oneohtwo

Another quick and easy adjustment is to tighten the throttle cable. Possibly not quite the same issue as hesitation/misfiring but I remember on mine the peddle response often felt slow and hesitant, but there was just a lot of slack in the cable. Tightening it up made a lot of difference. Other things I did that seemed to help around low rev and idle issues were replacing the ISV (or you can clean it - it gets a bit gummed up with carbon deposits and stuff, so if you can free it up and then clean it with brake cleaner it helps) and the dashpot (I swapped mine for a Passat one I think), but as Cressa says there's an awful lot that it could be!

Could be, I've no idea. Might just have seen an opportunity to save a few pence on costs with no loss of performance. Somewhat ironically, I think the cold starting issue (which started this process) may have just been due to a loss of pressure from fuel leaks. It's been sat for a couple of months whilst I looked into all this, so I replaced the battery and it started first time. Might replace the fuel pump anyway as the Bosch seems a good unit and it should give a lot more miles of service than the existing. The Pierburg can be a spare.

I did actually get a reply from Bosch (were pretty quick to respond on email tbf; the guy on the phone was useless), and they said the filter was deleted in 2022 by the factory, as removing it didn't impact performance. I find it slightly odd putting it in without, but as Bosch have presumably tested it and found it fine I'll go ahead. The VDO sender has arrived as well, and fits, so I think we are all good to go.

Interestingly I spoke to HEL and they reckoned they were suitable for fuel lines and are the standard ones they use and send out, and are the only connectors they use (other than for hard lines etc).

Circled in red. You can clearly see the mesh in a plastic ring. The ones I have don't have the mesh, but the clips are still there. I can't work out why this bit would be missing on some. Would Bosch have decided not to fit them? They even have the green QA pen marks else where, just not this bit.

I've picked up another one of the Bosch filters and it to is missing the pre-filter strainer over the inlet. Seems a bit odd. The Bosch website says a strainer is included, and there are pictures clearly showing a filter over the inlet, but they're obviously not being made with them. Spoke to someone from Bosch who was very little help. Not sure where to go from here, I am loathe to install the pump without a filter, but no idea where to get one that fits.

Has it gone in alright? I got the Bosch one but the part arrived without a wire filter over the inlet. The seller said they're other stock was the same, so ordered one elsewhere to compare. Otherwise it seems pretty good quality, and comes with installation instructions and all the clips and hoses needed which is reassuring. It's pretty different to the standard VDO type ones you see around so time will tell how well it fits I guess.

Ah thanks. I used the clamps that came with the HEL fuel lines they sent so assumed they were suitable, but having checked again they are just worm drive type clamps with an aluminium capping piece. I did notice that when I found the leak and retightened they did seem a bit loose. I will swap them out. The only nice thing is they finish off the braided hose quite nicely and stop any fraying.

I managed to get in contact with Bosch parts supply and they confirmed the pump would get up to 4 bar/run at 4 bar OK, so I think Keyo may have been mistaken. Can't find anywhere that mentions flow rate, or what that needs to be, but I think I am just going to go ahead with the Bosch pump as it is listed as a replacement part and there's now no question about the pressure issue, relevant or not.

Had a frustrating day with it last Weds. Finally got around replacing the sunroof motor I bought last year, and decided to investigate the clunking noise when the sunroof opens. Found the source of the clunk but in fiddling about in the to see what had made it start clunking I managed to break off the lug on the sliding mechanism that the spring catch clamps onto. Was very dumb as all I needed to do to fix it was replace the rubber O-ring on the spring catch so it would sit a bit lower when it engages with the slider. To cap it all I found the (expensive from classic parts) motor I bought last year was completely the wrong part. I didn't realise there are two part numbers. Really should have checked what was in the car before buying. So now I am lumped with a motor I can't use, and can't really return as it's been a year.

Yeah, I'm not sure what to think here. It is listed in the parts catalogue (7zap) as 4bar. This is for the Pierburg diagram so I guess listing the 4 bar VDO as a replacement: Perhaps it's a pressure rating for what it can withstand? Although that seems a bit on the limit. Or is it saying it can deliver the flow rate at that pressure? Keyo seemed to think the Bosch part is 3bar after calling them up (earlier in the thread). Does seem odd it is listed for that part number and not have the correct specs. I can't find the flow rate either.

The Lucas part has arrived, in an unbranded box with a Lucas sticker on it, so I suspect it's the same part as all the other unbranded sellers. No great surprise there though. Unfortunately this also means it has no specs on it anywhere to confirm whether it is 4bar or not. I've not been able to identify it anywhere else either, so unsure whether to just go ahead with it or send it back. Edit: I've thought on it some more and I think I am going to send it back and get a Vemo version instead. That is listed as 4bar, and although Vemo isn't really a big brand they are at least a global company that do manufacture some parts in Germany and brand their products accordingly. Most parts are probably manufactured in China, but they have a presence out there so perhaps have a bit more input into their supply chain, rather than just slapping a sticker on a box and shipping onwards. The part is also listed in their parts catalogue, unlike Lucas, which is a bit more comforting. The only visible difference I can see from pictures is the Vemo uses Torx screws for the top casing rather than plain crosshead on the Lucas part. That in itself doesn't mean it's better quality, but it is suggestive of a bit more thought into the design and manufacture process, using more specific parts, so potentially it indicates better quality.

Managed to check and I've got the Pierburg so mildly annoying as it's an extra £100 quid. Have gone for the Lucas pump as hadn't got a response about the pressure, so will see when it arrives.

Ah I better double check that. I thought it was only the very early VRs that had the Pierburgs. Mine is a 94 as well.

Ah, gotcha. That makes sense. So there's no joint in the hard line by the chassis rail? I guess, as you say then, it can only be from the where the rubber hoses connect. Will have another look around there. I suppose the slow start from cold could also be due to a leak especially if it's small. The pressure in the hose will drop over time, and air will get in. Then the pump has to overcome the pressure difference and force the air out before fuel starts getting to the injectors. Once it's running it can probably maintain it a bit. Pump might actually be fine. I'll tighten up all the hoses again and see if that makes a difference.