Dead 280GE - starting over and recommisioning
My 280GE has been stood at the bottom of the garden for a year due to me losing heart with it not running in my initial atempts to reinstate it to service. In between working on it I have been in hospital having spinal surgeyr which set me back both physically and mentally. Working on the G-Tank was daunting and I have become disheartened.
We are now running an Isuzu Trooper 3.1TD. It's heavy on furel, the electrics are garbage and it isn't very roomy either, I'd love to get the G running and gas it - solving these issues and getting us back in a german 4x4.
History
To recap, I bought it for 'not a lot' due to a fuel blockage in the tank. The tank was removed, drained, chemically cleaned and recoated then refitted. Following this I replaced the fuel pump and ignition components with genuine Mercedes parts.
The fuel pipes are now all clear up to the metering head and we have fuel pressure there.
Current state
Battery charged and fitted.
Air flow meter fitted.
Fuel distribution head removed due to the control plunger (I am now reading K-Jetronic injection manuals to educate myself!) being stuck.
Ignition system refitted.
Fuel pressure to fuel distributor.
Suspect vacuum system (new pipes ready and a Haynes Merc 280 passenger car manual for the diagram to refit them).
Observations right now
We had it running a few months ago. It was rough (very rough) and idled poorly. Due to other commitments, lack of vacuum pipe information and health it has stood since.
My thoughts at this point are to elimniate some basic issues in order to narrow down the running problems.
- I'm going to pop the spark plugs out to see how the fuel was burning to get an idea.
- The engine oil had fuel in it by the smell of it. I'm going to dump the oil and refill with fresh.
- I think one of the spark plugs had been cross threaded by the PO as it doesn't seat quite right (No.6 at the back - the awkward one! IIRC). Helicoil/thread cutter perhaps?
- The control plunger in the fuel distributor had jammed while off the car. It was stiff when originally removed for cleaning. I know not to dismantle this part so I will soak it in carb cleaner and see if I can work it out slowly, then attempt to get it to move freely.
- Refit the fuel distributorleaving the injector pipes disconnected, bridge the fuel pump relay connections and check the flow from each port by pressing the air flap. Does this make any sense?
- Refit the injector pipes, remove the injectors and do the same test as above (but in a container), checking flow pattern, rate and leakage after shutoff.
- Replace ALL the vacuum pipes to eliminate the possibility of air leakage.
Can anyone suggest any other potential issues I might come across in recommissioning the engine and getting this big lug to run once more?
Any help (virtual or in person) would be great right now. I really want to use the car. I have a spanner friendly mate who is good at basic mechanics but we are both G noobs really and sage-like guidance may be required to achieve this.
Hello G-Funk,
You have quite a task but gone about it the hard way and poosibly costly manner.
I will put thought into your issue and a draft of this will take a few days to respond to. As, soon as I have finished my draft, I will send you you my answer.
Cheers,
Have you got CORRECT fuel pressure at the metering head?? You can have fuel pumping out of the line but at insufficient pressure if the thing-i've-forgotten-the-name-of that sits between the fuel pump and the metering head to maintain the fuel pressure has failed. looks like an in-line fuel filter but isn't!
Chris G
PS I've remembered!! It's called the fuel accumulator.
Chris
" -I'm going to pop the spark plugs out to see how the fuel was burning to get an idea."
"I think one of the spark plugs had been cross threaded by the PO as it doesn't seat quite right (No.6 at the back - the awkward one! IIRC). Helicoil/thread cutter perhaps?"
Checked - No.1 isn't burning properly. This is the cross threaded plug, not No.6 as previously suggested.
"The control plunger in the fuel distributor had jammed while off the car. It was stiff when originally removed for cleaning. I know not to dismantle this part so I will soak it in carb cleaner and see if I can work it out slowly, then attempt to get it to move freely."
Was forced to split the fuel distributor as the plunger was solid in there. Rebuilt, cleaned and lubricated. Now works as it should and slides freely with gravity alone.
"Refit the fuel distributor leaving the injector pipes disconnected, bridge the fuel pump relay connections and check the flow from each port by pressing the air flap."
Refitted, new fuel and fuel pipes bled. Loads of pressure at the fuel distributor and at the ports.
"Replace ALL the vacuum pipes to eliminate the possibility of air leakage."
2 pipes replaced. It's hard to see under the plenum but we think it's all connected. An inspection from underneath the G will help.
So, the result is that for the first time the G fires up from the key for the first time in 3 years. - Idle is lumpy but we suspect this is down to plug No.1 that is not correctly seated. A thorough spark test next session will be carried out to confirm.
