Author Topic: Fuel pumps  (Read 244 times)

robertd

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Fuel pumps
« on: 15 February 2021, 04:54 PM »

Hoping for some advice on replacement fuel pump on a 1975 280SE Djet.
What is required to fit a Bosch Kjet fuel pump and make it work.
any info would be greatly appreciated
cheers Rob
116   1978 450SEL 6.9 #  4848
116   1979 450SEL  6.9 # 5884
116   1979 450SEL  6.9 # 6225  SOLD
116   1978 450SEL  6.9 # 5128  SOLD
116   1979 450SEL  6.9 # 5884  SOLD
116   1974 450SEL  DJet

daantjie

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Re: Fuel pumps
« Reply #1 on: 15 February 2021, 07:31 PM »
Check out mercedessource on youtube, he has a ton of vids on fuel package conversions.
Daniel
1977 450 SEL 6.9 - Astralsilber

Lance

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Re: Fuel pumps
« Reply #2 on: 15 February 2021, 08:00 PM »
Read my article in the MBCV magazine on the same problem for the W114. This procedure also suits the W116 as the set up is the same. It was in the July or August edition last year.

tcj

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Re: Fuel pumps
« Reply #3 on: 16 February 2021, 01:17 PM »
am I right to remember that Kjet-pumps run with much to high pressure for djet?
Why not rebuild your djet-pump? Martin Werminghausen can do it for you in high quality.
Djet needs 2bar and 650-860cm³ in 30sec.
KJet delivers 5.5bar. Your car will run, but will damage your pressure regulator in long term.
« Last Edit: 16 February 2021, 01:23 PM by tcj »
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robertd

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Re: Fuel pumps
« Reply #4 on: 16 February 2021, 02:27 PM »

Very interesting, Thank you all for your feed back.
116   1978 450SEL 6.9 #  4848
116   1979 450SEL  6.9 # 5884
116   1979 450SEL  6.9 # 6225  SOLD
116   1978 450SEL  6.9 # 5128  SOLD
116   1979 450SEL  6.9 # 5884  SOLD
116   1974 450SEL  DJet

robertd

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Re: Fuel pumps
« Reply #5 on: 16 February 2021, 10:38 PM »
Hi Lance,
I cannot find you magazine article anywhere?
can you confirm year and month please.
cheers
116   1978 450SEL 6.9 #  4848
116   1979 450SEL  6.9 # 5884
116   1979 450SEL  6.9 # 6225  SOLD
116   1978 450SEL  6.9 # 5128  SOLD
116   1979 450SEL  6.9 # 5884  SOLD
116   1974 450SEL  DJet

Pete49

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Re: Fuel pumps
« Reply #6 on: 17 February 2021, 07:21 PM »
or just put it up here....unless it leads to thousands of classic Mercedes being stolen.
What this country needs are more unemployed politicians.
Edward Langley,  Artist (1928-1995)

Lance

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Re: Fuel pumps
« Reply #7 on: 18 February 2021, 01:31 AM »
August 2020

Lance

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Re: Fuel pumps
« Reply #8 on: 18 February 2021, 01:32 AM »
W114 280E D-jetronic Fuel Pump
As these cars get older many of the parts are wearing out and failing. Some are very hard or impossible to get. Or suppliers increase the prices so you keep running old parts that are in poor shape with the risk of breakdown or running issues. One of the parts in this category is the d-jetronic fuel pump. Yours has probably done well for a long time but is now failing or not giving the output your car requires leading to running issues. A good working fuel pump is essential for good operation and to enable the engine to produce the power it should.
The Bosch pump is a very reliable unit but if yours is old, you don’t know it’s condition or if it has been replaced with an alternative then it may be worth replacing it. But what is available? Bosch have rationalised their range of pumps for classic cars into a few units with fitting parts for each application. For the W114 280E and other d-jetronic M110 powered cars the part number is now 0 580 464 999. This is a pump with a kit of parts to suit. However it retails for about $500 which leads you to a “I’ll just keep going with the old pump” attitude which is fine until you are left stranded by the side of the road with a dud fuel pump.
But there is an option. I had a pierburg pump on my W114 280E that struggled at times so I replaced it with a second hand pump. But I was never happy with this as I didn’t know if the pump was near the end of it’s life or even if the output was adequate. There is a simple test of the pump output which I will discuss later. However after changing the pump and other components on my W123 280TE I came up with a possible solution. This car has K-jetronic fuel injection and runs at a higher pressure but I thought that it would be easy enough to set this up on my W114. Read on before you call me mad as I will explain my plan.
The idea was to get the correct D-jet fuel pump but without the kit. This could then be combined with the hose used on the early W123 K-jet and adapted to the D-jet filter. The later K-jetronic components cannot be used. This requires the following components:
Bosch D-jetronic pump:  0 464 580 042, approx $200

