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Car wouldn't start engine


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Hi everyone

This is my first post as I normally find support ot resolve previous issues in the existing discussions

 

However I have a 1997 2.5 boxster manual  After replacing the coil packs the following day the car wouldn't start engine was cranking but wouldn't start, after jumping with a second car the car started instantly. During cranking the check light was flashing and a relay clicking in dashboard.

Next day again only started with a jump then would start off it's own battery but then would only crank after approx ten start tests.

We then refitted original coil packs but this made no difference. 

During the replacement my son removed relay one as per YouTube clip. 

I have checked and switched relays by alternating them around.

New battery fitted no differance

Used the car a few times requiring jump or bump start to get it going

But now the car won't start with a jump (haven't tried Bump again yet)

Further reading suggested CPS issues and with no movement on the tacho during cranking the sensor was removed and inspected no obvious issues A new one was ordered and fitted but the car still only cranks over and wont start and no movement on the tacho during cranking.

Checked relay 1 and 7 and both are activating on ignition key turn.

So any thought would be appreciated as to next possible fault and test that I can perform before I book it into local independent Porsche garage.

I do have auto com but cant get any info as it disconnects at each key turn.

Don't have Durametric system.

Many thanks in advance

Angus

 

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21 minutes ago, Angus M said:

Hi everyone

This is my first post as I normally find support ot resolve previous issues in the existing discussions

 

However I have a 1997 2.5 boxster manual  After replacing the coil packs the following day the car wouldn't start engine was cranking but wouldn't start, after jumping with a second car the car started instantly. During cranking the check light was flashing and a relay clicking in dashboard.

Next day again only started with a jump then would start off it's own battery but then would only crank after approx ten start tests.

We then refitted original coil packs but this made no difference. 

During the replacement my son removed relay one as per YouTube clip. 

I have checked and switched relays by alternating them around.

New battery fitted no differance

Used the car a few times requiring jump or bump start to get it going

But now the car won't start with a jump (haven't tried Bump again yet)

Further reading suggested CPS issues and with no movement on the tacho during cranking the sensor was removed and inspected no obvious issues A new one was ordered and fitted but the car still only cranks over and wont start and no movement on the tacho during cranking.

Checked relay 1 and 7 and both are activating on ignition key turn.

So any thought would be appreciated as to next possible fault and test that I can perform before I book it into local independent Porsche garage.

I do have auto com but cant get any info as it disconnects at each key turn.

Don't have Durametric system.

Many thanks in advance

Angus

 

 

Welcome to RennTech :welcomeani:

 

Your problems sound electrical; battery or battery cable related.  Check your primary battery cables for voltage drop, you should not see more than 0.5VDC drop across any primary cable.  If yours are higher, you need to replace them.

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1 minute ago, rogerjohnsen said:

This sounds so familiar to a problem I had a few years back. Turned out to be the starter but it happened on my Ferrari - not Porsche. It would only start with a jump. Looking at the voltage / electrical makes sense to me. 

 

That would be my next stop after checking the cables.  High cable resistance due to internal corrosion is common on these cars, which is why I would start there.........

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Update

Have inspected grounds that I can see  main to engine is good underlay seat all good cant see the coil pack grounds need to get the car up to see them  

Cleaned battery terminals but these where in good order. 

Tested voltage at relay 1 in boot during cranking this is under 11volts seamed low to me 

Car still not start but cranks strongly for multiple attempts  

After testing this we did give the car a tow and first pop of the clutch and engine started. Gave it a run and all seamed normal with stable idle, turn off and try to restart just cranks away but not start. Again tested on an incline and short rool and pop the clutch engine started instantly.

I'm thinking of temp positive lead direct to starter but access is not easy but as suggested it could be the issue may even try with second battery direct to starter.

May just book in to garage for a second opinion and check a window closed position fault I cant get to the bottom of.

Thanks for the suggestions and will keep you posted.

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  • 2 weeks later...

Update on starting issue

Local independent has advised the ECU has a fault  and I am looking for a replacement  can anyone confirm if a 99661860102 be replaced with a 99661860101 ECU the garage advised they can re code etc   struggling to find a ##02 @ sensible cost .

Thanks for any input 

Regards Angus

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1 hour ago, Angus M said:

Update on starting issue

Local independent has advised the ECU has a fault  and I am looking for a replacement  can anyone confirm if a 99661860102 be replaced with a 99661860101 ECU the garage advised they can re code etc   struggling to find a ##02 @ sensible cost .

