Hi all, new to joining the forum, but been lurking for a bit picking up tips and tricks so cheers.
I have a 2005 nc with 87k and I’ve just changed the thermostat. While doing the thermostat, I though it’d be a good idea to clean the MAF and throttle body.
I cleaned the MAF with contact cleaner, and the TB I used carb cleaner and a microfiber cloth.
All was well and the temperature gauge is now moving and sitting bang centre on the dial. However it runs beautifully until fully up to temp, then I’m getting pinging and bogging down at low rpm under load.
All hoses and clips are tight, so I figure I’ve messed up either the MAF or the TB and I was a little concerned when I came across this discussion https://www.mx5nutz.com/forum/index.php?showtopic=85498 which says you can damage the TB by cleaning.
Hmm, contact cleaner on the MAF? Really? Which parts?
You cleaned the outside parts of the engine air-fuel system, now you need to clean the insides.
The pinking etc is a classic case of “coked up”, so try a couple of tankfuls of V-Power to clean inside the engine and exhaust. Or if you are in a tearing hurry give Terraclean a go.
Yes it is possible you damaged the throttle body, or the MAF, but before spending a fortune chasing parts try the inner clean, so easy.
Cheers, I’ve got a bit of oil usage as well, so the plan this weekend is to do a piston soak with seafoam.
Could it be that the issue has arisen as a result of the engine running at a higher/normal temperature?
Thinking out loud that might make sense as the issue only comes up when its fully up to temp.
I cleaned both parts of the maf the temperature sensor and the air flow sensor inside.
Is it that bad to use contact cleaner? I’ve heard people say it before, but for every one of them theres someone who says it’s essentially the same stuff as maf cleaner. And from what I understand they’re both based on isopropyl alcohol.
My Dad’s Zodiac used to pink if it got too hot ( and it got hot because he used to take the fan off in Winter).
Pinking is pre-ignition, when the mixture explodes before the plug ignites it, as with a diesel.
My NC2 has a knock sensor, I wonder if your NC has one and you have disturbed it somehow?
As Richard says, it could be a coke build up but it’s odd that it would happen just after you messed with the engine.
Have you just filled up with a different fuel perhaps??
Could you have an airlock in the cylinder head water jacket??
Do you have a weak mixture to cause overheating?
Check a plug for colour, look for white electrodes.
It seems the early NC’s do have a knock sensor. The car isn’t throwing any codes, but I’m only using torque pro. Is it easy to get to to test with a multimeter?
I only bought the car 3 weeks ago and it never got up to temperature until I changed the thermostat, so I’ll definitely being attempting to de-coke it on my next day off.
If the car is burning a bit of oil the deposits will accumulate and ■■■ you suspect the slightly higher temperatures could make a difference. Even a healthy nc will protest a bit with full throttle in a higher gear at low revs.
Rings can get gummed up so if you can resolve that issue it may help.
As you probably know low oil level can kill these engines so keep a close eye on it.
If it is the proper stuff that actually works on tarnished contacts ( Servisol Super 10) then it leaves a protective lubricating film behind. The MAF will be unhappy.
If it is the carp “dry-clean” stuff (I was given three different ‘brands’ to try, possibly all off the same far east production line) then it is useless at cleaning contacts and has neither lubricant nor de-oxidant, but might be OK on the MAF.
Pure Isopropyl alcohol spray will be fine at removing oil (eg from a non-standard air filter) and general diesel dust (passing through an inadequate air filter).
I will be doing a piston soak this evening as I’ve got time to leave it til tuesday morning then change the oil.
I checked the pcv using the paper test and the rubber glove test and its definitely blowing out the filler cap.
I dont mind replacing it, but they’re all on back order (mx5 parts saying over 4 weeks)
I’m tired and can’t tell if this is a bad idea, but to avoid doing damage to the gaskets, I’m thinking of getting a vented filler cap or fitting a different pcv to the filler cap and run it to a catch can.
This would obviously be a temporary fix, but has anyone done anything similar? Would I be better off swallowing the oil costs until I can get a proper part and hope the gaskets hold?
Can you report back with your findings after the seafoam soak?
I imagine the best way to test it will be to make a note of exactly where the oil level is up to on the dip stick and then go for a good long drive and give it a bit of a thrashing… If its not made a difference, that will be sure to use some oil
Right so had a couple of days off and definitely made progress. Cant say for sure what worked, because I tried to rule out everything.
Had a Monday Tuesday off, so Sunday evening after work I began the seafoam piston soak, spark plugs were definitely showing signs of oil getting through. Then Monday afternoon I turned it over with the spark plugs out, most of the seafoam had leaked through over the course of about 18hours. I refilled and left it another 6hours then siphoned it all out and changed the oil.
Heres the bit where I open myself up for criticism. While the seafoam was soaking the second time, I took the valve cover off and set about installing a pcv valve onto the cover running to a catch tank. This is a temporary fix as I cant for love nor money find an NC pcv valve so I managed to get one for a Honda civic delivered next day. Changed the valve cover gasket then put it all back together.
Fired it up today and it smoked like a vape shop for a while, even blew a couple of smoke rings out the exhaust when I revved it, but it settles down and I took it for a long test drive.
Now there is almost no knock at all, except for a little at really low revs, but a massive improvement. Ill run another couple of tanks of v power through and continue to monitor oil usage.