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05' 955 CTT Intermittent Engine power loss while driving, no start


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Need some help...

 

I have a new to me 05 CTT, with 110k on the clock.  Was driving home last night and after a full throttle run from the light, over the next couple of miles started intermittently losing engine power and regaining it like it was being switched on and off like a light switch then subsequently dying completely.  Electrical power still on, engine still running at 2k during power loss, and basically as if the throttle pedal was inoperative.  It was very abrupt, dropping from 4-5k rpms, immediately to 2-2.5k rpms, then reengaging on power again as if a switch had been flipped on and off.  It would last 2-5 seconds each time, and over the next 2 miles became more frequent until the engine finally died completely, stranding me on the side of the road.  Initially, it acted as if it might turn over again with a chug here and there, but then it would only crank with no start.

 

No CEL at any point.

 

Towed home, let it cool overnight.  Tried cranking again, and it would only turn over, not fire. 

 

Pulled Fuse 13, no start.  Replaced 13, pulled 14, no start.  Replaced.  Note that just last week I replaced both fuel pumps, the FPR, and the Filter (flange).  

 

Plenty of fuel in the tank.

 

Hooked up the durametric, and the only codes were as follows:

P0513 Incorrect Mobilizer Key, Implausable signal, test conditions are not-completed, fault is not currently active and is not causing a DTC Light

P0130 O2 Sensor Circuit Bank 1 Sensor 1 - Implausable signal, test conditions are not-completed, fault is currently active and is not causing a DTC Light

P0150 O2 Sensor Circuit Bank 2 Sensor 1 - Implausable signal, test conditions are not-completed, fault is currently active and is not causing a DTC Light

 

Need some help on thoughts... again, no CEL, no faults on MAF or CPS, or throttle position sensor... which would have been my initial thoughts.  Have not opened up to look at MAF or done any testing on CPS yet...looking for where to start based on probable scenarios...

 

Thanks!! 

 

Edited by PCarMa
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After the repairs, it was running fine for 500+ miles after the repairs without issue, and these O2 sensor messages were not present at the time I did the repair so I put that on lower probability but could check... Also, not seeing faults on the fuel pump as I would see if no power to pumps, etc.

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49 minutes ago, PCarMa said:

Need some help...

 

I have a new to me 05 CTT, with 110k on the clock.  Was driving home last night and after a full throttle run from the light, over the next couple of miles started intermittently losing engine power and regaining it like it was being switched on and off like a light switch then subsequently dying completely.  Electrical power still on, engine still running at 2k during power loss, and basically as if the throttle pedal was inoperative.  It was very abrupt, dropping from 4-5k rpms, immediately to 2-2.5k rpms, then reengaging on power again as if a switch had been flipped on and off.  It would last 2-5 seconds each time, and over the next 2 miles became more frequent until the engine finally died completely, stranding me on the side of the road.  Initially, it acted as if it might turn over again with a chug here and there, but then it would only crank with no start.

 

No CEL at any point.

 

Towed home, let it cool overnight.  Tried cranking again, and it would only turn over, not fire. 

 

Pulled Fuse 13, no start.  Replaced 13, pulled 14, no start.  Replaced.  Note that just last week I replaced both fuel pumps, the FPR, and the Filter (flange).  

 

Plenty of fuel in the tank.

 

Hooked up the durametric, and the only codes were as follows:

P0513 Incorrect Mobilizer Key, Implausable signal, test conditions are not-completed, fault is not currently active and is not causing a DTC Light

P0130 O2 Sensor Circuit Bank 1 Sensor 1 - Implausable signal, test conditions are not-completed, fault is currently active and is not causing a DTC Light

P0150 O2 Sensor Circuit Bank 2 Sensor 1 - Implausable signal, test conditions are not-completed, fault is currently active and is not causing a DTC Light

 

Need some help on thoughts... again, no CEL, no faults on MAF or CPS, or throttle position sensor... which would have been my initial thoughts.  Have not opened up to look at MAF or done any testing on CPS yet...looking for where to start based on probable scenarios...

 

Thanks!! 

 

This is very weird! I just had my 06 ctt towed home due to a stall at the lights and it wouldn't restart. It was like I ran out of fuel cranking but just wouldnt start. Lucky a Tow truck was right next to me as I backed up the traffic which all gave me the horn lol. Towed home just 10 mins away. I jumped in to back it off the flat bed and I thought I bet it starts now, and the son of b*tch did! And no codes and no sign it ever stopped working. Ffs this is the worse breakdown type, as who knows when it will happen again? 

I have a also done some weeks back replaced both pumps and a longer while before that the regulator and further back the filter. At least 4000km since filter and regulator. Also fuel pumps don't find any issues with the old ones. At least 1500km since both pumps changed. 

 

No codes is a joke!!!

Edited by lewisweller
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3 hours ago, wizard said:

Intermittent fuel delivery related to the most recent work carried out?

