fredfelcher

I installed my C30-84 last year with the RRFPR and ran it like that for a while but then invested in some Saab Turbo Bosch 360's and dumped the RRFPR. I did the CrazyDave 10k pot trick as well and this has resulted in a perfect idle (around 650rpm, pulsewidths 0.8ms, AFR 15) so I'm happy with all that. What I'm not so happy with is intake temps of around 55-60 when doing 70 on the motorway (2800rpm) on these warmer days, and even higher when I 'press on' a bit, so I'm thinking of trying to cool the charge. It's a Mk2 VR6 (hope you C guys don't mind!!) so not much room for air/air IC and would prefer the more efficient water/air anyway. I'm impressed by the PWR/AVT barrel coolers and wondered if anyone knows what size would fit between the charger and the TB (it's OBD2). I PM'ed Lizard Racing on VR6OC but don't think he visits much anymore... Also, I've been going mad trying to eliminate knock at around 2800rpm and up on WOT (especially transition from mid to full throttle when accelerating from around 3000rpm) - the knock sensors are pulling plenty of timing according to my VCDS logs, up to the '15' limit occasionally... I've got a socketed ECU and have burned many chips with different 'maps'; I've got the fuel trims just right for low rpm using my Innovate LM2 in the exhaust (no cat to mess up results) but doing 'on road' testing and logging doesn't give much scope for lots of full throttle runs (I value my licence!) and VCDS logs so slowly with so many measuring blocks at once (for injection period, rpm, knock, lambda - why couldn't they have just one block with it all on?!?). It's quicker if I log with the LM2 but of course I only get Engine Load % this way, not injection time ms which is on the map axes and haven't found a reliable way to convert... WinOLS has plenty of timing maps to tinker with, and I've fiddled with the main ignition map, but wonder if just the air temp correction map would be better, or some combo - I noticed that there's much less knock, if any, if I boot it when the engine's just warmed up but the IAT hasn't caught up, ie early on in the trip. BTW it's a 1.8T relocated just before the TB to reduce heatsoak and for more rapid response. I've toyed with standalone but it's expensive and car would need to be off the road for a while (it's a daily); I could just take it to Stealth, but I'm a stubborn git and want to understand, rather than just throw money at the problem! So in short: - Anyone know which PWR/AVT chargecooler fits a Rotrexed VR6, or is there another good option? - Anyone got any help/guidance on the knock issue (eg how much advance to take out and in which map)? If you read this far then thanks for persevering!

Still very helpful info though Joni, will wire up as you suggest. Will have to find somewhere to run extension tubing along the front - it's currently inside the front wing, so no more room. Your guide on remapping was my inspiration for buying up all the parts I'll need so I'd say you've already done more than enough in sharing that info. Just need the courage to desolder the EEPROM now - can't find anyone else prepared to do it for me! Many thanks for your reply

Need some reassurance here please fellas... My setup: OBD2 VR6, Rotrex with 6psi pulley, Bosch red top injectors (315cc/min at 3 bar), Malpassi RRFPR, Dubsport 6 branch and decat. This thing is brilliant and drives really well but the Torque app on my phone is telling me that LTFT is between -10% and -12%. I expected this a bit with the bigger injectors and obviously the lambda sensor is trimming back but would prefer to have this less extreme. Also, a couple of faults keep coming up in VAGCOM - MAF short to B+ and idle adaptation limit exceeeded. It seems to me that these are also related to the MAF - it's clipping at WOT I suspect and I see the STFT at the limit (-25%) when slowing to a stop sometimes and then it idles badly for a few secs before it returns to normal STFT. Other times it goes open loop on decel and idles fine - not worked out the different conditions yet. I wonder whether it's because the air filter is stuck directly on the end of the MAF, which is directly on the elbow from the charger and I'm getting some reverse flow over the element. Anyway, I was thinking that wiring in the potentiometer mod would help sort some of these problems, but can't find any exact details on it from searching. Am I right in thinking I can simply wire in 2 poles of a standard pot to create a variable resistor in the blue (signal) wire and then adjust to get fuel trim back to around zero? Or do I NEED to have all three terminals on the pot wired up, one to ground? The MAF wiring came from the original car, which had the charger fitted at Storm. It has 2 resistors in series already giving a resistance of (from memory) 1.2kOhm. I was going to wire in series with this rather than undo all the loom tape. I do have a wideband, chip burner and spare ECU's, so will get round to tuning it myself one day (a la VR6Joni), but am too scared to desolder the tiny legs on the PLCC chip at the mo... Cheers for any thoughts - I get cars and I get computers but electronics just don't seem to click properly in my brain...

