Urgent Changed Spark Plugs Now Car Not Starting - Corolland: the Toyota Corolla Forums

2001 corolla. Decided to change the plugs.

Car was running fine (other than the infamous burning oil of this model).

I had some work done on this car at a local shop. It was having some issues and these were fixed for the most part. cat was bad due to burning oil, and that was replaced. exhaust manifold gasket blew (they said probably from years of clogged cats since this is my second cat change in 2 years), and that was changed.

The car was really running pretty perfectly after this was done. Prior to, I had changed the maf sensor and the pcv valve and everything was fine after coming out of the shop though there was still some studdering from the engine while idling on startup once in a while. The CEL was on for years. Everytime I change the cat it goes off for a while and then comes back on. This time it was off for less than a week and it came back on.

I figured, slight studdering, I know the thing is burning oil, and I know the plugs are probably fouled, so I got new plugs and had some time to change them tonight.

I did not drop the plugs. these are supposedly pre gapped and eyeballing them they looked correct (I cannot find my gap tool cause I recently moved and haven't unpacked everything).

Now when I took the denso's out (forgive me I don't know cylinder numbers) they were all caked on with white stuff that I've seen in pictures means they need to be replaced. "fouled" is what I believe it's called. The shop said there was a misfire detected in my ECU though everytime I've checked the codes I've never seen that code. Only a 420 and 121 or 171 or something like that which was a lean code. However the second cylinder from the left, had a good amount of oil when I pulled the plug. I cleaned out what I could but didn't wanna mess with it too much. The third and fourth from the left had a little oil but not nearly as much. I didn't clean those out because those plugs were clean.

So put the new ones in, reconnected everything, went to start and all I got was the cranking noise. Not the bad battery noise, and not the bad starter noise. I tried a couple times and it was the same everytime. Did not want to gas it really, as I don't see how that could be a problem, as I had just run the car maybe four or five hours ago.

So then I took the new plugs out, put the old ones back in and the same thing happened. Crank but no start.

I just left it at that since it's about 3 am where I am. I DO have to get to work tomorrow though so I really need help with this.

I did disconnect the battery while I was doing this so that the ECU could reset and see what codes I'm getting as well as how long it takes to get the CEL again seeing as I've reset before after changing the cat and it would come on in shorter intervals till it was always on. Could the battery being disconnected cause fuel to move away from the engine in that short of a time enough to where trying to start it 3 times, stopping, changing plugs back to the old ones and trying another 3 times still wouldn't be enough to get fuel back to the engine? Or...

Is some oil on the threads of ONE spark plug really going to keep the car from starting? My experience is one bad plug will not stop your car from starting. I'm staring at the new plugs that I put in and pulled out right now and only one of them has oil on the threads (from that second cylinder) the rest are clean. Just a tiny bit of oil on another one.

Or is it possible new spark plugs freaked out my ECU and now it doesn't want to do anything? Like there's too much spark now so it had a heart attack?

Or is it coincidence that maybe something else is wrong like my fuel filter just happened to give out right after I decided to change the plugs.

I realize it's also possible I messed up one of the wires when I disconnected the boots but ALL OF THEM? I really don't think so. I suppose I can check for spark tomorrow morning and maybe in that case distributor or something of that sort went bad?

There is a white connector attached to the rail that you have to unbolt and move aside to get the boots out that looks like it's just got one wire on it. I didn't break anything though, it looked like that when I took that black plastic cover off. Seems like a lot of connector for one wire though. But I don't see a loose wire and the dust on it looks like it's always been like that. Still really flimsy little wire for such a large connector that looks like it should have two wires coming out of it. But again, it looks like it was always like that and I didn't break anything.

Before anyone asks, YES I put all four spark plugs in both times, and yes I reconnected the boot wires each time. As for torque I do not have a torque wrench but I understand "tightness", and per a post I read by fish, follow the directions from manufacturer. NGK says not to overtighten and the box says (in picture form) screw on by hand, which is not an option the way they have it illustrated but I get the idea. Get it on and then torque. I had both sets on about as tight as I could get them with the spark plug wrench with one hand. I don't think I could have gotten them tighter. Just went as much as I could without getting to the point of fighting metal.

Anyway, please help as I'm sure this is probably a simple fix. I was just stupid and really should have done this when I didn't have to work the next day.

