Im posting this in here because I cant seem to get into the engines section on the forum. I recently had a rough idle issue, which turned out to be one of the vacum connections being disconnected - the ECU vacum advance. I reconnected it, and it started hunting (because the CO was then too rich), so I leaned the CO off until it ran a steady idle again. However, since i've connected the ECU vacum advance, its pinking badly at high revs, which is obviously not a good thing. I've re-set the timing to standard with the strobe, and even retarded it back until it runs so poor low down it develops a major flat spot off idle and the pinking still doesnt go away. Cam timing is spot on (the car was/is faster than my mates valver). The engine is standard bar the KR exhaust inlet cam and a 4 branch manifold. Funny thing is, you can floor it in 5th at 30mph and it wont pink, so its like it fuel starvation. Could this be; 1. Base CO setting too lean 2. Knackered injectors (recently put some injector cleaner through it) 3. Dodgy ECU 4. WUR adjustment 5. Something else? Help please!!
Hello mate, if didn't pink before the vaccum hose saga then it's most likely the CO. As you probably know although the book spec is 1% they run much better with base setting of 2-3%. If you've only guestimated the CO I'd get it checked properly.
Thanks golden. I'll take it down to the garage and put it on the analyser and see what it says. Cheers. Also, what effect does shimming the metering head to increase fuel pressure have on the running of the car? Will it let you run more advance or what?
I don't think shimming the pressure valve in the metering head will effect performance as it ups the line and control pressure. The only cheap way to increase fueling is the infamous WUR mod.
Wont be able to check the CO on the analyser until next week as the garage owner is away, i'll richen it a bit and see if it improves things in the meantime. Hopefully it will sort it!
Ok, last night I richened the CO until it started to hunt and then took it back a tad - which from previous experiences, reads well over 2% on the gas analyser. I've also retarded the timing back a bit from standard. ("guesstimated", but im pretty sure they are over-safe settings). Took it out for a run and its still pinking from 4k rpm onwards One thing I noticed is, if revs have been low for a while when driving, then I decide to plant it in second, it wont pink at all, but starts to pink a bit in third. But if I rag it from first gear I get a bit of pinking in second and then even more in third (dont know what 4th is like because I dont want to risk damaging the engine). So it looks like the problem is when its under load (its worse up hills and stuff). Its almost like the ECU is over-advancing if thats possible? I dont think the WUR has been tampered with, as the globe on the back of it is intact, should I take it off and take a look at it? Any help appreciated!
The vaccum hose is a load sensor for the ECU, where is it connected to on the engine side? Also how's the running temperature? When was the last time it had a decoke? How long has the vaccum hose not been connected? What was the performance like before/after refitting the vacum hose, forgeting the pinking?
1. The ECU vacum hose is connected directly to the one way valve (yellow and black) which leads to the servo and comes off the inlet manifold. 2. Running temp is fine, my MFA oil temp is not working but the dash temp gauge goes 1/2 way max. I've recently fitted a new water pump and matrix and given the whole system a flush (didnt have much crap in it anyway), then filled with fresh anti freeze and water 50/50. 3. Hasnt had a decoke since i've had it. Engine has 85K miles on it. 4. I think I knocked the hose off when fitting a new the speedo cable in october - on the same night I set the CO and timing up in the garage which is why I didnt notice any running problems. I actually had the same problem before this setup with the standard inlet cam, but it went away after so I thought the timing/CO setup was what fixed it, but it was the fact that I knocked the hose off. 5. Not too sure but I think it was a bit quicker before I fitted the vacum hose, presumably because it wasnt pinking. Not a huge loss in performance though.
Ok, think I've found the source of the problem. Just had it out at lunchtime, and kept the heaters on max heat with the blower on full.... no pinking! So I guess the problem is that its getting too hot. The temp gauge never reached half way with the blowers on, whearas with it off, it goes just a bit past half way. The fan does kick in though when its left to idle etc? The radiator is tiny on it, half as thin thin and only about 3/4 the length of the 8v one? Incidentally, I have an 8v one ready to fit, just need to get new hoses etc first. Would this be all thats causing it though? how about temp senders etc? could one of these be faulty and giving the ECU a duff reading?
I think the most likely thing from what you've said so far is that the engine is getting too hot. I never pay attention to the water temperature, unless its way off. Oil temperature is much better gauge of the engine temperature. Most likely the engine has been running retarded with the vacuum hose disconnected and now is using the normal ignition map and advancing the timing, showing up the pinking. Do as you suggest and change the rad and see what difference it makes.
I just fitted a new Rad this week on my 16v and the temp at 90mph sits just under the quarter mark or just on it. In traffic for ages it DOESNT go past half way ever. Mine pinked before when it was running hotter. Now it is cooler it also runs alot better and the oil temp is not as hot. Cheers, Toby
Ok, will do. I'll order the hoses as the ones on it kink when trying to reach the bigger rad. What does the temp sender on the side of the head for ignition/ecu do? is it work replacing that too?
i don't have the heater matrix, and i think the car is runing worse after the heater matrix was removed.. so, i can be runing to hot!? i'm constantly about 96 and some times, at 104...
Try a Neuspeed 180 Degree Thermostat and 3 Pole Fan Switch (standard are 195/197). Awesome GTI sell them in the engine section. Wish I'd known just fitted a new stat Edited by: Finite
I managed to get the MFA oil temp working now and its up at 104-106 driving normally, and thats with the heaters on hot, and the weather is pretty cold! dont want to let it run any hotter now so im keeping the heaters on full heat until I put the other rad in. Defo going to change the oil too when I sort the rad out, its bound to be a bit cooked
my oil temp is at 98 when driving normally, a few weeks ago it was at 108 ish. Now when i thrash the nuts off it it will go to 104/6 max. That new rad should make a big difference. My rad was the original from 1989!! Happy fitting, Toby
normal oil temp should be around 98 deg i think but no more really especially not under normal driving conditions also regarding the radiator the 16v radiator is not as wide as the 8v radiator, but the 16v radiator is dual core so should in theory be thicker it is a possibility that it has a 1.6 driver radiator on it that would only be single core but the same size as the 16v radiator and would look very similar (so someone could have made a mistake by fitting a similar one) i would have thought the 8v radiator would be good enough tho your engine temp should never really get over half way unless its a really hot hot day and your stuck in traffic for hours if it is getting up and the radiator dosent change it might be a good idea to get a new thermostat there a dodle to fit and really cheap the thermostat lets water into the radiaor when it gets above a certain temperature, but below that temporature its shuts off the flow to the radiator so the water can heat up (warming the engine up quicker when cold) if the thermostat was defective it would stop water getting through to the radiator even when hot (or maybe not as much water as it should) and this could cause over heating problems also poor timing setup will heat your engine up and cause it to over heat hope that helps
More than likely fuelling as Golden says, but don't rule out the overheating Have you taken the plugs out to see how it's running, signs of coolant etc...? Greenish/blueish tinge on the plugs may indicate a failing headgasket which 'could' be the cause of your hot running. failing that If you don't already, do you use 97/98 ron fuel? My boss filled up my car to send me on a course last week ( normal 95 ) - bastid thing was pinking at high-revs on my way home last night (set up at Stealth with 98 obviously) Edited by: G_V_K
it can be set up to 95, and run great with 95?? cause when the car came to me, it was running 95 and it runned great!!i could feel the power!! after some tweaks made by me, and even with 98, it seems to run bad 98 is so expensive 1l- 1.15
Anyone tried Redline water wetter? Claims to be able to drop the temps by up to 15C http://www.redlineoil.co.uk/trackcooling.htm
