280ge help needed please...........
Hi,i've been having an intermittent problem running my G for a while[F reg],it's now getting worse,to the point i'm going to hit it with a large hammer; i .Starting is a real issue especially if i dont use the jeep for 24hrs,if i start it everyday it seems to start fine,i have a good battery,thank goodness,and on the bad days it eventually starts,after say 5 to 10 minutes turning over and over and over and even then you have to be very canny with the throttle to catch it just right. ii. Once you do catch it,the revs must be kept sky high to stop it from conking out,around 3500-4000.If it conks out you're back to square one and it takes an age,albeit less time,to start her again. iii.Once driving it's a complete lottery,if driving around town it''s horrendous,every traffic light,roundabout etc where you have to slow down,change gears etc has the potential for the revs to drop and then it dies.If not in town,i.e.open roads,dual carriageway she drives fine,not great but you survive to get to your destination.
Any ideas please,i appreciate this may be a case of try this and try that and one of them will come up trumps .I have had the local landrover garage look at it and they have tried,but failed to find the fault,there are new plugs,leads,cap,thermostat in block and the other sensor beside it was replaced aswell............Many Thanks.nick
Hello Nick,
I feel that you may have two problems, if I am right. Firstly, I suspect you may have false air leaking into your inlet system. This could from the rubber hoses that make up the idle circuit, you will find this under the inlet manifold. The rubber hose do perish and can start leaking in additional air upsetting the fuel/air mixture for the engine to run well. You get difficult starting, idle speed hunting grossly, to maintain engine runing you may have to high idle, engine cuts off on over run, approaching round abouts etc. Check the rubber connectors to the hose from warm up regulator to inlet manifold.
One think that is puzzling me is, that your complaint is when the engine is used daily, the condition is not that bad. Using it after a few days, it becomes harder to start, which, would suggest to me fuel pressure loss problems. Try next time in these conditions to prime the engine a few times and then start it. If it starts better, then there is a fuel pressure loss problem in the fuel system. Do check the distributor cap and rotor condition.
On the whole more information is required.
Cheers,
Hi
LPG ??backfiring?? it all adds up now..... any single backfire at all on the 280ge M110 engine will blow vacuum pipes off and may even blow the airmass sensor off its base ...all causing loss of vacuum ..The" K" Jetronic machanical fuel system provides petrol with an electric pump via a distributor head to an injector for each cylinder..,the vacuum generated when you turn the engine with the starter pulls the air mass sensor open to mix air with petrol ---NO vacuum --- NO air ...NO start on petrol ..the lpg is supplied through the head of the air mass sensor and is much less prone to the air management created by the air mass sensor for the petrol ...until the integrity of the vacuum system is 100% the problems you are having will continue..there are a number of vacuum pipes under the inlet manifold and hard to reach plus the ones to the EGR valve and distributor base...another goes to the gearbox if automatic) if the air mass sensor body is not sitting square on its rubber base your problem will prevail even after all the pipes are in place...Note:: there in no fuel pumping action when you pump the accelerator you are simply jiggling the air mass sensor flap with the limited vacuum that is available.......the fuel system tuning is complicated enough and is only compounded when LPG is fitted......
Thanks for your help guys,i'll look at all the pipes in the morning,i'm pretty sure they are in place but i'll double check,it took a while to find the ones under the manifold but they were all in place last week,you're right about pipes blowing off,they do from time to time but its always been the same one and an easy fix,the gaitor below the air mass filter box,however this hasn't happened in years because its secured really tightly,i'm just thinking that it may be blowing somewhere else now,the pressure needs to blow somewhere ! .........It's a manual box.The air mass sensor,is this an electronic device or simply the box ontop of the manifold?If it's 'just' the box then it's sitting square to the manifold,rubber gaitor below,double clamped,i'll take it off again and check for splits tomorrow but i dont think its this,the flap inside is free and the barrel is clean as a whistle and regularly sprayed with wd40, but i'll check that again aswell.It's definately something to do with air flow,too much or too little,or perhaps as has been suggested an electrical wire earthing on the block but i dont think it's this,tomorrow will probably raise more questions than answers but heyho.Thanks for your help it's really appreciated,they are fantastic vehicles and i'm not giving up.I'll update tomorrow when i've had a good look at stuff mentioned here.cheers.nick
Hi Nick
