450 fortwo cdi PROBLEM

[si cdi]

Hi my smart 450 cdi 2001 has packed in the engine just cut out, it finally started then cut out twice on the way home only about half a mile from my house it will not start unless i give it a sniff of easy start then it will run on its own without the spray any ideas, it had a crank sensor last year, do they have a cam sensor? cheers

[Ocracoke]

I'd check the fuel pumps. A 2001 CDI I used to own had a fuel pump failure similar to how you are describing this.

[si cdi]

I checked the tank pump when I changed the fuel filter and seemed ok, ignition on while filter off pumped in to container im thinking more main pump but I don't understand how it runs with a sniff of easy start then runs on its own thanks for help

[tolsen]

Perhaps faulty crank sensor again. Did you fit original or cheap after market?

This engine does not have any cam position sensor. ECU works out which is number one cylinder by reading changes in angular velocity from crank sensor. Engine won't start unless engine can synchronise.
.

[Mr T]

If I was you i'd plug in a code reader & see what errors come up.

[si cdi]

ive had it plugged in Delphi and glowplug fault came up which I new about but ive changed them now

[tolsen]

An OBD/ EOBD code reader can't communicate with this car.

[heinkeljb]

Needs to be a MB Star or WIN Star diagnostic system to produce usable diagnostic information.

John

[tolsen]

Bring your Cdi to my Banchory Smart Centre and I'll attempt to diagnose the problem for a pint of good ale.

[si cdi]

banchory Aberdeen?

[lalli_d1]

when was the fuel filter last changed?

[si cdi]

fuel filter has been changed last week

[si cdi]

im going to plug it in again there must be an option for real time to see what fuel pressure is at the rail? I still think its pump related, I did read about a relay to be added but mine seems to work ok

[tolsen]

Yes, Banchory Aberdeenshire, perhaps too far north and near nowhere?

Way forward in my opinion is:

1) Connect to diagnostics and read rail pressure when cranking engine.

2) Carry out compression readings.

Both require special equipment.

Did you fit original Smart/ Mercedes engine speed/ crank sensor?

Does engine smoke a bit when running? Perhaps try Silver Hook diesel injector cleaner available from Toolstation for £3.15 per bottle, enough for two treatments?

Does your high pressure fuel pump leak? Common problem with this Bosch CP1 pump.

.

[si cdi]

crank sensor was from eurocarparts £45 im sure it was the same make, no fuel pump leaks and there is a bit of black smoke but always has been, what ya thinking possible valve issue if not pump I do have a compression set via glowplug which ive just changed should of done it then oops, i tried posting on your other replys but keeps saying text fault or something

[tolsen]

I suspect Eurocarparts sell cheap sensors at inflated prices. The Canadians have had lots of trouble with aftermarket crank sensors so I would therefore only fit orginal or Bosch.
One was reported to be too long and its business end got stripped off on first crank.

[si cdi]

Its a bosch sensor, i have changed it to my old sensor which failed when it gets hot its doing the same thing!

[10:45PM]

Have you tried a battery disconnect/cold boot ?

Could be the rail pressure sensor.

Could also take glow plugs out to confirm injectors are injecting, you should see atomised fuel come out on cranking.

[si cdi]

good point will try that

[tolsen]

Engine wll start with rail pressure sensor disconnected so easy to check if that sensor is the problem.

A real pity Delphi cannot display rail pressure for this 2001 Smart Cdi. Engine needs about 250 bar rail pressure to start. Perhaps you can try disconnecting connector to third pumping element on high pressure pump. Doing this may result in a fault code beng set but the main purpose is to allow all three pumping elements to pump. Pump element is enabled when solenoid is not energised. Solenoid simply operates a pin that keeps inlet valve in open position when solenoid is energised. The purpose of the cut off solenoid is solely to allow the pump to operate only two pumping elements, resulting in less engine power being absorbed at low engine loads.

More info: http://www.smartz.co.uk/showthread.p...Cdi-2002/page2

I suspect low compression. Low compresson wll make it harder for engine to synchronise on number one cylinder. Usually no fault codes. Similar to crank sensor failing.

How to measure compression on these engines: http://www.smartz.co.uk/showthread.p...re-compression

[Thrumbleux]

Could also take glow plugs out to confirm injectors are injecting, you should see atomised fuel come out on cranking.

As per Tolsen's post above - lack of compression during such a test will probably deny fuel.