W126 fuel accumulator rebuildable? - PeachParts Mercedes-Benz Forum

LandYaghtLover · #1 11-01-2011, 01:12 PM

Found the price of $180 to be a bit more than expected. I am certain mine is bad. After it sits overnight, it seems harder to start. When warm, it fires right up. So something seems to be leaking down when it sits. Given the age of the part, I would rather replace/fix it anyway.

I am guessing its not a part that can be rebuilt, but I thought I would check before spending $200 on a part.

porkface · #2 11-02-2011, 08:49 AM

no, it' s not rebuildable. no, you don't need 1. a bad accumulator causes long HOT starts. the system is designed to hold pressure for approx. 30 minutes. look at the ignition system, bad coil, wires, plugs, especially platinums-even new, cap, rotor. any or all can cause a long cold start. good luck, chuck.

ps2cho · #3 11-02-2011, 12:00 PM

As porkface said, its not your issue in this case.

Check engine temp sensor.

LandYaghtLover · #4 11-02-2011, 03:53 PM

Pretty sure all the temp sensors, besides the gauge one, are original. I will give that a try next. They are probably a lot cheaper than an accumulator!

Thanks guys.

Adler · #5 11-03-2011, 12:13 AM

most likely the OVP relay or the FP Relay . Cleaning the pins also helps
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LandYaghtLover · #6 11-03-2011, 01:18 PM

Quote:

Originally Posted by Adler

most likely the OVP relay or the FP Relay . Cleaning the pins also helps
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What is the FP relay. The OVP I just cleaned up actually. I will probably replace it, but its better than it has been for a while after soldering it up. But cold start problem is still there.

Maybe I should ask this. How many turns of the engine before it should fire up? For me its about 2 or 3. When warm, it start so fast I could not even count the time between starter engagement and it running. Its like flipping a switch.

Adler · #7 11-04-2011, 11:03 AM

FPR : Fuel pump relay . With ageing the cold solder joints can cause problems . If carefully re-soldered most intermittent starting faults are rectified.
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LandYaghtLover · #8 11-04-2011, 12:29 PM

Thanks Adler. Can I assume this relay is in the fuse box? Or is it external, like the OVP relay?

Mike Murrell · #9 11-04-2011, 12:41 PM

Fuel pump relay on 90-91 models is built into a component called a MAS.

Silver box shaped somewhat liked and sized a little larger than a pack of cigarettes.

Mounted more toward drivers side along fire wall. Black knob on top is used to loosen and remove - pulls straight out.

There's a test(I think it's pin 1 & 2 jumpered) to verify FPR circut on MAS equipped cars. Search archives to verify pins.

The MAS controls a half dozen or more circuits and is not diyer rebuildable.

Dealer cost 10 yrs ago was $500-$600 - 3rd party units are rebuilt and were close to $400 a yr. or so ago.

I was surprised by the $180 accumulator. I replaced one of these maybe 5 yrs. ago for way less than that.

LandYaghtLover · #10 11-04-2011, 05:33 PM

Ya, $180 is the best price I found for one.

I will look for the modules. But I think I may already have re-soldered it. There are two boxes to the right of the BOSCH ignition module. These I already re-soldered, one being the KILMA (or whatever). Then there is an open area next to the OVP. But nothing is there.

Unless you mean inside the car? I have not looked there yet.

Mike Murrell · #11 11-04-2011, 07:23 PM

My mistake - I looked up your 1991 560-SEL at the parts site here. You have a separate fuel pump relay - listed in the body electrical section - so you do not have a MAS.

You're lucky - you have independent relays. Mine are combined into the MAS - so if one goes - you replace a $300 + part.

LandYaghtLover · #12 11-04-2011, 10:10 PM

Yuk.

Well yay! for me then

I wonder if the check-valve when bad. I have a new one, but did not install since I think the system uses two. Plus I would like to replace the pumps.

I guess I will do the pumps and check valve(s) and go from there.