JFP in PA

Thks a lot again, AhsaiResultsVdrop airfilter bolt to engine case= 0.9-1.2vVdrop engine case to chassis side ground strap =1.5-1.6vVdrop chassis side ground strap to battery -VR terminal = 0.01vVdrop chassis side #1 to battery -be terminal = 0vJumper from battery -ve term to airfilter bolt did not see any improvement perhaps the jumper lead is thinner than 8 gauge.New discovery about #36, the engine side bolt is loose because I can wiggle the ground strap around but sadly I couldn't reach the bolt to tighten it. The wires inside the ground strap appears to be brown and in rusty colour. Are the wires supposed to be silver in colour inside the ground strap?Should I bring the car in to my Indy and him to replace #36 the r hind ground strap? Will this fix the low voltage problem for a while? Meanwhile I will order the #28 fix as well.

It sounds like the ground strap is not only loose, but is showing signs of corrosion. Time for a new one, being sure to clean off the contact point where it bolts on as well.

I wouldn't be worried if it were the pads only, I was talking about disks and pads.

The Porsche OEM rotors (Brembo or Zimmerman) are pretty good units, but as mentioned can wear much faster with harder compound pads. People have tried just about everything out there (cryro treated rotors, dimpled or grooved rather than cross drilled, etc.) but I have not really seen a major advantage of one type over the other from a wear rate consideration.

Here's a view of the ground strap with the engine remove. I think JFP is talking about this one...(correct me if I'm wrong). The frame attachment can be seen above the right turbo and the other end is beside the fuel regulator just under the air pump. I think it is possible to reach and to facilitate the job you should lower the engine about 4 inches .... Lowering the engine is easy especially if you got access to a floor jack. See attachment....

I did not read all your post on Rennlist and 6speed but have you check the power consumption at rest which is suppose to be .6 amps maximum ?

Secondary air pump removal can be seen in the repair manual page 641.

That is the one, always fun to get at.

Hi JFP,

Thank you for your reply again. Do you think my problem now sounds like the chassis ground strap? Can I go ahead and replace it with two 4 guage cables and try if it solves the problem before ordering one from the factory?

Is there anywhere that I can add more chassis ground strap to the engine and chassis? Will it bring any benefit to the seemingly small stock chassis ground strap?

As mentioned earlier, even Porsche recognized the ground straps and other cables were problematic, they are common weak point on these cars. Replacing a questionable cable is always a good idea, they cause no end of issues (codes, strange MIL lights with no basis, poor hot starts, diming lights, weird audio issues, etc.). We have found that just replacing the questionable cables is sufficient to putting an end to the problems; we have also never had to add any extra cables.

honestly i do not have the slightest idea of where to even start reading this. Which oxygen sensor needs to be replaced. There are 4 right? 2 in front and 2 in back?

OK, let's go from the basics: Bank 1 is the passenger's side of the car. 97-99 2.5L engines did not have pre cats, only the three way unit (the bigger one to the rear of the system). So ignoring the fact that the right hand system in the diagram shows a pre cat (item #2), the forward O2 sensor would be located where item #35 is in the pipe. Requires a 22MM wrench or O2 sensor socket to remove.

Hi JFP,

Thanks a lot for your informative reply :)

I think I might have made a big mistake in my original post. The resistance across all those no. 1, 4, 24, 28, 17 and 19 should be 0.07 Ohms, not 0.7 Ohms. It is because before I started the 4 tests that I conducted, I measured the resistance of my newly bought three-meter-long 4 gauge cable and the resistance was the same as all those in the car, almost close to none. I know it would have been better to have measured each cable end disconnected, but I simply do not have the skills and knowledge to take each of them out. But, however, I did disconnect no.1 (battery -ve lead) and no.24 (alternator to starter lead) to measure resistance on their own and the results were the same as those measured connected.

