A few VR6 Problems

[mrginge 0]

Right, i have let the issues build up a little the last few months which probably wasn't the best plan.

 

1. Oil temp not working on MFA - Never has since i purchased the car.

 

2. A big loss of power, the engine is so flat, the revs build up smooth and the car sounds normal but the speed has gone. It takes an age to do the traditional 2nd gear 40-60mph acceleration. Had a similar issue before which turned out to be the cam position sensor so it got a new one. Literally my Mk3 Polo GT with 80bhp could keep up with the Corrado up to 80mph easy. I don't even bother overtaking now. MPG hasn't noticeably changed.

 

3. Coolant runs very hot. Pretty much sits at 110 and doesn't move no matter if your in town of on the motorway.

 

Engine Spec (If it matters??)

Grant Motorsport P+P Head, 263 Cams, P+P Intake manifold + Throttle body, 6 branch and Miltek system, DG Autotech map, BMC CDA, Dub power leads.

 

Thanks for any help,

[floppyman 0]

Best you can do first is plug it in to vcds (vagcom). If youre anywhere near heathrow I can do it

[WigsVR6 0]

The lack of power could be loss of compression in one of the cylinders. I had the same symptoms as you describe. Hope its not though and its something that is cheaper to solve. The engines are prone to bore wear in cylinders 1 and 6.

[coullstar 0]

Have you checked your plugs to see what condition they are in? I find that gives you a good idea on how the engine is running and if all cyclinders are the same. Quick and easy to do.

 

Out of interested did you notice much difference with the P&P head?

[CazzaVR 0]

Maybe another cam sensor... or check the cam sensor wiring. As above though, I'd get it on VAGCOM ASAP.

 

Are the fans coming on OK? The coolant issue could be just the sensor in the stat housing. 10 mins to swap out and you can buy it from Ford. Otherwise, maybe the stat isn't opening properly.

[Kevin Bacon 5]

If an 80hp Polo can keep up with it, you have major compression issues, either through engine wear or incorrect cam timing or some other mechanical problem. A duff cam sensor only drops power by 25-30hp on an otherwise healthy engine, so you would be looking at 170hp worse case scenario. I can't see any electrical or software issues causing such a huge power loss, but stranger things have happened. It only takes a thorn in the Lion's foot to bring the beast down.....

 

As DG were the last people to look at it when they mapped it (presumably), they would be the best people to check it over for you. They probably know the car quite well as it's quite heavily modified....engine wise at least.

 

As Coullstar says, spark plugs can't lie and tell the complete story.

Black and sooty = mega rich = down on power.

White and powdery = mega lean = down on power.

Black and wet = Oil fouling = misfiring and down on power.

 

Dry and cardboard colour = Optimum burn = Happy engine and happy days.

[nrc 0]

For the oil temp, check the green wire leading to the sensor above the oil filter housing.

[mrginge 0]

floppyman: Shame you not local thanks though!

 

nrc: Well i can crack on with that simple enough then cheers.

 

wigsvr6: I hope its not a big engine issue, my head is my Grant one (Not second hand without history i purchased it from them) and my bottom end is from a 75k engine and was looked over ALOT before being fitted as my original 180k was worn.

 

coullstar: The head was done and the cams purchased at the same time so i cant really measure how much the head did, together they were a very nice improvement.

 

fishwick: Really then i need to get the spark plugs out to start with.

I would take the car back to DG but i got to take a day off work for that so i will probably book it in my towns VW place first.

Last time the cam sensor went i dropped from around 225bhp to 192bhp,

 

CazzaVR: The fans are on alot, the thing stays on for ages after i park up. Im glad i got the samco stuff if it really is running that hot though as a split pipes really makes a mess. This is my first car with VAGCOM so i should really make more use of it.

 

 

I will try and get the plugs out tonight and report back, and take it from there.

[andy 0]

For the oil temp, check the green wire leading to the sensor above the oil filter housing.