the petrol start is helped by a seventh injector which is activated by a temp sensor in the cylinder head and the cold start regulator on the side of the engine block ... ( like a choke ) the sequence is ..... switch on ignition and the electric fuel pump runs for a few seconds to pressurise the system....( audible drone ) the electrical circuit is activated by the temp sensor which allows power to the cold start regulator (heats a Bimetal strip) which then allows petrol to flow to the seventh injector....the fuel pump operation may be restricted by a dirty fuel filter ( located with the fuel accumulator near the fuel tank) or the temp sensor in the cylinder head may be faulty...or the cold start regulator may be faulty (common fault) .the air mass sensor is adjusted with a 3mm allen key in a raised access on top of the air mass sensor body ..the idle rpm is adjusted with the grey / white slotted head adjuster below and beside the spark plug distributor....very fine adjustment is required to get things running smoothly....I have detailed schematics and written procedures for calibrating the air mass / idle mixture which I can scan and E'mail to you if required
Well,it's cold out there this morning,especially when faffing around with bits of metal etc.So,my findings;rubber pipes all look good,gaitor checked and airmass flap all good,air mass box sitting nice and square,no visible pipes blown off,from above or below the manifold,no electric cables showing any sign of wear/chaffing.The only thing that looks out of place is a bare spigot ontop of what i assume is a sensor of some sort beneath the inlet manifold.It's a bugger to see and i only spotted it with my torch.If you sit/kneel on the wing you can just see it through some rubber pipes inbetween the second gap of the inlet manifold[2nd gap from the front of the jeep].So,is this meant to have a pipe ontop of the spigot going somewhere?I failed to find the open ended' 'spare' pipe i found last week and my concern is that this is the pipe to go on this spigot but it has now fallen off in the course of driving.I'm going to the garage later to put it up on the ramp and see if we cant find it again.Fuel mass accumulator/filter also sounds like promising chat and would point to loss of fuel pressure so will also look at these on the ramp.Oh and guess what,she started first time this morning,it's always the same,if i dont use it for a weekend i dread the monday morning start up,the rest of the week is just bearable,she starts but i bet she'll run like a back of bits when i head up the road.More later,cheers for your help,i'll update tonight.
Hi Nick
If the engine is on petrol and tuned correctly it should perform as follows-:
first cold start of the day... NO accelerator pressure ( try reaching in from outside and turning the key) after first or second turn of the engine it should start and run at approx 1200rpm with some exhaust emission steam/moisture --no black smoke--- as the water temp rises the rpm should drop to 7/800 rpm...and idle smooth enough to stand a glass of water on the rocker cover with no ripples....any hot start of the day with NO accelerator pressure and first turn of engine the rpm should rise to 1200prm for 5/10 seconds and drop to 7/800rpm ....no ripples!! if you have all the parameters correct the engine is tuned correctly and the emissions should be low.....hot start on LPG should be as quick but with no rpm increase to 1200rpm ...this engine does not run efficiently on LPG because there is no electrical pulse (as with electronic fuel management) to regulate the demand hence the tendency to backfire..try switching back to petrol (to clear the surplus gas from the inlet manifold) before switchng off the engine after each run it will then start on neat petrol not petrol mixed with the residue of LPG......
Hi Nick,
By priming, the fuel system I meant, turning on the ignition (not cranking), switch off and turn on the ignition and repeat this for about three to five times. Then, try to crank the engine to see if it starts.
Pumping the throttle will not do anything for fuel injection systems, they do not have a pump as such, for acceleration, fuel enrichment is all done by the injector body. An extremely clever design, the k-jetronic fuel injection.
Hi Nick,
I used to run an old Range Rover on LPG which backfired occasionally, throwing the engine out of tune because the hoses got blown off. The solution was to fit a one way valve onto the airbox, so that when it blew back the air had a place to go. After fitting this (very simple) device, we had no more problems after a slight bang.......
On your vacuum pipe issues, I have an old 126-series which when I bought it had all the problems you mentioned. Even if the pipes look OK, if the rubber is very hard, they are probably leaking. I replaced the entire set of vacuum hoses and the car has been running perfectly ever since. These hoses aren't very expensive to replace and for the hassle factor of doing it once and for all, motoring becomes a joy again.
Good luck,
Phileas
Hi Nick
I had a similar problem in my 463 300GEL however I think the fuel system is the same as your 460 280.Someone more knowlegable than me might be able to confirm that this is the case.
The cold start regulator on the K Jetronic is controlled by the Over Voltage Protection relay (OVP), this is the large relay with the twin fuses on top. It is found behind the fuseboard on a 463, not sure where it is on the 460.
When the OVP fails the cold start procedure fails to operate and it is like starting the vehicle without a choke. It requires much cranking and when the engine does eventualy catch it runs very badly and any attempt to use the throttle stalls the engine. After several attempts the engine will have warmed sufficently to gently apply the throttle and gradualy build the revs and then maintain them to allow the engine to obtain operating temperature after which it can be driven normaly.I think that this may match your cold start symptoms.
