Nissan Primera P11-144 misfire & loss of power |
Post Reply | Page 123 4> |
Author | ||
Neilski
NPOC Guest Joined: 06 Jun 2009 Online Status: Points: 17 |
Post Options
Thanks(0)
Posted: 11 Feb 2012 at 10:54pm |
|
Hoping someone recognises these symptoms and that the fix isn't horribly expensive...
For several months now, our P11-144 (GQ16DE) has been misbehaving. First, we noticed an intermittent-ish loss of power when opening it up at speed, but idling seemed OK. It's getting worse though, with "jumpiness" now getting to the point where we actually have to back off the throttle sometimes when what I can only call bucking gets quite severe. Idling is now a little uneven too. At an early point in the process, I noticed that the tacho needle wasn't holding steady at idle (or indeed at steady higher RPM) even when there was no detectable unevenness in the engine vibration (I'd have expected to feel a misfire very clearly). It was repeatedly jumping down a little and then recovering after a moment. The car has flagged a couple of diagnostic codes so far - mostly 300 (generic misfire) with one or two 335 (crankshaft pos). The 335 actually first showed up quite a while after I had first noticed the tacho needle wobble, which had caused me to go looking at the POS pin on the ECU with an oscilloscope but it looked fine (and still does). Argh. I've been browsing this website (for ages!) today looking for ideas and noticed that the P11-144 had a crankshaft/camshaft sensor recall - ours never got called back for this fix. But I've checked the signals reaching the ECU from both sensors and they look "sensible" (the way the FSM says they should). I have no clue really - fuel pump, MAF, TPS, ECU, coil packs, crank/cam sensors...? Our local independent garage (who service it) couldn't pin down any fault. They reckoned the plugs were basically fine, though one looked slightly differently coloured to the rest; however, the misfire has never felt like it was confined to a single cylinder. My little OBD unit says the MAF and TPS outputs look sensible. The MAF was actually replaced a couple of years ago with a 2nd-hand unit from an Almera, so I did suspect it but like I say the readings look OK... I also spent hours today pratting around with the 'scope again on the ECU connector, looking at the pulses from various pins (tacho, crankshaft, injectors, ignition) in the hope of learning what's wrong. (I could post pics if anyone thinks they'll help.) The tacho pulses are the only clear problem I can see on the 'scope: most of the pulses are as they should be - long high with short low - but quite a few stay low for the whole pulse instead, with a pattern often present (but I can't make sense of what the pattern is telling me). Another symptom that might be important: when accelerating, the problem is worst just after changing throttle setting. After maybe 2 or 3 seconds, it settles down significantly - not perfect but much less jumpy. In fact, this is a wee bit like something else that has happened ever since the car was new: when pulling away from traffic lights etc., and flooring it in first gear, the car really doesn't pull for the first second or two, and then BOOM it goes like a rocket. This was reported to two separate Nissan dealers who said there was nothing wrong. Maybe it's normal or maybe it's an indication of some broken-ness... Anyway, after remembering that the behaviour was worst just after changing throttle position, I looked at the ignition pulses just after taking the engine from idle to a fast tickover (like 3k), and saw something a little odd: some of the ignition pulses were much shorter than others. Mostly they were between 2 and 4 milliseconds long (much bigger variation than I expected) but the shortest ones were not much over half a millisecond... Not sure how long they should be (FSM doesn't say). Sorry for the length (!) but if you made it this far I really appreciate you taking the time to read it ;-) |
||
stonegrey
NPOC Guest Joined: 11 Mar 2007 Location: De Cymru Online Status: Points: 5672 |
Post Options
Thanks(0)
|
|
welcome to NPOC.
QG engines have been know to suffer chain stretch. if the juddering is around the 3500 - 4k rpm mark, this is when the vvl starts to kick in, and will cause what you are seeing. |
||
James_friel
NPOC Guest Joined: 16 Dec 2010 Location: Ireland,donegal Online Status: Points: 183 |
Post Options
Thanks(0)
|
|
Chain stretch is what it seems like, I have the same Problom with my car, and unless yOu get a brand new engine it's hard to knoW, you can fix yours, the kit is 200ish, if you take it to a Nissan garage they can check the timing for you
|
||
Psn- jamesedmund
Twitter- suctiontires Facebook- james Friel 00 P11-144 1.6 s |
||
Neilski
NPOC Guest Joined: 06 Jun 2009 Online Status: Points: 17 |
Post Options
Thanks(0)
|
|
Thanks very much guys!
Chain problems do sound hugely plausible. I will bung the 'scope back on in the morning and concentrate on comparing the POS and PHASE waveforms this time - that should prove it I guess. 200 quid doesn't sound too horrific - is the job doable for someone with half a clue and limited tools? :) And where does one go to try and buy such a kit? |
||
stetec
NPOC Guest Joined: 13 Dec 2007 Location: Durham Online Status: Points: 113 |
Post Options
Thanks(0)
|
|
Yeah sounds exactly like the timing chain issue I had with an Almera. Cost me about £140 for the kit from an Ebay store (very good quality) and paid a mechanic friend £100 to fit it. Problem fixed.
|
||
SteveB
NPOC Guest Joined: 12 Mar 2007 Location: Kent Online Status: Points: 1117 |
Post Options
Thanks(0)
|
|
It's a shame the sensors can't be moved a bit to compensate for some chain wear.
|
||
1997 2.0 SLX P11
|
||
stonegrey
NPOC Guest Joined: 11 Mar 2007 Location: De Cymru Online Status: Points: 5672 |
Post Options
Thanks(0)
|
|
Brilliant idea. if a cam chain has stretched, it needs replacing. end of. |
||
SteveB
NPOC Guest Joined: 12 Mar 2007 Location: Kent Online Status: Points: 1117 |
Post Options
Thanks(0)
|
|
Um, no. WHEN the cam chain wears/stretches (same thing) the chain tensioner takes up the slack to save the chain from needing replacement every 50,000m. Eventually the chain tensioner runs out of adjustment which is when the chain needs replacing. |
||
1997 2.0 SLX P11
|
||
Neilski
NPOC Guest Joined: 06 Jun 2009 Online Status: Points: 17 |
Post Options
Thanks(0)
|
|
So... the 'scope did indeed show some variation in the relative timings of the cam and crank sensors (less than I expected though). I guess this confirms the timing chain as the source of the problems...
Am currently asking the local garage to quote for the job (might source the parts from eBay mind you - thanks for that tip) as the FSM makes the job look well beyond my talents and toolkit. Not certain the car's worth it... hmm. It also suffers from a wobble at speed when under power (but not coasting) which the local garage think means the diff is worn and which they reckon would need a recon gearbox to fix (for about a grand!). |
||
Neilski
NPOC Guest Joined: 06 Jun 2009 Online Status: Points: 17 |
Post Options
Thanks(0)
|
|
So... My local garage guys reckon the labour will set me back around £280, which is fairly ouchish but not totally forgetaboutit.
Thus I'm now figuring out which part to buy. Kits with chain + guides are available out there (ballpark £120), and I nearly bought one. But then I spotted kits with chain + guides + sprockets (cams + crank), and thought "uhoh, if the sprockets are worn too, I'll still have problems after replacing the chain". Then, to really confuse me, I noticed that the chain kits which include sprockets say they are for the QG15DE and QG18DE, and don't mention the QG16DE. I'd be inclined to guess that anything that fits the 15 and 18 would fit the 16, but guesses like that sometimes work out badly :) So, am asking for advice again please: should I be buying chain+guides or trying to find a QG16DE kit which has sprockets too? Thanks! :) |
||
Post Reply | Page 123 4> |
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |