Philip G

Thx for all the feedback. Looks like a contact thermometer will give a better reading. I'll update in due course.

The thermometer is pretty accurate when I use it on heating / boiler pipes etc. If I rev the engine, the front of the cat does rise up through 150c but the exit of the cat is still cooler. Engine is running fine. It's this differential in cat temp that is interesting me ... theory says back of cat should be hotter than front ?

Yes. I removed it an it all looks ok. It's just the temp piece that has me unsure.

Pretty sure seal is ok, I will ultimately get the test but interested if anyone has tried this or has a rule of thumb as a start point.

Hi, I am recommissioning my 2012 R300 Duratec 2.0L. During COVID I had a problem where one of the injectors got stuck open and fuel entered the cat causing it to overheat to the extent that the trim on the cat heat shield melted and the car cutout. I fixed the injector at the time and the car runs very well. I have the opportunity to get a used cat but they ain't cheap so looking for a quick test without going full MOT route. The cat looks ok visually but I have run a temperature test that Google has guided me to, My understanding is that the out pipe temp should be higher than the in pipe temp as a result of the reaction. So I have idled the car up to op temp for 15 mins. Using a laser thermometer, the inlet pipes at the "gather end" are 56c, the front face of the cat, 94c, middle of cat 54c, back face 33c and outlet pipe to silencer is 38c. Am I reading this correctly that the cat is damaged and replacement is required or is the test too simple and this is normal ? Thank you for taking the time to read.

Thx p

Thx p

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.

Thx John.

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.

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.

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.

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.

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 ?

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.