Merc Misbehaving Malarky

[dollywobbler]

Following Cavette's winning idea of alliteration in car purchase scenarios (see Cavette's Carlton Collection Caper), I shall attempt to hijack this wonderful use of the English language.

 

So, to recap. I decided an all-Citroen fleet wasn't what I wanted, plus the Green Tiger as-was needed a fresh burst of enthusiasm. Enter one VolksAngyl. Lovely to see that car being transformed.

 

I then spent far too long trying to work out what to get next. I was very nervous about the idea of having just the 2CV and BX as a fleet - and rightly so as the 2CV's engine is borked. Perhaps I could actually get a car I really wanted. Something like a V8 Discovery, an Alfa 164 V6 or a Suzuki Cappuccino. Idea one got vetoed on the grounds of sanity. The Alfa and Suzuki came very close and had the 2CV not gone all fatally flawed, I might just have blown every penny I owned to have one of them.

 

Instead, what I really needed was a 20-year old sensible hatchback. Then I spotted the Merc for sale...

 

I drove a R107 300SL recently and that must have made quite an impression. I very much liked the typically-excellent Mercedes-Benz automatic gearbox and the engine that could turn from wonderfully smooth to rorty and powerful depending on throttle pedal position. Having spotted the Merc on Retro-Rides, and that it had been for sale since August, this looked like a slightly left-field view of temptation. It was up for £700, having dropped from £750 last summer. Given that the MOT was less than a month, there was no way I was paying that much. £500 was deemed to low, so I upped the ante to £575 and a deal was done. By text message.

 

Last night, I get a text from the seller's son saying that the car is misfiring so I should bring a trailer or cancel the deal. A tricky one. I'd kind of decided I really wanted the car by this stage, and had insured it and everything. Cancelling would cost me £15 for nothing. Given that the only real option was to go and have a look at the thing anyway, and try and diagnose the fault, I thought I'd go ahead. What could possibly go wrong?

 

My Skoda-loving friend conveniently decided to move from the North East to pretty much on my doorstep not long after we moved here and the idea of a stupid road trip was very appealing. He collected me in his modern Octavia VRS thing, which allowed me to laugh at the complete lack of suspension for almost the entire journey. It really was rather firm.

 

We arrived at the vendor's house not too much later than planned. He was at work but his wife gave us the keys and logbook, as well as a key to the lock-up garage and directions on how to find it. No money had changed hands at this point. I love how trusting some people are! The logbook was even signed.

 

We traipsed to the garage, opened the door and blinded a Mercedes with the sunlight.

 

It was about as interested in moving as I had been at 7am this morning. The starter wheezed a bit. No dice. The Octavia was put onto jump start duty. Still no dice. We poured a can of fuel in, seeing as how the gauge didn't move in the slightest when the ignition was turned on. Eventually, after much will-she, won't-she, the Mercedes deigned to fire up. Hoorah! That meant I could drive it out and have a good look at it for the first time.

 

Seemed alright. A touch of corrosion in the offside rear arch but the front wings were new and the underside looked sound - especially around the front suspension mounts. We drove the short distance back to the vendor's house, but the car started spluttering. I took it for a spin around the block. Very spluttery, but it did clear. I did the only sensible thing I could do. Handed over money and plotted the 150 mile drive home. The car refused to start and needed a jump start. This boded well!

 

Our journey started well. Which means that when I tried pulling out onto the main road, it died completely. I nervously reversed back around the corner with no PAS and a brake servo rapidly loosing pressure. They should teach you that on the MOT. In a car with a pedal-operated handbrake. Anyway, car parked up and we dashed off for more fuel, thinking stale unleaded might be the problem. It wasn't, but it felt better having a fuel light off! Then it wouldn't start again.

 

We were at least getting quite quick at the jump-lead shenanigans now, so soon power was restored. I realised that light throttle allowed it to pull away but give it a good shove of throttle and it died in dramatic fashion. This made roundabouts very interesting but I managed to get as far as a petrol station, where I only managed to get 56 litres in. Off we limped, with a few more 'exciting' moments on roundabouts.

 

In fact, pulling onto the motorway roundabout, the car died again. I pulled onto the verge while the Skoda gave protection from the rear - a big, blue crumple zone. I got it running again and considered the insanity of driving onto a motorway in a car that was clearly very unhappy. What the hell. The sliproad went down, so that should help. Off I spluttered.

 

And she came good. 70mph was swiftly arrived at and everything felt good. The odd belt squeal here and there, but that eased as the miles clocked up. With a warning of OMG TRAFFIK KAOS, we came off the M6, where I discovered that this car seems to be allergic to roundabouts. We pulled into a layby where I did a hot-wheel check - no brakes binding. Excellent. However, the car stank of richness - and I don't mean the money-type. Revving it up caused more spluttering and I now had to accelerate onto a dual carriageway. Splutter, splutter, OMGTHERESTRAFFICCOMING, splutter, vrooooom! A man could get very fed up with this.

 

After a spell on the A45, I decided to take us back to the M6. Roundabouts were hell and motorways tend not to have them. Problem is, they have this stuff.

