VR6 Misfire

[Dutch24V 0]

My MAF actually ends in 461 so should be a bit better at dealing with the oil as it has the 1000 degree C hot burn-off cycle.

 

...but fair point if there's no difference between OEM and K&N. Why take the risk of buggering the MAF!?

 

Hmmm, maybe I'm going to stick in an OEM filter to see if there's a difference. I've been running with the K&N for 5-6 years now so should be able to notice if a difference exists...

 

Dutch

[dr_mat 0]

K+N? It's the NOISE, not the performance.. :)

[Kevin Bacon 5]

K&N panel filters don't do anything to the MAF, it's too far away from it. If over oiling was an issue you'd clearly see oil spots on the MAF's inlet tube. It was the K&N 57is that sit an inch away from the MAF that caused the problems....and plums drenching the things with too much oil.

 

And as said, the hot wire burns off any contamination anyway.

 

I find the standard filter dulls the throttle response a bit but I use it only when the K&N is being cleaned.

[Dutch24V 0]

Pick-up "feels" sharper along with throttle repsonse if my memory serves me correct (which it probably doesn't having lived in clog land for so long)

 

BTW, how long do you normally take to clean the filter then Kev???

Took me about 2 hours with drying time.

 

Dutch

[RW1 0]

K+N? It's the NOISE, not the performance

 

Ohhh dead right, but the engine gradually didn't run right and changing the VW paper filter back in with a very gentle clean of the MAF (462 variety) brought it all back to normal again.

[Kevin Bacon 5]

BTW, how long do you normally take to clean the filter then Kev???

Took me about 2 hours with drying time.

 

Dutch

 

I just wash it with soap powder, dry it with a hair dryer and then a blast of oil on each pleated side....

[Dutch24V 0]

I blast or 2 ...and I presume you do not oil the 'engine-side' at all?

I only oiled the outside-air side, but with 2 fine coats!?

 

...After a nice long cruise to work on the highway yeserday morning decided to come back the 'country' route, and what joy did it bring.

 

Full power on a VR is quite a thing when you haven't had it for such a long time! (well, almost full power due to the dieing v.stems and/or rings on 2&6)

 

Also noticed that she doesn't produce as much/hardly any smoke when given some right foot when cold anymore either and fuel consumption is up too. Over fuelling could well have been contributing to plug 6 getting so fouled-up every 6-7000km too so I've replaced it with a new one and will monitor the situation.

 

Will leave the K&N in for now and see what happens as I don't recall any problems when fitted new.

 

Dutch

[dr_mat 0]

Not actually wishing to put a dampener on your current jubilation, but many people have reported in the past that the ECU reset provides respite from the stalling problem for a while. Wait a little while till it's re-adapted and see how it goes.

Given that you've replaced all the important components I'm sure it will be fine, but preparing for the worst will take the edge off the pain if it does in fact go wrong again.. If you see what I mean! :)

[Dutch24V 0]

I understand your concern, but in the last year I have replaced everything but the MAF and TPS and none of it fixed the current problem -so am used to it beleive me! I did a full disconnect of the battery each time something new went on too and it never felt like it did now so fingers crossed.

 

I also know that a rubuild is heading my way soon so am just glad to have it as it is now to be honest.

 

One thing though, I was reading the article on the ecu reset procedure and it states that if you have replaced the TPS then you need to follow the complete reset procedure, not just the last basic settings bit?

 

I didin't do this so should I do a complete reset? She is a little hesitant at times in low revs so was wondering if it would help to do the full reset??#

 

Cheers,

Dutch

[dr_mat 0]

Maybe, but other than the basic settings thing, the rest of the stuff will adapt automatically over time.

[RW1 0]

One thing though, I was reading the article on the ecu reset procedure and it states that if you have replaced the TPS then you need to follow the complete reset procedure, not just the last basic settings bit?

 

I didin't do this so should I do a complete reset? She is a little hesitant at times in low revs so was wondering if it would help to do the full reset??#

 

Yep, lambda adapts continuously for instance. In the first ten minutes it does rapid adjustments to get to the correct values, then after that it adjusts slowly as it is assumed that the conditions are more steady accept for such things as for fuel quality. Idle and mid throttle set themselves up inside the first ten minutes but the full throttle value for mapping offset in the ECU takes about 30 minutes to appear and stabilise.

 

Without the rapid adjustments mode, the ECU I calculated could take as much as 5,000 miles maybe even 10,000 to adjust correctly.

