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

[BobLawbla 0]

Good day,My 2005 Smart has a lack of performance. It's sluggish - I can barely make it over 100km/h. The other indication of a problem is that the intercooler fan is always on. The fan kicks in soon after the engine is started, and I don't think it is normal. No engine code other than the P0380 glow plug. The car was running before I replaced the alternator which now puts out the normal 13.7-14.1volts. To remove the engine I used the drop the engine method to acces the alternator from above.I tested the glow plug with a multimeter and yes the number 1 glow plug is toast. I got a much higher ohm (I can't remember how high, I think 3.2kohm but the others were 0.6) than the other two. Anyhow the glow plug problem (and the MIL) was there for a while and the car was running fine (lots of power). Therefore I dont think it is related to this new low power problem.I made various checks of the IAT, disconnecting it and reading the IAT reading on the OBDII gauge, which was -39C and bridging the connector brings the OBDII gauge reading to 150C, which I think is all normal. I froze the IAT, connected it back to the car and read the OBD reader as it reached the normal temperature slowly - about 22C (with engine off). All of this tells me that the IAT is fine. The ECT is also fine. I suspected the IAT because it is a sensor that controls the intercooler fans and fuel output. The running IAT temperature is around 26C.I looked and didn't see any vacuum leaks.I think the intercooler fan and the sluggish power are caused by the same cause, and both problems during the same period. But what caused this? Would you know what it is? Perhaps the EGR is dirty (but the car doesn't have much mileage on it [it's always broken and I have other cars I can drive]? Perhaps it's the fuel filter?Thanks for the helpBob

[CANMAN 23]

Hi Bob,How many kilometers?Any smoke out of the tailpipe?The dealer recommends changing the fuel/water separator at 33,000 km, but lots of people haven't changed them and they are over 100,000 km.I am thinking along the lines of turbo or intercooler.Do you hear any whistling sounds or if you have a scangauge is your boost press at least 15psi?Any oil on the left side of the engine?Do you change the oil regularly, using synthetic oil?Do you let the car idle for at least 30 seconds before shutting off the engine?Canman

[MikeT 744]

The IC fan runs normally when the IAT is over 25 or so, which in this weather is always. I doubt that's got anything to do with the issue.Is the car always dog slow or does it start off OK and then lock into the slow mode?

[tolsen 630]

I would start with the basics.Change or clean air filter and fuel filters, then see if power improves. If no change measure cylinder compression.IC fan running continuously is not normal. I verified operation of I/C fan some time ago. Fan cuts in at +60 C and cuts out at +39 C.

[MikeT 744]

Yours is weird. Mine - in BOTH cars - cuts in at under 30 C. My IAT rarely gets up to 60 C, even on a mountain road.

[bilgladstone 13]

My fan cuts in at 26C

[tolsen 630]

Yours is weird. Mine - in BOTH cars - cuts in at under 30 C. My IAT rarely gets up to 60 C, even on a mountain road.

My fan cuts in at 26C

When does it cut out then? At end of December?

[bilgladstone 13]

In my case, fan cuts off under no load idle on cool days, and pretty much all of October through March.

Coolant temp has only begun reaching 80C in the last few weeks as we get ambient over 20C daytime. 30C+ only from May through September. Rest of the year never sees three blobs. I have one of your v1.0 restrictor plugs ready to go in "one day."

B

[MikeT 744]

Basically the fan is never off in the summer. Also, 60 C is WAY too high for it to cut in. Surprised you wouldn't be aware of this.As I said, a 10 km climb at a steady 8% will not crack 60 degrees IAT in either of my cars. Without the fan it's at 60 in the first minute of such a climb.

[BobLawbla 0]

Thanks a lot!,

I have appended my answers or input to your comments/questions below. I was also thinking that It might have went into “safe mode”, I have disconnected the battery Saturday will reconnect it tonight and see it is fixed. Would going into “safe mode” give a CEL?

What MAP reading do you get from Scangauge? Or what is the normal reading?

Canman wrote:

How many kilometers? 42k kms

Any smoke out of the tailpipe? No, just the regular diesel exhaust fumes, as good as the day I had it E-tested.

The dealer recommends changing the fuel/water separator at 33,000 km, but lots of people haven't changed them and they are over 100,000 km. It was replaced around 28k kms. I will change it again just in case I had a bad batch of fuel, because I also recently filled up before this happened.

I am thinking along the lines of turbo or intercooler. I will exhaust other options, then will remove the EGR, but the car doesn’t have much mileage.

Do you hear any whistling sounds or if you have a scangauge is your boost press at least 15psi? The whistling is heard as per normal. But will check my scan gauge tonight and OBD reader and post the reading.

Any oil on the left side of the engine? I will specifically check tonight, but don’t think so.

Do you change the oil regularly, using synthetic oil? Yes and yes religiously change my oil with MB specified every season change and at around 5k kms.

Do you let the car idle for at least 30 seconds before shutting off the engine? Yes and even longer, while I enter my trip in my log book.

Mike T wrote:

The IC fan runs normally when the IAT is over 25 or so, which in this weather is always. I doubt that's got anything to do with the issue. I disconnected electrical connector from the IAT to cause it to sense its lowest temperature (-39c), it showed -39c on my OBD, but the fan still runs continuously (as if it is sensing above its threshold warmth). The ECT is also reading normal temperature.

Is the car always dog slow or does it start off OK and then lock into the slow mode? Yes always steadily sluggish during each trip.

Tolsen wrote:

would start with the basics.

Change or clean air filter and fuel filters, then see if power improves. If no change measure cylinder compression. Air filter is new, but will change the fuel filter in case I had a bad batch of fuel.