 

Note that my Skoda friend had decided to protect me from in front at this stage. Thankfully, the car behaved itself impeccably as the traffic ground to a halt. I could gawp snobbishly at the three-pointed star and ponder the lack of buttons in such an executive machine. However, there is a button that makes the rear head restraints collapse, so it's not all bad. The temperature gauge rose to somewhere slightly above 90 degrees, but the car was entirely unflustered by our lack of progress. Given that all throttle input was minimal, there was no misfiring. I'd forgotten how awesome an automatic is in traffic. Bliss.

 

Soon, we got onto the M54 and I could really open the taps. By golly. 188bhp is twice what the BX turbo diesel has, in a car only 50% heavier. It's brisk. And very civilised. I could get to like this. Then the motorway ran out and we approached Shrewsbury. Here, I could keep my speed up, even on the roundabouts thanks to good, deeply-treaded rubber. Don't get me wrong, I was hardly getting all Ken Block in my Teutonic Barge, but if the revs stayed up, the car behaved. Then we stopped for a break.

 

This was a mistake as I attempted to sneak through a small gap when we restarted our journey only for the Merc to stall in the middle of a busy road. Gah! Hopefully the misfiring as I struggled to get the thing moving proved to the annoyed folk who'd had to stop that I was having problems.

 

Welshpool was even worse. I had to stop at a roundabout and pulling away, it just spluttered and splutter. I gave it more throttle, it died even more. I was learning now though. Don't pump the pedal, just hold it down and it'll pick up. Sadly for the car which was about to overtake me, it picked up at just that moment, and 188bhp launched me down the road like a stung Alsation. In fact, I then went sprinting past a truck at an indicated 70mph, at which point I spotted two Police cars in a layby. Thankfully they didn't consider my behaviour bad enough to investigate.

 

I managed to get home without much further drama, but was concerned that the car might not actually have any anti-freeze in it. The coolant is entirely clear. The screenwash was certainly plain water. So, the 2CV has been turfed out of the garage and the Merc squeezed in. Tomorrow, I hope to get chance to try and investigate the misfire. The distributor is the first thing to check, though that wouldn't make it rich, or explain why it only misfires when hitting the throttle from fully-off.

 

Just got enough light for some pics when I got back.

[Mr_Bo11ox]

That looks flipping mint Derek_Wobbler. Fair play to you for persevering with it, I would have thrown in the towel after the second stalling incident.

 

Hopefully the problem will be something fairly trivial, I guess the fuelling and ignition will be fairly unremarkable Bosch stuff so you shouldn't have too much difficulty getting into it.

[cort16]

Epic. It sounds like a bloody nightmare but it's a great looking car.

Surely* it shouldn't be too hard to fix the stuttering problem.

[dollywobbler]

I must admit, previous ownership of a misbehaving Citroen CX auto and a Volvo 740 auto with a duff idle control valve gave me useful experience. Dealing with a misfiring automatic requires a lot of dexterity, hope and patience. It wasn't exactly stress-free but should hopefully be a simple fix. Probably. Oh and the MOT runs out first week in March, so I've got to get a shift on.

[Mr Lobster]

Thats a really nice looking car, hopefully only a minor problem causing its issues...

[Albert Ross]

IIRC I had a similar issue with my 1991 300SE. It had a wide "whitish" translucent vacuum hose running down the top of the nearside inner wing, and a rubber elbow had become disconnected near the back of the nearside headlamp. I believe it may have had something to do with the cruise control, as it only started working after that..... but it may have been a vacuum related coincidence. Worth a little look in any case. Either that, or it might be a manifold air leak....

[vulgalour]

A lot of car for not a lot of money, even with the peculiar splutter problem. I'm sure you'll figure it out.

[dollywobbler]

IIRC I had a similar issue with my 1991 300SE. It had a wide "whitish" translucent vacuum hose running down the top of the nearside inner wing, and a rubber elbow had become disconnected near the back of the nearside headlamp. I believe it may have had something to do with the cruise control, as it only started working after that..... but it may have been a vacuum related coincidence. Worth a little look in any case. Either that, or it might be a manifold air leak....

 

Ooh, thanks for that idea Albert. As it happens, the cruise control does not work. About the only thing that doesn't. Perhaps I should demand my money back as the ad clearly said that EVERYTHING works.

[Cavcraft]

I've just Googled it and according to some bloke called 'Eurotec' the distributor cap and rotor are a common weakness. I've tried to catch him out by asking why my 1989 190E hasn't got a soapy tit wank but I have to pay £24 to get an answer.

[Albert Ross]

Obviously you have to understand that it was a little over 10 years ago that I had the 300SE, my memory is a little faded!

[barmatt]

Excellent write up and kudos for getting another three pointed beauty out of the shadows.

 

This is my current coupe that I'm trying to trade in for an oil burning version but I'm struggling to part with it

 

[dollywobbler]

Nice. I do like the Coupes. Shame you're struggling to sell. They seem popular.

 

Another likely culprit for the misfiring is the OVP relay apparently. I'll start with the dizzy, but might have to get the soldering iron out.