 

Wizard, you have earned your moniker...

 

Update:  Went back and re-ran Durametric.  Found another code that was fuel level sensor... I am now hypothesizing that the lines that supply the fuel pump were not routed properly by yours truly, and was preventing the float from returning to...zero.  When my instrument panel told me I had 145 miles and the fuel gauge red 1/2 tank, that is/was due to the float being restricted from settling down past 1/2 tank.  Thus, my assumption was incorrect that I had plenty of fuel in the tank...I am out of f**king gas. 

 

Put in 1 gallon, cranked, started.   

 

So, looks like I still need some O2 sensors...and a full tank of gas.  And just FYI, the symptoms above as I described would be 100% in alignment with one running out of gas, no?  Good news is that the tank is now empty as it should be to open up the tank for line re-routing...and @lewisweller, it would have thrown a code saying 'low fuel' if I hadn't botched the line routing. ;) 

 

Ugh. Embarrassing.

Edited by PCarMa
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I got one new coil to replace a melted one which I found a few weeks ago, will swap that real quick and go to fuel station and fill up. I remember after changing the right pump I filled up and it only said just over 3/4 full. After that when I filled up it was full everytime and I dismissed it. Maybe the float was stuck but I'm thinking how does the right side float getting stuck stall the car . Then later it runs fine? 

Cycling the ignition will run both pumps and the car will start briefly on both pumps (hot start is 15 seconds) then it reverts to the left pump unless there is less than 15litres in the tank and both pumps run continously. So this doesn't make sense! 

 

I'm going to pull the left side fuse and check if the right side pump is running. And then the right side fuse.

 

Which brand pumps did you buy? I used vdo.  

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Well it isn't out of fuel. The fuel light just came on and both pumps are running. Removed fuse for left pump and it kept running on right pump. Engine changed pitch and running slightly when removing fuse and replacing fuse.

 

Swapped melted coil cylinder 2 and can't tell any difference. Checked for codes again and also looked at lambda sensors and fuel trims. Only thing I see is the bank 2 lambda sensor is not producing as high amperage when snap throttle test is done. I had this issue with bank 1 sensor a few months back and replaced the sensor, so now it seem bank 2 is also had enough and getting lazy. I did order 2 sensors before but the ebay supplier lied saying they had stock but only was able to supply 1. 

 

So I'm at a loss why the car stalled and wouldn't restart yesterday! Very frustrating and now scared to drive somewhere and get stuck. 

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9 hours ago, lewisweller said:

Which brand pumps did you buy? I used vdo.  

 

Yes, I used VDO as well. Was the 2nd round...I bought some that were cheaper off of a 3rd party seller on Amazon, and one of them had a cracked case, so sent those back.  Couldn't find any brand markings on them...sent both back and rebought VDO on Partsgeek for ~$248/ea.  Cheaper than Pelican by a bit. 

 

My lesson learned in this was - don't trust the gauge alone.  If you are showing 3/4 of a tank when full, the float is likely getting stuck on the fuel lines in the tank...did some research and it is a common thing after replacing the pumps.  It is hard to get the fuel lines properly positioned in that tight space and blindly when re-installing the FPR and Filter flanges.   I would not think that the fuel gauge float sticking would cause a stall by itself.  

 

I would look at things that are a) not in redundancy (fuel pumps, sensor banks, etc.) but rather are single points of failure, and b) not electronic (since no codes thrown)... 

 

Fuel, spark, air, timing....  My gut (not science) tells me 'no codes' reduces the likelyhood of issue being spark and timing, probably not an air issue, so I'd look at fuel to start.  The thing that is strange is that you got it to restart... maybe fuel resettled / drained back down from the fuel rail / etc. after the tow allowing you to get it started? 

    

 

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12 hours ago, PCarMa said:

 

Yes, I used VDO as well. Was the 2nd round...I bought some that were cheaper off of a 3rd party seller on Amazon, and one of them had a cracked case, so sent those back.  Couldn't find any brand markings on them...sent both back and rebought VDO on Partsgeek for ~$248/ea.  Cheaper than Pelican by a bit. 

 

My lesson learned in this was - don't trust the gauge alone.  If you are showing 3/4 of a tank when full, the float is likely getting stuck on the fuel lines in the tank...did some research and it is a common thing after replacing the pumps.  It is hard to get the fuel lines properly positioned in that tight space and blindly when re-installing the FPR and Filter flanges.   I would not think that the fuel gauge float sticking would cause a stall by itself.  

 

I would look at things that are a) not in redundancy (fuel pumps, sensor banks, etc.) but rather are single points of failure, and b) not electronic (since no codes thrown)... 

 

Fuel, spark, air, timing....  My gut (not science) tells me 'no codes' reduces the likelyhood of issue being spark and timing, probably not an air issue, so I'd look at fuel to start.  The thing that is strange is that you got it to restart... maybe fuel resettled / drained back down from the fuel rail / etc. after the tow allowing you to get it started? 