The problem with finding that the OVP is at fault can be tricky because it does not fail completely but starts off with an intermitent fault, as you stated some days it starts fine the next day it does'nt. In the 463 it is easier to diagnose because when the OVP fails to operate the ABS light stays illuminated. In the 460 you could test it was operating by touching the OVP housing as you activate the ignition, if you feel it click then it is operating. I am sure that it could be checked out of the car with a meter but I don't know how to do this.
Hopefuly this will be of some help because an OVP problem can be very difficult to diagnose.
Todays findings;i.EGR valve doesnt work.
ii.Fuel accumulator and filter look old and rusty.
iii.The garage was too busy to put the jeep up on the ramp so i couldnt get to find the missing pipe under the manifold.I have another jeep in the field for parts so am in the throes of removing the manifold to find out exactly whats beneath it and where everything goes.
All your advice has been great and i suspect spot on looking at what im finding,thank you all,further to the posts above can someone please tell me where the ; i. warm up regulator is.ii.the cold start regulator is[are these the same thing?] and lastly where the over voltage protection relay is ? It's an F reg 280 ge.
The list of parts above may or may not need to be replaced but in the event are they items that europarts stock or is it a case of MB only?
Cheers.Nick
p.s.fixwin,i love your chat about no ripples with a glass of water on the head,thats really something to aim for,i'm sure yours does exactly that but i bet if i tried it tomorrow................,well, you know where im at with the jeep right now.Yes i'd love the data for tuning the engine properly and maybe one day i'll get that glass to sit still,in which case i shall fill it with whiskey.cheers
Hi Nick
most EGR valves on G's are in bad shape ..or not there at all .....just make sure the vacuum supply has been isolated and blanked off....filter and accumulator external rust may be an indication of when they were changed last...if the electric fuel pump groans when the engine is idling chances are it is pushing hard to maintain the pressure...if you can drive the vehicle on petrol normally sometimes and not others then fuel supply could be the problem...when engine is hot enough for LPG does the engine run smooth as it used tio do?? all replacement parts are same as the 280 SL and 280 saloons of the era ...GSF Parts and Europarts have them for the cars but do not appear to understand the words G wagon... MB parts are pricey!
Nick
The OVP relay is found behind the fuseboard under the steering wheel on a 460.
Have a read of this it might help...
Just to update and to let everyone who has been very helpful with their advice know what the 'final' verdict is;fuel filter and egr valve knackered,ordered new ones,so should arrive next week,these were the two reasons for it running rough.The cold start is as yet undiagnosed,however the vacuum issue is ruled out,brake aerosol under the manifold,no increase in revs,no splits in tubes/mounting of air mass box or any other potential air leak,at the moment anyway.Conductivity test lined up for next week to pin point either,cold start sensor, ovp relay or the cold start mechanism.One of them is definately at fault.The tip from someone to run on petrol,after lpg use, just before i stop has worked a treat this week and my jeep has started reasonably ok on most days.Thanks again to everyone,i shall post a final findings once i have done the tests replaced parts and put into practice Peter's adjustments of the idle screw and air mass adjustor and drink a glass of whiskey,no ripples,as a toast to all.Many Thanks and Cheers.Nick
Hi again,the saga rumbles on........,can someone please confirm exactly which box is the ovp relay behind the fusebox.There are six to choose from?The one on the far rhs on the back,biggish black one, clicks when ignition turned on but this maybe the fuel relay?
Second,which is the temperature sensor for the cold start relay,is it the one in the middle of the three in the engine block?
Many Thanks,diagnosis still pending...........Cheers
Hi,still none the wiser re ovp relay,my bank of relays doesnt have anything with a fuse on top,i have six boxes to choose from behind the fusebox,any help identifying which one it is much appreciated.nick
Hi Nick, the OVP relay looks like this....
Hi
OVP has a flip top clear plastic cover under which the fuse / fuses sit
Thanks
Gav
Hi Nick
Just dropped my fusebox down tonight to check my OVP as i am having a bit of slow starting when cold and wanted to eliminate this.
After going through all the checks you have been doing already!!!
With the fuseboard hinged down it is easy to see the relay as per the pic in the previous post.
The 10 amp fuse is awkward to get out once you have flipped the lid but with the relay pulled from the board you should be ok.