- There is a fuel leak (minor) from somewhere on the fuel distributor. New copper washers will be fitted. A new fuel filter and accumulator have been ordered.
- Lots of smoke from the exhaust. I assume this is due to the oil being fuel contaminated. 14mm allen key to be sourced, oil filter ordered.
- The alternator belt squeals like a pig. Looks like it's a pain of a job to swap it due to the PAS pump location.
The battery is on a slow charge for the next session by which time I hope to have more service parts. Looking undernateh there will be brake lines, fuel lines and some welding required - but nothing horrendous. New brake friction parts may be required also.
Hello G-Funk,
Check out the link below:
May be not the efficient way to send a document but I am happy it has transmitted the information I wanted, sorry did not spell check the document.
Cheers,
Thanks for that Rakesh
Very useful information indeed. A compression test is a good idea. I will get a/borrow a tester next week.
Today we had the engine starting on it's own again. Not for long, but it does run. I'm going to get new oil tomorrow and more vacuum pipe. Your diagrams will be invaluable. The Haynes manual for the 280 car is OK, but not the same and the diagrams are somewhat basic. I'd like to get that side of things sorted and out of the equation.
I had to split the fuel distributor as there was no other way to remove the control plunger. Even with special pliers and lubrication over a period of time it was jammed right in there .
Splitting the halves wasn't that eventful. It's basically two machined halves with a rubber diaphragm between. I took care to split it without intruding into the diaphragm area so no damage was involved. Reassembly was easy too. I tightened the casings as hard as I dare. I can only think the advice is to prevent overtorquing or damage to the diaphragm.
Any advice on sorting the spark plug?
Hello G-Funk,
The fact you have to work on number 1 cylinder, better news than if it were number 6.
You may gain slightly better access if the rocker cover were to be removed.
Depending upon how badly the threads have been cross threaded; with thread chaser, fit that firstly into cylinder number 2, take a mental notes at the angle of the thread chaser. You want to recreate this same angle to cut into number 1 cylinder. The start of the cut will be difficult, you may have to gradually initiate the first cut at the correct enough angle.
If this is achieved, continue making small cuts and reverse the cut and go into the cut again, repeating this to and fro motion as slowly and in short cuts as the head will allow. This requires a great deal of patients and determination to do slowly and it should be surely achieved. If you are becoming frustrated, walk away from the job for about 10 -15 mins and come back when you are more composed.
Should this fail then either have a heli-coil or 'time-sert' inserted. They are both, effective repairs but I do prefer the 'time-sert'. It would be better if this could be professionally commissioned.
Good Luck,
I have now researched both the thread chaser and Time-sert/Helicoil options.
I'll get hold of a chaser first and take it slowly. I have tapped things out before so the process is familiar and the thread chaser seems a sympathetic way of working right now.
Good news! No thread chaser required. After some in and out action (by pure chance and repetition) it seated nicely.
This occured while we we doing compression level tests. Armed with a borrowed Gunson kit Matt and I checked the scores for each cylinder.
Working on the G is fun, certainly different to our lowered Mk2 Golfs.
Results below:
Cylinder Pressure (PSI)
1 138
2 125
3 78
4 140
5 130
6 125
While cylinder 3 is a little worrying there do not appear to be any leaks, loss of coolant or other pointers to the pressure loss. As the car has been stood a long while we are wondering if stuck rings could be causing it.
To this end, new oil, filters and engine flush have been picked up. We are going to run the engine for a while, flush it and then refill with the correct oil level. Then run and check again.
As the car hasn't run correctly for years and oil/fuel have been mixing as a result it will be sensibl;e to start with a clean slate and eliminate oil pressure/fuel contamination evident from past attempts to make it run.
Hello G-Funk,
Squirt a few pumps of engine oil into cylinder number three and conduct the compression test again, what readings do get then? If the reading is still low, check the valve clearances and re-do your compression test.
If still you have no improvement to the compression pressure, then the only leakage can be through burnt valves, only a cylinder leakage tester can confirm that. In which case should you keep runing your engine it will idle lumply and have poor acceleration and fuel economy. If you do have a burnt valve and continues runing could cause engine damage, dropped valve and hence further mechanical damage. It looks like a head off job, if the readings do not get better.
You could try and soaking the piston with some carbon cleaner squirted into the cylinder, left over night, before you fire up and, or change oil and filter. Just cap the spark plug hole so the carbon cleaner does not evaporate away quickly, squirt some penetrating fluid in as well.