    

 

Yeah my gut instinct when it happened was fuel is either run out or pump is dead. 

This could be a few possibilities then: 

1. The fuel pump relay for the the left pump failed (intermittently) if this was the case then cycling the ignition would have run right pump and engine would have run.  

2. The left fuel pump got hot or failed temporally again right side pump should have ran after cycling the ignition, unless the dme didn't see the failed pump as an actual issue and therefore would not know to switch the right pump on. This is more probable! 

3. Low fuel is ruled out and considering the left pump sucking jet pulls fuel from the right side of the tank, one side going empty is not likely. 

4. Totally un-fuel related issue of which I have no idea where to start? 

Edited by lewisweller
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Took car out for first time since break down, car started up lumpy and not sounding that good. After a few minutes it sorted it self out and ran ok to fuel station. I filled up to full but the fuel gauge said between 3/4 and full so I know I have some pipe in the way of the sensor on one of the sides. Need to check this when fuel is down a bit later in the week. I'm trying to imagine how this could cause a stall and no start and then later work fine with the fuel light not even coming on yet. Maybe it drained one side only and ran out. Then on flat bed it sorted itself out!? Strange. 

New coils for remains 7 cylinders also on the list to do as I now believe the newish coils got damaged when the head gaskets blew and car got overheated for many km whilst trying to pin point why. 

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Today I Took out the regulator to look for the reason why the tank level won't show full when it is full. 

It seems the right float level could have hit a pipe (return fuel from sucking jet on left side) but can't be sure. I adjusted it and refixed everything. With 1/4 tank I wouldn't know if this was the Fix until I refilled. 

I started the car and it started fine. Thought I best test each pump individually. Left pump was fine. But the right pump would idle but spluttered and coughed and back fires when trying to rev. Something was not right. 

 

I thought I best remove the right pump and put in the old one thinking the pump maybe at fault unless something else popped up like a broken pipe etc. 

When tearing back into it again, I needed to remove the filter to unplug the pipe from the right pump. I then notice the rightside suckjet return pipe which picks up fuel from the right side and dumps it into the left pipe casing was kinked! I repositions and locked in the pump anti clockwise some degrees and all looked to be good plus it was looking possible that pipe could have interfered with the left side fuel float as well when coming near full. 

Going back to the recently new right side pump I pulled it out and measured resistance and it was same as old pump 0.4ohms. I then rechecked the piping connections and realised one pipe (small pipe from right pump for the sucking jet over on the left side) I didn't disconnect it which means it was already disconnected I think it blew off at some point because the right pump did run on its own when new I tested it! 

So I used the recently new right pump and refitted it after finding this obvious problem. 

 

The car runs the same with the right pump only now just fine. But sadly no smoking gun for the stutter hesitation.

The kinked pipe return on the left side pump from the right side sucking jet was the reason I'm pretty sure it stalled and would not restart last week. My explanation is the left side tank was empty and the fuel wasn't being sucked from the right side of the tank to replenish it, (despite a small amount from the fuel pressure regulator return pipe coming back to the left pump it wasn't enough) being 1/4 tank or just under the right side pump wasn't yet called in for operation by the dme. When on the tow truck either the fuel sloshed around to balance the fuel from the right side over to the left or the angle the flat bed was sat at prior to unloading me when I decided to try and start the engine again was allowing the fuel level sensor floats to tell the dme the tank was nearly empty and then both pump would run and as if by magic it starts. 

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Fuel level issue was simply the pipe of the left pump was resting on top of the sensor pinning it down to the bottom of the tank. Repositioned it. 

Fuel gauge now reads correct. 

Fuel tank was full as I wanted to see the floats position as it is in the faulty condition. 

I will be happy to never have to get inside those tanks again. I stink of fuel and hands are sore. 

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17 hours ago, PCarMa said:

Glad you got this sorted lewisweller!  Those pipes are very tough to get positioned when it is largely a blind fit.  I second the notion that I will not miss getting inside the fuel tanks after 2x in...

Ha ha .....have to laugh. Day after car stank of fuel in the morning, so bad I got a headache on short drive to meeting. 

Opened the left side cover and see the fuel filter is having a puddle of fuel in it. I'm thinking how the f*ck the fuel got in there and the filter isn't cracked or leaking. 

Opened the filter and see the rubber gasket is partly hanging inside the tank and partly around the tank neck hole. I'm amazed how the fuel managed to to get up and around the lip into the cupped filter and didn't go anywhere else! Ta Da, Magical Porsche this one.  

Fannied around with it and got it to stay in place, f * king pos , it seem these rubber gaskets even new are too big to nicely fit the aperture. 

Anyhow no more leaks and no more smells. Smiley face with rolling eyes. 

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