Hi guys, I'm hoping somebody can help me out, I'm having a number of strange engine issues. I may have found solutions to some of them but I'm hoping you guys might have some pointers. 1) The car sometimes won't catch for ages. The starter's spinning OK. Eventually it'll cough and if you give it a bit of throttle it'll fire up. This is intermittent. It's generally worse when the car's been standing for a couple of nights, although it does occasionally do it after much shorter periods. 2) The car will occasionally stall when put into neutral. I think this is the ICV as the revs will dip below idle before recovering pretty regularly, sometimes it won't recover quickly enough and that's when it cuts out. 3) The very occasionally stalls when standing at idle for long periods of time, for example in heavy traffic. It'll start running rougher than normal, then struggle, then die. Could this also be down to the ICV? 4) The one I'm particularly concerned about is after it's stalled, it often won't want to start again. When this happens, the starter won't spin as if there's no charge in the battery. I've got dash lights, headlights etc all working without dimming. If I leave it for ten seconds or so, it'll then start again. None of these things are more than an annoyance on their own, but the first pair and second pair frequently happen one after the other, leaving me sat at green lights with a tail of annoyed commuters behind me. It's had a fair bit of work recently so here's a list of new parts: Fuel pump, spark plugs, battery. I'm ordering a new fuel relay and ICV. Basically I'm just after some advice and suggestions as to the potential causes. It's confusing me because it's acting sometimes like a fueling issue and sometimes like an ignition issue. I'm wondering if I might have two separate problems, here.
Check the Main battery to body earths behind the battery. Check all the earths have a good connection and make sure battery terminals are on tight.
I replaced the battery myself, so I know the terminals are good and tight. I did, however, do it at night. I am therefore not sure on the condition of the main earths. However, I'm not getting any weird electrical gremlins, so I'm tempted to say my earths are OK. Had a whole palava recently following some bad electrical connections and I gave the terminals a scrubbing then.
Hmm. The fact that the car doesn't even want to turn over after it has stalled to me says either a main supply or main earth somewhere is not right. Does the engine itself sound healthy? is it overheating? Idle control valves are a common cause of lumpy running and cutting out on an ABF, Unfortunately i am not very clued up on KR management although i do run an ABF myself its on digi. so my knowledge here is very limited. I am sure someone else will be able to point you in the right direction.
Right so I've fitted a new ISV, part number 037-906-457/C. The warm idle's now up to 1.5k, I had trouble keeping it going this morning when cold. Interestingly, when the old one was fitted, the warm idle was close to perfect. Is it possible somebody would have adjusted the idle to compensate for a knackered ISV? I'm not 100% on how these things work and what they're responsible for, to be honest. All I know is that they regulate the idle, I don't actually know how they do it!
Fiddling with the idle screw was enough to sort out the high idle when hot, so that's nice. It's idling really poorly when cold, though. About 600 rpm until it starts to get some warmth ad then it evens out. If anybody's got any ideas that'd be great, otherwise I'll just have to start changing parts until something sticks!
I see where you're coming from, but it only seems to happen in specific circumstances, when having stalled due to presumably some sort of starvation problem. Otherwise the starter spins no problem. No overheating and it doesn't sound any different to usual. When it's about to stall whilst idling, it'll cough first. Other than that I haven't noticed anything untoward. Thanks for your help, I appreciate it.
Try the three sensors on side of head particularly the feed for ECU this can cause issues. Also just worth cleaning everything air related and have it set up properly
Did you check the main earths, and your vac hoses? Is the metering flap clean? Fuel filter long on it? Could the fuel pick up be getting clogged? What's the ignition timing set to?
my mate was running abf on bike carbs and were have starting probs which sound ed like a sticky starter but turn out ignitoin timing was out causing this so as tristan say s check it ,
Thanks everyone, a good list of things to check there! I'd read elsewhere the three sensors on the head could cause problems so I've already ordered replacements. If that doesn't sort it out I shall start working through the list. I've also read the warm up regulator can cause problems so I shall check that out, too.
Sounds to me, the WUR is upsetting the metering head fuel mixture adjustment at start and ultimately at idle speed. In addition the idle by pass may be set too low, which causes the cutting off at standstill. You need to verify the former is all good before checking the latter. ABFs tend to run different adjustment setting to KR motors that is for sure.
OK, I'm struggling to work out how I can test the WUR. I can find plenty of guides on how to calibrate it, which seems to involve taking a rubber hammer to some internal pin, but I can't seem to find any information on testing if it's farked or not. I'm lacking a level of background education here, I think. Is there a simple method of narrowing the problem down to the WUR?
start with the basics: http://www.clubgti.com/showthread.php?195423 for testing the WUR as well as the system, control and residual pressures you need to hook up pressure gauges: http://www.clubgti.com/showthread.php?81658 also have a look in my signature link, I have a few k-jet guides in there, the bentley 'k-jetpressuretests.pdf' includes a chart for the control pressure as the car warms up (look at the fig 5-22 chart)
OK, so a bit of an update. I don't have the gear to test fuel pressure, so I took it to a garage. They have told me the WUR is OK and the fuel pressure is fine. The fifth injector is likewise OK. Some ropey vac lines have been replaced as has the rotor arm. The cold running problem is, however, still with me so I'm back trying to sort it out myself. I've had a multimeter on both the ICVs. The original with the faulty valve reads at 4.5 ohms, the replacement at 5.4 ohms. The overrun bypass valve appears to be completely non-functional (revs plummet from 2000+ without slowing until caught by ICV). Also, when the throttle switch is loosened so the arm doesn't engage with it, the idle speeds up a bit; I don't know whether this simply means the idle circuit isn't engaged and so the throttle registers as being slightly open or if it indicates a problem with the ICV? In any event, I have an ICV that is registering as being out of range, resistance-wise. However, having replaced the original ICV, the cold idle issue persists, leading me to believe that the issue isn't necessary the ICV's fault. So two questions: Would a reading of 5.4 ohms be enough to throw out the cold idle and, if so, would you expect the warm idle to be ok? Secondly, WTH even is an overrun idle valve and is it in any way responsible for cold vs hot idle?
Something else of note is that, again when cold, the car is pretty jerky until it warms up as though it's not firing on all cylinders. My gut's telling me this is some sort of electrical issue. I'm replacing all the HT leads and the deceleration cut-off valve. If anybody's got any further pointers I'd be tragically grateful. I'm losing the will to live a bit here. Car's fuel pressure at the WUR is starting off at ~20 and finishing up at ~45, if that helps narrow things down.
the over-run valve doesnt affect the cold idle, though if they fail they can make the car want to stall. if in doubt unplug it for now. if the idle changes when idle switch is not pressed this tells you it is working fine, and the signal is being sent out to the ecu and isv control unit. have you checked the static timing, ignition timing and idle speed yet?
