CDI SMART 450 cold start

[modex007 4]

HI, 

 

i'm form Europe but car the same I'm having trouble to start my smart fortwo cdi when temperature drop below 5C or 41F.

Changed glow plugs, tested them with multimeter, all get 12v. Changed fuel filter. 

No smoke, car drives as usual when it runs.

Where to search the cause ? 

Battery is also good because i could crank it 15-20 seconds without a problem (and it wont start for example today)

with OBD tested fuel pressure, when it runs it runs on 220-240bar. my SAM unit is old type because it's 2002 year. fuel pump works i can hear it.

 

Thanks!

[tolsen 630]

Have you confirmed glowplug controller is working?  Check voltage at each glow plug.  I think voltage is around 8 Volt.

 

Also check earth strap which connects from chassis to transmission.  The earth strap tends to disintegrate over time.

 

Try an injector cleaner additive.  If still difficult to start when cold, there may be low compression or bad injectors.

[tolsen 630]

By the way, this is the right place asking about cold starts.

 

I assume engine oil is suitable for cold weather and that alternator is not dragging.  Confirm the latter by turning engine by hand.

[modex007 4]

33 minutes ago, tolsen said:

Have you confirmed glowplug controller is working?  Check voltage at each glow plug.  I think voltage is around 8 Volt.

 

Also check earth strap which connects from chassis to transmission.  The earth strap tends to disintegrate over time.

 

Try an injector cleaner additive.  If still difficult to start when cold, there may be low compression or bad injectors.

Glow plugs connectors tested with multimeter all shows 11+volts on ignition on. for 20-30 seconds. so i assume controller works. Maybe will try to remove glow plugs and test them if they glow( but it's pain in the ass to remove them )

Ground connects are in perfect condition, checked them. forgot to mention, wynn's injector cleaner is added (around half tank is now driven) 

Oil is suitable. Alternator will need to check (how to turn engine by hand ? put wrench on alternator bolt and just turn ? ) alternator is charging 14.5v when it starts. 

 

I'm most afraid of compression, will need to find tester and time to check it. maybe will need to try some oil additive for compression "boost"....

 

Thanks

[tolsen 630]

You can check glow plugs by measuring their resistance and current. 

Do you have access to a DC clamp meter?

 

As for glow plug removal, I agree that is a Royal PITA. 

 

There are several guides on this forum on how to change them.

 

It is best done on a warm engine and with a torque wrench set at no more than 25 Nm to avoid stuck glow plug remains.  

[tolsen 630]

Have you read engine controller for fault codes?  

 

I think there will be a fault code or more if any of the glow plugs are burnt out. 

 

 

[modex007 4]

7 minutes ago, tolsen said:

You can check glow plugs by measuring their resistance and current. 

Do you have access to a DC clamp meter?

 

As for glow plug removal, I agree that is a Royal PITA. 

 

There are several guides on this forum on how to change them.

 

It is best done on a warm engine and with a torque wrench set at no more than 25 Nm to avoid stuck glow plug remains.  

Yeah i know i changed them last winter. all went good but too much stress  
I  will test resistance today again to make sure. no don't have DC clamp. 

 

yes tested, no error codes (except airbag dirvers seat, will need to change that stupid connector) 

I searched forum and found one video where states that try to start with brake cleaner to air intake. if it starts quickly then it should be problem with fuel pump or fuel injectors. will test that too.

 

[tolsen 630]

Here is a link to mine and Evilution’s guide on glow plug change. 

 

https://www.evilution.co.uk/mod/changing-glow-plugs.htm

 

Regrettably, most info is behind a paywall. 

[Willys 747]

Welcome to the site, club by the way....yes best CDi 450 site on the planet so we think...lol

Take glow plug controller apart and check internal blades for arc damage or corrosion which may restrict the flow of power to glow plugs. Use fine emery cloth to clean up these connections. Checking compression is a serious pain if you do not have a very long tester which inserts into glow plug hole.....I was forced to weld two together to get the length it required. The kits are reasonable on Amazon  but the plug ins are too short for our engines. You can't easily get the tester clipped onto the tube after it's in the glow plug hole. 

