hard starting issues on 09 GTS, fuel or spark?

[DAS_V8]

First time post... hope to start contributing to the forum now!

 

09 GTS with 93k and excellent maintenance history, recently getting long cranking times and sometimes rough idle at startup.  Starter is working properly so we can rule that out - not sure what to tackle first, coils?  fuel pumps?  HPFP?

 

Durametric codes:

1023 Ignition Coil D Primary/Secondary circuit - upper limit value exceeded

 

1026 Fuel high pressure implausible - value below lower limit value

 

The 1023 keeps coming back when cleared but never throws a CEL, the 1026 has been very intermittent but will throw a CEL.

 

I swapped coils 3 and 4 (assuming D is coil 4 and coil 4 is rear-passenger side of engine?) and still get the 1023 code for "D" but no misfire codes.

 

I tried pulling fuses 13 and 14, independently, and truck starts on both fuel pumps (with long crank).

 

Logged with Durametric the fuel setpoint vs. actual pressure and I get 40bar at idle and it seems to keep up OK while driving up to 120bar at WOT.

 

Plugs were changed at 80k but I believe to be on original coils and fuel pumps.

 

So before I start throwing parts at this, any advice on what to troubleshoot next?  Still fairly new to the Durametric so anythink I'm missing there with respect to data logging?

 

Cheers,

 

Eric

[JFP in PA]

 

As you are not getting a plug misfire code (P0304) for the number 4 plug, I think you have an electrical issue either with the connector or wiring on that cylinder as the code is saying it is getting an implausible signal from that location.

[DAS_V8]

 

As you are not getting a plug misfire code (P0304) for the number 4 plug, I think you have an electrical issue either with the connector or wiring on that cylinder as the code is saying it is getting an implausible signal from that location.

 

Also a thought I had, I can check voltage and ground easily at the connector, but going back to the root of the problem... based on the firing order, coil 4 shouldn't cause such a hard start issue since its nearly the end of the firing cycle right?  Which leads me to thinking its a fuel issue as well.  Fuel pumps can start to go "on the fritz" and still somewhat function even by testing with the fuse method to isolate them right?

 

Truck has been rock solid before this issue, just trying to keep from throwing money/parts at it.

[JFP in PA]

 

 

As you are not getting a plug misfire code (P0304) for the number 4 plug, I think you have an electrical issue either with the connector or wiring on that cylinder as the code is saying it is getting an implausible signal from that location.

 

Also a thought I had, I can check voltage and ground easily at the connector, but going back to the root of the problem... based on the firing order, coil 4 shouldn't cause such a hard start issue since its nearly the end of the firing cycle right?  Which leads me to thinking its a fuel issue as well.  Fuel pumps can start to go "on the fritz" and still somewhat function even by testing with the fuse method to isolate them right?

 

Truck has been rock solid before this issue, just trying to keep from throwing money/parts at it.

 

 

I thought you had already checked out the fuel system pressures and said they were OK?

[DAS_V8]

 

 

 

I thought you had already checked out the fuel system pressures and said they were OK?

 

 

I checked the low pressure side operation (fuse 13/14 method) and it seemed ok, and high pressure pump seems to be doing its job.  Ran another Durametric scan and logged fuel setpoint vs. high pressure value vs. pressure at rail vs. nominal fuel flow rate and the pressure is good at idle (40bar) and seems to hold up to WOT delivery at 120bar but does taper off at times.  Flow rate is all over the place and doesn't show a direct correlation with higher setpoint.  I'm thinking the problem lies on the low pressure side (maybe fuel regulator?).  Going to just do both pumps, filter, regulator and see if that fixes it. 

 

Then onto the electrical coil issue....

 

Happy 4th! 

[GTS08]

What happened?  Update?

[Nedlands]

Did you find a fix for this? I have the same issues on my 2009 GTS. Dealer changed battery claiming that is the issue but still facing problems

[lewisweller]

I reckon the regulator and or filter blocked was the problem and as the thread went dead he fixed it.

Long crank is sometimes because the regulator doesn't hold the fuel pressure in the line and it's required to build up again before starting. Plus the car had sat for 6 months so crud in tank and stuck faulty regulator does seem to point in the same direction. 

[Nedlands]

6 hours ago, lewisweller said:

I reckon the regulator and or filter blocked was the problem and as the thread went dead he fixed it.

Long crank is sometimes because the regulator doesn't hold the fuel pressure in the line and it's required to build up again before starting. Plus the car had sat for 6 months so crud in tank and stuck faulty regulator does seem to point in the same direction. 

Thanks.

the dealer told me that the regulator should be ok and that the filter is a lifetime part! I guess there's no harm in doing these as they are relatively cheap.

[turbonator5000]

i had a dying battery that was causing a lot of hard start issues and codes.. found out the hard way when finally had to jump my car.

[Nedlands]

On ‎12‎/‎12‎/‎2016 at 0:27 AM, turbonator5000 said:

i had a dying battery that was causing a lot of hard start issues and codes.. found out the hard way when finally had to jump my car.

Just spent way too much on a new battery from Porsche. The starting is slightly better but still too variable for my liking and getting the 1023 code.

Looking at DME set point vs Actual for the HPFP looks OK but I think the regulator might be funky as pressure seems to be a little erratic under load. Tank pumps are giving 5 bar so they look OK

[lewisweller]

13 hours ago, Nedlands said:

Just spent way too much on a new battery from Porsche. The starting is slightly better but still too variable for my liking and getting the 1023 code.

Looking at DME set point vs Actual for the HPFP looks OK but I think the regulator might be funky as pressure seems to be a little erratic under load. Tank pumps are giving 5 bar so they look OK

P1023, I'm assuming you taken each coil out and had a really good look for cracks melted parts, socket with spring and contact for plug all good? These coils are reknowed for being how shall we say........Absolute sh*te. Swap D location coil to the other bank and see it the code moves. 

 

Some member drive around with spares! 

 

I would fix this problem and it might very well fix the hard start too. 

 

Edited December 13, 2016 by lewisweller

[Nedlands]

Coils were new around 9 months ago. Starting is very variable. Some days good, some days bad. I'm going to do the for and filter and work from there. Moving coils is the ne t plan but I get a feeling it won't move with it 

Dealer senior tech thinks hpfp dieing... It's an expensive swap tropics exercise....