Thanks for any input 

Regards Angus

 

You still need to run a proper voltage drop across the primary battery cables.  This should be done before you do anything else as too high a voltage drop will cause all sorts of problems that can easily be misconstrued as something way more expensive, like replacing the DME.

 

Going from the DME ending in 102 to one ending in 101 is going backwards, the 102 unit is the one that superseded the 101.  Porsche does not do this unless there was a problem with the older style unit.  Even the 102 has been superseded twice, the current model is the DX, which retails here for a touch over $5K.

 

As these DME's do not fail very often, you really need to make sure you need to do this.

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21 hours ago, JFP in PA said:

 

You still need to run a proper voltage drop across the primary battery cables.  This should be done before you do anything else as too high a voltage drop will cause all sorts of problems that can easily be misconstrued as something way more expensive, like replacing the DME.

 

Going from the DME ending in 102 to one ending in 101 is going backwards, the 102 unit is the one that superseded the 101.  Porsche does not do this unless there was a problem with the older style unit.  Even the 102 has been superseded twice, the current model is the DX, which retails here for a touch over $5K.

 

As these DME's do not fail very often, you really need to make sure you need to do this.

Thanks for your input  I'm of a similar mind to you but I did check voltage at the DME relay during cranking and it was 11.4 volts  looking at the wiring the main cable to the splitter block uk behind ac in passenger footwell all in good order infact all cabling is intact and grounds etc are all clean. The garage advised that the ecu is not registering the CPS during cranking (new sensor fitted) I did ask them to check wiring around this and the coil packs incase something had been disturbed during replacement after which this issue started  but they advised all is well there too. I have found a company that test and repair ecu so I'm awaiting info they advise a test inspection is £40 with a full refurb at £160  so think that will be an option to test first.  I know manufactures tweak thinks and add new numbers but I think the Bosch part number on the units are the same suggesting the change is in the software that was why I inquired as to flashing my map onto the 01 unit .

Cant  spend crazy money  I would be better breaking the car selling the parts  and buying a newer model 

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1 hour ago, Angus M said:

Thanks for your input  I'm of a similar mind to you but I did check voltage at the DME relay during cranking and it was 11.4 volts  looking at the wiring the main cable to the splitter block uk behind ac in passenger footwell all in good order infact all cabling is intact and grounds etc are all clean. The garage advised that the ecu is not registering the CPS during cranking (new sensor fitted) I did ask them to check wiring around this and the coil packs incase something had been disturbed during replacement after which this issue started  but they advised all is well there too. I have found a company that test and repair ecu so I'm awaiting info they advise a test inspection is £40 with a full refurb at £160  so think that will be an option to test first.  I know manufactures tweak thinks and add new numbers but I think the Bosch part number on the units are the same suggesting the change is in the software that was why I inquired as to flashing my map onto the 01 unit .

Cant  spend crazy money  I would be better breaking the car selling the parts  and buying a newer model 

 

Visual inspection of the.primary cables is fine, but it does not tell you what is going INSIDE the cables, where a slight increase in resistance can result in significant voltage drops, which screws up just about everything, including how the DME functions.  If your DME was expecting 12.0 volts or better and only gets 11.4, it is already outside the acceptable voltage drop range.  If that is the actual case, there may be nothing wrong with the DME, other than it does not see the correct voltage...........

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21 hours ago, JFP in PA said:

 

Visual inspection of the.primary cables is fine, but it does not tell you what is going INSIDE the cables, where a slight increase in resistance can result in significant voltage drops, which screws up just about everything, including how the DME functions.  If your DME was expecting 12.0 volts or better and only gets 11.4, it is already outside the acceptable voltage drop range.  If that is the actual case, there may be nothing wrong with the DME, other than it does not see the correct voltage...........

Was going to get them to test with a stand alone supply to the DME relay and see what happened

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  • 3 weeks later...

Hi anyone that's interested 

I finally got my 1997 986 fixed the issue was infact a fault in the ECU with the communication module power supply failure.

This was identified by ECU Doctor and was refurbished at a reasonable cost of £250. The garage advised I had installed incorrect coilpacks I fitted Beru zs178 coils.

 

Anyway ecu returned and fitted new coils changed for different ones and the car is back up and running had a nice weekend away with it even if the weather was grey.

 

Thanks to all who took time to comment 

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