G1 ForTwo CDI starting problem saga

[polainm]

Hi

Ready for War & Peace? This is partly for Fudge's reference when I take the car over to him...

Normally an engine glitch eventually gets resolved, but this has been on-going for two years. Partly because it only happens when outside temperatures drop below 0C, and only for the first start of the day.

THE FAULT
The car is a 1999 City Coupe CDI LHD (G1 ForTwo) with 72,000 miles on engine. It is parked overnight on a gravel driveway, in the open, in Cambridge, UK. It will turn over but not start if temperature is below ~4C and it was below 0C overnight. Once started that day, will be fine all day. No limp mode, no fault lights, no loss of power, although average 55-60mpg around town driving isn't great for this engine. Some blue smoke on start up and under hard acceleration. No white smoke or black smoke.

Seeking vast database of knowledge! (Note, I err on economy rather than performance solutions, even though the two are linked).

5th March 2010
Well it was -2C this morning, and there was no way it was going to start again. It seems like there are no glowplugs working at all, even though this was supposed to have been checked by CSC a few months back and all the glowplugs have been renewed.

However, putting a fan heater on the engine would not do anything to the internal bore temperature (see pic), but just 10 mins with this fan and it starts fine.

Fudge has been very diplomatic and has been suggesting a number of possibilities on the forums and via chat over the phone (thanks Fudge). CSC are having another think about it, although I've ploughed nearly £1k into parts and their labour to try and remedy this (the car is only worth about £2k!). Their latest option, to replace turbo and EGR valve (again) seems a bit overkill. CSC have a CDI turbo unit complete with less than 500miles on it, and might offer a 12month warranty with it. £900 inc labout though It already has a ~6 month old EGR valve that they fitted as part of the very expensive attempt to fix.

Tolsen and martin8462003 have also offered many fine possibilities (thanks!).

I'm now working two forums, this one and Smartz. Here are the suggestions I'm working through, and as reference for Fudge:

1. Earth strap high resistance - engine cranks fine.
2. Poor battery performance - overkill spec battery fitted, cranks fine.
3. Faulty MAP sensor - no idea, maybe?
4. EGR valve clogged up - maybe, but would this stop engine starting, I don't think so?
5. Turbo leaking oil into EGR valve so valve clogs up quick - no idea, Turbo not removed to check, but would not stop starting.
6. Fuel lines and/or pump faulty - CSC checked this.
7. Glowplugs not working - CSC checked this and replaced them.
8. Air getting into fuel line - CSC checked this.
9. Bad fuel - not across so many tanks of fuel.
10. Low cylinder compression - not checked, but would this effect starting? Power is OK.
11. Headgasket blown - no sludge in water. Power is OK.
12. Fuel filter - CSC checked this.
13. Hose to boost control split - not checked, but would this affect starting?
14. Hole where hose connects to turbo inlet not blocked - unlikely, engine power is OK.
15. EGR short to ground. CSC did not say there was a P1403 or P1401 fault code, but they think it is the EGR valve, but this would not cause starting problems?
16. Turbo actuator control pipe seized - unlikely, as power is OK. Does not go into limp mode, no warning lights.
17. Marginal signal from TDC sensor - once engine has started that day, in the evening at -5C it starts fine. Overnight seems to be the problem, and why I think it might be moisture related.
18. Parked on gravel - more moisture comes up through grass/gravel than tarmac/concrete. Might be a factor, but what is this affecting?
19. Oil in TIK pipes makes CSC think it is turbo wear - Tolsen thinks this is more likely to be restricted breather pipes. Blue smoke on start up, and a little under hard acceleration (70k mile engine).
20. K7 relay under seat faulty? But then engine starts fine after first start of the day.

An interesting option is to blank off the EGR valve altogether as suggested by Tolsen. He says there is a slight performance improvement as he blanked off exhaust supply to EGR valve at the turbo, not at EGR valve. He says this means the volume of exhaust that needs be pressurised to spin the turbo around is less, hence turbo reacts quicker. I may ask Fudge to do this (family + work = no time).

Information sourced from:

http://www.smartmania.co.uk/forums/s...ead.php?t=7840
http://www.smartmania.co.uk/forums/s...ead.php?t=8058
http://www.smartmania.co.uk/forums/s...ead.php?t=7976
http://forum.onsmart.co.uk/viewtopic.php?f=3&t=3024

Thanks for any advice offered.

try cycleling the ignition a few time when the temp is below 4 degrees that might help.
this video is at one extream but its basically the same princeple http://www.youtube.com/watch?v=DcJnD5rdVoQ

[polainm]

Yeah this is a great video and seen it before. I wish this was the solution! I do lots of cycling of the glow plugs, makes no difference

When mine starts it sounds a lot better than this!

I've also just driven my 190,000mile Mercedes through French Alps this winter down to -19C, with snowchains and a big shovel (to find it) so I have a good idea of starting diesels in very cold temperatures ( my hand stuck to a fuel pump in one station!).

This is why it really baffles me what this problem on my City Coupe....

[polainm]

Here:

http://www.youtube.com/watch?v=MrsCV_RTmE4&NR=1

Duckjock said the problem was caused by a TDC PowerBOXCR. What is this and where is it, and how much is a replacement? Anyone?

[polainm]

I don't have a Powerbox fiitted, but I wondered if this had replaced some other starting ECU, and so this might be at fault?

it sounds like a sensor is faulting when cold. i think we had a similar fault with a diesel x-type at work and if i recall correctly it was the cam shaft position sensor, but thats a jag and not a smart so that doesnt really help. has it been plugged in on a proper mercedes STAR diagnostic machine to see what codes are logged when it faults?
has an 'injector leak of test' been done? maybe a faulty injector?

[Wildfire]

These symptoms may be air/fuel related, in that when sat overnight, the fuel syphons back into the tank, leaving an air slug at the engine. Is the car parked in the same position each night, or was it different on the 'cold' nights? another issue is fuel filter - diesels tend to be an absolute pain if the filter 'clogs' up. The heat issue may aid in that the fuel lines once heated, by reducing the viscosity and helping the fuel to pass through the filter and into the engine. I realise this sound like teaching granny to suck eggs! but I've been amazed so many times how sensitive to fuel filters diesels have been.

Good Luck.