Toby85 Posted December 17, 2014 Share Posted December 17, 2014 (edited) Hi, So I'm at my wits end and hate my trusty old steed! It's my daily, family owned since new, 211,000 miles (still on the original clutch) 2004 UK GT coupe, however, ongoing issues are ruining it! The issues I'm having are a bouncing Rev counter and an intermittent rough running - related or not I don't know. The car sounds deeper, kind of like the timing is retarded or something, and splutters/bogs on wide throttle openings, but this intermittently clears and runs/sounds great! I've noticed that when I drop the clutch and let the revs drop they drop down to about 700rpm before jumping back up to about 1200rpm and slowly falling back to idle (always idles a touch high at 760rpm) as I'd expect. Oddly, if I let the car slow whilst in gear, ie use engine braking, it almost always starts with this rough running but if I avoid this it can run fine for whole journeys. Only code I get is an occasional p0300 which comes and goes. I'm not sure it is misfiring, sounds too smooth and unplugging each cool makes a marked difference. i have obd scanning facilities and the only interesting thing is the timing which at idle (760rpm) is at 7 degrees. I've tried coil packs, spark plugs, injectors. Any midlands specialists fancy a look?! Thanks in advance, Toby Edited December 31, 2014 by Toby85 Quote Link to comment Share on other sites More sharing options...
Commander Posted December 17, 2014 Share Posted December 17, 2014 211k on an original clutch? lol, awesome. Throttle position sensor faulty? Cam/crank sensors? Cleaned the MAF lately? Quote Link to comment Share on other sites More sharing options...
Toby85 Posted December 17, 2014 Author Share Posted December 17, 2014 Haha, I know. Goes to show, treat it carefully and it lasts! I've considered next moves as crank sensor and throttle body. But - would this not throw a code? I cleaned the MAF at las service and OBD data looks ok. Thanks! Quote Link to comment Share on other sites More sharing options...
Ricey Posted December 17, 2014 Share Posted December 17, 2014 Crank and cam sensors are fairly cheap to replace and eliminate If memory serves. Quote Link to comment Share on other sites More sharing options...
gareth29 Posted December 17, 2014 Share Posted December 17, 2014 at that mileage, could it be a stretched timing chain? you can check this by measuring the extension of the tensioner Quote Link to comment Share on other sites More sharing options...
Toby85 Posted December 17, 2014 Author Share Posted December 17, 2014 I don't think so - no way it would behave so on/off intermittent as this! Be interesting to gauge wear mind. Quote Link to comment Share on other sites More sharing options...
Mark@Abbey m/s Posted December 17, 2014 Share Posted December 17, 2014 If it had a stretch chain it would throw cam DTC codes. I would say it would be crank trigger issues. Timing at idle should be around 15deg's. Have you reset the ECU? Just disconnect the ECU plug under passengers side dash. Thanks Quote Link to comment Share on other sites More sharing options...
Ogman Posted December 18, 2014 Share Posted December 18, 2014 I can't really help but that mileage is impressive!! Hope you get sorted Quote Link to comment Share on other sites More sharing options...
Toby85 Posted December 18, 2014 Author Share Posted December 18, 2014 (edited) Thanks for all advice! Would love to sort this, want to do a track day next year! I'm going to try a good crank sensor. I've tried the ecu reset using the peddle dance which reset the idle but this always reverts to idling too high. I'll try unplugging it for a bit though and report back. Thanks again Edited December 18, 2014 by Toby85 Quote Link to comment Share on other sites More sharing options...
Toby85 Posted December 19, 2014 Author Share Posted December 19, 2014 How long would the ecu need leaving unplugged for to reset? I unplugged it for 10 seconds or so which seemed to have no impact whatsoever! Thanks Quote Link to comment Share on other sites More sharing options...
Voodoo Vix Posted December 19, 2014 Share Posted December 19, 2014 I just unplug my battery for an hour, seems to clear any glitches. Quote Link to comment Share on other sites More sharing options...
Toby85 Posted December 19, 2014 Author Share Posted December 19, 2014 Ok thanks! Quote Link to comment Share on other sites More sharing options...
a2orry Posted December 19, 2014 Share Posted December 19, 2014 If the cam and crank sensors don't stay within specified limits of each other the ECU will retard the timing stretched chain would be my thoughts. Quote Link to comment Share on other sites More sharing options...
Toby85 Posted December 19, 2014 Author Share Posted December 19, 2014 Hmm, still not convinced due to the on/off behaviour of the issue - but plausible. I will look at the tensioner protrusion at some point to see how far it's stretched. Thanks Quote Link to comment Share on other sites More sharing options...