Are you getting any white smoke from exhaust showing unburnt air/fuel mixture?  IF not I'd be going after a fuel pressure or other fuel issue over an electrical one....but...to each their own.

As for Evilution.....pay the smallest donation level as it will unlock the vast wealth of knowledge hidden behind the pay wall. That site is well worth the cost of this charge...especially when you first get your Smart Car.  IMHO.   Kane has generated so much valuable knowledge  and deserves something for all his efforts.  It also isn't a chat site so you must research your issues on your own. At first it will be a pain to figure out how to locate everything as it's not imho the best set up in my head way of doing things......you must delete the cars or models from the left top corner box to leave the model you own to only show the remaining car's information. At least that is how I figured it out to work the best. Then you must ask or select the area you are researching. IF it doesn't kick up the information you want simply go into every section .....I know....strange BUT, you'll find that almost everything is there once you figure out where it's hidden....lol.

BUT....the 2005-2006 CDI 450 model year car is what this site specializes in IMHO as it's the most popular car we speak about at this site even after all these years.  I do not know what year etc you have but if it's not those two years maybe Evilution will have more information on the other models as we didn't get those here. Just saying....is all.  

Again welcome and keep us informed as to your progress.

 

[tolsen 630]

Another solution to hard cold start is to do as our forefathers. 

 

Drain oil and coolant at end of each day and keep next to your wood burner. 

 

Fill back in car whenever it is needed.  

 

A second solution is to place a Primus stove under engine sump to heat engine. 

[modex007 4]

2 hours ago, tolsen said:

Another solution to hard cold start is to do as our forefathers. 

 

Drain oil and coolant at end of each day and keep next to your wood burner. 

 

Fill back in car whenever it is needed.  

 

A second solution is to place a Primus stove under engine sump to heat engine. 

thanks! Tried to start - no luck. Just sprayed 1second of brake cleaner into intake and it started right away. 

 

no white smoke. Running like litle tractor 😂 all ok

 

 

So i'm asuming it will be injectors or HP fuel pump issue. Will try tonight remove and spray with some wd40 or brake cleaner. 

[tolsen 630]

My bet is on your glow plugs. 

 

Did you ream the bores when replacing your glow plugs a year ago. 

 

Glow plugs tend tend to fail prematurely if you don’t ream. Why I don’t know but maybe someone can explain. 

 

So buy a suitable clamp meter and measure what current your glow plugs draw.

[Mjolinor 91]

Copper grease on the glowplugs when you put them back.

 

It makes next time less stressful.

 

[tolsen 630]

Glow plugs in the Smart 450 Cdi have M10 x 1 threads.  Max torque when removing is 35Nm according to Beru.  Recommended torque when installing is 15Nm. Some manufacturers specify an angle turn of 30 degrees when installing.

 

If bore is not reamed and threads and seal area are not cleaned, then you may not be able to screw in glow plug by hand and feel when it bottoms out.

Even if correct torque or angle turn is applied, the glow plug may then later leak in way of seal area or work itself loose resulting in hard soot covering the threads resulting in difficult removal of glow plug later.

 

Due to manufacturing tolerances, diameter of glow tube vary a tiny amount.  Forcing a slightly larger diameter glow plug glow tube into the built up hard coak area in the bore may sufficiently stress the glow plug such that if will fail prematurely or even at time of fitting.

 

[modex007 4]

I just made myself huge huge problem and 20x more work. I made a drillbit soldered to bolt was cleaning glow plug ports and drill bit just fell inside.... now i'm lost and looking for info how to remove head, without removing engine from the car 😂 my smart is little bastard.

[tolsen 630]

That is bad luck.  Perhaps you can ream out bore 0.5 mm wider and try fishing out drill bit with a magnet?  Make sure drill is extra long or braze nut to drill.  If drill is still partly in the bore, try gently turning engine by hand to push it higher.

