hmmm. Not done any real investigation yet, so it MAY be something really obvious. Anglesey trackday yesterday, first trackday since Elvington (where it performed faultlessley). Morning was wet, but noticed a tiny bit of Pinking under full load, so tweaked the timing a TINY bit, to just stop it pinking. Car felt OK, best reference was out of the hairpin, in 3rd, was changing into 4th Gear before a white line on the track. Every lap and it was about 20 ft before the white line. The car felt to be getting slower, did the hairpin > white line test again and I wasn`t needing 4th until 30ft AFTER the line Cars that I could catch in the morning, were leaving me in the afternoon. I think it was noticeable from mid-morning onwards. Did a side by side drag race on track with a friend in a 306 Rallye, he was 2-up, 170HP (ish), I was by myself, he pulled away as if I was in a gear too high Car was a pig to start today when I brought it home. Ended up unplugging the Coil > dictributer HT lead, turned it over for 10 secs, reconnected lead and it fireed up 1st time, was then hesitant to tickover. All 4 plugs are very light coloured, no oil in water or water in oil, so pretty sure HG is OK. The symptoms suggest to me some sort of fuelling issue. Don`t have the gauges to check the pressure, so having a look for solutions. I think the filter could be clogged, but it would be nice to have some way to test. GVK has already suggested checking the inlet side for any leaks which could lean the mixture off. I changed the timing belt the other week, but I don`t think its that. The performance in the morning was normal, it noticeably decreased throughout the day. Anyone got a suggestion?
oops Yes, in my MK2 Track Golf. Standard injection, with WUR Mod and 50mm inlet manifold. Been fine all year, power just fell off during the day at Anglesey. /// wanders off to google ARF meter ///
best thing really is have the fuel pressure checked, tyhis will tell you what is wrong with the fuel delivery system if anything.
You mentioned changing the timing. Might be worth checking that you tightened everything up again in case the timing has moved since.
Fuel pressure check would be good, as already said. If you don't have gauges, have a look in the Tools and Equipment section, as a load of people have just imported them from the US. One of them might be local to you ;o)
Fuel Pump ! i had the same problem a few years ago, fitted new pump and problem solved. p.s. i have one of the fuel pressure testers on the way to me.
Right, this doesn`t seem right at all ! I can start the car with the 5th injector and WUR disconnected Connecting them makes NO difference at all There are zero volts on any of the wires leading to the WUR. I`m guessing this could contribute to the power / starting problem? I didn`t know if anyone would believe me, so I`ve taken a video to show you ! Unfortunately, I`ve loaned out my Haynes manual so am struggling to diagnose the missing voltage Ideas ??
wur plug is only a heater to make it warm up a bit quicker so im not really surprised, it gets 12v whenever the fuel pump relay is running. as for isv it should buzz with engine off and ign on, if not the isv control unit isnt workin right. check the idle switch!
