Gutless and code P0193

[Toxophilite 29]

My 2005 smart 450 CDI became suddenly gutless coming up the big hill up to my place after work yesterday. This morn the engine light was one and it was the very weak most of the day. i thought it was in safe mode. At one point I couldn't get up enough speed on the freeway so I had to get right off. For puttering around on the flat it seems okay. Oh and in the last week the exhaust seems smellier

The code reader says P0193 

Fuel rail pressure Sensor A circuit high.

 

The code seems to indicate a fuel pressure problem which can be a number of things. wiring, fuel rail, fuel pump, fuel filter, etc.

there is plenty of diesel in the car but we have been having a cold snap..(cold that is , for Vancouver)

 

Any suggestions as to the first things I should check and or most common things?

 

Thanks and Happy Valentines day!

Edited February 15, 2019 by Toxophilite

[Toxophilite 29]

No insights?

[Leadwing 565]

I don't have a code reader, so I don't know what the numbers mean, but the description of your issue sounds like something similar to the problem I had with my '05 smart last fall.  Normal power when no engine light showing, but totally gutless with the engine light on.  It turned out to be a slight over-boost in the turbo.

 

That said, the check engine light has may things that will set it off.  Over-boost is only one.  Fuel cap not properly tightened is another.  I am sure others will chime in when they get a chance.

[LooseLugNuts 557]

my first thought was loss of boost pressure

 

but the code is for high voltage on fuel pressure sensor...could be high pressure or low pressure im not sure how that specific sensor works

 

could also be a bad sensor?..maybe clogged injectors?

 

normally id hook up a scan tool and watch the information for clues as i test drive it

Edited February 16, 2019 by LooseLugNuts

[Toxophilite 29]

My code reader does have a series of things it can scan when the engine is running

What should I look for?

 

Also My Smart is a Canadian model. I've read that model just has the one combo water separator/fuel filter, is that right?

Or do I have the smaller inline fuel filter as well?

 

[LooseLugNuts 557]

look for anything out of the ordinary...

 

the filter is underneath ...in the area below the floor rear of driver seat position ...if you remove the rear half of the big plastic cover you cant miss it

[Toxophilite 29]

I've read the Canadian model only has a combo fuel filter water separator and not the inline filter. Is that right?

Edited February 18, 2019 by Toxophilite

[Nigel 287]

That is correct.

[Toxophilite 29]

hmmm. Just replaced it. It was probably the original made in Austria part, didn't look dirty inside. However I replaced it anyway. I'm sure if it had every been replaced but the car is at 78K so maybe a good idea. I'm going to disconnect the battery and see if the engine light goes off, though I'm not holding out hope.

Edited February 18, 2019 by Toxophilite

[Toxophilite 29]

Well, engine light still on and same lackluster performance. Basically feels like the throttle is useless past halfway.

 

[LooseLugNuts 557]

id be trying to find out how to check fuel pressures and rail pressure sensor if it was my car

 

 

[mender 42]

Collapsed muffler? I would disconnect the exhaust pipe from the manifold and go for a (loud) run. Cheap and easy test.

Edited February 18, 2019 by mender

[Toxophilite 29]

Can't find how to check fuel pressure but i will try the collapsed muffler thing when I take the back end to check the waster gate.

Though the code is for the fuel rail pressure sensor

 

[Toxophilite 29]

have the back off and poked around looking at connectors and what not. All seems to be well.

The wastegate moves as it should. On a whim I phoned Mercedes about a fuel pressure sensor (because that's where the code is coming from.) They said it cost a cool $436...bahaHA  oh and it was on back order...20 to 30 days.

Anyone have any valuable insights ?

I can drive the car and on the flat it'll get up to freeway speeds adequately. It just sees that in each gear there is a point where the gas pedal just stops working and actually seems to start slowing the car down unless you shift.

In case it's in safe mode I've tried taking it out by disconnecting the battery for 30+ seconds a couple times and no dice.

Any insights would be hugely appreciated

[Sydney 218]

Any chance of lucking out and checking a wrecking yard for a smart. You might find a fuel pressure sensor for a few bucks.  

Worth a shot anyway.

The way these older smart cars are, it seems like I good idea to have 2,3 or 4 spare parts cars, just in case. Lol

[tolsen 630]

Read rail pressure using a diagnostics scanner.

[Toxophilite 29]

Can I read the rail pressure using a vaccuum / fuel pressure guage?

I don't have a diagnostic scanner

Supposedly there's a bluetooth device I can get that will work with the ancient iphone4 I never use if I download an application (don't use any cell phones..ick!) I have a couple computers but no laptops

[dguy 22]

Do not attempt to connect a standard vacuum gauge or (gasoline) fuel pressure gauge set to the injector rail.  Common rail diesel pressure is generally 100 bar or higher, which is well outside the range of those tools.

[tolsen 630]

You can read signal from rail pressure sensor with a multimeter.

[Toxophilite 29]

Oh I definitely have a multimeter. I build my own guitar amps!

Thanks!

 

Should I be disconnecting the plug and clipping my probe to the sensor or testing it while it's all hooked up properly

 

[LooseLugNuts 557]

while connected properly and running

 

it needs the 5 volt supply to give out readings

[tolsen 630]

Interesting video:

 

[tolsen 630]

Note that above video shows the later and slightly higher pressure common rail system with piezo electric injectors.  Otherwise all details are  identical to our system.

[Toxophilite 29]

Looking at my engine from the rear my fuel pressure sensor would seem to be where they have the fuel pressure limiter. Is that correct for my car

It looks like the unit you have pictured with the flattish 3 wire plug. 

[Toxophilite 29]

My unit has blue, yellow and white wires coming out of it blue being closest to the front of the car.

using the engine (block) as a ground I get 5VDC at both the blue and yellow wires with the engine off but the ignition on and with the engine on at idle and revving, no change

I have to use the engine ground (block) to achieve this as the sensor ground doesn't seem to work to get readings.

Interesting both the blue and yellow wires have continuity to engine ground (block) while the white wire which I would assume was the ground has no continuity to engine ground.

i'm not sure if that is correct.

 

I could be measuring this worng

I had difficulties trying to determine where to measure from. Not being familiar with smart cars and modern engines in general.

I ended up inserting wire leads into each connection in the plug (not invasively see picture) so that I could take measurements with the plug installed, otherwise it's pretty well impossible as it appears to be a pretty sealed unit. Likely there is a better way to do this which is obvious to those more familiar with these engines.

 

Tolsen's drawing seems to suggest that:

blue would be the 5V supply,

yellow would be signal voltage

and white would be ground.

 

If this is wrong what is the actual pinout on this plug, including wire colours ?

 

 

Thanks

Edited February 23, 2019 by Toxophilite
alien masters gave prime directive.