I've had to do a couple of these, the wire leading to the sensor is quite feeble. The sensors are pretty cheap I seem to remember too. Easy fix either way.

Your engine flatness does sound like a duff cam position sensor to me. The symptoms sound very similar, again I've had a couple go over the years. Easy fix, not too dear either. I suspect you might have overestimated the drop in power with the polo comment! Something is terribly wrong if its that slow!

[VW_OwneR_85 2]

the cam position sensor, is this also called the knock sensor? and is this located on the front of the engine by the oil filter houseing? just bolts to the block by an m6 allen head bolt? cheers.

[Purple Tom 0]

Nope, the camshaft position sensor is only fitted to the coilpack equipped VR6's and is to be found behind the coilpack on the upper timing chain cover. Held on by an M6 allen head bolt and very easy to change once the coilpack is off.

[VW_OwneR_85 2]

ah ok so whats that sensor i just mentioned ? i was certain that was the cam postion sensor, my engine is a dizzy not coil pack, reason i ask is because i think my corrado vr6 is down on power as my mk3 vr6 {dizzy} just seems alot more brutal on acceleration then the corrado, thought it might be worth replaceing that sensor seeing as i have no idea when it was last replaced anyway.

[floppyman 0]

The sensor you were saying is the knock sensor.... If youre replacing that one, dont forget to buy 2... Theres another one on the back of the block... I might be rong but these never go rong?

[Purple Tom 0]

If its held on by an M6 allen head bolt and its between the oil filter housing and flywheel on the lower section of the block then its the crankshaft impulse sensor. Generally pretty reliable but when it goes faulty it can cause poor starting and general poor running in all sorts of ways.

 

Best to Vag-Com it for faults but make sure the engine is running when you do because if you scan it when the engine isn't running the ECU will flag up the impulse sensor as faulty - it only does this because it can't detect a signal.

[VW_OwneR_85 2]

just tryed looking on etka for it and i cant find it!!! the only sensor i can find that looks the same is called engine speed sensor 021 906 433A this the same thing?, my engine runs fine sometimes takes awhile to start especialy when warm, iv got new temp senders for ecu and gauge, my m8 cleared some faults on vag com a few months ago and there was a fault camxxxxxx? cant remember exactly ,but we did start the program with the engine off so thats probably why,other then that nothing was out of the ordinary,its only because iv been driveing the mk3 vr6 iv thought maybe somethings not right as the mk3 vr6's acceleration is alot more lively!!! compared to the corrado, i can actualy feel it push me into the seat and im the driver!. ill get my m8 to scan it again at somepoint and see what comes up... cheers

[Purple Tom 0]

Is the Mk3 OBD1 or OBD2? You'll find that the OBD2 VR6's have a lot more low down torque than the Corrado's OBD1 setup. Partly due to the more advanced engine management but also due to the throttle body having a smaller throat which promotes higher speed inlet flow and therefore more torque.

 

That sensor is indeed the one that you describe. Have you checked all of the normal things first - plugs/leads/distributor components/air filter/fuel filter etc?

[Kevin Bacon 5]

You might still get a cam error in VAG-COM on a dizzy engine as it uses the hall sender in the dizzy to calculate injection time. So you could either have a worn dizzy or tired hall sender, or the crank sensor you mentioned (on the front block face, 5mm allen head bolt). When the crank sensor starts to go, it does indeed cause lengthy starts until eventually it won't start at all.

 

Remove the crank sensor and put a voltmeter across pins 1 and 2. Get an assistant to move a metal (steel) object in front of the sensor and look for a voltage spike. If you see a healthy spike, the sensor is OK. If you get a feeble one, it's dying....

[Robbo149 0]

Doh... replying to post on bottom of page 1... muppet!

[WigsVR6 0]

I hope it's something easy to fathom out. When my car went down on power it sounded the same as normal but was more show than go even Mr Ford Focus would keep up with me. Do the easy stuff first then think about getting a compression test done.

 

cheers Alan