electrical is still a possibility but a low probability based on common issues I read here. Also I drive over some pretty bumpy roads and the faults do NOT correspond with vibrations making/breaking electrical conductivity so I'll rule that out as well for now.

Replaced AOS which had died and perhaps precipitated these issues?

Replaced Pre CAT sensors but no change there.

New Spark plugs and Coils look good and would be causing missfires if damaged and I am not getting misfires so cross the ignition section off the list.

New Fuel Filter, Checked Fuel pressure in the shop but not while driving and experiencing the hessitation so Fuel Pump is still a possibility.
The Fuel Pump relay can also be added to the potentials list since it is related.
Fuel flow is also good in the garage so that eliminates obstructed fuel lines and filters.

New Air Filter, better check the duct work for any obstructions just in case.
I have heard that turbulence at the MAF can cause problems and is why EVO intake folks sometimes experience MAF problems.

The battery had died while in the garage so it might have been weak, but its replaced now.

The computer ECU seems to work fine in every respect and the car still starts so the Computer is not fried,
however cold solder joints in the computer or loose ground connections to sensors is still possible but a low probability.
I did jiggle all the connectors leading into it and no changes were evident.

Vacuum leaks and smoke testing did not reveal any obvious leaks but that does not mean there is not a crack that could open up under real driving conditions and pressure, however nothing blatant was revealed as it was smoked from the intake side and through the Oil filler side with no leaks showing up under a few psi of pressure.

The only high probability items I can think of is the Fuel Pump and Ignition switch as many folks have done it from what I have read.

Those items don't seem to be monitored by any fault codes either so perhaps those should be my next efforts.

I have read that ignition switches going bad can produce all manner of strange issues but have absolutely no evidence or history pointing to the switch as suspect.

I have found a diagram showing the MAF pin-outs so I think I'll check that before buying more parts just in case its a faulty sensor ground connection or an out of spec supply voltage.



Looks like I'll have my 90,000 (Its only 72k on my odometer) mile service done by the time I replace all the wear and tear parts !
Should be good for another 10 years if the engine holds out.

[wawa]

I had change the fuel pump without any change. I had been told it usualy is not faulty, but I didnt want to take the chance.

You could try passing a second ground wire and run it for a time to see if it still happen?

Later

Wawa

[jb92563]

Originally Posted by wawa

I had change the fuel pump without any change. I had been told it usualy is not faulty, but I didnt want to take the chance.

You could try passing a second ground wire and run it for a time to see if it still happen?

Later

Wawa

Being that it is intermittent and seems to be all or nothing, working as normal or running bad, its hard to imagine a fuel pump failing in that way, unless there is an obstruction in the tank.

Perhaps its worth a look at least as I have heard of one fuel pump that broke free from its brackets and was hanging loosely in the tank by its hoses.

You never know if someone has shoved a plastic bag up the fuel noozle so the next person pumping gas gets it in his fuel tank.

[jb92563]

The saga continues and I'm near the point of giving up and taking it to an indy and letting them try.

I read some stuff about testing the MAF for a bad ground so yesterday I was fiddling with the MAF and trying to get my
multimeter hooked up so I could test the ground in situ.

I used sewing pins in the top of the MAF harness to make the connections but something slipped and the
MAF ground pin touched (shorted) the Supply 12v pin.

I heard the throttle plate make a hard smack at the same time and feared I damaged something
with the momentary short.

I then started the car and the Egas throttle was unresponsive, although the car started and idled.

I checked all the fuses and they all seemed fine.

I reset the computer disconnecting the battery, no luck, still no gas pedal response.

I checked the codes and the Egas Potentiometer codes are now present with implausible reading,
as well as the throttle position sensor codes and the MAF code that was there before.

I hope I did not fry something.

I took the throttle body apart and looked at the potentiometer and it looks fine and does not smell burnt.

I'll need to find the Egas potentiometers next and see if they look OK.

I hope the ECU is ok, as the car runs and otherwise functions properly.
Just no gas pedal response.

I wonder if the ECU has its own fuses?

It still acts like the ground is bad for the MAF so I read that the C9 pin at the ECU is the MAF ground
so will check that as well.


I found these helpful but I need to add a DSO scope to my toolkit.
https://www.youtube.com/channel/UCrf6f8hn5oy4alB2WXJCIqA

[jb92563]

Ordered a working Throttle body and Pedal module from a dismantler.

Hopefully that will fix my "Mistake/Accident" issue.

If not then I'll have to take a look at the ECU to see if it got damaged.

I also bought an ECU, Immobilizer, Ignition/key assembly matched set in case i need to try the ECU replacement, only $265 delivered for all 3 for my exact model year 2001 S.

I also discovered/read about another set of high amp (60A+) fuses hidden away in the car but I doubt these have anything to do with my problem.

I'll try the Throttle body first, then the pedal, ECU is a last resort.

[jb92563]

Update -

I tried swaping out the Throttle Body and the E-gas pedal potentiometer/sensor and still no luck.

The car starts and idles ok but does not respond at all to the gas pedal.