IC fan running continuously is not normal. I verified operation of I/C fan some time ago. Fan cuts in at +60 C and cuts out at +39 C. Good info thanks! that is the way it was before, only ran once in while during hot days.

[Henry 40]

HiIntercooler fan has me puzzled but check the hose between the egr and the intake, mine wore through and I lost a lot of power. The hose has wire loom that runs across it and the vibration of the engine causes it to chafe right though the top portion of the egr hose. It never leaked at idle, or that was noticable but would leak as soon as the turbo spooled up. This happened around the 50,000 km mark.Alan

[pinhead19 0]

I was thinking the same ^. If the turbo is running more than normal the IC fan will too. A worn or loose hose will cause this.IC fan is control by computer MAP. If people have different results, they likely have different maps.A stuck EGR will cause problems, but you should have a light, check on statup that the bulb is working.My original map; the fan would run all summer, from startup to shutdown + 45 seconds. Whichever one is in my car now, well, it is never on when the car isn't anyhow, and I don't pay much more attention than that.

[tolsen 630]

Basically the fan is never off in the summer. Also, 60 C is WAY too high for it to cut in. Surprised you wouldn't be aware of this.

As I said, a 10 km climb at a steady 8% will not crack 60 degrees IAT in either of my cars. Without the fan it's at 60 in the first minute of such a climb.

Here is a graph showing typical inlet air temperatures before and after charge cooler and turbo boost pressure.

Chart is not from a Smart Cdi but from a typical turbo diesel engine.

There is always enough air for efficient combustion so no real benefit letting charge cooler fan labour excessively trying to force manifold air temperature lower than what is required. I therefore assume there is a problem with your instrumentation if Mike's and Bil's charge air cooler fan appears to cut in below 30 degrees C. Perhaps you can check using an old fashioned temperature gauge in inlet duct after charge cooler.

[CANMAN 23]

I agree with Henry,Check the intercooler hose at the top left side of the engine, it is known to chafe.You might want to check the sensor at the bottom of the intercooler, it controls the operation of the intercooler fan, if it came out of its socket it would cause a loss of boost pressure.Canman

[tolsen 630]

Perhaps you can read turbo boost pressure at full load. Should be close to 1.2 bar gauge pressure or there is a leak somewhere.As for charge cooler fan problem, fan will run continuously whenever electrical plug to IAT sensor is unplugged or there is an open circuit. Check accuracy of IAT sensor by reading temperature with sensor removed from charge cooler. Temperature indicated should of course be the ambient.

[scwmcan 0]

Just another data point on the fan, mine runs the same as Bill and Mikes fan. I would say that this is normal for our Canadian cars, may run differently for Tolsen's for some reason.

[Pingu 0]

In order to meet Canadian requirements for NOX emissions, smart had to keep combustion temperature as low as possible. Perhaps this explains different IC fan settings. This would be consistent with Pinhead19's comment #12 above.

[MikeT 744]

There you go.

[tolsen 630]

In order to meet Canadian requirements for NOX emissions, smart had to keep combustion temperature as low as possible. Perhaps this explains different IC fan settings. This would be consistent with Pinhead19's comment #12 above.

Did those that experimented with different MAPS notice any change in charge cooler fan operation?

[MikeT 744]

Perhaps yours is just knackered; is it us or is it you? ;)Drove the two smarts to Victoria this evening so the 2005 can get its A/C upgrade (gratuit comme on dit) and the highest IAT I could register on the 2005 with its new intercooler fan on the 352 metre climb of Malahat Mountain was 39C, that was at 14 ambient and nearly full boost, delta T 25 in other words. This is the car with 234,000 km. That was heading south.Heading north in the white Canada 1 BRABUS, which is the far steeper route, with two up instead of one, the IAT peaked at 46C, this was after a climb at 1.15 bar boost for at least three minutes, foot to the floor, 95+ km/h on a very steep hill. Delta T in this case was 32C. 60C would be attainable in these conditions if ambient was maybe 30 degrees.

[bilgladstone 13]

Mine is remapped and the i/c fan profile is the same as unmapped cdi.I echo Mike's experience with IAT:ambient around Δt typically 20-25CHot summer days approaching 40 ambient is another story altogether.

[tolsen 630]

I am not convinced you are reading true IAT temperature. Has anyone checked IAT using proper diagnostics like Star or WinStar?Just to remind you guys, I am still waiting in anticipation for fan cut out temperature and I did not get exact cut in temperature either.

[scwmcan 0]

Bill, I think the remap that was being talked about were the " free" ones from the European smarts, not an actual tuner remap, which would indeed mean that smart had to do some reprogramming when they brought the car over here. I can't comment as I am pretty sure when I did run that programming that my fan was not working even then, I am back at factory Canadian programming as I wanted to use the x-gauge that I bought for the car.Tolsen our readings are coming from the same information that the star program gets, the OBDII data so I think it is as true as your readings. As well at current temps the fan comes on as soon as the car is started, when it was colder it would not come on until the IAT hit about 25-30 degrees, ambient is that temp now, the fan wouldn't be coming on when I first start the car if it wasn't turning on until 60c so I do think there is a difference in the programming between our Canadian smarts and yours.

[MikeT 744]

Oh ye of little to no faith....my fan turns on within 5 seconds of a cold start when ambient is about 27C. Or is my home thermometer wrong too?

[tolsen 630]

It would appear I am blessed with a sensible regulation of charge air cooler fan. Did some confirmatory checks this afternoon using Winstar. Fan cuts in at 55 degrees C and cuts out at 36 degrees C. Those with less sensible fan regulation obviously ought to make sure your charge air cooler scoops are fitted and in a good condition to ensure optimum air flow across charge air cooler.