Will not start after repair

Tiny
MATT OELTJEN
  • MEMBER
  • 2008 MERCEDES BENZ R350
  • 3.5L
  • V6
  • 4WD
  • AUTOMATIC
  • 144,000 MILES
I removed the intake to repair the door flaps, everything went smooth. But now it tries to start but just wont quite get there. I have fuel pressure and spark. Ran before I did the work.
Sunday, April 12th, 2020 AT 9:15 AM

7 Replies

Tiny
BMDOUBLE
  • MECHANIC
  • 1,139 POSTS
I'm sure you have done it, but the first thing that I do is check all of the connectors because this engine as well as most modern engines, will have several electrical connectors that can easily be either forgotten or not fully engaged. Also the intake gaskets can fall off during install (see picture), some technicians will tie strap the intake gasket to the intake before installation, or use spray tack before attaching the gasket to the intake.
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Sunday, April 12th, 2020 AT 11:15 AM
Tiny
MATT OELTJEN
  • MEMBER
  • 4 POSTS
I used 3m spray tac to hold the gaskets. I agree it should be a plug, I have gone over them multiple times. I got it to run for about a second. It's not throwing any codes either. I would be looking at timing, but it ran before I did the work. The car had very little power, that's why I was repairing the manifold. But it did start every time with no problem. Have a listen in the attachment.
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Sunday, April 12th, 2020 AT 11:37 AM
Tiny
DANNY L
  • MECHANIC
  • 5,648 POSTS
Hello, I'm Danny.

Just to add my 2 cents have you checked to see if you're still getting accurate fuel pressure after the repair? Sounds like might starving for fuel. Hope this helps and thanks again for using 2CarPros.
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Sunday, April 12th, 2020 AT 7:23 PM
Tiny
BMDOUBLE
  • MECHANIC
  • 1,139 POSTS
Have you tried to see if it will start up with brake clean or carburetor cleaner? If not then that's what I would try! If it starts then I would check that fuel pressure and also get a fuel sample to see if it contaminated.
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Monday, April 13th, 2020 AT 10:17 AM
Tiny
MATT OELTJEN
  • MEMBER
  • 4 POSTS
Thanks everyone, I'm a weekend warrior so lets see what next weekend brings.
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Tuesday, April 14th, 2020 AT 12:42 PM
Tiny
MATT OELTJEN
  • MEMBER
  • 4 POSTS
I have 52 Psi at the rail, With a fully charged battery it turned over enough to stop the auto start and ran on it's own for about 1 second. Tried starting fluid and was worse. Could have been because the battery was drained down a little. Only thing that is weird to me is there is no fuel pressure until you turn the key to start. Still no codes. No way I missed a plug. Only thing I can think to do is remove the manifold again. Timing makes sense but it ran before I did the work.
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Friday, April 17th, 2020 AT 6:14 PM
Tiny
BMDOUBLE
  • MECHANIC
  • 1,139 POSTS
I've attached an operation description of the fuel pump circuit so you can get a clear understanding on how the circuit works. I agree that the next logical step would be to remove the intake, at least that's what I would do.
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Saturday, April 18th, 2020 AT 2:20 PM

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