650 rpm is about right for a VR6; shouldn't be stalling at all from there. If you haven't been able to do a 'Basic Settings' procedure (as above and the Wiki), then a poor man's version is to disconnect the battery for a few minutes and let the ECU reset then teach it by driving around for 30 mins or so trying a few 3rd and 4th gear accelerations at mid and full throttle, plus an idle for at least a minute. If your ISV has been steadily failing for a while then the computer may have been compensating with learned values. It doesn't know you've replaced it. Failing that, the usual suspects would be HT leads and/or plugs, coil pack, MAF.

Thanks for the replies guys. I looked at the page Buttles but unfortunately nothing relevant there (over the last couple of weeks I reckon I've looked at every page Google can find on VR6 MAFs and G70 sensors...) Kev, that's interesting info about the problem with FI. I think it may have coincided with fitting the CAI - perhaps that's just a tiny bit too much extra airflow...! I've been trying to avoid looking through the loom for a short, but at some point I'll have to get my hands dirty. I'll give the voltmeter idea a go first. I don't feel the engine 'hiccup' as such, just the low rpm smoothness not there any more when picking up from low speed (eg 15mph in 3rd, 25mph in 5th) which is there when I clear the code. It's not been remapped yet. I've got some 268s and a VGI to go on before that. I need to get an OBD2 throttle body adapter from Stealth anyway since my manifold's OBD1 from my old car so perhaps I can pick Vince's brains then - never met the guy, will it be like meeting God or something...? My only reservation is that he'll probably persuade me I need one of his lovely turbo kits (and I don't need much persuading!!) - that'll be more saving up then! Cheers for your time fellas

Hi guys, I'm having an intermittent MAF fault: 00553 - Mass Air Flow Sensor (G70) 28-10 - Short to B+ (intermittent) Interestingly this only happens when I give it some welly, not if I pootle about (which is NOT what I want to do in a VR6...) It's an OBD2 in a Mk2 Golf (sorry it's not a C :( ). I've cleaned the MAF then tried two other known good MAFs without any luck. I've checked the wiring at the plug (even taken out the pins with a special tool I bought) and found the insulation had slightly split. Wrapped them properly in insulating tape but same as before. On VAGCOM the airflow values look OK from idle and normal driving. They do shoot up to about 160g/s at full throttle but don't know if this is right or not? The car is well modified - BMC CAI, Dubpower manifold, Magnex with cat bypass and was rolling roaded at 200bhp BEFORE the manifold was put on. I'm wondering if the airflow at high throttle is now somehow too much for the MAF and causing a fault? I can really feel the difference - before I boot it to induce the fault, the low down power is smooth and steady; after it is slightly hesitant just off idle and some minor bucking. Nothing terrible and still great at anything over about 1500rpm, but just not quite right lower down. If anyone has any thoughts or ideas I'd be grateful before I go and get another MAF for $$$ Cheers!

This is excellent news; I didn't know that there was a narrowband output in some of these. It's always put me off fitting one because of the idea of having to drill the exhaust and fit a boss to put a wideband in alongside the existing narrowband. I also read that the sensor needs to be powered every time the engine runs to prevent rapid damage and failure, and the idea of crawling under the car to screw it in or out depending on whether I want to use it for tuning or not was a major turn-off! Now you've got me thinking about it again G60_Marc, thanks. Any idea whether the LC1 or LM1 kits have an appropriate sensor for this?

Hi all, I'm wondering whether anyone has links or documents they could post which explain a bit of the technical aspect of the ECU? I've used VAGCOM for ages and find it as indispensible as a spanner or screwdriver now. The only thing is, I can't find anything in depth about the Motronic software. I bought the Charles Probst book way back when I had a K-Jet; it's got a little bit about Motronic but only generic stuff about what a map is and what it's for. I'm looking for more detail - like for instance how the ECU adapts, under what conditions, special modes, etc. I've searched and read posts by Kevhaywire and RW1 which show they have a huge amount of knowledge in this area, so just wondering where you guys picked this up? For instance, RW1 - how did you find out about the ECU basic settings sequence? Are you trained in this or just enthusiastic amateurs like me? I suppose the ultimate would be to go down VR6Joni's route and learn how to do it all myself. This really appeals to the inner geek in me (no offence Joni...) but I haven't really got the spare time and frankly the cost (widebands, EPROM readers, etc) puts me off with a second baby on the way! Any pointers to material would be much appreciated. I'm not looking to bombard those with knowledge with a hundred questions; I'm an intelligent bloke who should be able to work it out himself, as long as I get the basic info to work from. Cheers for any help you can give!

