What should VR6 HT leads look like?

[Hofmiester 10]

My car has what looks to be a mixed set of HT leads. They are all Black but 4 have a mat finish and some serial numbers in White but no brand. 2 of them are shiney Black finish and have Bosch written on them. My guess is that this is a mixed set?

 

The reason I ask is that the car sometimes has a slightly rough idle, nothing major but you notice it in contrast to when it is running smoothly.

 

The previous owner changed the TB, intake pipe to Maf and checked for leaks etc and then changed the throttle damper (dash pot) and that fixed it, mostly.

 

I remember that my old vr6 had a little bump on idle that was down to duff HT leads so wondering if it could be the case with this?

 

 

Cheers

 

Ron

[nrc 0]

For under £40 you could have a new set of leads from Dubpower and it's worth doing since the condition of the current leads seems to be suspect. Have a look at the plugs while you're at it.

 

Looks like you have an early VR6 with a dizzy, so check the cap and rotor too.

[Hofmiester 10]

Thanks for the recomendation, they have some good stuff on their website!

 

Condition looks OK but the fact that they are not a matching set makes me suspect that a lead or 2 has failed and been replaced individually.

My car has the coil pack but it looks pretty new and I have a receipt in the history for it having been replaced. So I suspect it is leads or plugs.

[Stonejag 10]

In my experience I'd say the expensive lead sets are mostly sold on handwaving and voodoo. Provided you don't have any gross faults in the cable, it'll either strike an arc across the spark plug or not - the coils and plugs have much more influence on performance than the leads do.

 

I spent £20 on wire (wanted orange to match the rest of my engine bay - otherwise I would have used the 50p/m silicone stuff on eBay), cut to length and twisted it into the self-tapping fittings on the lead ends from my old lead set. Been working fine for at least six months now in all weathers, and the whole lot cost me under £30.

 

Also note that if you go for wires wider than 7mm you just get some extra insulation thickness - it does nothing for the performance, just means they don't fit the plastic guides and you have to cable-tie them in place! Don't bother.

 

Stone

[RW1 0]

Take each lead and check for electrical continuity. Each lead on a digital volt meter will show “circuit” with a line resistance of 5 kohm (4.5 – 5.5Kohm in practice).

 

It should not make much difference having different leads if the resistance values are in the range above. Any open circuit of higher resistance substitute.

 

After that, first make sure the Engine ECU is not carrying any fault codes which may have reverted ECU to a secondary mode.

 

The other thing, have you performed "Basic Settings" on the ECU as per the wiki ECU reset 2nd part using VCDS. The first part of driving doesn't need to be done for this exercise.

 

Finally. I get roughness occassionally like you describe. Put it done to the fuel. These days the plugs are not the same clean whiteness on the insulator due the higher octane enhancers. (Have the same on the other two cars as well). With the white insulator being fouled, the spark is being interrupted due to the way it travels from the centre electrode onto the insulator then along to hop off onto the earth electrode on its inside face.

 

Failing that, clean the MAF connection with switch cleaner. Then perform Basic Settings again.

 

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Edited October 30, 2012 by RW1

[Hofmiester 10]

Take each lead and check for electrical continuity. Each lead on a digital volt meter will show “circuit” with a line resistance of 5 kohm (4.5 – 5.5Kohm in practice).

 

It should not make much difference having different leads if the resistance values are in the range above. Any open circuit of higher resistance substitute.

 

After that, first make sure the Engine ECU is not carrying any fault codes which may have reverted ECU to a secondary mode.

 

The other thing, have you performed "Basic Settings" on the ECU as per the wiki ECU reset 2nd part using VCDS. The first part of driving doesn't need to be done for this exercise.

 

Finally. I get roughness occassionally like you describe. Put it done to the fuel. These days the plugs are not the same clean whiteness on the insulator due the higher octane enhancers. (Have the same on the other two cars as well). With the white insulator being fouled, the spark is being interrupted due to the way it travels from the centre electrode onto the insulator then along to hop off onto the earth electrode on its inside face.

 

Failing that, clean the MAF connection with switch cleaner. Then perform Basic Settings again.

 

.

 

Hi, thanks for your moments guys. I agree with stonejag in that the fancy leads are just snake oil. So was Bly planning on getting some cheap ones.

 

Could you point me in the direction of a link for the basic settings wiki? I have VCDS, do I need the 2x2 converter for is car? It is a 1993 but with coil pack rather than dizzy.

 

One thing I need to check is the plugs as I remember my old vr6 didn't like it when I ran plugs that we not to the original spec (platinum I think they were and £60 a set?) I used some from ECP and it ran rough.

 

When I say rough, I mean only a bit. It runs fine when accelerating etc and doesn't stall. Half the time the idle is very smooth but sometimes I get a shudder felt. The car has vibratechnics mounts and so it could just be that.

 

It also has a cone filter which I have heard can make them run a bit rough.

[RW1 0]

Wiki ECU setup http://wiki.the-corrado.net/vr6_ecu_reset_procedure.html

 

16pin diagnostics, just lift the gear shifter surround.

 

Spark plugs, I always use the original NGK BKR5EKU (VW Part no.: 101 000 035AB) These are not the later platinium for the post 1995 Golf VR6 & 24valvers, the longlife "035AH". http://www.ebay.co.uk/itm/6x-VW-Passat-B3-35I-Saloon-Variant1-NGK-Yellow-Box-Spark-Plugs-Kit-Service-/330810405167?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Cars+Type%3A2.8+VR6&hash=item4d05d6312f

 

Yes understand your description. Had similar about a couple of months ago. Caused by the fuel pump relay being pulled for the last winter storage. When refitted, didn't clear the fault code. This caused a sympathy fault code with the MAF which put the ECU into a secondary mode. Cleared the fault codes and did a Basic Settings 5 minutes duration while out driving. Cleaned the MAF connector on return home. Been alright since, no codes, clean exhaust tail pipe you can wipe with no soot and running very smoothly.

 

I have a Vibratechnics front mount. Normal rear. Vibration and the engine is rock steady in the bay with no lumpiness to the idle, no missed beats.

 

Gave up with my K&N flat panel filter years ago as it caused rough running, much more than just a mild stuttering. Have used standard VW paper filters since in the housing, changing every 10,000 miles.

 

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Edited October 30, 2012 by RW1