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Cranking Not Starting?

MPSIII
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MPSIII Member

MPSIII

Posted
Posted

Hello,

 

So my car started, as soon as the AC kicked on the revs dropped (which it ordinarily does), except this time the revs dropped until it stalled.   I tried to start it again, and it will crank continuously without starting.  There seems to be no shortage of battery power, just no firing for some reason.  After it happened first, I waited a few hours, tried again, waited a few more hours, and tried again, still with the same result.  No decrease in the ability to crank, so it doesn't seem to be a battery problem.   The only other thing I can think of is it had just gotten rained on in the parking lot, could something have shorted out?

 

Thanks for the help, I've tried some searches but haven't found anything yet.

MPSIII Member

MPSIII

Posted
  • Author
Posted

No, haven't looked at fuses yet.  This of course happens while I'm working overnights for 2 weeks, and as soon as I'm off I want to go straight to bed.... I'll check those if I get a free moment.  Are they fuel pump/system fuses?  

  • 11 months later...
Lakeview3 Member

Lakeview3

Posted
Posted

Related to this topic I am searching for some answers to a non starting car also..... It is a 2000 996 Cab. I bought the car with the motor out after it had returned from Motor Meister.... I bought a running salvage car and had the motor swapped in. The car won't start. I have checked all related fuses, check ok. Changed the fuel pump relay from the running car, no start still. Checking the fuel pump cannot get voltage to any terminal on the fuel pump plug with the key on. Should their be voltage at the plug without cranking the motor??? Trying to rule out the fuel pump before needlessly changing it out. Any help in direction would be greatly appreciated. 

Thanks in advance. Let me also know if I should start a new thread, not real proficient here. 

  • Moderators
JFP in PA Member

JFP in PA

Posted
  • Moderators
Posted

Related to this topic I am searching for some answers to a non starting car also..... It is a 2000 996 Cab. I bought the car with the motor out after it had returned from Motor Meister.... I bought a running salvage car and had the motor swapped in. The car won't start. I have checked all related fuses, check ok. Changed the fuel pump relay from the running car, no start still. Checking the fuel pump cannot get voltage to any terminal on the fuel pump plug with the key on. Should their be voltage at the plug without cranking the motor??? Trying to rule out the fuel pump before needlessly changing it out. Any help in direction would be greatly appreciated. 

Thanks in advance. Let me also know if I should start a new thread, not real proficient here. 

 

There should only be voltage at the pump is the car's DME and immobilizer have "shaken hands", which it sounds like is not happening.  As Motor Meister where well known butchers, they could have done just about anything to the car.

 

As a first step, I would get the car towed to a shop with either a PST II or PIWIS system and have the electronics checked to make sure they are communicating, without which you are going no where.

Lakeview3 Member

Lakeview3

Posted
Posted

First, thanks for the reply. 

I don't think MM butchered anything up, it was all unplugged. I did buy a 99 model car/motor and changed out the intake and throttle body due to being cable versus electronic. Also used the wiring harness that came with the car. 

 

During my hours of searching I discovered two possibilities that I have not investigated. The DME relay in the back of the car,  and I think I read something about the crank sensor being bad will not let the fuel pump come on. It could be unplugged, damaged in the change out, etc............

 

Is PST II the newest version of Porsche diagnostics??? Took the place of PIWIS? I have an OTC Genysis with european software, but I haven't tried it to see if it will read something like that. Would that DURAMETRIC? reader tell that? I need to buy something since I have several cars I'm working on....

 

Thanks.

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JFP in PA Member

JFP in PA

Posted
  • Moderators
Posted

First, thanks for the reply. 

I don't think MM butchered anything up, it was all unplugged. I did buy a 99 model car/motor and changed out the intake and throttle body due to being cable versus electronic. Also used the wiring harness that came with the car. 

 

During my hours of searching I discovered two possibilities that I have not investigated. The DME relay in the back of the car,  and I think I read something about the crank sensor being bad will not let the fuel pump come on. It could be unplugged, damaged in the change out, etc............

 

Is PST II the newest version of Porsche diagnostics??? Took the place of PIWIS? I have an OTC Genysis with european software, but I haven't tried it to see if it will read something like that. Would that DURAMETRIC? reader tell that? I need to buy something since I have several cars I'm working on....

 

Thanks.

 

MM could have switched the DME or immobilizers between cars, which would leave the car unable to start. 

 

The crank position sensor would shut down the fuel pump if it were bad or disconnected.

 

PST II was Porsche's diagnostic system when the car was built, it was replaced by the PIWIS and then the PIWIS II, the most current version.  I do not believe the tool you have would be of help in this, and I know the Durametric (which cannot do the type of coding required to match the immobilizer and DME) won't be of much help either.  You need the Porsche tool, of which the current version is lease only at around $20K for the first year.

Ahsai Member

Ahsai

Posted
Posted

I'm a bit confused what's the car/engine/DME/egas combo you have now. Can you clarify a bit?

 

Engine in question is a '99 so throttle cabled but the car itself came with egas and egas DME?

 

Did you checked fuses C1 to C4 and E1? Does the tach needle bounce a bit when you crank. The fact that your car cranks means the immobilizer is closing the start lock relay so that should rule out immobilizer issue. Agree that the crank position sensor and DME relay are suspects. Maybe you can check if all the sensors are plugged in.

tac27 Member

tac27

Posted
Posted (edited)

Odd coincidence, I'm experiencing a similar issue.

