Smart Is Sluggish, Barely Goes Over 100km/h, Intercooling Fan Always On

[pinhead19 0]

'sensible regulation' - I'd agree with this term. I do not miss the foolish sound of the fan running 105% of the time the car is running in the summer. Well Bob, did you have a look at the hose between the EGR and the INTAKE manifold?

[bilgladstone 13]

Agreed: very important the scoop is fitted and whole.

[MikeT 744]

Yup, all are good!

[scwmcan 0]

That is my next step, put in the fan this spring, I'm not driving it a lot right now ( and don't know when I will be again, need to get a new job first) but will be getting a new scoop etc as soon as I can afford it. These two items from what I can tell were not working / there when I got the car 2 years/ 100,000km ago. The temp is much lower with the fan working, but still going ove 60 c on the highway with temps around 30c so need the scoop to get more air through the cooler. It does almost seem as if my A/C is working better now to, could just be my imagination though.

[Pingu 0]

The smart has the highest NOx emissions per kilometer driven of all the vehicles approved by Transport Canada. That's why I suggested that smart may have had to lower the intake air temperature to meet the regulations.

[bilgladstone 13]

... and reduce the intake oxygen by EGR.I'm a bit surprised by the "highest NOx emissions" though. Do you have an online citation for that please?B

[BobLawbla 0]

Good day & thank you for the responses. This forum is very healthy!I did a full Inlet Air Temperature (IAT) [the sensor at the bottom of the intercooler (IC) fan] and Engine Control Module (ECU) related check with multi-meter, computer diagnostic system, and thermometer and heat/cooling producing apparatus. I performed basically the same check on the Engine Coolant Temperature (ECT) which basically is the same tests. The tests are too long list here, but if needed I could list them. All looks good. The thermo transistor are showing the proper, accurate and various temperature changes to the ECU.When driving the car, my running IAT temperature is between 26C to 36C. it is higher then the ambient temperature, but it si normal considering that it is closed to the engine and the PCV is rejecting in the intake hot oily air. I would think that IAT is proper.The fans used to be running only at times (I think), just as many are saying here. I now think it is normal for this time of the year to be on. I would say the cooler the air coming to the combustion chamber, means it’s more dense, therefore means more air psi to burn and power.The low power could be related to the IC fan always running as they could be functionally related (turbo). I will look further for an electrical diagram to see what this will tell me. But then again it might not be related at all. My Check Engine Light (CEL) is functioning because it is showing P0380 error (glow plug), which is an error that I really don’t think is related.Thank you Henry - my hose has signs of rubbing, but not rubbed through. Mine has an indentation in it but not through for it to leak. It will need to be replaced soon; I think it would have lasted for another 8,000 km to bring the mileage to 50,000 km just like you said. I will change this as well as the other things that are worn out in the car. The turbo pressures rating is at idle -0.2 psi and varying to 19 psi under a high load (pedal to the metal). 19 PSI seems high and could be the clue to my power/performance problem. The Manifold Absolute Pressure (MAP) reads between 29 in to 69in under load. I now suspect the wastegate is stuck, probably stuck partially open. I will confirm this hypothesis tomorrow - more to follow.I appreciate all the good information received so far. Thanks!

[bilgladstone 13]

... 19PSI seems high... ...I now suspect the wastegate is stuck, probably stuck partially open.

Yes 19psi (1.3bar) would very likely trip overboost, inducing self-protective "limp home mode." Sticky wastegate... I think you're on the right track now! Also double-check the short (10cm?) curved hose that goes from the brass barb on the turbo to the wastegate actuator head. Same symptom might appear if that is holed. First hand experience of that here haha :waving:Bil

[tolsen 630]

If turbo overboost is your problem, deleting the DTC will sort it out until next time you get an overboost condition. Mine struggled to do 75 km/hour when I had this problem. You should get a DTC relating to excessive inlet manifold pressure.

[Pingu 0]

Bil - I don't think the NOx emissions for individual cars are published -- only for fleets. The smart would have been lumped in with the other Mercedes cars to meet the fleet requirements. My information is from the engineer from the Department of the Environment who was responsible for ensuring that the smart met the requirements before Transport Canada approved it.

