smokin hymer

Hymer baby

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Hi can anyone help. I have a problem with my 1989 Merc Hymer 660s, 5 cylinder non turbo, (couldn't pull the skin off a rice pudding but we love her) We have had new glow plugs, new fuel filter, compression test, reconditioned the fuel pump and injectors, she has been run off a separate fuel tank and we still have a problem. From cold she starts on the button but after 30 seconds she seems to miss on a cylinder and start smoking white smoke (not steam) after 2 minutes she clears and runs fine apart from decelerating from speed to stop at traffic lights, where she seems to what to stall, judders and smokes slightly. On hills she struggles, smokes and doesn't run evenly. We are turning gray, running out of mechanics and money and no one has been able to sort it or come up with any solutions to solve the problem. we are based in Sevenoaks in Kent. Any ideas!!! :eek:
 
Not fully clued up on the hymer but is this engine the same as merc sprinters?? if so you need to start looking at the octopus as its called..its a junction pipe just by the main fuel pump the pipe bits split allwing air into the fuel system..failing that as some dont have the octopus fitted check the main fuel pump for a leak in the lift pump diaphram.
also a idea is check the EGR valve is not clogged up (you can make a blanking plate and blank the EGR valve off as its not needed for the emmision test) these can fail in the open position causeing a lack of power as well
 
thanks for your reply ive had the fuel pump completly overhald so im hopeing that is all ok sorry if i sound a bit thick but what is an egr valve im kind of learning as i go and not doing much of it myself ...i can at least point my poor stressed mechanic in the right direction
 
it sound to me like an injector or the pump, white smoke is lack of fuel,blue smoke is burning oil and black smoke is excesive fuel,on the compression test were all cyl's same? get the injectors tested again
it also white smokes if there's water in the fuel?
ask round and try to find an old fitter, landrover or tractor enthusiast:eek::D
 
EGR = Exhaust recurculation valve.

forgot to ask as well is the misfire regular .
It could be a engine valve in the engine not seating properly every now and then when hot.
 
Hymer baby said:
Hi can anyone help. I have a problem with my 1989 Merc Hymer 660s, 5 cylinder non turbo, (couldn't pull the skin off a rice pudding but we love her) We have had new glow plugs, new fuel filter, compression test, reconditioned the fuel pump and injectors, she has been run off a separate fuel tank and we still have a problem. From cold she starts on the button but after 30 seconds she seems to miss on a cylinder and start smoking white smoke (not steam) after 2 minutes she clears and runs fine apart from decelerating from speed to stop at traffic lights, where she seems to what to stall, judders and smokes slightly. On hills she struggles, smokes and doesn't run evenly. We are turning gray, running out of mechanics and money and no one has been able to sort it or come up with any solutions to solve the problem. we are based in Sevenoaks in Kent. Any ideas!!! :eek:
Click to expand...

Could be lots of things, many of which you appear to have already ruled out. Where in Kent are you - I know of a very good diesel mechanic down that way, but don't know how close he is to you. I tend to find more elderly mechanics are better with the older engines ( I have the old 2.4 Merc straight diesel on my 1985 motorhome). On the positive side, it doesn't sound massively serious to me. Out of interest, has your engine git the same knob mine has on the dash which allows you to change the fuel pump? On mine it's like a black plastic key just to the left of the steering wheel (mine is RHD) and right of heater controls.
 
I'd be looking at the injectors again as Old Arfur said. Its not uncommon in older engines to recalibrate the injectors and then the pump not be upto the task. (Remember this is a mechanical fuel pump pre electronic anything)

The other thing to look for is the little inline fuel filter just before the injection pump, they often get forgotten in a service and when they block they cause all sorts of fuel starvation problems.

Another check needs to look at the timing of the pump, pistons, valves, injectors.

Another thought is that you might need to crack open each pipe as it joins the injector whilst manually pumping the injection pump - not a preferred option to clear air. Best to get an "old" (over 50) diesel mechanic who knows how to actually work on an engine and not just read a computer diagnosis.
 
caspar said:
Out of interest, has your engine git the same knob mine has on the dash which allows you to change the fuel pump? On mine it's like a black plastic key just to the left of the steering wheel (mine is RHD) and right of heater controls.
Click to expand...

Thats the engine hand throttle and can be used to get the engine revving higher when a PTO is fitted, it basically just push/pulls the throttle linkage.
 
thank you for your reply roger ...your right my dad used to work on massive diesel generators that were used for emergency runway lights they would actually light a small fire in a pit below in order to get the fuel hot enough to start he was old school ...those kind of guys are few and far between .i will check through those things youve suggested , i dont have a black key thing on the dash
 
Smoking Hymer

Hi Hymer Baby

Did you ever get to the bottom of your white smoke problem? I have a Hymer S550 with the 2.9 Merc diesel engine and it occasionaly does the white smoke thing and lose all power - normally when going up steep hills. I've had the fuel tank drained and cleaned out twice, with new fuel lines and a larger inline fuel filter fitted. It'd driving me mad and none of the garages I've been to so far have managed to fix.

Think my next port of call will be to get the fuel pump itself looked at. Do you know if there is another inline fuel filter somewhere in the engine bay?

Look forward to hearing how you got on.

If anyone can recommend a good diesel mechanic in Hants or Dorset, I would be grateful.

Thanks

Rob
 
Smoke

I bought my third Hymer 2 years ago, its a 93, 5 cylinder 670 merc non turbo hymer, 5 speed manual, I had the same problem, I went through all the usual things the same as you, then I read that with timing chain stretch it can make a difference of up to 3deg on the injection timing before the chain is outside of wear limits, I advanced the timing, a little at a time, as I adjusted the timing so the symptoms improved & so did power & mpg, a small adjustment makes a big difference, I knew if I went to far I could damage the engine so I advanced the pump over 4 stages & maybe 800 miles keeping an eye on engine temp etc, finally I was happy with it.
I set off for France last June from Ireland via UK, down the east coast, across the Pyrenees & up the west coast to roscoff & home, 5000klm (3000 miles) round trip, I do not drive the hymer hard, around 90-100 kph on main roads, I don’t use tolls, like my last hymer (660) its slow up hills but a great motorhome, we averaged 24mpg over the holiday
The engine now starts from cold without smoke & ticks over evenly, after a while as the engine warms up it drops down to its slower tick over, it runs even without smoke.
I understand that aggressive gear changing & harsh clutch work can cause premature timing chain stretch, which is common on these underpowered vehicles
 
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