 

The TPS is harmonised in Basic Settings. Without this sequence the ECU guesses where the throttle is and so at small throttle settings and certain low rpm (Less than 1500 rpm). That struggling results symptoms such as stalling on the overrun, roughish engine behaviour (like a slight misfire), the engine slowing slightly without movement of the throttle at small throttle openings, hiccup on pick-up from idle, dullness in the throttle response from shut until opened up a fair way resultling in the car leaping forward as things wake-up, ie. the ECU doesn't see throttle movement, then suddenly does. Not every Corrado behaves the same as tolerance of components masks some of the symptons. The errors in higher revs are less pronouced due to the driving not being, how should I say "delicate".

 

Well, I did write the article plus another one for the Auto Corrado during work with Ross-Tech on VAG-COM in late 2000.

 

DutchVR6, if as you've already said early done the first part the other day, ie. disconnecting the ECU and then a drive, then just follow the second section "Basic Settings", selecting the right group for your ECU fitted ie. 000 or 001. You can do this second section as many times as you want, infact the service schedule calls up the BS sequence every 20,000 miles (30,000 km) but many dealer techs don't do it. Mainly because every VW model year and engine since 1992 have generated loads of different methods. How can a techie be expected to remember them and does he have time to consult manuals. The Corrado BS procedures for each engine (and in some cases certain years of manufacture) are buried away in the manuals and in some cases not obvious to spot.

 

Doing BS on the VR6 will not "show" anything while you've got the engine ECU in this mode. It will be afterwards when you drive that you should notice a subtle change.

[Dutch24V 0]

that's what I was thinking, so will leave it as I drive a fair way each week anyhow.

 

Dutch

[StormyTommy 0]

Update on vr6 misfire: since changing the camshaft position sensor. Its definitely running a lot better, (acceleration faster/smoother) but there is still a problem of slight hesition, think I will have to change the MAF eventually. I've sent a letter to Bosch UK to clarify differences between MAF part #'s 021 906 462 & ... ... 462A but no reply yet. I think StormVR6 fitted the 462A part without problem. In the meantime I'll try to get the throttle body cleaned out (there is oil residue in there?) & battery replaced (putting out low volts). I've also got a head lamp loom from h100vw which I have to fit - never enough time... :roll:

[Dutch24V 0]

If you take your MAF of there should be both a VW and a Bosch number on it.

 

I went to my local Bosch dealer and they ordered the correct part first time based on my license plate and this number. There are/were 3 Bosch part numbers for the Corrado VR MAF and apparently the one in my car has just been supperceeded. Mine was 461 but now it's a 462A!! My ecu ends in AG and is from '94 btw. I checked the MAF before fitting and the 462A has 6 connecting pins, but only 5 are used (as it still has the hot burn of cycle) . I think that 462 only has 4 pins as it doesn't have this cycle & AFAIK thats the only difference bewtweeen the 2 and you can only buy 462 and 462A's now.

 

Anyway, my point is trust Bosch as they will get you the correct part if you order it direct. It was also an exchange part that *only* cost 279 euro inc. VAT!!

 

RW1 - I didn't disconnect my ECU btw and have not done so for well over 4 months now. Based on what you're saying then I should really do this and then the basic settings again to get everything set up properly quicker!?

 

Dutch

[RW1 0]

RW1 - I didn't disconnect my ECU btw and have not done so for well over 4 months now. Based on what you're saying then I should really do this and then the basic settings again to get everything set up properly quicker!?

 

Yep, given the parts changed, disconnect battery, reconnect and drive. Do Basic Settings after a couple of hours running (engine stops/starting won't affect it as longs as the engine gets to operating temperature on each use) and the three lambda fixed settings in measuring blocks group 006 have appeared and settled.

[Dutch24V 0]

OK, will do so this evening and see what comes of it.

Cheers...

[Kevin Bacon 5]

I think a stickied thread of the basic settings procedure might be useful?

 

I've only tried it on block 000 and didn't notice much, but it might help other folks to know the procedure if they want to try it? I don't know the other blocks to try...

 

Cheers

[Dutch24V 0]

Good idea!

 

...It might also be usefull to try and list the procedure for the other measuring block too as I have no idea what to do when in Basic Settings in those. (...if infact they do anything or does basic settings reset all measuring blocks regardless of what group you're in??)

 

Maybe helpfull to include the driving requirements after resetting the ECU in the same place also?

 

Dutch

[RW1 0]

I've only tried it on block 000 and didn't notice much, but it might help other folks to know the procedure if they want to try it? I don't know the other blocks to try...

 

Kev,

Only two groups to use for Corrado VR6 when putting the engine ECU into "Basic Settings" depending on which part number as listed at the bottom of the knowledge procedure.

