Robbo149 0 Posted June 16, 2004 Hi all, I've still got a couple of minor problems to sort after having a head rebuild/chains/etc done on my VR. It's now running on all six after replacing the coil pack & leads, but I'm now getting a flat spot/hesitancy when applying the throttle (worse if doing it after overrun). I had exactly the same symptoms when I first got the car & tracked it down to a faulty CPS. As this was only replaced about 6 months ago, I'm a bit sceptical that it's knackered again! (unless it was damaged during the head rebuild of course!). So, just a couple of questions- Has anyone known the CPS sender wheel be faulty? Is it possible to fit the sender wheel wrongly? Can the sender wheel be accessed without removing the manifold & rocker cover, just the cam sprocket cover? and does the sprocket bolt need to be removed? And finally, are there any other sensors that could give the same symptoms? Unfortunately I don't have access to diagnostic gear at the moment. Thanks guys, Robbo Quote Share this post Link to post Share on other sites
corradovr6sc 0 Posted June 16, 2004 The cps only fits one way. It sits just under the black plastic cover, above the coilpack. You just have to pull the 3 leads out, remove the cover, unplug the connector and loosen the hex bolt which holds it on. A failing maf sensor could give similar symptoms. If the sensor isn't that old it should still be under warranty. Quote Share this post Link to post Share on other sites
Robbo149 0 Posted June 16, 2004 It was actually the sender wheel I was referring to, which is attached to the camshaft sprocket, not the cps itself. Cheers anyway, Robbo Quote Share this post Link to post Share on other sites
corradovr6sc 0 Posted June 16, 2004 Could be something to do with the timing being changed after you had the chains done so the ecu needs resetting to adapt to the new cam position. Quote Share this post Link to post Share on other sites
Kevin Bacon 5 Posted June 16, 2004 There is no sender wheel as such. The exhaust cam sprocket has a raised section which provides the 'air gap' for the Cam sensor. You'd know if the cam sensor was dead because you'll be down 30 brake. When you say flat spot, do you mean a lack of pull when initially pulling away? How about when you're on a part throttle cruise at around 1500-2000rpm, does it jerk and hesitate? My instincts are pointing towards MAF but they're pretty tough to diagnose properly. Yank the plug when it's idling and if the engine note doesn't change, it's dead. Then take it for a drive, if no change, it's *definitely* dead! If it drives like crap, the MAF is OK and something else is up. If you plan on keeping this car, invest in VAG-COM mate. £124 from Ross-tech at the mo, make use of the current exchange rate :wink: Quote Share this post Link to post Share on other sites
Robbo149 0 Posted June 16, 2004 Yeah, symptoms are as you describe Kev, I wouldn't say it drives like crap though! definitely feels much tighter with the recon head (& no more blue smoke). hesitancy seems to be mainly when re-applying throttle immediately after lifting off. Unplugging the MAF definitely makes a difference, so I doubt it's that. My Porter manual shows a sender wheel attached to the cam sprocket, & there was one on the cam that came with the recon head... plastic I think, possibly with a magnet inside??? I'll try & get it on VAG-COM as soon as I can I think. Cheers, Robbo Quote Share this post Link to post Share on other sites
Kevin Bacon 5 Posted June 16, 2004 Yeah I know the cam wheel you are talking about. Ekta shows it as being on the inlet cam on the ABV engine, which is bollocks cause it's on the exhaust cam, seen it with my very own eyes! I think some Golfs used that method. On a 1994 head at least, it's just a bit of metal inside the cam sprocket as mentioned earlier. Mine behaves like yours does too occasionally but nothing comes up on VAG-COM. Might try another CPS in case mine is losing it's resolution. K Quote Share this post Link to post Share on other sites
Robbo149 0 Posted June 16, 2004 The recon head (with cams) I got was from a Golf, but I had my original '93 2.9 cams put back in, so I guess my exhaust cam won't have the sender wheel then? Looks like it's either the CPS (again!), or the MAF. Mmmmm... £30 versus £200... place your bets please! I've just been out to see a mate with Bosch diagnostic gear at his garage, so he's gonna try & fit it in tonight. Cheers, Robbo Quote Share this post Link to post Share on other sites
PhatVR6 0 Posted June 16, 2004 both cam sprockets are the same, the cam trigger wheel is seperate, and about £9, and is keyed in position on the rear cam. Quote Share this post Link to post Share on other sites
