Philip G Posted August 8, 2020 Share Posted August 8, 2020 Took car out for a run today. First time in a year .. all fluids checked etc and took it easy for first mile. It only has 2000 miles on the clock and engine is standard. It then started to lose power, felt like a misfire that got worse. Got it into side of road waited five mins and it started again but it was rough, ran it done a hill on way back to home but couldn't keep engine going. Pulled off road and noticed the edge protector on the cat shield was smoking and melting in the road with the heat from the cat.Had it trailered back. Three of the plugs look nice and grey, one looks carbon black. Lambda sensor looks light grey when I removed it.Would be grateful for any ideas of where to start, particularly why cat was so hot. I have located the OBD port. Will this help me if I get a code reader ?Thx for taking time to read. Link to comment Share on other sites More sharing options...
simon_h Posted August 8, 2020 Share Posted August 8, 2020 Generally the only thing that makes a cat really overheat in use is a chronic misfire and unburnt fuel getting to it. Plug lead coming loose or coil failure often the cause. Link to comment Share on other sites More sharing options...
ScottR400D Posted August 8, 2020 Share Posted August 8, 2020 Black plug cylinder missing and its fuel burning in the cat? Link to comment Share on other sites More sharing options...
ChrisC Posted August 8, 2020 Share Posted August 8, 2020 Agreed sounds like a miss fire to me. You can swap the coil packs help diagnose a coil pack problem. Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted August 8, 2020 Share Posted August 8, 2020 Could also be the wiring loom, either a partially broken wire or bad connector. Even with the upgraded sub-loom on my 2012 R400D I had a poor connector on the loom to the coil pack on cylinder 1 that caused a misfire, seemed to be due to excessive vibration of the wire and connector. Replaced the sub-loom to rectify the issue and put foam tape on the inside of the coil cover.to gently press against the connectors to avoid future vibration. Link to comment Share on other sites More sharing options...
John Vine Posted August 9, 2020 Share Posted August 9, 2020 Which plug was black? The problem could well be a faulty or fractured wire in one of the coil-on-plug (COP) connectors. This most often happens on COP #1, due (as James says) to excessive engine vibration.The usual cure is to replace the standard COP loom with a beefed-up version. When I fitted one to my 2008 R400D, I had to splice it in to the existing engine loom, but it could be that a 2012 car already has the loom connector in place.The bad news is that your cat may well be terminally damaged. That's exactly what happened to me, and is the main reason I now run with a decat pipe.If your car doesn't already have one, you might also want to consider fitting a beefed-up TPS sub-loom, as the standard one is also very sensitive to engine vibration.JV Link to comment Share on other sites More sharing options...
Philip G Posted August 9, 2020 Author Share Posted August 9, 2020 Thx for all the responses. The black plug is No 2. I will not be seeing the car for another three weeks but these posts are very helpful. The first part of my short run was down hill with little throttle and when I opened the throttle I think I dumped the fuel from the cylinder not firing into the cat. I will have a look at loom and connections etc. I'll re-post when I have worked it through. I previously had a vibration related loom problem that caused fuel pump not to prime. i assume the only way to know if the cat is damaged will be at MOT emissions test ? Link to comment Share on other sites More sharing options...
John Vine Posted August 12, 2020 Share Posted August 12, 2020 i assume the only way to know if the cat is damaged will be at MOT emissions test ?You could try asking at a friendly MOT station if their tester is willing to run a separate emissions test for you (which is what I did after my cat was damaged).Or you can take the cat off and peek down inside to see if the matrix is still in good shape. This is what mine looked like:Outlet side: Inlet side (not a pretty sight):JV Link to comment Share on other sites More sharing options...
David_Long Posted August 12, 2020 Share Posted August 12, 2020 If it has been laid up, I would suspect an injector has jammed open. Tap the faulty cylinder injector with a screwdriver handle. Link to comment Share on other sites More sharing options...
Philip G Posted August 13, 2020 Author Share Posted August 13, 2020 Hadn't thought of injector ... good call and could explain why was running fine last time it was out and now missing. I'll try this also when I get back to car. Thx also for photos of Cat which is a good baseline for me to work from. Link to comment Share on other sites More sharing options...
Philip G Posted August 13, 2020 Author Share Posted August 13, 2020 Hadn't thought of injector ... good call and could explain why was running fine last time it was out and now missing. I'll try this also when I get back to car. Thx also for photos of Cat which is a good baseline for me to work from. Link to comment Share on other sites More sharing options...