Very very many thanks for the quick reply RW1; comprehensive and informative as expected! :cheers: Now a small apology: When I checked the induction system over, the MAF was on erm... backwards :epicfail: I've just been out again, with it the right way round now of course, and everything is better including the adaptation values. So, no code thrown for the MAF (presumably as there is still air flow it doesn't know anything's wrong) and the adaptation not happening was the only obvious symptom! Once again, thanks for replying and I hope I didn't waste too much of your time! :oops:

Hope you'll bear with me - I've got a G, not a C :shock: It's an OBD1, 95 VR and it runs well - normally. I decided to 'fiddle' a couple of days ago and check/tighten the induction system, MAF, PCV and filter (BMC CDA). I put it all back on and went to get some V-Power. Probably my imagination but it seemed even more powerful and responsive than normal. On the way home, I stalled at a roundabout; this has not happened before. "Oh good!" I thought, "I've eliminated a major air leak and the ECU adaptation is too far out, I'll just do an ECU reset and enjoy the extra few bhp I've found for free." I noted that the Lambda values (Group 006) were: idle 1.109, part 0.899, full 1.016 before I disconnected the battery. I did the 10 minute 3rd/4th/idle sequences, then the 20 minute drive (OK, with a bit of boy racer silliness thrown in but hey - these Type R's need a lesson now and then...). I pulled over and checked the Group 006 values but they were all exactly 1.000 except the 'Active' value which was fluctuating as expected. Also, I had a couple more stalls sporadically and noted the ISV adaptation in Group 005 was exactly 1.000 (can't remember before, but not 1.000). I thought perhaps having the laptop plugged in from straight after the reset might have prevented the ECU learning somehow (although never heard of this), so unplugged and it did drive a bit better after another 20 minutes or so, but kept idling at 1000rpm after overrun, dropping down to 650rpm after a few seconds. I did a Basic Settings, but reading tonight, perhaps it was too soon. I've been out again tonight, done the same things (laptop only plugged in later this time) and it's the same story - no adaptation and idle dropping to 1,000 initially then 650 after a few seconds. I did notice that this was always true if I decelerated from high rpms (eg over 3000), but if I coasted to a stop in gear and declutched at around 800rpm then the revs usually went to 650 - which is how it always was before. I also noticed, when doing Basic Settings again tonight, that now the Lambda is fluctuating around 1.035 to 1.080, whereas before it would go from 0.970 to 1.025; I think this means it's lean. There are no other driveability problems - in fact it feels a bit quicker than before but perhaps that's in my head. There are no fault codes stored (I cleared an ISV code after those early stalls and it didn't return). So, eventually, to my question: Why won't my ECU adapt? Is it because I haven't left it long enough. Am I being too impatient? Is it because the engine did stall on one occasion during the 10 minute 'quick learn'? If the wife will let me, I'll take it all apart again tomorrow and also clean the ISV - but that was working flawlessly immediately before I fiddled the other day - coincidence? I took my time putting it back together and checked all the hoses carefully for cracks and holes before putting them back. I squirted some contact cleaner on the MAF element too, but I've done that before many times without problems. Any help would be much appreciated. Oh, and thanks if you made it this far without giving up; I thought all the detail would be important!

Cheers gents, suppose I thought have thought of it myself... but that's partly what the forum's for isn't it - helping a thicko like me! :nuts: Both flanges turn smoothly with a bar across for leverage. Thanks again for taking the time to post! :salute:

@ Mrbeige Thanks, I was thinking I'm probably not strong enough to turn it just with my hands; better get the breaker bar out then @CorradoVR6-Turbo and pete_griff Cheers for that, will have a look inside just to be sure. I assume that the drive flange should still turn though, so presumably I'm just being to weedy by hand?

Hi guys, need a little help here. I've bought an 02A with a Peloquin (used) which was APPARENTLY working perfectly well before the guy sold it to me. I trust him not to be lying... My question is, should the driveshaft cups be 'turnable' by hand - they aren't and sound as though there is an obstruction (as if it's in gear). I've tried all the positions of the shifter tower and it seems to be the same. My questions are: - can you turn the cups by hand when it's in neutral or does it take more torque? - how do I know what position is neutral - I can't find any pictures of the shifter tower position for neutral on the net. I need to know before I swap my existing gearbox (without LSD) because I obviously don't want to put in a jammed gearbox - it's going to be hard work enough as it is!!! Thanks for any help you guys can give!