I have heard of people trying to get to it from though the dash panel at the side of the steering wheel and although you can just
see it you are a better man than me if you can get it out as its hard up against the loom
Thanks
Gav
Thanks Gav and bigblock,i couldn't find the ovp,the box with a fuse ontop because mine aint got a fuse ontop,bloody thing is different,it's a sealed black box,no fuse and nine pins on the base not the 7 that yours have,your type is the only type available and i'm just in the throes of finding out if i can put the new one in the same place as the old one by breaking off the plastic locating pin so it fits the base unit AND still configures to the same terminals as the old one..................................Life is sweet............... .I'll let you know how i get on.cheers.nick
Hi Nick
I have some good inside parts info...
If you can give me the part number off the relay i can check it out for you tonight or over the weekend
The part number should be like this AXXX 545 XX 05 or AXXX 540 XX 45 with the XXX's being other numbers.
If you PM me your chassis number i can check what should be fitted from the factory and see what options you have.
I havnt seen a MB vehicle from the late seventies to the mid nineties that did not have a overload protection relay with a fuse in!!
But you never know i guess?
Did you manage to drop the fuse board down so you could see all the relays?
Thanks
Gav
One last thought
I have only seen this once but i can remember having a vehicle in with the relay missing
Know one could understand how it run at first until we looked closely and fould a wire bridging two pins
and bypassing the relay?
This could be your issue....have you an empty relay hole?
Gav
Second last thought!!!!!!
I just remember i had the chassis number still from the '81 280GE i used to run a few years ago.
On checking out the OVP on the MB EPC it lists part number A126 540 47 45 Switch that is no longer available
but Superceeds to a A201 540 08 45 Overload Protection Relay plus 1 x Additional part which is A123 545 06 28 Plug.
Which is the part the relay sits in and has the same pins as the plug for the early relay just in a different configeration.
Those old type plugs are in two halves and the lid is the same on both and once in two halves the pins /wires just pop out.
The only issue i guess is getting the pins in the right place??!!??
From memory the OVP is approx £59 plus vat from the dealer and the plug a few quid
Hope this helps
Thanks to everyone for all your advice and help,yes the ovp was gubbed and adjusting the air mass sensor helped with general running however i did a compression check a few weeks back and found the real problem was no compression on 1,2 and 3 cylinders and 120ish on the other three.She is still running!The general consensus is that the lpg running hot has burnt either the valves, stems, stem seals or all of the above.Basically take off head machine as necessary and replace,but special MB tool needed to adjust valve springs once re installed.Currently running around in a £400 bmw e30 estate which is good fun,until i decide what to do next/get the money together,/find someone recommended to do the work[not my local garage,i've had enough of them for now]to get it fixed,anyone got an idea of cost,i'm assuming all said and done it's going to be £1000????????cheers.nick
if you don't value originality the 103 series 2962cc engine would be a transplant option or even the 24v 104 3 litre engine as they are both K-jetronic like the 2.8.
Scotland 2007, remember it well. http://web.mac.com/ianwatson158/G_Wizzer/Scotland_Winter_2007.html
Is it using oil, valve guide stems are an issue even without LPG, tried gibsons autos , or to far?
Nice video,hadnt seen that one before,just reminded me of what a great day out that was.still no further on with the engine,having too much fun in my new car,shouldnt really say that on here,but in principle i have a plan,i just need to implement it.i'll let you know how,and when,it gets done.cheers for all the help everyone.nick
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Hi Rakesh,
Thanks for your help,i think we met a while back on the scottish run about with Fred near some dam in the borders a couple of years ago,your name rings a bell but i maybe wrong.Anyway thank you for your thoughts,i'll check those pipes again,i'm pretty sure we found two pipes,one about 25mm diametre,it looked ok and was attatched,i'll look again,and another about 12mm that was connected at one end only,if you put your finger on the end of it the engine fads away,so it was assumed its a breather and left?
I presume you mean pumping the throttle to prime the engine?I'll try that anyway.
Dizzie cap and rotar arm are new but i'll check for wear and cracks in the morning.
Basically you have, i think, hit the nail on the head.I'm convinced it is an air fuel mixture problem somewhere,i didnt want to say in my first post so as not to influence the direction of great minds at work!
If it's a loss of fuel pressure is that a tank,pipe or fuel filter issue,i guess it's potentially all of them,in fact as i write, there is a leak in the tank,i never fill it up,just £20 a go as it runs mainly on lpg,i only use petrol to start it,it NEVER starts on lpg.It's always had the leak,3 years and i've never bothered about it because i use petrol to start only and its always been fine,maybe the hole is bigger now!.In its current state i run alot of petrol,the jeep dies much more readily with lpg and backfires to hell,its a bit scary sometimes.
Before i got onto the fuel tank stuff i was going to ask if you think it may be the ecu,wherever that is?Cheers Nick