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Discussion Starter #1 (Edited)
Hi,

I own a 2003 Fortwo (type 450) 0.6 turbo.

Last week I rebuilt the whole engine. I've changed all the internals parts (pistons, piston rings, valves, rod bearings, timing chain...), plus clutch, coils, spark plugs, filters, sensors, and so on...

Problem is, the engine turns over but won't fire up. All lights on the instrument cluster are normal. And there is no DTC codes raised by the ECU...

What I've checked so far :

- There are sparks on the spark plugs
- Fuel is coming to the rail AND into the cylinders (spark plugs are wet)
- Timing is good (and I think even with a tooth off, the engine would (badly) start)
- Checked and rechecked that clutch has been mounted properly (because of the gap in the flywheel for the CPS - crankshaft position sensor)
- CPS is brand new
- No error in the wiring
- All fuses are OK
- Compressions are good
- I guess ECU is OK since it responds to my Scantool, I even can read parameters in realtime (advance, air intake temp, throttle position, etc)

I surely miss something here but I'm totally stuck. There is fuel, there is spark, the camshaft moves : how a engine could not start with all that ?

Any help would be greatly appreciated !
 

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There are not a huge amount of the 450 cars in the USA, Might want to try the Canadian smart car site as they have a lot more of the 450 models up there

Forums - Club smart Car

Sounds to me like you have everything covered and it should run.
 

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I surely miss something here but I'm totally stuck. There is fuel, there is spark, the camshaft moves : how a engine could not start with all that ?

Any help would be greatly appreciated !
Seems like you've checked everything already, but it sounds like a distributor which is 180-degrees out of phase, and firing on the exhaust stroke... if you only had a distributor.
:eek:
I'd pull the valve cover, rig up a timing light and aim it at the cam to verify correct engine timing - both mechanical & electrical.

~toaster
 

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Make sure the flywheel is indexed. If you did not install the flywheel in one of three holes the timing will be off. Any other questions IM me.

Leroy
 

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Discussion Starter #7
Thank you guys. I'll try to post my question on an Canadian or UK forum as well.

About the flywheel, I've already checked it twice. There is a location pin to prevent improper mounting of the clutch assembly, so it seems unlikely to make a mistake here.

But I have the feeling, like Toaster, that the ignition may be out of phase.

Unfortunately I don't have a strobe light... Is there anything I can do to check the ignition phase without this particular tool ?
 

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If you are sure the flywheel is indexed correctly that is good. I have overhauled many 450 engines gas and diesel engines. When people bring me their cars after replacing the clutch the most common problem was the indexing. Have you made sure the fuel line is not backwards? The pressure and return lines if they are hooked up wrong it can cause a no start. Will it fire on starting fluid? When you set the timing marks did you have the engine on top dead center by the mark on the balancer on the timing cover? and on the top gear were the marks aligned? Did you use a picture to line them up? Did you use new lifters or did you pre oiled the lifters? Did you bleed off the lifters when installing them? Does the engine turn over real fast with the no start? If the lifters are not siting correctly it can cause the valves to stay open. Were the valves ground or new valves? It can cause change the valve closing all the way. The way that can be checked is with a compression gauge? That can tell me a lot if you have parts installed correctly. Is your car a G&K car? Do you have access to a STAR machine? It can help to determined if all the sensors are sending the correct readings that do not show up as a engine code. When you installed the rings did you check to make sure they were the correct ones. There were two types of rings that were used on the engine. If you were to use the wrong ones you would have very low compression.

Leroy
 

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In France, that makes a big difference in helping someone. We can always give advise. But hands on is hard to do when so far away.

Leroy
 

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Discussion Starter #11
Yes I'm in France. Leroy, thank you for your PM but for some reason I can't reply to it.

Let me answer to your questions :

Have you made sure the fuel line is not backwards?

I think so. I put the return line into a tank to see if the fuel pump is working, and there is a steady flow when the engine is cranking. I assumed the fuel lines are correctly hooked up.

This is a picture of the fuel lines :



Will it fire on starting fluid?

Not tested yet but I will.

When you set the timing marks did you have the engine on top dead center by the mark on the balancer on the timing cover? and on the top gear were the marks aligned?

Yes and yes.

Did you use a picture to line them up?

A picture ? I've mainly used the fq101 website instructions.

Did you use new lifters or did you pre oiled the lifters?

I've used the original lifters but I cleaned and pre oiled them before reinstalling.

Did you bleed off the lifters when installing them?

Ah, no I didn't. How do I suppose to bleed a lifter ?

Does the engine turn over real fast with the no start?

No, it turns normally.

Were the valves ground or new valves?

The 6 valves are new.

The way that can be checked is with a compression gauge?

I have 9.0 bars in the 3 cylinders.

Is your car a G&K car?

Sorry, I don't know what a G&K car is :shrug:

Do you have access to a STAR machine?

No but I have a Scantool with genuine ELM327. No DTC recorded. All sensors are sending correct values. For instance, advance timing shows 4 to 6 deg BTDC when cranking.

When you installed the rings did you check to make sure they were the correct ones.

I bought them in a Mercedes store with the VIN of the car, so I guess they were the correct ones. If not, I suppose there would be no compression at all, or a very low compression.

Anyway I hugely appreciate the help, that's very nice !
 

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What other things can stop a 450 from starting? Brake light switch? Crank position sensor? Just throwing out that it may be some other system causing the problem. :)
 

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Unfortunately I don't have a strobe light... Is there anything I can do to check the ignition phase without this particular tool ?
Beg, borrow or eBay one? :wink:


I see you've installed a new crankshaft position sensor... have you tried re-installing the old one? Possibly the new one is defective.

Does this engine have a camshaft position sensor also? I suspect not, which is what makes the orientation of the flywheel on the crankshaft important.

~toaster
 

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Discussion Starter #14
OK folks, 2 months later and problem solved! I'm sure you're curious to know what the problem was :D

Initially I was convinced that I missed a little detail somewhere, but actually it was a bit more serious than that.

Well I took the whole engine apart once again, and when I removed the pistons, I noticed the middle compression rings were completely stuck deep inside the pistons grooves (on the 3 pistons).

These rings sets were aftermarket ones... So I ordered a new set of rings from a local MB dealer and reassembled the engine. Guess what? The car started at first crank!

I guess the first rings sets had a problem, or maybe I've done something wrong when putting them on, I don't know...

Now the interesting question is: how could the compressions be OK in such a case, since I had 9 bars verified in each cylinder? My theory, for what it's worth, is the compression was good... as long as there was no explosion in the cylinders.

Anyway, hopefully this experience will help another Smart enthusiast!

Thanks to all of you for your support :wink:
 
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