450 fortwo cdi PROBLEM

[tolsen]

Mine failed to start in 2007 after having been for four weeks to main dealer for clutch related surgery. Being used to old style diesels and unfamiliar with the Smart Cdi, I removed number 2 injector and rigged it up connected to rail so I could see if fuel was injected which I confirmed it did. May not have worked had I done same on number 1. Cause for no start turned out to be seized alternator.

Whether ECU is programmed smart enough to attempt synchronising on number 2 or 3 if failed on number 1 is anybody's guess.

[tolsen]

I also stupidly connected a pressure gauge to the rail and nearly blew it to the moon. Only use diagnstics to read pressure on common rails.

[si cdi]

Thanks for the replies I have ordered another compression tester I only have a petrol one, should be here Monday, I did check the pressure on the rail for the pri pump in tank 25-30 psi does that sound ok its only to get to the high pressure pump so seemed ok to me?

[tolsen]

You bought a diesel compression tester? The probe won't fit unless you remove inlet
manifold. You can borrow my probe if you pay deposit and postage. It is well traveled. Has been to Canada twice.
One problem is I am on my way to Isle of Mull. Only GPRS there if I am lucky. It is 19 years since I last visited so anxious to get back. Petrified trees, lava flows, hexagonal basalt columns etc all worth seeing before you leave this world.

[si cdi]

Thanks for the offer tolsen, I have already modified one of my old glow plugs so should be fine its starting to annoy me not being able to diagnose the fault,

I have a mk4 supra and 12 motorbikes which I have rebuilt restored and never had this much of a headache I have never been to isle of mull must send pictures when your back

[tolsen]

Mull is just wet, midgy and miserable. Same as 19 years ago. Good thing I brought enough Lidl whisky this time.

[tolsen]

Feed pump pressure.
Mine delivers 2.5 bar. Not sure what is specified minimum but misterauto has one where delivery pressure is stated to be 2.0 bar.
WIS is not of much help as designed for unintelligent grease monkeys.

[si cdi]

Hi, compression test 20 bar on all 3 cylinders give or take a small amount

[tolsen]

So low compression is not the problem.
The Canadians have had start problems caused by bad injectors. Perhaps you can try diesel injector cleaner, see one of my previous post for a good one available cheaply from Toolstation depots.

[si cdi]

Thanks tolsen, I have a spare set of injectors already tried them, tonight ive been trying to find the third pumping element valve thing lol does it face towards the rear of the car? with 2 wire plug on looks like a solanoid behind tik pipe

[tolsen]

Yes must be it. Only one electrical connector on high price pump.

Question.
Does engine crank at normal speed?
Does engine start if you roll start down a hill?

[si cdi]

Yes engine cranks at normal speed and alternator is fine, i didnt no you could bump a smart will have to get creative an tow it, i disconnected 3rd pump element thing and yes No start, does the pump not have a shut off solanoid?

[tolsen]

There is no overall shut off solenoid in high pressure pump except third pumping element shut off solenoid. This one shuts off fuel supply from third pumping element when energised. Traditional diesel injector pump solenoids shut off fuel when power is turned off.

Roll starting is easy:

Find a hill or get someone to push.
Ignition on.
Foot on brake.
Hold gear shift lever in plus position.
Depress accelerator and hold.
Engine normally starts as soon as car has gained sufficient speed.

I've been looking for a suitable injector noid light to check for injector pulse. There are loads of them on eBay for petrol engines but nothing for diesel.
The only way I know of checking for pulse is by connecting an oscilloscope in parallel with injector. Voltage is high around 90 volts which would burn out any petrol noid light.

[mottofreee]

What is the voltage measured on connectors the injectors?
Terms of measurement:
- engine off
- ignition on
- the jacks injectors removed.

[tolsen]

One can only measure injector pulse voltage using an oscilloscope. Pulse width is very short only a few milliseconds long.
Voltage is high up to 90 volt.