Had a go at checking the fuel pressures on the Golf after getting a correct hose end made up. My system pressure is good at 5.1 bar but my control pressure doesn't drop much. Sitting at 4.9 bar instead of between 3.4 - 3.8 My residual pressure drops nicely to no less than 2.6 bar. So my 8v has a problem with the WUR or control pressure regulator as the Bentley states. Thinking I may go the 16v route version to set it up better, unless someone knows of a way to sort the 8v one. I cant even undo the flathead screws on the back.
I have ordered a wur rebuild kit so will see what happens when I have done this. Also managed to get a 16v version for £45 posted, but will see what turns up. I would like to stick with original, but do like the idea of adjusting the 16v version. And thanks to a previous mention by Isaac I ordered some kjetronic deloreon shims and they arrived the next day. Brilliant service , so thanks for spotting them
Bloody car..... I get no time for it, was running okay ish and today decided NOT to bloody start. Just catches and fires but nothing else. 1000 checks later and I have zero residual pressure. I linked the fuel pump and built up pressure at the WUR and then she started . I was wanting to fine tune things but this just sets me back A replacement 8v WUR has turned up and I had also ordered a rebuild kit. I will do this soon hopefully and also look at why I am not holding pressure
Rebuilt my old WUR yesterday, giving it a damned good clean inside. I forced carb cleaner through the fuel ports and now have a very clean filter mesh. All back on and the fuel pressures test was good, slowly rising to 3.8 bar control pressure with a 5.1 bar system pressure. But the moment I switched it off I lost all pressure.... The only other item I messed about with is the main pressure.... i will sort this, one day
I may have found the issue after a little googling. I pulled out the complete pressure regulator screw including the end part. Only to find a mashed up o ring. Time to find some replacements
This, unfortunately, is another example of automotive Ball Ache, to your credit, you're sticking with it.
Absolute Ball ache I managed to get some o rings today and tested the car. 3.8 bar control pressure 5.1 bar system pressure And when I switch off the pressure is 2.8 bar and not dropping below 2.6 in 10 mins. So I may have FINALLY sorted the pressure side and will move on to checking the actual injector flow rates. Again... The car starts immediately hot or cold, but isn't quite running right. As though it occasionally misses or when coming off the throttle it's revs dip below a happy place!! So still a ball ache, but I accept the challenge
On the Costelometer of Ball Ache - where are you currently? (0 = Absolute Doddle - 10 = Gonad Rupturing Tormentation)
Sitting at a constant 7..... I must be enjoying the pain. I walk away from it, to take more of my time up researching, then go back for another kick in the balls. Vicious circle
To test my patience I decided to check the fuel flow rate at the injectors now that the pressures are correct. And they are way out. Should be 20ml in 2 mins at idle and mine is double that at 40 ml. Spent the next hour messing around adjusting the flow rates and can't get them any lower than 30mls. I changed the shim to adjust the system pressure down to 4.9bar in the hope that this would help lower the flow, but NO... as i think the WUR keeps the pressure at 3.8 bar. I dont quite know how to sort this one yet!, Balls definitely aching....
I keep faffing with the idle RJ as I can't seem to get it smooth below 1000tpm. The car starts really well, but doesn't seem great as it gets warmer. Seems to really struggle with its revs as it drops below in a hunting tick over. I hear the valve next to the metering head clicking to sort it out. I think my next plan is to replace the 4x filters at the injector lines and check flow rates with the metering plate fully open. Hopefully I can get the flow rate to acceptable figures and then recheck idle flow rates. I also plan to check the valve tucked in front of the inlet manifold to make sure that is working correctly. I am slowly getting there and having a pressure gauge is 100% needed for anyone with kjetronic Any ideas gratefully received
The extent to which the slits in the plunger barrell are open has an influence on fuel flow. Since you appear to have all the pressures correct, is it maybe that the plungers current position is too high in the barrel for the corresponding air flow plate postion? Ideally you need a CO tester to set things, but if you don't have access to one you could try gradually turning the adjustment screw anticlockwise (very small amounts) and tweaking the idle as you go to keep things running. The emissions / air fuel ratio may end up being way off and need sorting later on, but might allow you to drop the fuel flow further as the plunger will be sitting lower with less open slit for the same previous air flow plate position?