 

On the drive home from work on Monday the car ran fine, no issues.  When I went to start up this morning, it will crank but will not start.  

 

I hooked up the Durametric and found there were no codes.  When  I ran the 'Short test all modules' under the 'Function' tab it did its thing and returned these values. 

 

21

W lead (DME Immobilizer)

 

49

K lead

 

60

Control locking limit position lock not reached

 

54

Radio receiver defective

 

33

Interior sensor faulty

 

18

Pressure sensor lumbar open circuit

 

I have been looking through both the Bentley book and this site, but I'm having difficulty finding these numbers listed.

 

Could any of these, especially the DME immobilizer, cause the problem?

 

Thank you,

Tim

 

Post edit:  I searched all of the terms, both singularly and as a whole (i.e. "21" and "21 W Lead DME Immobilizer)" and didn't get any returns either in the 996 forum or under the DIY OB II fault text code for my car/DME/engine.  I did find a post by 'Dahrn55' posted on June 7, 2009 (I would post a link to it but I don't know how) that he talked about the same issue with Loren.  They discovered that it was a faulty crank shaft position sensor.  Dahrn55 had additional P codes that led Loren to believe it was the sensor which I am not getting when I run the Durametric scan.  I would prefer not 'throwing parts at it' until it starts working again, so any advice would be appreciated.  

Edited by tac27
  • Admin
Loren Member

Loren

Posted
  • Admin
Posted

When it won't start you need to run a DME only test.

Then report back all fault codes (also please specify whether they are P-codes or Porsche DTC codes - as there is some numbering overlap).

Lakeview3 Member

Lakeview3

Posted
Posted

Thanks for the input. Now just have to make time for more diagnostics. 

 

Ahsai- Yes the donor motor was a cable throttle body. Intake, throttle body and wiring harness were change from the original car. I hired out the swap since I don't have a lift. The shop said the engine would run on starting fluid. They suggested it needed a fuel pump. Since I have my own rollback, I told them I would take over from there. I have checked all the fuses and changed the fuel pump relay with no luck. Have to make time to check that everything is plugged in or didn't get damaged in change. Haven't noticed tach needle bounce. Its a convertible so I have to figure out how to get to the DME relay. I do have the Bentley book and skimmed that section.......

 

What is the opinion here of the "knock off" version of the PIWIS???

  • Moderators
JFP in PA Member

JFP in PA

Posted
  • Moderators
Posted

What is the opinion here of the "knock off" version of the PIWIS???

 

Not very good.  Many of them are actually old and out of date Durametric systems that are no longer supported, the rest are a total unknown, and there have been reports of some of them actually causing problems.

Ahsai Member

Ahsai

Posted
Posted

Lakeview, so the car is a 2001 cab c4 (e-gas) and you put a '99 cable throttled donar engine in it and reused the engine wiring harness from the c4 on the donar engine?

Does the starter spin at all when you crank? To test the fuel pump, you can just unplug the electrical connector on it and apply 12v to the correct pins (with the correct polarity) and see if it runs. If you can disconnect the fuel line (e.g., from the fuel filter) or tap into the fuel rail, you can even measure pressure and flow.

Lakeview3 Member

Lakeview3

Posted
Posted

No, the car is a 2000 996 Cabriolet, not a C4. And, I used the donor motor from a 1999 996 Coupe, also not a C4. 

 

Yes the starter spins and the motor turns over, just not starting. 

 

I have checked for 12V at the pump connector and had none. I have not tried putting 12V to the fuel pump yet. 

 

One other thing I forgot to mention is the shop did not put any coolant in the car. Would that have any affect on it not starting? Some sensor no sending a signal that the coolant was low????

Ahsai Member

Ahsai

Posted
Posted

Ok, I guess what's not clear to me is you mentioned e-gas and I wonder if your car is e-gas.

 

You can remove one of the spark plugs to check for sparks. Normally the DME may or may not power the fuel pump when you turn the key to the accessories position. Even if it turns on the fuel pump, it will last only a few seconds. So if you measure the plug after this window, there will be no power and that's normal. I think it's better just to hot wire the pump and see if it works.

 

If there's spark, you can pretty much eliminate any sensor issues and can focus more on fuel delivery or lack thereof.

Ahsai Member

Ahsai

Posted
Posted

 

All 996 normally aspirated models are e-gas with one exception the the 1999 C2.

 

Great point.

 

Thanks for pointing that out. That clears my confusion.

 

Lakeview, in that case you may want to do an e-gas calibration and see if that helps. Just leave the key to accessories position for one minute, then turn key to OFF. You should hear high pitch noise and the throttle plate calibrating itself. 

Lakeview3 Member

Lakeview3

Posted
Posted

Hello,

 

So my car started, as soon as the AC kicked on the revs dropped (which it ordinarily does), except this time the revs dropped until it stalled.   I tried to start it again, and it will crank continuously without starting.  There seems to be no shortage of battery power, just no firing for some reason.  After it happened first, I waited a few hours, tried again, waited a few more hours, and tried again, still with the same result.  No decrease in the ability to crank, so it doesn't seem to be a battery problem.   The only other thing I can think of is it had just gotten rained on in the parking lot, could something have shorted out?

 

Thanks for the help, I've tried some searches but haven't found anything yet.

Sorry MPSIII..........Didn't mean to hijack your thread!

 

Did you get your car started?

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