Cheers,
Thanks Rakesh, I will try that.
I am hoping its not a head off job and we can move onto other work but if that is the case I will prgress accordingly and get the head off to the engine shop.
The tips in your posts are proving very helpful. Again, thanks very much
Well it's been a while since my last diatribe but here we are.
In July last year I was contacted by Gav Helme who offered his time and skills to come and assess the state of affairs on the G.
With some components already swapped he drew up an impressive checklist and by September he turned up one evening, tooled up and motivated to fix the G. I was working late but Gav worked alone until I got home fuelled only by cups of tea and my generally basic information.
Once he ascertained that the ignition system was set up correctly and we had fuel and a spark the compression was tested. One cylinder was low but we poured some oil in the bores and the ratio was instantly improved. This is probably a result of the G being stood for a while.
He replaced the shabby, incomplete vacuum pipes and ensured it was connected up as MB had intended.
Issues with the fuel pump relay and flat batteries aside Gav got a lot done and we were some way to working out where the problem really was. We suspected either the fuel pump relay or a fault at the fuel distribution system (metering head, mixture etc).
All in all I was overwhelmed by how helpful he was and the level of reassurance I got from knowing my basic checks and prior works were not a total waste of time. I was on the right track but needed another pair of eyes. I can't say how much his input to date has benefited me - I really couldn't have done it without Gav.
-
Within a month Gav had looked at the Fuel Pump Relay, checked the internal joints and I had tried to start the G with it installed, all to no avail. With this in mind I was convinced the metering head was at fault. Everything pointed to overfuelling and the original issue of sticky, old fuel blocked at that point never left me.
I looked around, asked and called various breakers but a replacement part was hard to source. Thankfully in late January I came across one on Ebay and bit the bullet and forked out £145 on a used but 'guaranteed working' part which turned up during the snow.
Frustrated (and by now on shifts) I put it to one side to attempt another day.
-
Last weekend Matt and I (bored) on one of my days off, decided to spend the morning on the G. We replaced the part, checked the battery and other systems to refresh our memories and attempted to fire her up. Everything sounded good but she wouldn't fire!
Spark checked out fine and we were a little confused. Pulling the fuel line before the distributor revealed we had drained the tank in testing so 10 minutes later a dollop of unleaded was forced into the tank and a drop in the airflow meter flap.
First time she coughed, spluttered and came into life. Rough and smoky but idling well. Trying to restart in succession proved successful and a smoother idle came about over time.
After 3 years, with a few parts, the assistance of Gav and Matt and more than a little patience my G runs!!!!!!
We now have to replace some fuel lines, the squeaky alternator belt and ditch the fuel filled oil but I feel very happy and am looking forward to having her moving soon and getting the old, worn and untidy issues sorted ready for an MOT>
Expect an update and a lot sooner than past ones! :-)
Although this doesn't seem to be your problem here I have had clogged metering heads on Mk 1 GTI's for similar reasons to a G [rusty tank, fuel filler etc] and have with care, split them to clean out the gunk. Great story, enjoy the 280 engine, revvy and smooth
I did split the old one and managed to do so without ruining the original diaphragm gasket but it seems it was just the valve sticking.
Perhaps a chemical clean might have done a better job but it was moving freely for a while before I refitted it. Definitely the same issue as the Golfs though. I have a 1985 GTI myself and am all too aware of how they suffer. I guess most K-Jet cars of the time are susceptible to it.
More of an issue with mk 1 Golfs and both Sciroccos as their fuel filler necks corrode and dump crud, rust etc into the tank, this gets pushed through when fuel levels are low. Not an issue with the mk 2 Golf as it has a plastic tank. However w460 G-wagen steel tanks corrode top down from the area where the exhaust passes over the tank, the rust gunk crud etc 1st destroys the fuel pump then heads towards the fuel metering head. Best long term solution is a later plastic tank and re-routing the exhaust
Well at the time I searched everywhere for an affordable plastic tank with no luck whatsover.
In the end I reconditioned my steel one which was just gummed up really.
With regard to the exhaust - it's rotten from the downpipe back so a tidy side exit in front of the rear wheel looks to be the best solution. A stainless one made up to suit will be lots cheaper than the OEM restrictor and longer lasting.
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Rakesh,
So far cost has been quite l;imited. Only service parts and a chemical cleaning kit for the tank.
I know where the accumulator is. What would be ideal is a fuel pressure test but I don't have the equipment yet. I also run VW Golfs so the testing gear is the same and may be a worthwhile investment.