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Emergency. My 04CTT sputters and dies after I start it. Now wtf do I d

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Started the vehicle this AM around 10 to leave and the idle starts dropping right away but slowly while in park. Drops really low, then picks back up. Does this a few times while I'm going OH****. Put er in Drive and the idle drops again. It dies. I start it right back up and if I gave it gas same drop then dead. I'm going to test the other fuel pump with fuse on primary pulled.


Last week we had humming coming from the fuel pump but it went away. While driving last day or so idle seemed rough.


I'll be looking for the tech writeup on the fuel pump tests.

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Pulled fuse 14 and turned the car off. Restarted and engine ran great. Drove it to the mechanic. Should I order two fuel pumps or just the primary, and is that L or R? If one goes can the secondary be far behind?

I know I should replace the seals and the fuel filter/flange. What else?


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  • 2 weeks later...

Pulled fuse for pump#2 to de pressurize system, and replaced both pumps , pressure regulator and filter flanges and gaskets L&R. Lost pump one fuse so car started fine on pump two. Had maybe an inch of gas on left side of tank and practically a beach in the bottom, wish I could have siphoned that crap out. Went and bought 5 gallons of gas and added that to the freshly sealed system. Later went and bought fuses to replace missing #1 pump fuse. Started car and kinda had to floor it to get the RPMs up, the system flowing and full of gas again, I guess. Parked and locked, keyless entry was acting up and had to manually lock the car. Got up next AM to fill tank and grab a coffee before starting on wife's X5 brake job. Car starts perfectly,perfect acceleration, smooth and vastly improved experience. Reach station and fill it up. I start the car and it sputters and dies exactly as before the pump replacement. Several attempts and zilch. Gas gauge only reads 7/8 full despite purchasing a full tank. I end up pulling the #1 pump fuse AGAIN and car idles rough running on pump two. I then notice that #1 pump fuse has popped! Super weird. I'm pretty sure the instrument cluster display started acting funny and I had a CEL in orange illuminated. Nevertheless it starts on pump two and I head to grab an espresso, then go home.

At this point I'm really unclear what the F happened. EVERYTHING is brand new. Why is that fuse popping and the #1 pump dying? I'm back to square one. What should I do?

Edited by ALEV8
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Disconnect the pump 1 electrical connection from the pump, replace the pump 1 fuse, start her up a few times and see if the fuse blows again with #1 pump disconnected.

That should give us a clue to what's going on.

Edited by bigbuzuki
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I'll add that the driver-side electrical connection at the flange/pressure regulator I broke the tab off trying to remove it but it securely fits on the plug it's just not locked on with the click tab.

And now that I think about it the fuse might've been a 10 amp and when I replaced it with a 15 amp it's stopped blowing, but the behavior remains of pump one sputters and croaks after a short idle as if I had replaced nothing.

Changed my oil today.

Edited by ALEV8
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when I changed the pumps on mine  it would die after warm up


or randomly sputter and die   no codes


they replaced both mafs no issues so far


see if you can swap maf with other cayenne for testing or


or at least read the maf input ( also other sensors input)


Good luck.

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MAFs for fuel pump etc issues??? Educate me please, thank you.

Actually it really does follow. If your CTT is 10 years old it would be a good idea to clean the throttle body and the MAFS. The MAF sensors  do effect fuel metering in your CTT.



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I will clean them. Does anyone have a DIY on that? I'll check the download section.

I picked up the car from my mechanic today who did not have time to work on it, but he says the starter needs a new cable, and that we dumped another quantity of oil out of the tube behind the driver side intercooler, and this is evidence of needing a turbo replacement or rebuild. Strangely enough the car starts perfectly so I don't know what he's talking about nor have I heard of anyone replacing the starter cable, and the last time the oil accumulated behind that inter cooler in the elbow back in 2011, and we dumped it there was no turbo issue. I feel like this is a car I want to keep and have not heard of turbo issues at all in these cars.

Leakdown test shows fuel pressure is not maintained after shutoff. Immediately drops (should be steady for 10 min).

Just thought I would toss that in there, and make things even more fun.

I'm going to drain the gas tank and double check ALL the connections first.

Then.... figure out why Sonnen sent me a 90 black degree adapter for one of the new style pumps that I didn't need as well as a weird really narrow straw on a flexible line coming from the fuel filter flange which had a fitting sort of like a skirt around it, but didn't snap into anything, although the pass side fuel pump did have a hole to accept it, and that's where i installed it.

WEIRD. Guys weigh in if ya can.

Edited by ALEV8
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1-if you replaced both pumps no need to use the adapter


take all the hoses and tubes and test for leaks outside of the tank 


replace both flanges (regulators ) on top since your there.


2-the oil leak could be something simple (oil lines) maybe  .


3- what's wrong with the starter first to say the cable needs replacing  .




be patient

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Yeah super weird guys. EVERYTHING is new. Both pumps and flanges. WHY is there not perfect starting? It's just as before the pumps were replaced. I'm running the tank almost empty to investigate again. Is running the tank dry just about, a problem when everything gets buttoned back up....like should I have primed the pump on the driver's side somehow? There was a bit of gas in the passenger side and almost none at all on the driver side. The other weird paranoia I have is somehow parts are incorrect. The new style pumps are different to be sure....I don't know where he is getting the starter cable issue or turbo blow-by collecting in that elbow other than it's 8 hours of labor to replace the starter. Minus one fuel pump it's a tad harder to start the car some times. I have not read about ANY turbos going on any forums in our cars. Anyone?

Edited by ALEV8
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When I saw him scan the car all I saw was a vacuum leak fault. When the CTT died the very first time AFTER replacing everything (the following day when refueling) I got a CEL. Pulled fuse on pump 1 to start it and get to mechanic. If I tried to start with pump 1 then it would die and CEL.

Now, the starting is balky using pump 2. Car will start and then sputters and dies, then second attempt car will start, and idle slowly picks up and continues running.

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connect all fuses and check the {pumps relays fuse box close to brake master cylinder} check all wiring

run both pumps .


is fuel pressure reading is steady at idle ? 


also is it steady at for example 2000 rpm ?


test Thorley to rule out fuel related issues then


post any new fault codes here

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OK I will double check electrical connections at flange of course and test the relay for continuity. My mech has fuel pressure gauges and the scanner so I can visit him tomorrow.

Edited by ALEV8
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