Im hoping someone will be able to help me with a problem with the wifes 1.6 eunos roadster (im pretty sure its a 1990 vintage)…
When the car is really cold (its fine in the summer, but every winter, if we have had a frost overnight) the car misfires something rotten, the whole car shakes and it hardly pulls at all. Once the car has been running a while and slowly gets warm, the misfire slowly dissapears, by the time its warm she goes like a train?! I have replaced spark plugs and leads, and my local garage changed the engine coolant temperature sensor, none of these have made a difference. I have come on here as unfortunately i dont have a bottomless pit of money to pay the garage, I am fairly confident with a spanner, but I’m not very good at diagnosing these problems!
Also, all year round, mainly when the engine is cold, the car smells as though it is running very rich, i dont know if this has any bearing on the problem, when i mentioned this to my local garage, they said this is “fairly normal”.
If anyone has got any opinions on what the cure for these problems (most importantly being the misfire!) they would be most appreciated!!
I think it may be a lose or degraded cable. Maybe an earthing problem. When its warmer the metal is expanding & gives you a better or tighter conection & when its cold the oposite happens.
Mine is doing something similar at the moment in these really cold temperatures. If it is below freezing it starts fine without any misfire, then I back it out of the “shack” i park it in, get out to shut the doors and it then sounds like it is running on three cylinders. Once I have driven a few hundred yards it seams to run fine so I dont know what it is, maybe a slightly dodgy lead as they have not been changed. Odd thing is that if it is just above freezing or wet it is fine.
I will check all the engine earths as soon as i get a chance - probably will be the weekend now, as for the sensor, i dont know exactly which one they changed, i will dig the bill out when i get home and see if it is more specific. Is there two? Are you saying that the one at the back of the engine is the one that may cause this issue?
Sorry for my ignorance, i am more used to working on mini engines which are alot more basic! Just a carb and distributor to worry about!
As far as I am aware the one at the rear of the engine is used for the ECU/fueling signal. It would I guess allow for extra fuel/rich mixture for cold starting and then weaken off the mixture as the temp rises. So if starting is ok it and it runs well when warm it would suggest to me that the sensor is ok.
Thanks again for the replies, unfortunately due to work i have not had a chance to have a look yet, but i can report that for the last two there has been no misfire? (Still smells rich though )
In fact, it has been fine since i have filled her up with shell v power… normally we put cheapo morrisons petrol in… would this make such a difference? Or just a coincidence?
Ok, so its been doing it again clearly the V Power hadn’t worked I can only find one temp sender, on what looks to be the thermostat housing just behind the radiator, this doesn’t look new, but i cant find the one at the back of the engine? Could anyone point me in the direction of the other one, so i can make sure it looks as though it has been replaced?
I have checked all the engine earths that i can see, and they all seem to be in good working order.
If there is anything else any one can suggest, it would be most appreciated!!
Also, any ideas why it smells so rich? Especially when cold? Could this be related?
Hi Steve, I had a similar problem with my 1990 Miata. I must however mention that my car was “on blocks” for almost 6 years while I worked overseas. Anyway, here goes - after replacing all fluids, filters, hoses, belts, sparkplugs & leads, battery, checking electrics etc., etc., the engine fired up immediately but ran on 3 cylinders. After a few hundred meters (slow) driving, the engine started running on all 4 cylinders but with a “rich smell”. Next morning (cold) the same thing! After various checks I de-pressurized the fuel system, removed the fuel injectors and had it cleaned. Re-fitted the injectors and presto! - the engine starts on all 4 cylinders, no more rich smell, runs perfect. Regards, Johann
Geoff - thanks for the picture, so it is right at the back, by the looks of things if i follow the hose from the heater back to the engine i should find it :P
From what i remember from looking under the bonnet - thats not easy to get to?! lol, ill have a look on my day off though
Thanks also to Johann for taking the time to reply, is cleaning fuel injectors something that can easily be done at home? As i have mentioned before I am confident with a spanner, but know very little about modern fuel injection systems… i will do some research into how to take all that apart
You could try a fuel addative, something like Red X fuel system cleaner to see if that helps. Or perhaps a spray cleaner that you can use to clean by spraying in the inlet manifold. I have used fuel addatives before but not the induction cleaners. As far as I am aware you must not spray through the air filter but remove the inlet trunking from the throttle body/inlet manifold and spray in there while the engine is running. Dont quote me on this but perhaps someone else who has used them may be able to advise.
Well unfortunately, as I don’t have much free time, I have decided to take it to the garage again, I have taken it to a different garage, this time I have taken it to a bloke who comes very highly recommended, and when I met him when I was dropping the car off this morning he seemed very friendly and knowledgeable. Thank you very much for all your posts and as and when I find out what the cause of the problem was, I will post again to let you all know
I have the exact same problem, occassionally from a cold start it fires up fine but only runs on 3 cylinders, but clears fairly quickly and is back to 100% performance.
Well a bit of an update, spoke to the garage today, he has done a leak-down test and apparently it was 30% so he was happy with that, which means he has no reason to suspect the head gasket is at fault. He has figured out that the misfire is on cylinder 3, but it still seems to be sparking. What he has done is swapped the injectors from cylinders 1 & 3 so he is hoping that the fault will move to cylinder 1, and therefore the injector will be at fault… His reasoning behind this is he thinks that the injector is leaking too much fuel into the cylinder and therefore flooding that cylinder, causing the misfire and the petrol smell coming out of the back… The only thing is since he swapped the injector around the car has been fine. So he is keeping the car overnight again, hoping that the fault will come back tomorrow morning when its cold…
Injector fault sounds like a likely culprit, luckily its not a big job. Some people report good results with one of the ultrasonic jewelery cleaners, so may have to invest in one!
Just a quick update. Apparently the car has been behaving quite well since he has moved the injectors around, but I think that is to do with the fact the weather has been a bit milder.
He has been poking around a lot under the bonnet, and when he had it in his workshop he noticed that occasionally the coil pack was arcing from the coil pack to the cylinder head. So he is going to change the coil pack anyway, and see how it goes… if the misfire comes back I will have to see if it has moved from cylinder 3 or not… hopefully I will be picking the car up tomorrow…
)
clearly the V Power hadn’t worked 