Could be a number of possible culprits in this case. Could be pretty simple - like a missing/disconnected wiring, plug well and coil on plug igniter that has oil on it (will short to ground), or bad connection between the plug and the igniter.

I'd definitely check for spark at each plug. Easiest way is to this is to disconnect all the wiring to the plugs - remove one plug and coil assembly - make sure the plug is securely inserted in the coil on plug unit and that the connection is perfectly dry. Ground the plug (ground strap) to a chassis ground, have someone crank the engine. If it is getting a signal - then you should see the spark jump. It may be hard to see in bright light, might have to pull the car into a garage, use something to shield it from some light, or wait until it gets dark.

Most likely, something happened at the main wiring loom (that runs right behind the plug connectors) or that connector with a bunch of wiring running to it, as that is either the chassis ground or EMF noise suppressor. Since you have to unbolt that to get better access to the plugs - that would be one of the first places I would look.

Another possibility is that you are not getting any fuel or the engine is flooded from all that cranking. One way to test for fuel is to crank the engine for a couple of seconds - then immediately pull the plugs. They might have a light coating of fuel and there will be a strong fuel odor in each cylinder. As for flooding - just stand on the gas pedal, hold it to the floor. That will hold the throttle plate open and allow some extra air in there.

Thanks fish, I did finally get it to start after giving the engine a firm talking to with my foot on the gas pedal. This was first with the old plugs in, drove it around the block. It was running horribly. I then decided, hey, if it's running with these chalk coated plugs now, should be good when I switch back to the new ones. put the new ones back in, and the car started up faster than it has EVER started since owning it.

Here's what I think happened:

When I removed the old plugs there was oil in that second well. and dabs here and there in the other wells but the other plugs were all dry... I didn't really clean the well out. I figured that plug worked fine soaked in oil.... ( I know dumb right ) but I personally don't think that had anything to do with it not starting.

When I put the coil packs back on, I didn't really check for a connection. Mind you I've changed spark plugs, WIRES, cap and rotor before on some other cars, so I didn't realize, the coil packs don't "click" on to the spark plugs like wires do... (right?) so I wasn't even checking for fitment. Plus I saw a video of some guy changing plugs and when he reassembled he didn't mention a click and I couldn't hear one and it looked like he didn't even really push them down other than the pressure of putting the bolt back on the cover. I don't think this had anything to do with it not starting either. Plus I don't think there is really anyway to have the plugs secure in the coil packs. I tried putting them together out of the well and no matter how hard I tried, I could not get a "click" and lock to occur. I don't think they do... right?

I REALLY doubt the car wouldn't run just because of a loose connection or oil covered plug on a few. But I do think, all that coupled with the cars already advanced doctorate in oil burning and a myriad of other problems, it was too much for the car to handle. Change all four plugs, some not connected, some covered in oil, and then try starting it? I think that's where my problem was.

THEN, I tried starting it again. Kept trying. From what I've read, you can't really flood an efi engine... I think this is wrong.

When I got up this morning from my two hours of sleep, to only see a reply from fish, I went back to the garage. floored the pedal and kept cranking the engine. Eventually I got tired of making it seem like there are elephants living in our garage. I figured, hey, maybe it's dead anyway so who cares, and started pumping the gas at the same time. Eventually I heard it starting to turn over, and then I kept alternating. pedal then turn key, turn key then pedal, turn key and pedal, and every other iteration in between.

It then finally started up, terrible idle but it was running. had to keep hitting the throttle otherwise it probably would have stalled. drove around the block and back home. parked. pulled old plugs, cleaned wells (of what I COULD), cleaned the oil off the plug wrench, cleaned the oil off the new plugs, re-installed the new plugs, prayed to god in a not very nice way, turned the key,--- and it started really fast and really smooth. drove around the block again and it ran OK. Parked it and got ready for work. came out, started again, and all seemed well.

on my way to work the CEL came on (and I had JUST reconnected the battery) so I've probably got a lean code again, or the never ending 420 code again, ONLY ONE WEEK after the cat was changed. but the car was running fine. I was pretty low on fuel by the time I got to work (1 hour drive). when I left work I went to get gas. mileage shows despite all this, I still got 340 miles off this last tank of gas.

I will take it to a autozone sometime in the near future and see what codes are in it right now. and later when I have time I will make a full write up of how the car has been since my last post which was YEARS ago, and what has been fixed and not fixed since then.