190E Starting problems

[Gregor Marshall]

I've had the car for almost three years and about 8 weeks ago it wouldn't start one cold, dewy morning. The engine would turn over but it just wouldn't spark. I checked all the usual and everything seemed ok, so I left it for the day and tried again to start it in but no, same thing. I managed to bump start the car and it has been fine ever since, until this morning, same thing!! Luckily I had parked on a hill and managed to bump start it and I am now dreading leaving work and giving trying it.

It is a 1986 190E, manual, I know the entire history of the car, from when it was ordered new, up until it's second (my uncle), third (my Dad) and now me and it has only done 89k. I checked with my Uncle to see if he'd had the problem and it happened to him about 3 times in 6 years, he changed everything on it the second time but it happened again and was then fine, fixed itself. I asked if my late Dad had the problem and apparently he did and when he asked my Uncle about it he denied all knowlege (brotherly love for you!!) but again it just seemed to sort itself out.

Anyone have any ideas what might be causing this? At the moment I can see no reason for it.

[Lagerlout]

Get yourself on www.190revolution.net - there are a load of enthusiasts on there and lots of technical advice

[madras]

starter motor - can be intermitant but a sign it's on it's way out - they don't last forever you know.

[Gregor Marshall]

Lagerlout said:

Get yourself on www.190revolution.net - there are a load of enthusiasts on there and lots of technical advice

Thanks for that, have registered with them and posted this morning. I did have a look through previosu posts and there were a few starting problems but all very differant, but fingers crossed.

[Gregor Marshall]

madras said:

starter motor - can be intermitant but a sign it's on it's way out - they don't last forever you know.

IO have checked the starter motor and it seems okay and it was replaced about 15k miles ago plus it still turns the engine over perfectly but I'll check it again. Anyway, I thought these MErcs were the most engineered and toughest of the lot!!

[Pentoman]

from my experiences:
1st culprit - fuel pump relay. Fails intermittently. Next time it won't start, listen for the buzz from the fuel pumps (under the rear of the car) when you turn the ignition on. Should be able to hear it inside, goes for about 1 second. If not the relay is bad (or maybe the pump). Very good chance as the relay fails ALL the time if aged.

2nd culprit - ignition computer (on the front wing), had to replace mine after intermittent starting, then finally death

3rd culprit - crank position sensor, the one on the back or the front one.

4th - other stuff that I've never had problems with! Or more traditional stuff such as fuel pumps failed, distributor, rotor, that sort of thing.

post back!

[Lagerlout]

Pento has covered a lot of it. You might also want to get the dizzy cover off, the caps actually have a plastic shroud over them which makes the cap look like it is intact. However, I have seen three 190's when the cover/cap is removed, the dizzy cap falls to pieces. You could have a marginal ignition system and the damp mornings is making it worse/harder to start.

[madras]

yep - what pento said. I had fuel relay go on mine - managed to fix it with a drawing pin as it was just the solder cracked off a contact so check the circuit board if it, as it could be a very cheap repair - thought I kept running our of fuel initially - was intermitant as well.

[Pentoman]

Update please?