'87 300GD fuelpump/relay or something else fault?
Just spent some more enjoyable time under the bonnet (?!?) replacing fuel filters and checking electrical connections after G died yesterday. Electrics all seemed to fail on ignition (including emergency hazards and interior lights etc, this followed no warning) although clicking could be heard near fuses. Come back short while later and lights back on but on attempting ignition all died again, and repeat... finally abandoned car to return today to replace fuel filters as step 1 in trying to diagnose fault - worth doing anyway even if not immediate cure. Engine now trying to start (so at least achieved something) but no fuel being pumped through to filters. Can no longer hear any clicking from relays behind fuse panel (lowered to check whilst trying ignition). SO, could relay be the problem (how to check and which one, from L to R 2 medium sized (Hella's...), 1 large (wischin something or other) and 1 small, than on back in center another small relay) or could the fuel pump be an issue? It was sold to me with 62k miles (not been able to confirm as no paperwork but doesn't seem unreasonable considering general state). Any help really welcome - still having to defend decision to buy G and not 'cheaper' but modern disco etc. Have to say every time I tinker more impressed with standard of engineering. Doesn't help my defence though!
Cheers, Stewart
You say 300 GD - that is a diesel, so no fuel pump ??
As the above thread says, there is no fuel pump relay.
Sounds like a Battery fault, have you tested this? If Battery is OK, could be earthing fault or...... the list can on and so can I.
Best thing is to get the Battery tested, followed by the charging system and more questions will arise but let us hear about the results of the battery.
W460 -300GD would have a mechanical fuel pump; this needs priming to bleed fuel into the newly changed filter(s). Do this before you crank the engine over to start.
Cheers,
As previously said, there should be no link between the electrical and fuel systems on an '87 diesel G Wagen. The only possibility I can think of is if someone has fitted a fuel shut off solenoid in one of the fuel lines as part of an aftermarket alarm/immobiliser. Your electrical fault sounds like a dead battery, or bad connections/bad earth etc, check the fuses as well, even if they look ok, they corrode on the ends and give bad connections. All in all you would struggle to find a simpler vehicle to work on, so I'm sure you'll get it sorted without too much trouble. Keep us posted and we'll help further if needed.
hi When you say both filters ( one is a caniater filter beside the power steering reservoir and the other is a small white inline filter next to the fuel pump on the main inlet pipe from the tank ..what gave you reason to change the filters? was there much sediment in the small white inline filter? of the road for ten years can cause the old diesel fuel to "Gel" creating blockages and fuel starvation...to bleed the system using the hand pump on the side if the injector pump is long a and tedious..best done by loosening the pipe at the top of the injector one at a time..pump until you get a flow of diesel at the injector and nip the nut closed in mid pump ( against the pressure ) do each one and after tightening the pipe nuts operate the pump until it get hard to press ... turn the ignition on and off without starting and repeat three times watching the heater plug light go out each time.... turn the key to start and all should be well...
something else to try - can you see fuel in the inline fuel filter? if not then it would be worth pulling out the sender unit in the tank - it has a filter on the bottom which can get clogged with sediment. lift the carpet in the rear and you will see a small panel 150mm x 100mm with 4 screws. Remove it and disconect the electrics. Disconect the fuel lines.Turn the sender unit anticlockwise untill it becomes loose then withdraw upwards.Take it out and see if the bottom of the tube is clean.
Just read your last post, they can be a bugger to prime manually sometimes, you could try filling the fuel filter with diesel before re-fitting it. If it's just pumping air it's possible the line from the tank has corroded and is drawing air rather than fuel, this will show up worse when trying to bleed than when the vehicle is running, often you find these kind of faults when servicing a vehicle that was running perfectly before you started! Another trick is to plumb it up to a can of diesel under the bonnet for testing purposes to eliminate the lines to the tank, and I can't remember if theres a filter on the end of the sender in the tank? This comes out through the boot floor. Good luck, keep us posted.
Hi
If i remember right didnt the ingnition switch on the back of the steering lock cause all sorts of random electrical faults as it was going down. They used to wear inside and give intermitant and faulty connections..Quite cheap to replace and the same as the old 307d vans if i remember rightly on the diesels.
Also i can remember the vacuum diaphragm that shuts the engine off going faulty once and causing the vehicle not to start.
Pistonhead or Fixwin might confirm this with their expert mechanical knowledge.
Just ideas on my behalf.
Gav
Seems you have 2 seperate issues here.
1. Electrical .. could just be an earth wire or dodgy connection somewhere
2. Fuel ;1988 300GD should go
fuel tank
filter inside tank (remove from top with level gauge.. watch out as it tends to fall off the black rubber bellows at the bottom)
fuel lines forward
lift pump on injector pump with manual pump
in line clear filter (sometimes; mine has this)
swollen supply hose to damp pressure pulses (it is not straight hose)
fuel canister with bleed nipple on top to front of injection pump
Injection pump
injection pipes
injectors
.. then spill lines back to tank.