ahh. I thought it needed the WUR to be `working` to start. Thanks for that. I was testing for loose wires, unplugged it and wondered why the car didn`t stall
check the bottom cam belt pully , the key way can some times sheer and throw the cam belt timeing , check the big bolt holding the pully to crank, is tight, giv it a compresion test, , cheers paul
Warmed car up then disconnected Coil. Removed all spark plugs, fitted Compression Gauge and had helper (Matty), full depress the throttle and turn the engine over a few times. All 4 cylinders were withing 0.2 Bar of each other. DRY compression results Cylinder 1 - 13.1 Bar Cylinder 2 - 12.9 Bar Cylinder 3 - 13.1 Bar Cylinder 4 - 13.0 Bar That is as good an indication as I can get that the HG is OK :thumb: Next was a `wet` compression test. The plugs are deep inside the head on the Golf, so I needed to get a bit of Oil into the Bores. I used a bit of brake bleeding hose and the end of a Silicone tube as a small `funnel`. Used clean fresh engine oil to run a small amount into Cylinder 1 Turned the engine over twice, with an old rag over the hole to stop the oil blowing all over. I then fitted the compression gauge and carried out the compression test. Repeated for all 4 cylinders. WET compression results Cylinder 1 - 16.7 Bar Cylinder 2 - 16.6 Bar Cylinder 3 - 16.8 Bar Cylinder 4 - 16.7 Bar That (I think), tells me the engine is in pretty good condition. The wet results let me know there is some bore / piston ring wear which I had already suspected and discussed with Steph at Anglesey (I`m getting a bit of pressure in my oil catch pot, indicating piston blow-by). Next tests I`ll be doing is the Fuel pressure, I need to get an adapter on Monday to fit my gauge to the fuel lines. Had a GOOD look at the telemetry from the weekend today (no screenshots, but I will when I have time). Compared several morning laps (2-up) and late afternoon laps (when I was 1-up). Best morning lap was 1:56.6 That included a lift for Church and noticeable drop in corner speed., I was flat through there all afternoon.I STILL achieved a 3mph higher speed in the morning than in the afternoon, even after being flat for the previous corner and no passenger. On the run to / from the hairpin, the afternoon traces clearly fall away as the car accelerates. I achieved 7mph LESS on apprach to the hairpin and 9MPH LESS on the straight after the hairpin in the afternoon. Best afternoon lap, in the dry and 1-up was 1:59.8 :blink: At least that ties in with my seat of the pants feeling and the `white line > 4th` benchmark I`d been using. I stuck a length of dowel in the No1 spark plug hole. Removed all 4 plugs and with a socket on the bottom pulley watched the Dowell until it was at the top, turned engine clockwise and anticlockwise until I was sure it was at the very top (by eye). I THEN looked at the mark on the cam pulley and the V was lined up EXACTLY with the notch, as it should be. So I`m pretty confident that the timing belt hasn`t slipped and is OK. Tomorrow, I`ll be sorting the gauge to check the fuel pressure. That seems to be a common suggestion in this thread and so is the next thing I`ll be checking.
Trace from Anglesey, the best lap in the morning and the best late afternoon (1-up) lap As you can see, Apex speeds are similar, but acceleration, even with passenger is much better (red trace). The Red traces in acceleration zones are `steeper`.
Using the information on ClubGTi HERE I tested my Fuel control and system pressure. Called at my local Pirtek store to buy the necessary fittings. Connected up the test gauge / valve Started Engine, when settled, saw thew Control pressure which should be 48psi (3.3Bar). Mine was 58psi (4Bar). This is BAD, higher actually means LESS fuel, which is what I was seeing on my plugs compared to before. I then closed the Valve to check the System pressure This should be around 5 Bar, mine was almost 6 ! I made a short video to show how to do it (I`ll add this to my build thread later). To adjust the Control pressure, I need to adjust to Warm Up Regulator, however, I tried adjusting the WUR and the adjusting allen key made NO difference. Now I am sure thats the problem, when it was setup at stealth, adjusting the allen key affected the control pressure (as it should). I`ll source another WUR and fit that. Hopefully it will be the source of the missing horsepower (I`m pretty confident it is).. Fingers crossed thats what it is, the symptoms pointed to the Compression or Fuel, tests so far indicate Fuel.. I`ll be back to report more when I get a replacement WUR...
thing is, when you close the valve as above you've isolated the wur from the equation, so its not that. You have a problem in the metering head or fuel return making the pressure too high! edit: the 2 main fuel pump feed & return banjo bolts have a wee mesh filter inside, it could be one/both of these is blocked? I fitted a pair of bolts without filters on my ABF conversion (nicked off a scirocco), fuel pressure was a touch over 5 bar but still within spec
Jonny, the 6 Bar SYSTEM pressure is due to the valve in the metering head that I need to remove shims to drop the 6bar to 5bar. The CONTROL pressure is adjusted by the WUR when the valve open, as per the guide I linked to. There are 2 adjustments required, I`ll do the 6 > 5 bar first, then the WUR, but as my WUR adjusting screw makes no difference, everything is pointing at that being the culprit. I`m trying to source another at the moment.