 

 

I silver brazed a collar nut to my drill bit.  No chance of nut coming loose from drill bit in that case.

 

 

Above photo shows more tools.

 

Small screw driver and bent plate for unclipping cable tray.

Puller for plling glow plug.

Two compression testing adapters (one is attached to compression hose for compression tester) that would not fit and finally my homemade rather long compression testing adapter. 

[modex007 4]

I was thinking to turn engine but my question is, i won't touch any of valves with that drill bit inside when turning engine? Drill is 100mm long so i still can see top of it. If that drill woul push to the top then  maybe i could fish it with something...  Don't have any magnet witch could fit into that 55mm hole...

 

 

Maybe know what is the travel distance of piston? That i wont turn wrong way, then it would drop inside.

[Willys 747]

Take injector out to see which way piston is traveling or do you have a bore scope that can fit down the injector hole?  IF you can see it down the glow plug hole it may be straight enough to push it back up and with the bore scope you may be able to figure out if this is a fact? I agree pushing the drill up at the wrong angle will be possibly more dangerous than taking the head off...?   Because once the head is off, then you can decide if head work is possible, valves, rockers, seals, etc etc...lol.    THAT is my problem...I like to make things either like new or modify them ......all costing money....better than going to the bar or smoking I suppose..?

[tolsen 630]

Glow plug sits at an angle so perhaps drill will break if you try pushing drill bit up by turning engine. 

 

Drill bit must be fairly loose in the bore if it dropped. 

 

Get a small and strong magnet and try pulling it out. 

[tolsen 630]

Perhaps a strong vacuum may suck it out. 

[Mjolinor 91]

Can you get a picture?

 

I would not be doing anything until you get a bit more input and a picture would help.

 

Strawberry jam may work. I have done that in the past with success.

 

Do not turn the engine yet. If the drill bit fell then it is loose at the moment. Even a small turn of the engine may jam it.

Edited November 17, 2022 by Mjolinor

[modex007 4]

What is strawberry jam? (I hope thats not literally)

 

I put small dip of two part glue on bolt ant put on top of the drill. Waiting to cure, maybe that will help. But i think it's holding not so losely, because it broke when i was turning welded bolt+drill

 And on turn it broke. 

 

If no luck with glue i will take a picture of it

 

But now i'm thinking maybe try put some penetrating fluid to the hole and then to turn engine, it should push slightly that drill.

Pull lightly from top with glued drill and turn engine.till it starts pushing...

Im lost, dont want to make damage but also do not want to remove head. Would cost a lot of money or time. 

[Mjolinor 91]

It is literal.

 

Has a lot of uses in this sort of situation. It stops crud falling down when you are cleaning out the hole and is wonderful doing spark plug helicoils without removing the head.

 

 

[tolsen 630]

From memory I recall glow plug sits at about 45 degree angle relative to top face of piston. Therefore likely drill bit will break if we attempt to turn engine to let piston push drill bit out. 

 

I now can think of four ways to get drill bit out excluding cyl head removal:

 

1) Use vacuum. Drill bit weighs about 12 to 14 gram.  A good vacuum cleaner such as my old mains powered Hitachi pulls just above 0.2 bar vacuum. That is a force of 40 gram. 

 

2) Use some kind of glue but risk of drill bit being glued solid in place. 

 

3) Use a strong magnet. 

 

4) Press it out with compressed air or oil.

This will require some setting up but is sure to work. You have to remove valve cover and the injector. Then hold drill bit in place with a magnet and turn engine such that piston moves to its bottom dead centre. Try compressed air first. 

Use oil and a hydraulic pump if compressed air fails. You obviously need suitable pipe fittings or adapters to make a good seal. Forgot to say that air or oil will enter through injector bore. 

[modex007 4]

Damn... i think head removing now sounds most easy 😂😂

 

I tried tu turn engine slowly it stops didnt use force and turned back.