.. oh and make sure when you pull the filter/sendor out of the tank that you get the 2 small pipes the right way around; that maybe a fault if someone has already been trying to fault find.
The engine will run without electrics and you have to have Vacuum generated by pump (opposite injection pump on same shaft) to operate the stop switch on the ignition .. so pull that pipe off the injector pump if you think it is a problem.
Some very good advice given to you above, I can understand you could be lost with a bombardment of ideas.
To strenghten advice given by fixwin38; from the evdence so far, the battery is OK, your engine cut out before the renewal of filters, your engine ran whilst there was fuel in the filters and now you are at a stage where fuel is not being drawn into the filters. I think it is safe to say there is or has to be a problem from the tank and inbetween the primer pump. It could be, as one contributor mentions, cleaning of the fuel sender in the tank. Gav.helm mentions a very good and important issue of the fuel cut out, check to see if the lever opens with the igintion on.
Before tinkering with the tank, it may be an idea to have fuel in a portable tank and pipe that to the fuel line before the injector pump; in this way you can establish after priming the fuel filters, if the engine continues runing, that you definately have a tank or line issue.
Armed with this information, you can address the tank issues with confidence rather than do the work and be concerned if you are on the right track. When it comes to the tank, check and clean the sender unit, take care, dismantling the sender unit, the work requires Mission Impossible acurracy because the sensor wire in the sender unit is thinner than a strand of hair, this is your moment of runing the mission impossible tune runing in your head whilst dismantleing the sender unit. Clean the unit reassemble. You can get some cleaning agents from the motor factor, add the additive into your tank. The additive is a baterial cleaning agent, add more fuel, check the fuel feed and return lines and connect up.
Then let us know how you got on.
Cheers,
Hi all and thanks for all the advice.
Agree two faults. Firstly electrical. Not sure what was causing this but WD40 on earth points and cleaning battery connectors seems to have solved this issue (at least for the moment) - although general tinkering and somebody immobilising the immobiliser may have reunited a possible dodgy connection somewhere else.
Fuel issue. Spent bleedin' hours trying to bleed. Would recommend to all attempting this if parked on a hill make sure facing downhill - trying to fight gravity and I lost. Using 2 metre length of hose was able to 'suck' fuel through, but unfortunately also lots of air and hence at no stage could I get the manual primer 'priming' (possibly indicates air leak in system somewhere - had checked sender unit first, removed and replaced and all seemed clean and secure, plus never any signs of diesel leak anywhere. Anyway after a couple of hours of one step forward two back, out with tow rope, bit of manoeuvering and got the G facing downhill. By this time dark and rain started - ah, the dripping of water from the bonnet down your neck, not to mention being parked on a road where buses turn and pass literally inches from my arse. Anyway, with gravity now on my side, a bit more sucking, more priming and gentle words of encouragement (?!?) plus additional jump leads connected - hurrah! [ps; had filled new filter with diesel prior to refit]. Hope it starts again when I go and collect it hopefully in next couple of days!
Thanks again everyone - number of other points raised I might investigate if I get any time, otherwise bring on the snow!
Stewart
Hi
If you do go down the route on the electrical side of the ing switch they are listed as the same on mostof these
W114 / W115 / W116 / W123 Series MB Cars from 70's 80's and the 307 / 308 / 407 / 408 etc van from 70's to 90's as well as most G's
Petrol or Diesel
Hi Gav
from my experience the diesel ignition switch incorporates the vacuum supply for the injector pump stop lever whereas the petrol ignition switch does not have this feature....hence the need for the correct switch when converting a petrol engined G' to diesel power
Hi Fixwin
Yes the steering lock housing itself has the small cut out to take the vac stop plunger with 2 pipes for the diesel and so are different but the electrical switch that unbolts off the back is the same on the old ones...I think W124 / W201 / W463 etc they are different petrol and diesel though and also the diesels have that little plastic excentric lobe to activate the stop plunger.
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Hi,
Thanks for rapid response. Right, no fuel pump relay - eliminates that then!!! Tried battery (hence checking all earths I could find and cleaning battery leads etc) and seems OK, since fault originally occurred dash lights all nice and bright and starter motor purring away nicely. Started straight-up immediately after replacing both filters (fuel residue) before stopping but since then as stated no fuel coming through (tank half full). Tried manual priming and this wasn't drawing anything through hence fuel filters remaining 'dry' - possible airlocks or blockage in fuel lines? G still guarding parents drive - hopefully get back to her tomorrow (25 miles) if something to 'try'. Cheers in advance, Stewart.