Toby85 Posted December 20, 2014 Author Share Posted December 20, 2014 I've got some screenshots here of what my car is doing on warm idle. Much look amiss here? Worth noting - when it's playing up, it's only audible from ~1250rpm, what changes here? Cam timing? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted December 22, 2014 Share Posted December 22, 2014 Ignition timing is retarded, however it could just be a response to another condition, IE stretched timing chain causing spurious reading s from cam sensors, if the scale for AFM was in voltage I could tell you if it was correct, its also pointless checking bank 2 O2 sensors as they are only cat monitors and don't effect fuelling. Quote Link to comment Share on other sites More sharing options...
Sam Mcgoo Posted December 22, 2014 Share Posted December 22, 2014 its also pointless checking bank 2 O2 sensors as they are only cat monitors and don't effect fuelling. Nope, it's sensor 2 that is post cat. :wink: Sensor 1 Bank 1= Driver side Sensor 1 Bank 2 = passenger side Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted December 22, 2014 Share Posted December 22, 2014 (edited) its also pointless checking bank 2 O2 sensors as they are only cat monitors and don't effect fuelling. Nope, it's sensor 2 that is post cat. :wink: Sensor 1 Bank 1= Driver side Sensor 1 Bank 2 = passenger side Thought I saw sensor 2 there earlier, oh well we all make mistakes. Edited December 22, 2014 by Tricky-Ricky Quote Link to comment Share on other sites More sharing options...
Toby85 Posted December 31, 2014 Author Share Posted December 31, 2014 Hi, Thanks for all responses. I finally got a spare 15 mins today so checked the cam chain. The tensioner protrusion I measured at 21mm, which I hear is a bad thing. So, this raises some questions regarding the original issue. This may well be causing the retarded timing I'm seeing at idle but I can't see what the intermittency of the wierd sound / bogging under power is all about - if the chain is stretched, it's stretched so why would this issue come and go? And regardless of whether or not it's running roughly, the obd scanner always reports the timing the same so I still think there is something else at play here! Bearing in mind the car is getting old and at 211000 miles, I don't think its worth replacing the cam chain if it doesn't solve the original issue, I need to be sure. I think I need someone with a consult-II. Anyone know anywhere good aroubd the midlands? Thanks for the help so far. Toby Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted December 31, 2014 Share Posted December 31, 2014 I would suspect that if you drove it at various loads you would be seeing a different story with timing advance, Its quite likely that because the chain is stretched the cam sensors are reporting varying signals, and some of these are beyond the ECUs expectations in turn triggering the bogging, not doubt a little longer and the condition will be permanent as the ECU goes into limp mode. Quote Link to comment Share on other sites More sharing options...
Toby85 Posted December 31, 2014 Author Share Posted December 31, 2014 (edited) Thanks, It is odd. When it's ok, it can be ok for a whole journey and performs strongly - I can push it through to the limiter at full throttle and it's perfectly happy! It's irrelevant of load, engine speed etc. Also worth noting its been ongoing for about 30,000 miles or so with no change! If I do decide to replace the chain when the weather starts to warm and I can use the bike for work, where is a reputable place to buy from? Chain kits seem to be in abundance in America but finding one over here is a challenge! Thanks Toby Edited December 31, 2014 by Toby85 Quote Link to comment Share on other sites More sharing options...
Toby85 Posted December 31, 2014 Author Share Posted December 31, 2014 Another update - I drove it earlier and let it idle for ages, the idles eventually dropped to about 720 which, although still not within spec, is lower than usual and the ignition advance was closer to speak at between 9 - 12 degrees. This leads me to believe that the retarded timing is more a side affect of the idle speed being too high. I then logged a run when the engine sounded sweet at just shy of 50mph in 6th which read about 34 degrees of advance. Putting my foot flat dropped to about 20 or below. After a little drive I heard the engine note change and it started playing up. I did the same test and got results almost identical, I don't think the ignition time is causing the rough running. The difference in how it runs is night and day, the ignition timing is impossible to detect a change. The culprit, in my eyes, is still at large and affecting other things such as idle speed. Shame about the cam chain! Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted January 1, 2015 Share Posted January 1, 2015 Just a couple of further thoughts... its obviously something that's not triggering a CEL so going on the premise, and as its intermittent I am wondering if its an air leak IE perhaps the one way valve in the PCV system is leaking when hot enough and allowing extra air into the combustion process, I do know that in theory the lambda feedback should throw a CEL when out of range, but the ECU will start to use the the cat lambda sensor when the primary is going bad, and as the reponce time for the secondary is a lot slower its not triggering the CEL. The other possibility could be the AFM being dirty, or has a bad connection/dry joint that's influenced by heat/vibration, should also throw a CEL but you never know. Quote Link to comment Share on other sites More sharing options...
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