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Just thought I would post a few pics of my most recent bt of maintenance on the car. To explain what happened, I was driving the car pretty hard, just overtook a car and during the overtake I noticed what felt like a misfire. I slowed down and the car felt OK but I was aware it felt like the cruise control was on as it was not decelerating as normal. Next thing I noticed was zero brake boost meaning a super stiff and ineffective brake pedal. When I pulled over the idle was around 1500rpm but other than that it seemed fine. Popping the bonnet I could hear a big vacuum leak, so I made the decision to drive the car the 10 miles back home. I got home OK, did a bit of research of the symptoms and found many forum threads suggesting a failed 'Jet suction pump'. So, I decided to just buy the spare parts - new pump 058 133 753D £20, inlet manifold gaskets 077129717R x 2 £40, some orings and some stainless single ear hose clips £30 and between yesterday and today I replaced the part. The diagnosis was correct, the original pump (why is it called a pump when it is really just a valve?) had separated causing a huge air leak in the system, indeed the open part is the part that feeds the brake booster so it fully explains the symptoms.
On to the job, well it's pretty straightforward really but there are one or two irritating and tricky parts to it, namely; getting access to some of the buried hoses to remove the single use hose clips, getting the same hoses removed and re-fitted on the steel pipes, and generally the fact that it a LOT of dismantling with just about every underbonnet electrical connection and air hose fitting needing to be opened. Anyway, all in it's around 10 hours for a first time at it, I reckon if I did it again tomorrow I could get it done in about 8 hours, but only because I learnt a few tricks in how to access the most difficult to reach hoses etc. However, even at 8 hours it's a full on job, but obviously very rewarding to get it done and get the car back on the road.
I'm not going to do a DIY write-up but I personally followed the official service manual guide and it describes the job perfectly well for anyone. Basic summary: Remove front bumper, remove air box, drain coolant, disconnect top radiator hoses, put car in service position, remove front intake pipe, remove injector rails and injectors, disconnect all vacuum lines and hoses, remove inlet manifold, clean everything up, fit new parts, re-assemble!!!. Anyway, here's some pics of the job. I didn't really take any of putting it back together but other than getting the 2 most awkward air hoses below the inlet manifold reconnected it was pretty easy.

Useful description of the symptoms there. Cheapo part causing lots of grief. Speciality of the house.

They call it a suction pump because it uses Venturi principal to “pump” the air. Presumably the valve but is just a non-return jobby.

I missed one thing ou in the above report: When I scanned for fault codes before I commenced work these 2 came up (as would be expected from a lean running / air leak situation):
17538 - Fuel Trim; Bank 2 (Mult)
P1130 - 001 - System too Lean - MIL ON
17536 - Fuel Trim; Bank 1 (Mult)
P1128 - 001 - System too Lean - MIL ON

On my car the MIL light was not illuminated however, not sure why.

Probably because it takes 3 consecutive occurrences of the fault for the MIL light to actually come on. I'm guessing you sorted the problem pretty much immeditely. The "MIL on" message is confusing though.

Shoppinit wrote: ↑

Tue Jan 28, 2020 11:59 am

Probably because it takes 3 consecutive occurrences of the fault for the MIL light to actually come on. I'm guessing you sorted the problem pretty much immeditely. The "MIL on" message is confusing though.

Yeah, I took the car straight home when the problem occured, and perhaps I shut the engine off once and restarted at that point, so maybe the MIL came on when the car was in my shed on the 3rd start? Not sure to be honest, but it certainly did not illuminate at the time of failure.

Anyway, here's some pics of the new (on left) vs old (on right) valves. As can be seen the new type is more robust than the old and the top part cannot be removed, so hopefully this new one will not fail any time soon! Also, one very good tip for this job and any others that involved removing and re-fitting the airbox, simply remove the MAF's from the airbox and fit directly on to the intake pipes to save the hassle of getting the whole airbox on and off multiple times when checking the system over! Could save a lot of time! Obviously refit the airbox properly when everything is running right!

Oh, also, the 4th picture down shows the 2 very difficult to get to hoses after re-connecting. The way to deal with these is to connect them before dropping the inlet manifold down on its studs, and try to get the manifold as far forward as possible while still allowing you to get the hoses on. Difficult to explain, but if you do this job I can guarantee you will understand what I mean!!!