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No Boost - No leaks, No codes

8 posts in this topic

Hi fellow Smart Fixers
Here is the deal. A few weeks ago my Smart (160k) starts making a high pitch whistling sound. Like a boost leak. I think - It sounds like the Intercooler has sprung a leak. I had repaired the holes in the old IC with JB Weld. The car works well but makes this crazy whistle sound.
Bonus! I find an intact (not holed) intercooler on Kijiji. On the weekend I switch out the IC. Everything looks hunky dory. I have power in the beginning but the whistle is still there. A few days later and all at once- no power.  The motor won't rev past 3k
So I figure...
1. the hose from the EGR to the turbo  - It happened to me before so I reinstall the pipe. - Same deal
2. EGR is stuck - I remove and check it. I had put a blocker plate last year - Nope slides perfectly
3. intake pressure sensor mounted near the dipstick - Nope
4. intake pressure sensor mounted on the intercooler - Nope in tight.
5. limp home mode. - disconnect the battery for 10 minutes - Still no power
6. leaky waste gate pressure hose (the short one that goes from the turbo high side barb to the actuator head) - Looks good
7. Struck waste gate - Lubed and loosen but seemed OK. I lengthened the arm to see if it was not sitting well - Nope
8, Crappy new IC - I changed out the IC and put back the old one which was OK BTW. Checked all the hoses and fittings. - Same crap.
This leaves me with
9. bad turbo - I was wondering if it wasn't the whistling sound wasn't it giving up the ghost before I lost power
What do you guys think? Are there any checks I missed? Anyone have one kicking around? Should I get it rebuilt? It's kind of a pricey part to change out just to see if that's it.


Ideas?  Thanks - I'm in Montreal.

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2 hours ago, Jocko said:
bad turbo - I was wondering if it wasn't the whistling sound wasn't it giving up the ghost before I lost power


Take off the intake tube and the muffler

check to see if the impeller wheel and the compressor wheel  turn freely, and are actually still connected


but !!

2 hours ago, Jocko said:
The motor won't rev past 3k


that says that the motor is in electronic 'safe' mode

The ECU is limiting fuel and boost to limit the RPM's

Will still boost to about 160, rather than 225


A bad turbo will still let the engine rev past 3000, no problem. Gutless, but rev's OK


Whistling, means boost escaping... turbo working at least a little

Is your upper intake pressure hose 'worn thru' from chafing of the abrasive shielding laying on top of it ?


Back to the electronics.

No engine light ? no Codes ? No reader ?



Edited by cadillacman

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Yeah I was kinda thinking along your train of though and was thinking electrical. I seem to have seen this in a thread somewhere before but its the usual suspects - the EGR valve or the waste gate.

Even with a holed IC it still revved to 4k so it's not an boost leak. Maybe a sensor somewhere that I'm unaware of? I can hear the turbo spin and I get good acceleration up until it starts to build boost or 3k which ever comes first which made me think it was a boost leak and why I changed out the IC again but now I would rule it out.


The car ran fine. I got out of the car to run a errand (20 min) got back in and started driving - no boost. Usually you restart the car and the boost comes back but not this time. Its out for good.


I have a scanner but it didn't throw a code. No CEL. Nada! It just won't rev, Even with no load. in neutral - floored I only get 3k.

Sounds like safe mode but I did the disconnect the battery thing and nothing changed.


Another weird thing happened the other day but it may be unrelated.  I'm still driving the car but using the paddles because it won't rev high enough to shift in automatic. I usually leave it in auto.  All at once the actuator gets all fuddled and I get the 3 bars of death. First time in this car. So I don't panic (much) and I shut off the car, wait 10 secs and restart. Transmission is OK.


Alright that's weird! Almost like it didn't have enough electrical power. I'm going to look at the actuator tomorrow but would a battery on it's way out cause this type of problem? I'll check the alternator too while I'm at it.


It's almost like the fuel pump isn't getting enough power or creating enough pressure. I rewired the fuel pump directly to the power via a fuse in the fuse box rather than do the relay when the pin went out on the SAM this winter. Could the fuel pump be starved by a bad fuel filter? The air filter is really dirty but I did the same test with the filter removed and still 3k.


I checked the ground wires and they're OK. I could throw the battery on the charger but its summer and the car is used regularly so I doubt its the battery.


Thanks for the input, I'm gonna keep looking why it won't rev.  It sounds and feels like limp home mode or safe mode

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So I got back under the car today.

I undid the intake to the turbo to check the impeller and for piece of mind. Started the car and the turbo sucks air no problem and sounds good. = It's NOT the turbo.


Took off the actuator only to find it's a sealed unit. I open the boot to clean and check as much as I could. Sprayed some white grease as Tolsen recommends and buttoned it back up. The connector is intact and clean. The transmission wires ditto. I'm anal about loose wires so I tend to tie wrap everything so it's tight and doesn't rub or chafe. These motors shake a lot and wreck havoc on the wires and hoses if they rub.


So lets forget the turbo, IC, the hoses, the actuator. I checked them all twice

Lets call this is a case of limp home/ safe mode with no codes.


WTF am I supposed to do with that?


Please don't tell me to go to MB! Anything but that! They're such losers. They can't even do a proper brake job, forget diagnose something like this.

I'll bet money that I go there and they tell me it's the turbo and charge me $3k? This is of course after I just checked it and it works fine. Any takers?

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Peace of mind would be better than piece of mind....


Too bad your dealers aren't trustworthy - on Vancouver Island they are excellent, if a tad pricy.

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2 hours ago, Jocko said:

Lets call this is a case of limp home/ safe mode with no codes.


One of the few things that can do that is actually the EGR.

Might do it a few times till it finally spits a code.


I would suggest sourcing an EGR-emulator and seeing the diff.

A lot cheaper than the $tealership, and you'll never have to clean the EGR again.


Or finding a new/used EGR.

Or, know a friend with a smart? Swap the EGR actuator and see it clears up.

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OK so what I need now is a list of things that can make the car go limp home/safe mode but won't necessarily throw a code.


The Waste gate will do this sometimes but I checked it and it moves freely and it's manual.


The EGR may do it. - I'm tempted to unplug the clip and provoke a code to see if by clearing it I can get it back to normal. The piston moves free and the solenoid looks OK. I had put a block plate a while back so it's oily but not crusty.


I did notice a bit of oil in the IC and the intake hoses but would a blocked rebreather valve cause a limp home?


I'm going to pull off the wheel and check the alternator. It squeeks a bit but who knows at this point so may a well check that.


Can anyone think of anything else?


Thanks for the support.

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on my 454, i have that whistle sound too, however i got jumped one time when i had overused battery on radio and it went away:huh:. Generally i have a problem i haven't gotten around to understanding. the car shows an engine light the occasionally wont start. if its in a incline too it wont start i have to being it to a flat to get it to start. after moving around in town doing bills it can also also just shut down while moving only to start up in limp home/safe mode. wait 5 to 10 minutes it starts up like it didn't just stop in the middle or a high way. i had it hooked to a scanner but nothing came up even with the engine light showing:huh:

i believe it might be the fuel pressure, but on reading your post seems you cleared that, my aproach however was to actually do a replacement of the pump than rewiring 

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