The procedure is identical for either group selections. There isn't anything more for the Corrado VR6 so a sticky thread won't gain anything more IMHO, its all there in Knowledge Base. (Other VW's - later ones, well thet can be more fun as motorised throttles are involved.). Later Corrado 8v, 16v and the autobox are another game.

 

The effect of basic settings is subtle and dependant on how far out the C is from the final position of the C's ECU optimum settings when all the inputs it looks at during Basic Settings are taken into account. Some cars the effects are mild, some can have quite a change.

 

Dutch,

In your case an ECU part number ending "AG" means selecting group 001 when in Basic Settings.

 

Basic Settings does not affect the measuring blocks and there is no VAG-COM/VAG 1551 procedure to change or "zero" as the ECU hasn't got that facility. That's why the battery has to be disconnected for more than 5 seconds to make it forget.

 

Chris

[Kevin Bacon 5]

Cheers RW1, I forgot Joe's post was in there.

[Dutch24V 0]

hmmm, I did it on group 000!

 

I'm going to do the whole procedure again tonight though with a reset first - so will make sure I select group 001 this time.

 

...so does basic settings actually do anything when on group 000?

[RW1 0]

Dutch,

 

000? No, it's either 000 or 001 active when in Basic Settings mode depending on the Engine ECU fitted .

 

On the C the only other things to dabble with in the Engine ECU are the fault codes, measuring blocks as shown and 03 Output Tests (Output tests not to be done while the C is moving under power!!).

 

Measuring Blocks group 000 is not defined for the Corrado directly but each field in group 000 is a range of values and the workshop manual may say, start engine from cold, select MB Group 000 and check field "Z" goes from "X" to "Y" before the oil temperature reaches 80'C. The other Groups 001 to 006 are as labelled. VAG-COM was running with my label file in the attached illustration from Uwe Ross's VAG-COM website so the display on your PC may be different for some fields unless the 021 906 258 label file is loaded into the "labels" directory associated with VAG-COM.

 

Output Tests lets you check that the six injectors are working electrically, checks the ISV electrically, Charcoal Filter Valve electrically, Lambda probe relay, exhasut gas recirc and two stage manifold change over. The Last three may not work depending on the C and it's components. My 1995 didn't but the relay is fitted, hmmmm.... Either silent clicks or the wiring diagram is telling me porkies.

 

Output test can only be done once per interrogation of the ECU ie. Engine 01 selected. The ignition then has to be cycled off/on to reprime the ECU. Basically you turn the ignition on but don't start the engine, select 03 Output Tests. The screen will present you with a "Start/Next" button. Press it, then press the accelerator fully and release. Injector No.1 will fire 5 clicks rapidly, press the accelerator again fully and No.2 will do the same ..... upto No.6. After No.6 injector has clicked away, press the "Start/Next" again and the ISV will start to cycle at about 2 second intervals continuously until..... Press the "Start/Next" again and the Charcoal Filter valve will cycle. Press the "Start/Next" again and the Lambda Probe heating relay will tick (not mine though). Press the "Start/Next" again and the last two are Exhaust Gas Recirc valve and Two Stage manifold if either are fitted (not UK VR6 models). Exit via "Done/Go Back". To do it all again, the igniton must be switched off/on.

 

Summary:

 

Engine ECU - Fault Codes, Measuring Blocks 000 to 006, Basic Settings for ECU/Throttle matching, Output Tests.

 

ABS ECU - Fault codes only.

 

Key Immobiliser - Fault codes and Basic Settings for Key replacement, key & Engine ECU matching (post October 1994 C's with 021 906 258CP engine ECU immobiliser compatible standard fitted).

 

Autobox ECU - Fault Codes, Measuring Blocks, groups 001 to 005, Basic Settings for Engine ECU-Auto ECU-Throttle matching.

 

Thats the lot on the VR6 C. Other engined C's 1992 onwards have varying very different set-ups/checks for their engines (ie. 9A 16v, 2E 8v, ADY 8v) but the rest if fitted (ie. ABS, Auto & Immobiliser) are standard across the Corrado range.

 

I think that's about it.

C

[Dutch24V 0]

You think that's about it?

 

That's more than enough mate and answers just about everything I could possibly ask!

 

Thanks for such a comprehensive guide, I can now go an play with confidence!

 

Didn't get a chance to do the ecu reset yet btw, hopefully will sort her over the weekend though...

 

Cheers again,

Dutch

[fla 9]

DutchVR6, I would add that RW1, does ahve a huge depth of knowledge on the VR and how to get more from VAGCOM - hes certainly helped isolate and solve some awkward issues on my car. RW1, you can post that tenner now :wink: