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Injector return leak test, Bad injector?

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Old Sep 11, 2018 | 09:36 PM
  #1  
Anthony Porta's Avatar
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Ml350
Injector return leak test, Bad injector?

So I have been having an issue with no MIL/CEL, but reduced power and during long periods of coasting (think colorado) when I go back to the throttle I get white smoke out the exhaust. Other than that, no smoke.

I removed the injector return line and ran the vehicle for 30 seconds. Every injector returned about the same fuel except the cylinder in the passenger side rear. That was about double the fullness of the others.

Thoughts? Things I should check in the Driveline CAN?

Im leaning to replacing that injector.




Left side

Right side
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Old Sep 12, 2018 | 08:36 AM
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2012 e350 bluetec
Interesting. I had a similar experience. My wife and I were on vacation in CO and were coming down Pikes Peak. I was using low gears all the the way down as you're supposed to stay off the brakes. About a third of the way down I got a smoke screen of white smoke coming from the tailpipe. I drove it a couple hundred yards until I could pull over, The car behind me must have thought my car was on fire or something. No check engine or CEL light on.

I shut the car off for a few minutes after checking around and seeing that the smoke was only coming from the tailpipe and started it up again. The smoke stopped and I proceeded down the mountain without any further issues. I went directly to the dealer in Colorado Springs. They said they have seen the same problem before on occasion. They said it probably was a regen that started while coming down the mountain at closed throttle.

The car was fine by then so I proceeded on and have never had the problem again. Maybe it was a combination of altitude, regen timing, and a long period of closed throttle that did it.
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Old Sep 12, 2018 | 10:04 AM
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Similar anecdote:
Driving across the country last summer, I had my daughter driving the Benz. She's a bit more conservative than I with the go pedal, and we swapped seats after a few hundred miles of easy interstate (75mph) driving. I hit the on ramp and just before the merge, floored it. The car jumped forward like I like, but looking in the rear view mirror to make sure the BMW was well behind showed the grey smokescreen I had left behind. Oops... Sorry BMW (well, sort of anyway). Subsequent 100% power yielded less and less of a cloud of smoke, until there was nothing. I'm thinking crud builds up in the intake? EGR? somewhere and a full throttle turbo push blows it all back out the tailpipe. Haven't worried about it.

The point? Flog it every now and then. Drive happy.

There is no throttle. Just the addition of fuel.
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Old Sep 12, 2018 | 12:10 PM
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Well
1) It cant be a regen
2) I was towing for 12 hours straight, so any loose crud would have come loose
3) There is still power loss ( I need 1 lower gear entirely towing over vail pass)
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Old Sep 13, 2018 | 01:50 PM
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New injector ordered. Ill post up another leak test after I install it.
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Old Sep 14, 2018 | 02:53 PM
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Ok, So indeed that injector was an issue. Full power has returned (a reminder that there was no cel)

After getting the engine hot, it was really easy to take out and a cork is a nice plug while cleaning.

After replacing the injector I repeated the test, The far injector was 3" the middle 3.25" and the front was now 4".

This is a cheap test $2 bucks in hose, that is worth doing when you are changing air filters or fuel filters. To remove the return lines just pull up on the round clips.



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Old Sep 14, 2018 | 07:57 PM
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From: In the Shadow of the Tetons
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Thanks for the followup! Good to know you have the issue resolved.
How much did you get dinged for the injector? Did you get a new or a reman'd one?
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Old Sep 18, 2018 | 10:50 AM
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I was able to find the injector for $323 online with a 49.00 core, but I got hooked up elsewhere.
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Old Jul 13, 2019 | 07:44 AM
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Did you have to do adaptations to program the new injector in? Was there any pooling on top of the motor? Had you viewed any live data of correction factors on each injector?
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Old Jul 13, 2019 | 04:57 PM
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Originally Posted by TGcville
Did you have to do adaptations to program the new injector in? Was there any pooling on top of the motor? Had you viewed any live data of correction factors on each injector?

No, it adapted over time.

No, i replaced the orings on top of the injectors. Everything else doesnt have a seal

I have.
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