Hose pump to filter: 123 470 06 75, about $30
 
Cap nut: 123 990 00 53, about $10, also available from a wreckers
 
Banjo bolt:    Cost: not much if you get it from a wreckers, possibly still available new. Be sure to get the correct one, it is fitted to the early model W123, any dealer can identify the part number. I can’t check the part number as my access to the MB parts application is not working at the moment.
M12x1.5 female to M14x1.5 male reducer
Available here:
https://www.ebay.com.au/itm/Hydraulic-Metric-Fitting-M14-M14X1-5-Male-to-M12-M12X1-5-Female-Adapter/163696674066?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
 
Some rubber sheet from Clark rubber or similar supplier. 3-4mm thick should be adequate.
And lastly, copper washers to suit.
The reducer is the critical component as that allows you to connect this set up to the standard D-jet fuel filter. The all up cost ends up being less than $300, which is cheaper than a recovery truck. Installation is straightforward and is best understood by looking at the attached photo. The hose connects to the pump and is held in place with the cap nut. The reducer is screwed into the fuel pump then the banjo bolt connects the other end of the hose to the fuel filter. Be sure to use quality copper washers. Get them from a hydraulics retailer. If you can’t bend them easily by hand then don’t use them. The cheap ones from the large auto parts suppliers are too hard and won’t seal. The rubber sheet is because the pump is a smaller diameter than the original. You will need it to take up the space in the fuel pump mount to ensure a tight fit.
The only other thing required is to reshape the cover to make room for the cap nut, as this pump has an end outlet rather that side. I did this with a ball pein hammer and a vice. It is thin metal and stretches easily. You will need to do this anyway if you used the official Bosch kit.
Once you have completed the installation you need to carry out the checks. Start and run the car and check for leaks. Re-tighten fittings if you see any weeping. If you have used good quality washers then this won’t be a problem. Check fuel flow, though this is not essential, but a before and after check would be worthwhile. Details are below and in the manual. Mine flowed at 1.3 litres in 30 seconds, which is higher than the 1 litre in 30 seconds required by Mercedes. This won’t be a problem as it just means extra fuel through the return line. Also check pressure, again according to the manual. I had to lower my pressure slightly.
You will end up with a fuel supply system that is better than original and give you many years of worry free motoring. And if your old fuel pump was worn out then you will notice the extra power from having adequate fuel flow. Remember, this set up should be suitable for all D-jetronic powered M110 engines, so that also covers W116 models.
And like all old cars while fixing one problem you will find two more. While laying underneath the car installing the components I noticed a leaking diff seal and CV joint boots that are perished. It never ends does it?
Appendix:
Fuel flow test:
-   remove supply line in the engine bay and install it in a graduated container
-   remove the fuel pump relay and bridge connectors 30 and 87
-   Turn on ignition for 30 seconds and measure quantity ejected
Pressure test:
-   you need  a pressure gauge with a barb fitting
-   remove the cold start valve and connect the gauge
-   turn on the fuel pump as for the flow test
-   check pressure, setting is 2-2.2 bar

Lance

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Re: Fuel pumps
« Reply #9 on: 18 February 2021, 01:34 AM »
Hope this works

Lance

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Re: Fuel pumps
« Reply #10 on: 18 February 2021, 01:35 AM »
I was trying to post a word document which has some images but couldn't do it.

Lance

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Re: Fuel pumps
« Reply #11 on: 18 February 2021, 01:36 AM »
Actually, it did work, word document attached to the post with the images

robertd

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Re: Fuel pumps
« Reply #12 on: 18 February 2021, 06:46 PM »
Great,  thanks Lance.  A well written and informative article
116   1978 450SEL 6.9 #  4848
116   1979 450SEL  6.9 # 5884
116   1979 450SEL  6.9 # 6225  SOLD
116   1978 450SEL  6.9 # 5128  SOLD
116   1979 450SEL  6.9 # 5884  SOLD
116   1974 450SEL  DJet

mrkozzy

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Re: Fuel pumps
« Reply #13 on: 18 February 2021, 07:47 PM »
Yes great Info. Thx Lance.

RobertD, I'm curious. Did you want the information because you cannot source a D-Jet suitable pump or you have a K_ jet pump lying around you want to make use of.?

Kozzy
MrKozzy

robertd

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Re: Fuel pumps
« Reply #14 on: 21 February 2021, 01:58 PM »
Hi mrkozzy,
How you dooin,  I was asked this question by someone in the process of restoring an early 280SE,  1974 model. had an issue with finding genuine Djet fuel pump.
cheers,
116   1978 450SEL 6.9 #  4848
116   1979 450SEL  6.9 # 5884
116   1979 450SEL  6.9 # 6225  SOLD
116   1978 450SEL  6.9 # 5128  SOLD
116   1979 450SEL  6.9 # 5884  SOLD
116   1974 450SEL  DJet