Johnny 5C Posted August 15, 2015 Report Share Posted August 15, 2015 (edited) I know there a re s**t loads of threads and posts about the N42, but im going mad reading them. It's a bit circular! A bad N42 can be a bit of a dog, but I thought I would briefly explain my problem and see if any of you have any words of wisdom. I have a dodgy idle, that is, when slowing down to a stop, the idle dips below normal and comes back. It also hesitates when you pull away. I researched this, cleaned the MAF and replaced the chain tensioner, which did improve it, but it's still not good. I'm thinking go onto cam sensors next, as they are easy to get to? Also, my AC doesn't work, but if I put it on, the revs rise and the problem virtually goes away. Any ideas? An anyone in Gosport/Portsmouth can a code reader? Cheers Edited August 15, 2015 by Johnny 5C Link to comment Share on other sites More sharing options...
Naj Posted August 15, 2015 Report Share Posted August 15, 2015 I read this, and thought instantly of what issues I had with mine. I did a service (Oil, oil filter, spark plugs (which were blaaaaaack), air filter, cabin filter) Changed the timing chain tensioner (which had zero tension on it) And cleaned the MAF with some electrical contact cleaner And haven't had any issues since. So in your case, maybe check the spark plugs? *I have very little to no mechanical experience, just suggesting stuff that I have done on mine Link to comment Share on other sites More sharing options...
Johnny 5C Posted August 15, 2015 Author Report Share Posted August 15, 2015 Thanks for the quick comeback Naj. I will pop the plugs out tomorrow and have an eyeball. Link to comment Share on other sites More sharing options...
Ilferco Posted August 15, 2015 Report Share Posted August 15, 2015 With it being an N42 it could be one of many, many issues. Unplug the Valvetronic Stepper Motor and see if anything changes. Take it for a little blast around the block and report back. (Valvetronic Unit is this silver cylinder, plug goes where I have circled http://i.imgur.com/n1oFBjj.jpg) Link to comment Share on other sites More sharing options...
Johnny 5C Posted August 15, 2015 Author Report Share Posted August 15, 2015 Is that the electrical plug behind the oil filler? If so, I have taken that off, and it had no effect. But what does that mean? This engine is bothering me. I had an M43 I was happy to work on before. I got this car real cheap, because i knocked the seller down for these things, thinking they would be a simple fix, like the CCV on the M43.... I tried to convince the other half to look at 2.2's, but got vetoed. Paying for it now huh! Link to comment Share on other sites More sharing options...
Ilferco Posted August 15, 2015 Report Share Posted August 15, 2015 Is that the electrical plug behind the oil filler? If so, I have taken that off, and it had no effect. But what does that mean? This engine is bothering me. I had an M43 I was happy to work on before. I got this car real cheap, because i knocked the seller down for these things, thinking they would be a simple fix, like the CCV on the M43.... I tried to convince the other half to look at 2.2's, but got vetoed. Paying for it now huh! Its on the top of the engine, between spark plug/coil 2 and 3. If that makes the idle better you have a valvetronic problem. Link to comment Share on other sites More sharing options...
Johnny 5C Posted August 15, 2015 Author Report Share Posted August 15, 2015 OK, I will have a look for it and give it a go. The plug i pulled before was right by the oil filler and did this: The valvetronic is disabled in this case by disconnecting the eccentric shaft sensor, this will put valvetronic function in limp mode home. In this mode, the valvetronic opening would be set to 100% and DME will use back the throttle to control the engine. This made no difference but I guess if the stepper is FUBAR unplugging its controller wont do anything! Presume i have to remove the cover to get to the stepper? Link to comment Share on other sites More sharing options...
Ilferco Posted August 16, 2015 Report Share Posted August 16, 2015 OK, I will have a look for it and give it a go. The plug i pulled before was right by the oil filler and did this: The valvetronic is disabled in this case by disconnecting the eccentric shaft sensor, this will put valvetronic function in limp mode home. In this mode, the valvetronic opening would be set to 100% and DME will use back the throttle to control the engine. This made no difference but I guess if the stepper is FUBAR unplugging its controller wont do anything! Presume i have to remove the cover to get to the stepper? Only the plastic cover that is over the coils, just pulls off. Link to comment Share on other sites More sharing options...
Johnny 5C Posted August 16, 2015 Author Report Share Posted August 16, 2015 Unplugged the stepper motor and went for a drive. Resounding meh. Idle is still OK when stopped, but its all over the place when driving. It dips well under 500rpm and nearly cuts out. Changing down through the gears is awful. I'm not entirely convinced the flat spot at 2500-2800rpm is valve related, as its right at a change up point, so could be me backing off the throttle anticipating changing gear. Strange thing is, if I put my (non working) aircon on, the revs rise slightly, and the idle doesn't dip at all. Link to comment Share on other sites More sharing options...
Ilferco Posted August 17, 2015 Report Share Posted August 17, 2015 When the aircon gets turned on the engines RPMs get slightly higher to accommodate for the extra load caused by the AC clutch being engaged. You really need codes read. Everything is a guess at this point as these engines have so many sensors. Link to comment Share on other sites More sharing options...
Johnny 5C Posted August 17, 2015 Author Report Share Posted August 17, 2015 Well, I'm definitely going to get my codes read. Went out in the car today with the stepper disconnected. The EML light (the letters EML) came on and the revs wouldnt go above 2-3k. Reconnected the stepper, and the car started and stalled. Started it again with bit of throttle and it sorted itself out, but now the engine light is on, but the EML is out. I think i saw a flash of the light between the dials too, but only briefly. The idle is hovering just above 500rpm, and when you dip the throttle, it hesitates a bit before rising. Really takes the fun out of driving. Put the AC on the car is OK to drive again. At least i know my AC clutch is engaging... Link to comment Share on other sites More sharing options...
