First problem with VR6

[Niges16V 0]

I upgraded to a VR6 a few wks back from a valver, it certainly is a different beast in alot ways, but still fantastic!!

 

Noticed my first problem today, the throttle seems to be a bit tempermental when you lift off as it cuts the engine completely for a moment which gives a bit of a jolt. First noticed it at slow speeds and thought it needed a slight adjustment on the timing (but I don't think this is possible on a VR). Now I am experiencing it at motorway speeds ie. when you ease off from an acceleration, the car jolts as though the electrics have been cust for a moment.

 

Does the VR have a throttle sensor or similar that may be the cause? It's not the fr mount as I changed this to a VT just after I got it.

 

Any advise greatly appreciated.

[dr_mat 0]

Yes, VR has a throttle sensor. Most likely you have one or other engine sensor out. Might be worth giving the ECU a probe with a friendly VAG-COM setup, see what the ECU thinks the problem is..

[mr.ots 10]

I have a similar situation (a jolt when coming off the accelerator) with my vr but suspect it is probably more related to a sloppy mount. If i come of the gas more gradually it doesn't happen.

[dr_mat 0]

Gearbox mount is full of sticky black oil - if the near side subframe is covered in it, chances are that engine mount is kaput. Catch it quick, cos it'll soon cost you the rear head-to-heater-matrix hose, and if you're really unlucky, the exhaust downpipe too ...! (The hose is ~£50 but the exhaust downpipe is nearer £300+VAT!)

[dinkus 10]

The first (and cheapest) thing to do is make sure the basic throttle settings have been setup correctly.

 

If the battery has been disconnected for 15mins+ then the ECU loses all of it's settings and needs to learn a new base-point for the throttle is. If you don't do this then it just guesses and corrects for errors using the MAF - this causes crappy throttle response and could make the engine jolt about.

 

All you need to do is hook it up to VAG-COM and put the ECU into basic settings mode and let the car idle for 5mins or so. The longer you leave it, the better, but 5mins should be fine. This gives the ECU time to check everything over and make sure that it's registering the throttle in the correct place and it'll make minor adjustments.

 

Just make sure that the fans aren't on when you exit basic settings mode and you're done - the throttle should be much more responsive after that.

[RW1 0]

Dinkus, the time actually depends what’s hanging on the battery circuit in the way of accessories and their 12 volt “capacitance”.

 

A bare Corrado VR6 looses it within 30 seconds. If ICE etc can back feed the 12 volt battery circuit (not the ignition), then the ECU memory is powered for longer after the battery is disconnected. Disconnect the battery earth lead, not the positive when it's done.

 

Basic Settings is discussed in more detail here and the procedure is in the image on the first page. Can be done any time and as many times. Servicing calls it up every 20k miles.

 

http://the-corrado.net/.archive/forum/viewtopic. ... highlight=

 

Important to blip the throttle part way so the ECU sees the engine go up above 2,500 rpm (say 3,000 rpm) for a couple of seconds (higher and longer are not necessary) at the beginning after entering Basic Settings. The minimum sample time is 2 minutes and no electrical loads such as interior fan, radio, HRW should be on. It is OK if the rad fan switches on and off. When time is past 2 minutes since the throttle blip, then exit when no electrical loads are on other than the ignition, ie. the radiator fan. The maximum time in B.S. doesn’t matter. 2 minutes minimum allows enough sampling in the offset mode for the ECU to complete the necessaries.

 

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[dinkus 10]

Ah thanks RW1, I was trying to remember what you told me at Utterly :)

 

I'm going to be doing mine next weekend, so I shall report any noticable changes...

[RW1 0]

You weren't far out D. :wink:

 

The change varies from car to car, some hardly anything, some a very noticable change. Don't bother with the ECU disconnect as I've found that it takes about 4 hours driving to "settle" the ECU memory on the lambda probe side of things. It should be OK as it is. Just do the the B.S., but check the measuring blocks group 006 for the probe is oscillating in the range 0.95 - 1.05 with the engine full warmed up. Don't be too bothered by the idle, mid (part) and full throttle fixed values in the other three fields.

 

Oh, AND no faults in the engine ECU. Not just clearing them but they mustn't re-occur.

 

Here's a typical sample of the VR6 measuring blocks. There is a lot of variance between engines.

 

 

 

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[Niges16V 0]

Thanks Guys, more information than I could have hoped for.

 

I will be checking the GB mnt but I do suspect it will be a sensor/ECU issue. VAG COM here I come.