My main point is that with the engine running at idle with full load (a/c on, all lights on), I did still see the full 14.0v when I measured from the back of the alternator to -ve alternator case, engine case, transmission case and fuel filter case whether the engine was hot or cold. The only time I saw 12.0-12.8v was when I measured the back of the alternator to the car's chassis, such as the airfilter bolt, the actually chassis, the cross member under the car and the silver door latch, all only showed 12.0-12.8v. I think I located the engine to chassis ground, no. 36, and the reason why I did not have any measurement for that was because my hands and tools could not reach it even with the wheel off and car on jack stand. But, I could see about 1/3 of that cable's plastic shield had been sliced open for some unknown reason. Does this sound like a bad engine to chassis ground to you?

Moreover, my car starts every time and the engine turns quickly every time.

Could you advise if no. 36, the engine to chassis ground is the one shown in the attachment? If so, how can I get to the top of engine bolt of that ground cable from under the car? Or, can I only approach it from the top without lowering the engine? I am a DIYer with limited tools at home and at where I live, there is no shop that will bench test my new and old alternators.

Thank you very much for your help again.

James

#36 is a chassis ground strap, which unfortunately is not accessible from underneath the car. To get at it from above requires pulling some components from the engine, such as part of the intake system.

The manager at an Autozone told me the Duralast AGM was basically the same as the Optima... haven't had time to validate that, YMMV. Maybe he was just talking about the glass mat portion.

They are not the same; Optima has a patent on the spiral wound cell design (AKA the "six pack" shape), which is the core of its claims for superior vibration resistance and longer life expectancy.

Having spent hours of research and jacking the car up and down, I will call this my last report because I've had enough of test car and that’s it if I still cant get it fixed by next week. Last night, I carried out the final voltage and resistance tests with cold & hot engine using the multimeter based on the 996tt electrical diagram attached. Let me list out the possible problems with my low voltage symptom. 1. 85A battery (new) 2. Bosch alternator 997-603-012-06 TIP (new) 3. regulator & alternator pulley (new, comes with item 2) 4. alternator to starter hardness 996 607 03 204 (no.28 ) Test 1 5. engine ground strap 996 607 034 01(no.36) Test 2 6. –ve battery lead 997 611-090 00 (no.1) Test 4 7. +ve battery lead 996 612 090 09 (no.4) Test 4 7. long cable from starter to ECU 996 612 044 00 (no.19) 8. engine terminal to transmission terminal 996 607 033 02 (no.24) So I focused on testing on no.24, 28, 36, 1 and 4. Not, 19 because I cant actually see it. According to the diagram, I assumed no.29 = +ve engine terminal and no.25 = transmission terminal. Test 1 (to prove alternator to starter hardness no.28 is OK even with the engine HOT) With the car hot or cold, battery +ve & -ve unhooked Resistance @ 200 Ohm setting +ve engine terminal (no.29) to +ve transmission terminal (no.25) = 0.7 Ohm +ve engine terminal (no.29) to +ve battery lead (no.4) = 0.7 Ohm +ve transmission terminal (no.25) to +ve battery lead (no.4) =0.7 Ohm -ve airfilter bolt to –ve battery terminal lead (no.1) = 0.7 Ohm -ve airfilter bolt to –ve chassis /door latch= 0.7 Ohm -ve airfilter bolt to –ve Hydraulicoil body/engine/gearbox/alternator case = 0.7 Ohm –ve Hydraulicoil oil body/engine/gearbox/alternator case to –ve chassis = 0.7 Ohm Voltage +ve directly from alternator (I fitted an independent lead from the alternator) -ve Hydraulicoil oil body / engine / gearbox / alternator case =14.0v (hot/cold) +ve directly from alternator -ve airfilter bolt / chassis / door lock =12.2v (hot) or 12.8v (cold) +ve transmission terminal -ve engine / gearbox / alternator case =14.0v (hot/cold) +ve transmission terminal -ve airfilter bolt / chassis / door lock =12.2v (hot) or 12.8v (cold) Results 1. Voltage always 14.0v if –ve are measured from engine/gearbox/fuel filter casings. Voltage always 12.2-12.8v if –ve are measured from chassis (airfilter bolt/door latch/chassis metal). 2. But, resistance of no.28 is the same hot or cold, it seems to be in good order. No.28 seems to be fine and the problem seems to be on the chassis ground. So, I conducted Test 2. Test 2 (to test engine ground cable, no.36) Hooked up 2 thick truck-grade jump leads from engine case (-ve) to chassis (ground) and door latch (ground) = nothing happened to all voltage measurements (same as unhooked) Cold measurements, idling At battery 12.9v (cold) On dash voltmeter 12.9v +ve engine terminal to airfilter bolt 13.2v +ve directly from altern. to altern. case / Hydraulicoil oil tank body / fuel filter 14.0v Hot measurements, with aircon and headlights on: batt multimeter 12.1v (hot) dash voltmeter 12.1v engine terminal 12.4v alternator terminal 13.9v Results Adding extra engine to ground leads did not do anything or helped the stock engine ground cable. So, no.38 is in good order, too. Test 3 (to test no.17 & 19) COLD voltage +ve alternator terminal to airfilter bolt (chassis ground) = 13.2v +ve batt to –ve batt = 12.9v HOT voltage +ve alternator terminal to airfilter bolt (chassis ground) = 12.4v +ve batt to –ve batt = 12.1v Results No.17 & 19 are using or losing 0.3v because there is always a 0.3v difference between the back of the engine to the front of the car. I can say theses 2 long cables are in good order because how far voltage has to travel here. Test 4 (to test no.1 & 4, hot and cold engine) Took them off the car, measured resistance before cleaning them and they never got hot even after 30 mins of driving. Always 0.6 Ohm Results No. 1 & 4 are in good order. It seems to me all the cables are in good order. Who can help me to solve this my low voltage problem? a million thanks

James

Interesting testing sequence; that said, your alternator voltage looks too low at times, which is indicative of a weak voltage regulator or diodes. I would pull the alternator and have it load tested at either an alternator repair shop, or a parts outlet that do these tests for free, if for no other reason than to eliminate it.

You also have cable issues based upon your measurement of 0.7 ohms (this test should have been run with the cable ends disconnected so you are only looking at the cables), the cable resistance is also too high, which is a very common phenomenon on these cars (if memory serves, Porsche released a TSB on the subject as well as updated parts). Cable resistance should be much lower:

The resistance, R, of a length of wire is described by the expression:

• [*]R = ρL/A

where

• [*]ρ = resistivity of the material composing the wire,L = length of the wire, andA = area of the conducting cross section of the wire.

On that basis, a new "0" AWG battery cable would have a measured resistance level of 0.09 ohms over a length of 1000 feet, you are seeing 0.7 ohms across a couple of feet.

Is there any aftermarket alternative brake sets for our cars that last longer? I have just paid for a full set that set me back 1400... Fronts lasted 30000km and rears 20000km. Every time I have had to change brake pads, I ended up changing disks also.Perhaps I should try to drive in a more conservative way, but what would the point be?Do Brembos last longer?

Two things to consider about switching to pads with longer life expectancy: First, they tend to be much noisier than the OEM style pads due to the harder pad compound, Second, longer wearing pads tend to be harder on the rotors and wear them faster.

Except for track use, we tend to stay away from harder pad compounds as they tend to lead to more customer complaints on the street.

OK Thanks, i found the workshop manual 996 ,the engine does not interfere with the upper screws ?

Which "screws" are you referring to, the torque convert to flex plate bolts?

Pulling the Tiptronic out of the Boxster today to ship off and have it rebuilt and it is ready to drop except the the selector cable does not want to detach from the linkage at the tip. It pulls off around the cable eyelet correct?

Should pop off; sometimes it needs some encouragement with a trim tool that is shaped like a "Y".

I am removing the tip from a 2000 Boxster right now using the Bentley Manual and it has been great until the point of unbolting from engine and it is not clear on removing the selector cable from the tiptronic. Also, I think the TC gets pushed into the transmission after unbolting from Flywheel and it does do not call this step out.

Be sure to secure the converter to the trans while removing it (bit of wire between the converter and a bell housing bolt hole will do the trick) lest it come off the trans while tilting the gearbox. If you drop and dent one of these things, it is toast.....

Hey guys this is my first post but this forum has been great help with working on my porsche. It is a 99' 986 boxster with 63k miles that i bought toward the end of last year. Thanks to this forum i have resolved issues with replaced the radiator cap, cleaning out throttle body and icv( replacing new gaskets and seals for them as well). New air filter, fuel filter, MAF( although i had to reorder from pelican because they send a faulty one). But for my two pressing issues atm.

i have a idling issue that i have mostly resovled due to cleaing the icv and throttle body but it still stalls occasionally on idling when i turn on the a/c. I am hoping that the new MAF will fix the problem when it comes in( i have tried cleaning it already with the MAF cleaner and it helped slightly but not much) other than that i dont know what else could be bothering the idle.

I bought the durametric scanner because i saw many of you highly recommend it and i do not have a CEL anymore but the only code that is coming up is

"P0134 O2 sensor ahead of cat bank 2"

. i have tried looking through forums for a definite answer to how to fix this or even locate but i have not found anything so it would be a great help. I do not have inspection or regisration tags and am trying to get them but will it pass inspection with the 02 sensor code coming up? any and all info is appreciated. Thanks guys

P0134 is for a lack of activity on that sensor, either a dead sensor or a harness issue. I seriously doubt the car will pass inspection with that code. This should help with location:

Thanks! Which cat is considered "bank 1"? I got a check engine light P0420, swapped the O2's side to side, and the same code came back, so it's got to be the cat.

The best way to determine if a cat is toast is by looking at the O2 sensor voltages before and after the cat, if the sensor voltage after the cat remains fairly constant while the voltage for the sensor before the cat swings back and forth, the cat is good. If the voltage for the sensor after the cat follows the pattern for the sensor before it, the cat is gone:

Thanks for responding, JFP.

Other than PCM thing, which I don't understand (I'd like to), the write-up seems to be exactly in line with the possible fault causes you listed, so I'm not sure why you said "so much for"..

Why do you say it's an air leak or poor fuel delivery necessarily, as opposed to a bad MAF sensor? Do MAF sensors rarely fail on Boxsters? Or would it likely throw another code on top of the P0171/P0174 (too lean on both banks) codes?

In what order would you tackle testing out the possible fault causes?

Should I test the fuel pressure and clean the MAF sensor first, since those are relatively easy for me to do at home for low/no cost? Then if that doesn't work, take it to a mechanic to pay for a smoke test, since I don't know if I'd be able to find an air leak at home? And finally as a last resort, buy and replace the MAF sensor? I'm hoping it's not the injectors, but I guess if all the other tests/fixes failed at that point, I'd have to have them checked. I will of course check the oil filler cap seal first.

Any further elaboration is appreciated.

Thanks!

PCM is "Porsche Communications Managament" system, or the nav, stereo, and cell phone, hence why I don't think it is involved.

Your MAF really is not doing much until 3,500-4,000RPM, so it is rarely involved in these codes. While MAF's can and do fail, most people do not know how to correctly test them before doing so, and they are often changed without testing them first.

What you need to be doing is getting the car scanned with a Porsche specific system (PIWIS, PST II, Durametric) all of which can see the MAF and other sensor values in real time, quickly eliminating those functioning correctly from contention. You would need a proper fuel pressure test tool to check the volume delivery and pressure as well.

As for backyard checks, look over the connections, hoses, oil filler cap, AOS system, etc. looking for signs of a leak point. You would be surprised at how often these problems come down to a small hose that fell off its connection, or one that has rubbed a small hole in itself.

Well, so much for "generic write-ups"; these two codes are indicative of the car running overly lean on both banks. It is not O2 sensor related, and it is rarely MAF related; and what connection it could possibly have to the PCM software totally eludes me, but more likely it is because of an air leak into the intake system or poor fuel delivery (volume and/or pressure).

Possible fault causes:- Incorrect signal from MAF sensor- Intake air system leaking- Fuel pressure too low- Volume supply of fuel pump too low- Fuel injectors fouled- PCV valve leaks- Cap of oil filler neck not closed correctly or seal is damagedLooks like you have an air leak...

After trying all sorts of things to figure out why my battery wont re charge all that well (I put a new voltage regulator in the alternator, and had it bench tested) checked all connections , did voltage checks etc ??? Anyhow, one member here suggested although the battery tested ok as well, it just could be a tired weak battery. Therefore I'm going to get a Optima one with at least 900 CCA/ cranking amps, perhaps 1000 would be better ? Anyone know the model/part # that would fit , and is recommended ? I sure hope this helps, as with lights and a/c running it barley gets over 13.2 volts at 3000 rpm, and I would like to see a steady 13.8 at least. I hope a new Optima will cure all the trouble I've had with this issue ? Any suggestions, on them, CCA , and one that fits ? Thanks Brit Dave.

Did you test and/or replace the cables for the battery as you were advised to do in another post? If they are bad, which is common on the 996, no battery (even a higher CCA unit) is going to make the situation better.

That said, a 34R Optima will fit.

Hi:

Got a BK fire extinguisher mount for my 996. I know that bracket holds a 2.5 lbs. bottle but does anyone here knows what's the biggest bottle I can attach to the 996 BK bracket?

Thanks.

2 1/2 Lb.

Probably 65-75% of boost related issues come down to leaks in the pressurized intake system, usually hoses or hose clamps. I'd start there.

Hey All,I got rear-ended this evening by a hippy girl with no insurance. We were going around 15-20 mph, the guy in front of me put his brakes on, and she hit me from behind.Anyway, the only visible consequences of this encounter are that my left bumperette came loose at the top (the tabs popped off the ring but did not break), there's a small circular mark on the right bumperette (very minor), and a bit of her paint on my exhaust tips.So....I'm wondering how I should handle this. No plastic cracked, no paint chipped, etc.--is there any possibility that anything serious happened that isn't visible (bent frame, etc. etc.). Should I have the car checked out?Is popping that bumperette back on something I can do myself, or would I be better off taking it into the dealership?Am I better off not to report this at all, since it's so minor and I'd end up paying a deductible since she was uninsured?Anything here I'm not thinking of?Thanks for your advice!

Take the car to a proper repair shop that specializes in Porsches, get it looked at and estimated. Regardless of the other driver's insurance situation, you want the car returned to "like new condition"; if she won't/can't pay for it, have your insurance cover it and let them sue her to recover. It should not become your problem.

Is the pill receiver unique to the ECU like the alarm module or are they all the same for similar models?

OK, the way the system works is that the car is programmed to accept the key, so each key has a uniquely coded pill, which cannot be reprogramed. The receiver in the dash will "listen" to any key that comes within range, and relays the code information to the alarm module. The alarm system has code "slots" (four if memory serves) that may or may not be reprogrammable, so if they are all used, you may be in the market for a brand new module (read $). To do the alarm system programing, you will need access to a PST II or PIWIS system, the car's IPAS codes, and usually paper work to prove you own the car.

As they disconnected the battery, it sounds like the windows limits need to be reset. From the factory manual (should also be in your owner's manual), to reset the limit position of the windows the procedure is lower the window completely.Then with the window completely down, press and hold the rocker switch to raise the window and once the window is all the way up release the switch. Then press the switch's raise position again (the "front half") to store the limit position in the control module.Repeat for the other window.

porsche also calls it alarm sensor or signal trandsucer.

The alarm module is under the seat. The key pill receiver is near the ignition switch in the dash.

Where is the signal amplifier located on this model. 2000 boxster type s?

thanks.

What "signal amplifier" are you referring to?

Starter would not turn , and im getting code p1570 code 39.

P1570 meanwhile is the code for an implausible operating range on the immobilizer. Possible causes: Wiring break between the DME and alarm system, short circuit, or faulty alarm module.