I wish I had. Co tester, but I must stop buying things . My plan was to get the car about right and then get it set up properly. May have to resort to a plan B. I think your comment about the plunger explains the fuel flow very well so I will try winding it. Hmm clockwise or anti clockwise though
Okay, so I had another play with this today. and noticed my timing was out!! Via the distributor.. So I reset this. Still not perfect, yet, but slightly better. I did check the aux. Air valve and that works fine. Hopefully fuel filters and flow check tomorrow. I'm going mad doing the same adjusting on the CO screw and trying to get the revs down and have it running nice. It's a challenge I tell myself !
Stick with me... my brain needs to be able to see / hold something to understand it, I struggle with written explainations which is a bit of a handicap on a forum! So... some random thoughts, but as I might've picked up something wrongly, just ignore me if I have. I know your specs. are based on what Bentley quotes, but is there some way of confirming they are as equally applicible to European / UK engines as well? Bentley is written from a US slant, I'm thinking for example of the differences in their more stringent emission requirements etc., and you might possibly be chasing your tail trying to match the incorrect flow rates? Are you using the replacement 16v control pressure regulator or the engines standard one? Do you have some (preferrably Bosch) numbers for either, just to double check they are what we believe they are? What are the warm / cold control pressures for whichever of them it is that you have fitted? If your flow rate is too great you can (as you have tried) adjust the system pressure downwards via the primary pressure regulator shims, but I believe the control pressure will subsequently have to be adjusted also and consequently this combination of changes will affect the fueling curve through out it's entire range and not just at idle. You can also change the flow rate solely by adjusting the control pressure at the regulator, I may be wrong here as it's a bit grey to me at the moment and I've maybe misunderstood, however it's possible this predominately changes the flow rate at idle only. Increasing the control pressure should mean the fuel distributor plunger requires more air flow sensor plate upward movement to attain the same previous upward travel of its own. Did you refurb the throttle body and if so was it reset back to it's base line spec. afterwards? Even it wasn't touched, would be a worth while thing to check... you don't know what's been adjusted over the years, either intentionally of through wear. You need it to be correct so as to then be able to set up the exact zero position of your air flow sensor plate. If the plates out, for example sitting too high, it'll have the knock on effect of making the fuel distributor plunger sit too high also thereby increasing the flow rate. Is your fuel pump new... can you check it's flow rate / pressure is high enough to run consistantly above system pressure? Your residual pressure dropping off too quickly could be at the primary pressure regulator, you've changed the O ring at the plungers tip but remember there's the tiny one we talked about before that's on the smaller push valve that's inside the main body? Engine off and at rest that push valve is intended to stop fuel that was circulating through the control pressure regulator getting back to the tank via the primary pressure regulator, thereby preventing it leeching off some residual pressure. The accumulators potential issues I'm sure your well aware of, but there's also a non-return valve on the fuel pump to consider as it's there for the same reason. Going to stop there, mind is thinking up more questions than answers!
All good points and hopefully would help others at some point too. I am using my original 8v WUR that I refurbished and it happily sat in the correct pressure range. Be nice to get it slightly lower maybe. The one I purchased turned up also as an 8v so that is here in a box. The throttle body got refurbished too and I did test the micro switch works fine, as does the flap movement. I will look at the Bentley a bit more in this. Apologies if I didn't put in this thread that I sorted the immediate drop in reidual pressure when switched off. The very small o-ring on the End as you say, was the culprit. My fuel pumps were new and I recently tested the volume and found it exceeds the Bentley. Accumulator was also new. Should just be a case of setting it all up correctly. After a busy weekend of nights and damaging my fuel distributor/regulator, I have stripped it all down again, rebuilt and painted I today. Groundhog day will start again soon... Ball ache hit a solid 12 out of 10 yesterday