It just seems like there must be a fuse somewhere thats blown but all the fuses look good except the drivers seat adjustment, which has an issue that I know about.

I also found some more relays and fuses in the trunk but the fuse there looks fine as well.

I also disconnected the ECU in the trunk and used contact cleaner on the pins.

I took the ECU apart and nothing looks burned or fried. Solder joints look good.
I was surprised the ECU is not even a sealed unit, and looks cheap. Any moisture in the trunk would be a bad thing for sure.

As a last resort I have a matched used ECU/DME/Ignition assembly for a 2001 S same as mine, so I'll give that swap a try and keep my fingers crossed.

If no luck then I need to find a very talented Indy with the right skills and tools to figure this out.

Still the same codes for the egas potentiometer, Throttle Body and MAF but those are symptoms, not the root cause, as my swaps have proven.

No Check engine light suprisingly.

[woodsman]

Wow- just read the whole thread. It's been a while-- have you taken it to a pro???? If not keep up the good fight! Either way I appreciate that you've detailed your efforts...

[jb92563]

Originally Posted by woodsman

Wow- just read the whole thread. It's been a while-- have you taken it to a pro???? If not keep up the good fight! Either way I appreciate that you've detailed your efforts...

This weekend I will replace the stock ECU, Immobilizer and ignition assembly with the matched set I got from a dismanteler.

Wish me luck!

If that option fails then I need to talk to a good indy with the diagnostic tools and experience to figure out what is going on, as I have replaced a lot of stuff already, all the typical suspect things.

Im having Boxster driving withdrawl symptoms too so I need this resolved soon.

[Topless]

Wow is right.

Try the new DME and if you don't get results it is probably time to take it in. Document your path so they know where you have been and why. Black Forest in SD might be the best for diagnosing phantom issues like this. Good luck Ray!

[jb92563]

Originally Posted by Topless

Wow is right.

Try the new DME and if you don't get results it is probably time to take it in. Document your path so they know where you have been and why. Black Forest in SD might be the best for diagnosing phantom issues like this. Good luck Ray!

This thread is probably a pretty good account of all the things I've tried, and I have become intimate the car inside and out. I'm hoping its the DME system and that I'll have a bunch of spares afterwards.

I was also thinking that Black Forest might be able to sleuth this issue, if it comes to that, so thanks for your suggestion.

I figure that at 72k miles its just as well that a bunch of things get replaced anyway so its not a waste in any case.

Fortunately my mindset with the Boxster was a fun Project Sports car/racer, 2ndary transportation and expected a few bumps in the road on a lucky 13 year old car.

Like I always say, every broken part is an upgrade opportunity
, but you have to be able to determine which part is broken first

[jb92563]

Finally some positive results.

Today I put in the ECU, Immobilizer and ignition module set that I got from the dismantler.

I swapped the matched set key RFID chip into my key as they all have to match to work, but the key is cut for my door and ignition, hence the swap of RFID chip and transmitter from the dismanteler key into my original unit.

So I got it all hooked up crossed my fingers, reconnected the battery and turned the key to ON and let it do the 1 minute adaptation process without touching the egas pedal. Then off for 10 seconds and START.

The engine started right up and settled into a nice idle. The gas pedal was responding and reving the engine....hurray!!!!
It was not acting funny at all, the idle was steady and normal.

Tomorrow I will test drive it to verify its all working normal again and check for thrown codes.

Now the only issue I am seeing is the airbag light and the doors will not lock.
I click the remote to lock and I can hear the doors lock, and then they click again and unlock.

I used the key to lock the driver side door which works but the passenger side will not lock, and then I found out that the passenger door does not have a key opening. Hmmmm never noticed that before.

Since the donor cars ECU, Immobilizer were from a car that was in an accident and the front air bags deployed I figured I may have to reset something to get rid of the airbag light.
I figure that the computer also makes sure the doors remain unlocked in an accident when the bags deploy so its probably related.

[Steve Tinker]

Well done......
A lot of us would have given up long ago and taken it to the OPC for evaluation and fix.
You now deserve a cold beer (or two)!!

[guesswecan777]

Ooooh great post!

[Gilles]

Originally Posted by Steve Tinker

Well done......
A lot of us would have given up long ago and taken it to the OPC for evaluation and fix.
You now deserve a cold beer (or two)!!

Congratulations..! Like the saying goes;

Persistence drops panties.. :-)

.

[jb92563]

On to the Test drive.

It now runs better than ever, with all the new plugs, O2 sensors etc.

Test Drive was flawless.

I cleared the airbag error codes with the Durametric.
It had a voltage to unit error and a seat belt system error.
I'm assuming those were stored from the Donor Boxsters crash.
Looks like it hit a pole head on from the pictures.
No more Airbag light once those codes were cleared.

The only remaining issue is not being able to lock the doors.

I'll do some google searching and see what turns up on that issue.

May have to visit the dealer or indy with a piwis system to reset or enable something in the security system.

Every thing else works normal.

The one thing that bothers me is WHY my computer died?

Just a coincidence or did something short out in the process of replacing my AOS which was the beginning of all my trouble.