Ok, started the test after the car was driven home from work, up to full temp and left for an hour to cool! Connect up the tester (same one Gareth used)! System pressure was at 5.1 bar - so i was happy with that as i did not have any shims left it cool for 10 mins - dropped to 2.8 bar left a further 10 mins - dropped to 2.7 bar That's good is'n it? opened up the valve and started again, pressure rose evenly from 2.7, 3.0, 3.4, 3.8, 4.2, 4.6, 4.8, 5.0 and held on 5.0 bar as the control pressure from the wur! way to high, so i adjusted it down to 3.4 bar as reccomended! turned off engine and have left it for over an hour and it dropped to 3.4 bar! Does that all sound good? Also if left overnight, should the pressure drop to 0.0 bar?
All sounds ok from what you've tested so far, 5 bar is too high for warm control pressure so resetting it to 3.4 bar is about right via the adjustment on the WUR. If your problems are concerned with cold starting then you need to test the car from stone cold and watch the pressure rise - note it down every 15 secs from cold start to fully warm (that should now be 3.4 bar if you've set it right). Not sure if it will start from 0 bar as I think when the pump primes with the ignition you get a small pressure to start with, I forget now.
Cheers Stu! i got to post the gauge back tomorrow, so i got to disconnect tonight I just checked after 2 hours and it's at 0.6 bar, so it does lose pressure all the way to 0.0 then?, then the fuel pump primes and adds some pressure yes? Paul, it's definatelly linked with the wurs, as this 3rd one i had off ro, sort of increased the starting problem, then when i drilled the wur i must have turned the thing like mad by accident, thus the 5.0 control pressure! and it time sthe problem by 100!! So how long is it for the car to be stone cold? is it when the pressure drops to 0.0 bar? 2 hours? or more Thanks
A couple of hours outside with the bonnet up should cool it down enough to test the cold control pressure and watch it increase during warm up. What you need is a nice smooth transition from low to high control pressure as the car warms up rather than a sudden jerky increase. You'll probably find it'll all work nicely now the hot control pressure is set correctly, just keep your drill away from that allen screw!
Cheers Stu, it's in the garage, but i got the door open and windows open also, i'll leave it untill 9:30 that's 3 hours, should be fine then i guess! I know, those damn drills I actually drove to work with the pressure like that today! OMG! I had no power after 2000 rpm in each gear it took ages to get to 70 on the M4 was better when it warmed up, but was still not right! I now know why
Ok, left her to cool down for 3 hours! pressure was at 0.2 bar primed her, it shot to 1.6 bar, started her and she fired up on the button , the pressure rose slowely and evenly to 3.4 bar, took around 40 - 60secs. Sound about right?
got any pics kev of what you've done? nice to hear its working ok! looking forward to fixing mine now.
No pics, i always think afterwards, damn should have done a FAQ! I can take a pic of the gauge, it's still on the car if that is any help? btw - are my figures fine?
i was thinking more of the mods to the WUR but hey never mind. As for the pressures i haven't got a clue!
Aha, just for you Here is the back of the wur, with the brass cap drilled: Here is the set up of the fuel gauge: Edited by: gti_kev
The fuel system should retain some pressure. Check or change the fuel accumulator you may also have a slight leak from the injectors. Edited by: philip walker
That's what i thought! it was right down this morning! I have new injectors coming soon, specially imported from portugal Q1)- One prime and it goes up to 1.6 bar! is that enough to start ok? Q2) - also if the injectors or accumulator are leaking is it causing an airlock? which is why before it took about 5-10 secs to idle fine from a cold start? Q3) - I tried her this morning she started strong and rose very smoothly up to 3.4 bar and stopped there, it took 1 minute 20 seconds to reach 3.4 bar! Does that sound ok? Thanks
hmmmm..... Nice gauge you got there gti_kev !!! I bet that you don't live far from Gareth :-) Should look familiar to Stu as he borrowed it as well !!! Glad to see that it is helping you guys to sort out your WUR probs.
150PDGTI - so your the man to thank! Yes that gauge is brilliant and easy to connect! Thanks so much for lending it out! Did you make up the connections? or can you but it like that? btw - i'll get it in the post to you ASAP!
Thanks gti_kev !! I bought the gauge about 10 years ago, it has imperial threads. At the time my Dad had access to a lathe, he turned the adapter pieces to allow the easy connection.
Nice! Can you help on these questions - Q1)- One prime and it goes up to 1.6 bar! is that enough to start ok? Q2) - also if the injectors or accumulator are leaking is it causing an airlock? which is why before it took about 5-10 secs to idle fine from a cold start? Q3) - I tried her this morning she started strong and rose very smoothly up to 3.4 bar and stopped there, it took 1 minute 20 seconds to reach 3.4 bar! Does that sound ok? Thanks
Q1 - What goes to 1.6 bar? control or system pressure. To be honest if it starts ok and the control pressure goes from about 1 bar to about 3.4 bar then the WUR is working fine. If the system pressure is around 5 bar once started then that is fine too. Q2 - To check this you need to do a "Rest Pressure" test. Run the engine up to warm and turn it off the pressure should not drop below about 2.3 bar over the next 20 minutes. If it does then either the pump check valve or the accumulator or the injectors are leaking. The injectors are easy to check, just pull them out and put them in jars after running and see if any fuel drips !! The check valve and accumulator are hard to test in isolation without dismantling (pipes and connections break on disassambly as well !!!) Q3 - sounds fine, this is something that you cannot really alter from the manufacturers spec, ie the WUR is heated from the engine and resistor which bends a bimetallic strip hence increasing the control pressure by restriction.