David Knaresborough Posted August 26, 2020 Share Posted August 26, 2020 Hi Philip,Did you get to the bottom of this and fix the misfire?I have a similar problem with my R300 duratec. It started after a particularly long (and fun) blat out for 9ish hours followed by a track day.I've swapped all the spark plugs for new ones but the problem is still there. My plan is to get new coil pack and swap each one out individually and take it for a run to see if it fixes it or not.I already have the upgraded coil sub loom and the cabling looks sold into the coil connectors so I don't currently think it's the sub loom.Thanks,David Link to comment Share on other sites More sharing options...
Philip G Posted September 2, 2020 Author Share Posted September 2, 2020 Update. Had some time with the car today. Checked coils and used power probe to ensure the injectors were "clicking". Started car and it ran smoothly and rev'd. Temp on header nearest scuttle was 120 and between 140 - 150 on other three. After about 30mins and some more revving, exhaust popped once and engine ran a little less evenly with an almost irregular "chuff" sound and a slightly deeper exhaust note. The temp of header furthest from scuttle had dropped to 90 degrees. No smoke from exhaust at any point. For most of the running, had thought original problem was injector that had been stuck open and that it had resolved itself with some gentle "taps" and power probe. Not so sure now. Don't want to take it for a run and put engine under load in case i need recovered again. Will have another go at running over next few days. Probably need to get it booked in for a proper service with professional diagnostics. I will[ also be be checking cat with inspection camera to check for damage from original issue. Link to comment Share on other sites More sharing options...
Alan Reeves Posted September 3, 2020 Share Posted September 3, 2020 John Vine, if one buys the uprated TPS is there any adjustments needed ? as in could I screw it up swapping over ?i was going to change to the uprated loom but like you mine is not a straight swop so I have avoided the cut and splice...are you back in the UK? Link to comment Share on other sites More sharing options...
John Vine Posted September 3, 2020 Share Posted September 3, 2020 Hi Alan,I've sent you a PM.JV Link to comment Share on other sites More sharing options...
Philip G Posted September 3, 2020 Author Share Posted September 3, 2020 Hopefully last update.Have changed to "beefier" loom suggested by John Vine. I haven't done TPS loom as I would need to cut into loom. The "missing" I was getting at idle yesterday seems to have been cleared with new plugs today and a good few rev cycles. Like many faults, not sure what specifically caused initial issue but going through the system with the help of Blatchat members has got me to better place. Still got cat to check and crossed fingers for next MOT. Thx for all help and support. Link to comment Share on other sites More sharing options...
John Vine Posted September 4, 2020 Share Posted September 4, 2020 The temp of header furthest from scuttle had dropped to 90 degrees.Interesting. That matches reports that cyl #1 is generally the one to suffer from COP wiring fractures.I haven't done TPS loom as I would need to cut into loom.If you feel competent with a crimping tool, it's an easy job. You'll need to cut the existing TPS wires and attach a 3-way Econoseal female connector (ESC3F) to mate with the sub-loom (which, I note is back in stock at CC): .JV Link to comment Share on other sites More sharing options...
Philip G Posted September 4, 2020 Author Share Posted September 4, 2020 Thx John. Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted September 5, 2020 Share Posted September 5, 2020 Look at the connector on cylinder 1 coil, too. I had poor contact due to persistent vibration degrading the clamping of the connector contact, had to check with a magnifying glass to see slight discolouration due to arcing. Replaced the subloom in my case to solve the problem and put foam tape on the coil cover to reduce future connector vibration. Link to comment Share on other sites More sharing options...
John Vine Posted September 6, 2020 Share Posted September 6, 2020 Re #19:James is absolutely right. That's exactly what happened to me (including the arcing) on several occasions before I fitted the race loom.JV Link to comment Share on other sites More sharing options...
Philip G Posted September 6, 2020 Author Share Posted September 6, 2020 Thx Guys. Where is the foam tape attached ? The top of the coil or the connector to make cover press down on it to dampen vibration ? I have checked cat with inspection camera and the mesh looks intact on in and out sides. I'll wait until MOT. Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted September 6, 2020 Share Posted September 6, 2020 I put the foam tape on the underside of the coil cover to line up with the coil connectors (one strip the length of the cover). I also have a strip of foam tape on the top of the cover to prevent chaffing on the underside of the bonnet. I used the 3mm x 25mm foam tape that is is the same as between the edge of the bonnet flanges and body. Link to comment Share on other sites More sharing options...
Philip G Posted September 6, 2020 Author Share Posted September 6, 2020 Thx p Link to comment Share on other sites More sharing options...
Philip G Posted September 6, 2020 Author Share Posted September 6, 2020 Thx p Link to comment Share on other sites More sharing options...
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