[barmatt]

Nice. I do like the Coupes. Shame you're struggling to sell. They seem popular.

 

Sorry I didn't phrase that correctly, I'm not struggling to sell it, the struggle is to make myself sell it for something more sensible

[dollywobbler]

Ah, that I can understand! Sensible is one thing my Merc isn't, but I like it.

[phil_lihp]

You've done alright there DW, seems like a lot of car for the money and looks like it's in outstanding condition for its age - I actually rate that a mega-sensible purchase, it's a solid, reliable*, spacious, comfortable cruiser, what more could you ask from a sub-£600 car?

 

Hope the problem's a quick fix, these were one of the last 'proper' built-like-a-tank Mercs weren't they? (he says having never actually even been in one before).

[philibusmo]

I had a similar issue on my Cressida when I had it. There was a little pump on the carb with what seemed like a leather seal. This pump was there to put a squirt of extra fuel in when suddenly giving it the beans, such as when pulling away or taking a round-a-bout. problem was that the seal had swollen gotten bigger so either wouldn't open, meaning a very slow get away or would stick open, flooding the engine and causing it to cut out.

I expect this has injection though so please disregard my previous statement. It was a while back as well so my recollection of what that little pump did may be completely wrong.

[seacow]

Brilliant write up - great adventure - top posting!!

[Lord Sterling]

Great write up DW. Top purchasing too withthe Merc, not tried one of these (from what I can remember anyway, I could be wrong) but my cousin does/did have a similar Merc Coupe to BarMatts. I'm fairly sure the misfiring problem is a small problem that cen be fixed.

[Barry Cade]

My fave cars, and the straight 6 3l is a brilliant engine. Before you do anything else, replace the dizzy cap and rotor arm. Use only genuine parts. Not Beru....... You will find that this will 99% cure all your stalling/missfiring issues. Both Mercs I've had with the 3l 6 cyl lump have been bought with this problem have been 100% cured with a new cap and rotor.

 

I have a new head set and fuel filter on top of my kitchen cupboard for one of these (doesn't everyone on here) . Yours for the price of post if you need it.

[Spiny Norman]

That looks an excellent old bus, I'm sure the engine maladies will prove to be quite fixable in one that age, I don't think there's anything too terrifying in them.

Vac pipe maybe?

I'd love a W124, not so much for the old cliche of them being the last properly built Benz and all that, but just for the wonderfully traditional angular 80s styling of the things. My W210 is a great car but it looks so boring in comparison to the older ones IMO.

 

Top purchase that man.

[hairnet]

^^ what they said about gen parts - friend had this on 500 sec

 

rotor and cap from mb sorted it

 

http://forums.mercedesclub.org.uk/showt ... hp?t=50146

[Paul Dupart]

 

 

That photo was taken about 100yds away from where I live! Never seen the Merc about it but does look a good 'un.

[dollywobbler]

Blimey. Small world! I did spot a lovely W123 saloon in white not very far from where this was taken. Chap who sold me this now has a red W126.

[Rocket88]

My fave cars, and the straight 6 3l is a brilliant engine. Before you do anything else, replace the dizzy cap and rotor arm. Use only genuine parts. Not Beru....... You will find that this will 99% cure all your stalling/missfiring issues. Both Mercs I've had with the 3l 6 cyl lump have been bought with this problem have been 100% cured with a new cap and rotor.

 

 

 

Plus eleventy for this...........with any old Merc with problems, start from here!

[dollywobbler]

I'm glad I remembered that the bonnet hinges on a Merc can be switched to open the bonnet right up. Bit scary though as it's very windy today. Also note bonnet insulation of fail remnants.

 

Just about managed to get the dizzy cap off. Not an easy job with poor access, and the bottom bolt is blind. Ugh. Inside the cap, the reasons for the misfire became apparent.

 

Not exactly fresh is it? New Bosch cap and rotor arm on their way for an eye-watering £86. I almost wept.

[Rocket88]

I bet a fairly large amount of Curly Wurlys that's your problem

[hairnet]

dont make him fat

 

break out the sand paper for the time being

[Barry Cade]

Ouch, £73 for the pair from carparts4less, and spend over 75 quid you get £10 discount. add a wiper blade or oil filter to make up the difference. Always check them first as they are part of Euro Car Parts, but usually quite a bit cheaper. Still, it'll be the best 86 quid you'll even spend on a 6 cyl Merc.

 

You may already know, but this site's a big help in getting part numbers, http://partscatalog.ru/mercedes/ which you can type in part numbers into this site to get prices etc. http://www.mercedes-benz-parts.co.uk/

 

Merc parts from Merc are surprisingly reasonable, and often cheaper than factors.

[Skizzer]

Brilliant write-up DW.

 

Fingers crossed for the dizzy fixing it, cos that looks like a grand conveyance to roll around in. Am officially jealous.

[Barry Cade]

http://www.youtube.com/watch?v=OKBB7ZyC ... zVug1W6cfg

 

Development of the W124

 

 

 

How Mercedes is in my mind.. when they were proper.