Joseph B

My car just started hesitating and it sounds like its running on less than 4 cylinders so I havent been driving it. Today, I changed the plugs, wires, and coils and its still suffering from the same problem. I also flashed the original tune for my car hoping there was something wrong with the tune, but to no avail. Any suggestions before I douse it in gasoline and light it on fire?

Faeflora

iTrader: (2)

Subies sound badass. You are lucky. wud wud wud wud wud bruuuuuddddddddddddd

Does it sound liek that when revving at idle? Perhaps try disconnecting one plug at a time, rev it, see if it sounds worse. When you hit the plug that does not change the sound, you have the problem right there on that signal path roger wilco.

Joseph B

It sounds like this at idle and I'm at a loss, since I changed the coils, wires, and installed new bkr7es gapped at around .22. My Deatschwerks injectors also have less than 2000 miles on them, so I don't think it can be an injector..

Faeflora

iTrader: (2)

Riiiight---

my point is that if the car does not sound worse when you pull power to the plug that means that plug is not firing.

Joseph B

Well, I just did this and all of the wires are firing, however the sound of the engine does not change when I pull the wire from cylinder 4. Ironically, this is the cylinder that has a threaded insert in the head for the spark plug. My wideband is also reading lean at idle.

Faeflora

iTrader: (2)

That indicates that the problem, whatever it may be is centered around cylinder 4. Or I could be totally wrong :|

If you pull the plug for that cylinder, plug it into the wire, and lay it on top of the block, can you see the plug sparking with the motor running (or while cranking)?

FRT_Fun

iTrader: (19)

Have a friend hold spark plug to tongue, crank.

jk

But yes faeflora is correct if you pull the plug and no change in the engine it is most likely an issue with that cylinder. Might not be spark, could be fuel or compression too. But those are all easy to check. Do work son.

Miataman28

You may have some water in the cylinders, it sounds like my engine before i found out there was water in the cylinder. You may want to pull the plugs and check the cylinders, if you see one piston that is wet or alot cleaner then the rest then there lies your problem. You may also want to run a leakdown test while both warm and cold and see if you have a loss of compression.

Joseph B

I checked all of the cylinders last weekend and they all have carbon deposits, none of them have been steamed clean. The plug for cylinder 4 is sparking when I remove it.

Miataman28

Next step for me would be a leakdown test.

Joseph B

This is what I've been dreading all week as I waited for my ignition parts to arrive.. I'll keep you guys posted..

Reverant

iTrader: (10)

Compare all four cylinders (spark). Mine did the same, spark on all four cyls but one was much worse than others. It appeared lean on the master wideband, but one of the individual cylinders was waaayyy rich, indicating a problem there. Changed a coil and all was well again.

Faeflora

iTrader: (2)

Hmm rut roh.

I say switch injector between the possible problem cylinder and another. If it still sounds crappy, pull plug wire by wire again and listen. If the cylinder you switched the injector to now does not affect the sound I would then say it is the injector.

Miataman28

Another test you can run is buy a cheap injector testlight it is basically a spacer between the injector and the harness, if the injector is firing the light will illuminate, if not then that may be your problem.

Sean

iTrader: (12)

Also check the gound on the harness on the passenger side in the back neat the back of the engine that the coil and injector harness is gounded to. I would also check to see if the oil or antifreeze has oil/water in it.

Faeflora

iTrader: (2)

But that will not show if there is actually fuel coming out of the injector right?

Sean

iTrader: (12)

No but you would have to assume if you have fuel preassure witch you do because the car runs, and the fact that the injectors are almost new and not junk ebay, that if there is a signal that it is firing not saying it is a 100% but it is close.

Miataman28

If it is firing, it is releasing fuel. Unless the injector is all gummed up. But if you switch the injector around you will need new seals. But it is an effective and cheap way to test them. But the test light will also indicate if you have a harness or grounding issue for that injector.

curly

iTrader: (25)

Hmm. Some inconclusive/incomplete engine diagnosing going on in here.

Spark fires on 1&4 and 2&3. Injectors fire on 1&3 and 2&4. This makes it very easy to diagnoise spark/fuel problems.

I like to take ALL four plugs out, put them back in my COPs (wires in your case), and lay them all on the valve cover. Not only is it pretty in a dark garage, but it tells me for sure if everything is working. Sounds like you've tried something similar, and if you're confident that you did the testing correctly and the spark was strong enough, than your ignition system is fine.

Now, if your ignition system is fine, you need to look at fuel next. You said cylinder #2 IS changing the idle. If this is the case, than your wiring for fuel injectors should be fine up until it splits for the #4 injector, and the #4 injector itself, since both spark and injection are batched fired on a stock ignition and fuel system. Check the harness if you want to, although unless you've stressed it a bunch there's not a huge chance it broke. After that, I'd follow whats-his-face's (don't wanna scroll up) advice and swap injectors, see if it changes anything. Might try your stock injectors if they're still laying around, just don't do any tests above idle, and don't forget to change your req fuel.

curly

iTrader: (25)

P.S. I've diagnosed A LOT of 2/3 cylinder issues, so listen to me.

Also, a very quick method is so: If it starts fairly easy except sounds like a Subbie and has decreased power, that's 3 cylinders.
If it starts very hard and has an outrageously low idle and barely has enough power to move itself, that's 2 cylinders.

I don't think our engines will run on 1 cylinder.