stevie_b Posted August 18, 2015 Share Posted August 18, 2015 (edited) I changed the spark plugs on my Cmax at the weekend. Photo of the old ones is attached. Numbered left to right as 1 to 4, what's your opinions about the mixture? Is cylinder 2 about right, and the others too rich? I've looked up guides on the internet, e.g. here: http://ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp. In the good old days this info used to be at the back of a Haynes manual. The plugs are exactly how they came out of the engine: not wiped down, not rolled around on the ground picking up dirt either. The reason for asking is that the car had a cough at a particular point in the rev range, and it also has trouble warm-starting occasionally. The cough might have been fixed by the change of plugs (I've already changed the air filter), but all this has prompted me to take a close look at how the engine's running. My next question if some are too rich/lean, is how to correct it, but I'll see what you think of the plugs first. Edited August 18, 2015 by stevie_b (see edit history) Quote Link to comment Share on other sites More sharing options...
Benjy Posted August 18, 2015 Share Posted August 18, 2015 Dude, you worry too much. If it was too rich, the car would know about it and put the EML on, much the same if it was too lean. Mixture control is governed by the ECU, so if there was a fault, I'm pretty sure you wouldn't be able to do anything about it with the relevant diagnostic kit. Just drive it man! EDIT: What engine is it out of curiousity? Quote Link to comment Share on other sites More sharing options...
stevie_b Posted August 18, 2015 Author Share Posted August 18, 2015 It's a 1.8 duratec petrol. I'm not that bothered by it, I just like to know the health of the engine, and generally interested. I used to have a spreadsheet of my supra's mpg over several years. Some would say OCD, others would say it's a useful indicator of problems before you'd otherwise notice them. You decide! Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted August 18, 2015 Share Posted August 18, 2015 Unless you stop the engine at the RPM/load that you want to check, plug colour is just a rough indicator, and by no means conclusive, but I cant see anything there that I wouldn't expect on a modern engine. Quote Link to comment Share on other sites More sharing options...
Benjy Posted August 18, 2015 Share Posted August 18, 2015 It's a 1.8 duratec petrol. I'm not that bothered by it, I just like to know the health of the engine, and generally interested. I used to have a spreadsheet of my supra's mpg over several years. Some would say OCD, others would say it's a useful indicator of problems before you'd otherwise notice them. You decide! I guarantee you a modern ECU will notice a problem before you do! Lol The only thing to watch out for is oil consumption mate. Those Duratec HE engines do like to use a bit. Quote Link to comment Share on other sites More sharing options...
stevie_b Posted August 18, 2015 Author Share Posted August 18, 2015 Fair enough, thanks for the advice chaps! Quote Link to comment Share on other sites More sharing options...
stevie_b Posted September 9, 2015 Author Share Posted September 9, 2015 I guarantee you a modern ECU will notice a problem before you do! Lol The only thing to watch out for is oil consumption mate. Those Duratec HE engines do like to use a bit. Timely advice about the oil: I've discovered mine has a thirst for it. I think I'll clean the PCV valve, do a compression test, leakdown test, then a kerosene flush (!) in that order. Oil control rings (same as piston rings?) seem to be commonly blamed for it, and the kerosene allegedly shifts some carbon deposits that may be causing them to stick. Has potential for causing more damage though. Do some fault codes get logged without the EML coming on? I don't have the EML light, but the hesitation suggests something's not right. Quote Link to comment Share on other sites More sharing options...
Benjy Posted September 9, 2015 Share Posted September 9, 2015 It may store a pending fault code or historical fault code, but not for use of oil. I would look at Fortë Engine flush. You can get it on ebay. Bottle of that, idle until the fan kicks in, drain it and refill with 5/40 fully synthetic oil and see how it gets on. Sometimes the oil control rings stick, sometimes they wear out. Quote Link to comment Share on other sites More sharing options...
stevie_b Posted September 9, 2015 Author Share Posted September 9, 2015 I'll get some of that flush, thank you for the advice. I was thinking of getting an OBD2 reader to try and diagnose the engine cough. With the EML light not coming on, do you think it could help? Quote Link to comment Share on other sites More sharing options...
Benjy Posted September 9, 2015 Share Posted September 9, 2015 Doubtful, unless you look at live data and know what you're looking for. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted September 18, 2015 Share Posted September 18, 2015 Has this car had, or showing symptoms of, head gasket trouble, or water loss? BTW, reading modern plugs in engines run on modern unleaded fuels is a bit of a waste of time, the "colouring" in the old days was mainly due to how hot the lead oxides became. Now there's no lead... Quote Link to comment Share on other sites More sharing options...
stevie_b Posted September 18, 2015 Author Share Posted September 18, 2015 No water loss or mayonnaise in the engine. I've only owned it for 2 or 3 months and I've no knowledge of the history before then. The only engine-related oddities I've noticed are: - A short cough in all gears at about 2700rpm once the engine is thoroughly warmed up. - Consumption of oil Quote Link to comment Share on other sites More sharing options...
stevie_b Posted January 15, 2016 Author Share Posted January 15, 2016 Update: the engine cough is much reduced after I removed the throttle body for a good clean. This video gave me the idea to do it: Oil consumption is still high. I'll try the Forte flush tomorrow. I suspect the cause of my issues is sticking/worn oil control rings as Benjy suggested. The engine's only got 75k miles on it so hopefully they're not worn. I'm guessing that sticky rings are causing excessive oil to be recirculated via the EGR. This is coating the throttle plate in grime, which in turn causes things like the misfire. I'm jumping the gun here, but I've done some research on my next course of action if the Forte doesn't help. I'm considering Terraclean, or a kerosene flush to free up those rings. I've read that some people have had good results from using both, specifically the kerosene for helping oil consumption. I'd use a 4l oil to 500ml kerosene mix. Others suggest that running for a few minutes on kerosene is a really great way to knacker your engine as it strips away the lubricants on the moving parts. Any suggestions? Quote Link to comment Share on other sites More sharing options...
goldenvtr Posted January 15, 2016 Share Posted January 15, 2016 (edited) those engines are prone to coilpack failure, done quite a few last year alone. also they dont always throw the ems light on with this issue but pretty cheap and easy for the coil pack and leads IF you add it as a service item. those plugs looks fine too lol all these new carbon cleaning systems /additive are abit of a gimmick.. they might do a bit of good but nothing major unless you keep on running them. redex is basically kerosene and does nafall. the BG44k has worked for me in the past with a small but noticable increase in mpg on my old daily (mazda 323 sport) Edited January 15, 2016 by goldenvtr (see edit history) Quote Link to comment Share on other sites More sharing options...
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