MAYDAY MAYDSY 1988 280GE W460 wagon - not holding revs/backfires and black smoke from exhaust
Hi fellow g owners
So I could do with some help/advice please
After being away for couple of weeks I started my G but after a couple minutes idling it dropped the revs so I tried again and sane thing (could not rev it up) then it backfired (very loudly) a couple of times and benched out a cloud of grey/black. (See photo)
called the RAC and the guy thought it might be the ignition could- he cleaned the terminals, started the G which raved as it should and we left it idling for about 20 minutes.
At his suggestion the following day I replaced the coil but same story- idling for a couple of minutes, not able to rev it past the 2k- engine stopped so stated it again, loud backfire (twice) bleched back smoke and I haven't tried it since.
Any thoughts/suggestions and or help would be greatly appreciated.
Thanks
HenryC
Hmm.
Others will know more, but that's K-Jetronic and idling and mix etc is controlled from that. Assuming you didn't change anything (there is not much to change) or knock anyhting, I am thinking Vacuum system leakage which is what controls everything with Jetronic
Check under the airbox acorss the engine, there is a pipe there which the heat cracks until it splits. Or the feed over to the brake servo.
I think if you fix the air/vacuum it will revert to being good.
Just a guess though.
K-Jetrronic, looks to be a flapper air flow meter as used on Ford Orion 1.6i .. and therefore prone to the flapper getting bent by a backfire .. so now it will think it is getting a lot of air and so will supply too much fuel so runs super rich (or was it the other way around). Fix was to bend flapper back .. back in the day .. but then would need to check the air/fuel ratio on the Lambda sensor. When cold it would run on the "choke" but then as it warms up that will be cut back .. so if it stalls then must be too lean? Smell the tail pipe and look at the spark plugs.. you can smell the rich mixture and wet plugs .. or if plugs are dry then it is too lean. Maybe not helpful but a pointer that you need a K-Jetronics expert .. think they were on Golf Gti too of that era .. hard to find the right person as everyone now expects a plug in computer solution... or if you are lucky they understand carbs.. but this is inbetween.
Yes this sounds promising/likely.
There is a good Jetronics mechanic in Reading ( I will dig out the garage/name) and on Youtube there is a quirky expert on all things Jetronic (the Ke means it is ECU managed)
I also like Kent Bergsma for all things Merc: https://youtu.be/pOZRHt-GkHY
Hi
could be Air / fuel mix issue. Check for air leaks in cracked hoses maybe?
KE jetronic has an ECU, K jet doesn't.
On my 500SEL with K jetronic, I once had an issue with stalling when coming up to a stop. I tweaked the mixture adjusting screw, and then put it back where it was initially, and this fixed the problem. Apparently something internally to the fuel metering unit gets stuck and this frees it up.
As others have suggested, check for vacuum leaks. On the M117 engine, there is a rubber 'shoe' underneath the metering head which likes to rot away and cause vacuum leaks... not sure if the M110 has this too, but it's worth checking out. I seem to remember they weren't too expensive.
Do you have access to a CO tester? This would tell you if the mixture is right. I think it's around 1 or 1.5% from memory, but it's been a while since I messed with these. I used to use a cheap (back then) Gunsons gastester.
Hi Jdring and thanks for your message and the links and it turned out that the breather valve was getting stuck so throwing out the mixture- the system has now been dismantled and as soon as it's been cleaned and refitted hopefully that will be the fix.
Best
Henry
Thanks Gooch - hoses all good and yes mixture was being compromised by the sticking valve. The system has been disconnected and will be cleaned and once it's re fitted hopefully that will sort the issue out.
Thanks for your input.
all the best Henry
Thanks Ben for your input- yup mixture wrong and it's being compromised by the actual breather valve. The system is being cleaned and once fitted hopefully it will sort the problem out.
Thanks again henryc
What actually is the breather valve on a 280GE ? Trying to figure out where that is, in case I get similar symptoms ever.
Hi Jdring - that's what the guy called it- will try and send you a photo when we get back to the UK
Hello, first port of call is to change your fuel filter, once that is done you need to be looking at the warm up regulator, this is crucial for a 280 to run properly, if the car has been standing for sometime, the warm up reg gets clogged with stale fuel
I have had issues with this too on a friends G , its now running
Check out YouTube, there is a guy in the north east with a 280 with the same problem
Does sound like a vacum leak to me but K-jet can lead you down many blind alleys
I had the very same problem. Replaced the warm up regulator and problem solved.
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Hi there - appreciated your thoughts -
it might be a very good guess.I'll check it out tomorrow
Thanks again
H