[CANMAN 23]

Bob,You have to take both rear side panels and the back panel off as a unit to get at the turbo wastegate, a second person to help would be a good idea.Get a spray can of Graphite grease ( high temperature lubricant ) and clamp a pair of vise grips on the arm of the wastegate.Spray the graphite and work the arm back and forth, spray some more until it moves freely ( as free as it can against the spring pressure).Canman

[BobLawbla 0]

Good day,Yep it was the wastegate. The wastegate was stuck partially open and caused the overboost (and probably went into safe mode). The wastegate actuator was also seized. The max turbo boost prior to fixing this was 18-19psi now it’s at 14.5psi.Here are the steps I took to fix it:- removed the rear panel; - removed the plastic intake tube;- disconnected the wastegate actuator from the wastegate lever, discovered that both were seized;- used penetrating oil on the wastegate level to free it up, it become loose; then spayed it with graphite lube- used silicone lube to free up the actuator, then applied synthetic brake grease (rubber safe and high heat resistant); - checked the vacuum to wastegate actuator hose, was all good;- put it all back together in the reverse order;- test drove the car [without the rear panel ] to my great surprise the power was back :)I noticed that the IC fan is still always running.The next repair I will be performing is to clean the EGR, change the glow plugs and change the EGR to engine intake tube.Should I be looking at other repairs while I am in the engine? Which engine parts usually wear out? I changed the alternator recently and the belts about 5000 kms ago. I just changed the air filter. Oil and oil filters are brand new. I lubricate my clutch actuator at every oil change and seal the boot with tie rap so that crud and snow don’t get in there.I just want to do preventive maintenance so that I doesn't break down on the road (I had too many of those).Thank you all for the great inputs.Bob

[bilgladstone 13]

RESULT!

[MikeT 744]

IC fan running = good! Glad you sussed the problem.

[tolsen 630]

Strange your scanner reported no DTC relating to high manifold pressure. OBD2 tools cannot always read all fault codes so perhaps that is the reason. On my Cdi I have to erase the DTC to get engine out of the limp home mode. Did yours require same action?

[smart142 605]

I just want to do preventive maintenance so that I doesn't break down on the road (I had too many of those).

I would change the tranny fluid if you haven't already done it.Do you still have an intercooler scoop? The majority are broken off.Do oil changes every 6000kms is the big one!

[BobLawbla 0]

I will change the transmission fluids for sure with Mobil 1 Synth ATF D. I will follow the information on this thread http://clubsmartcar.com/index.php?showtopi...nsmission+fluid

I had no CEL, possibly because it didn’t reach its threshold. The wastegate was seized partially opened. I can’t tell for sure that it went on safe mode because I always disconnect the battery when performing repairs on my cars and had no OBD indication or code for it. The P0380 code is still there, I didn't erase any codes, but the glow plugs needs to be replaced. Tolsen is right; going into a limp mode should cause an OBD code which should be captured by any OBDII reader or scanner. After all it is an emission fault (car performance fault). Which OBDII code should it have produced?

Pingu; this Smart emission control talk bring to mind that the Smart met CEPA in spite that certain OBDII readers/scanners (off the shelf at the local store) jumps the Smart odometer. At that time it probably wasn’t known.

Thanks

[Francesco 71]

...Because I read through this thread before mending my IAT plug...

My fan works the same way TOlsen's works, on around 60°, off around 40°, and maintains about 20° above ambient with my improvised scoop.

[MikeT 744]

Interesting. My car's IAT is nearly never 60C. But the fan is on a lot.

[Francesco 71]

My fan only comes on when necessary it seems.

[Francesco 71]

Spirited highway drive home at 2:00 am, IAT was still consistently 20° above ambient (37°/17°) under full load, the fan never came on.

[LooseLugNuts 557]

i guess i need to do some adjustments after reading this thread

my turbo is reading 14.5 psi at idle/coast and max 25 to 26 psi on accell ...(with no codes being set)

feels a bit lazy compared to another smart i drove but i didnt think much about it until now

Edited August 11, 2015 by LooseLugNuts

[Francesco 71]

At normal acceleration, turbo pressures of 11 to 15 psi are very normal. Read the maximum under full, hard acceleration to redline in second and third gears. If it doesn't go over 15 psi, perhaps you have a boost leak, or the waste gate is under-set or even slightly leaky.

[LooseLugNuts 557]

ok now ive just noticed my map reading with key on engine off is 14.2 psi..so i need to compensate for atmospheric pressure? (using autel ms609 to read live data)

so im guessing its safe to say when saw 26 psi max boost that was actually only 11.8 psi and i should turn it up by moving the adjust nuts closer to actuator ?

(05 cdi 450 in case i never mentioned it )

Edited August 12, 2015 by LooseLugNuts

[Francesco 71]

I would look for a boost leak before playing with the actuator rod setting.