spark plug coil pack

gbimmer · 02-05-2004, 09:56 AM

Hey guys,

New here....anyone ever had trouble with their coil packs? What are the symptoms of faulty coil packs? Right now my cars backfiring like crazy....oh, already changed the spark plugs.
Thanks.

Jared at Pelican Parts · 02-05-2004, 10:01 AM

Might help if I new what kind of car this is.....

blkongry · 02-05-2004, 10:03 AM

There are several threads relating to coil packs, and issues they can cause when malfunctioning. Backfiring is a problem caused by too much unfired fuel and air making their way down the exhaust. It's when they hit the hot exhaust that they ignite and explode in a 'back-fire'. A coil pack could contribute to this kind of a symptom, but it would also leave the engine seriously lacking power. Is the engine showing erratic behavior as well as the backfiring issue?

gbimmer · 02-05-2004, 12:10 PM

Sorry guys, the car is a 92 325i with about 180,000 on it. Along with the backfireing their is also a lost in power. Doesn't seem to accelerate as fast and backfire occurs even when driving. Any help would be appreciated guys....I'm also affraid it could be my timing chain is off. what do you guys think?

blkongry · 02-05-2004, 02:03 PM

I would look at your spark plugs first, and then the coil packs. If you see wear on the plugs, they are cheap enough to just replace. Once you rule the plugs out (and if you are still having problems) you'll need to find someone who can test your coil packs. Once they are tested, either ruling them out or pointing at them as the problem, we can diagnose it further. Just remember, you are getting unspent fuel down in your exhaust... and a lot of it to cause backfiring. That would mean fuel is not getting ignited... spark would be the first thing to look at.... then other possible issues like engine/fuel management control, bad sensors, and a misaligned valve train (which I doubt... chains can stretch, making the valve timing a little off, and stretch shouldn't cause this much of a problem... timing chains rarely slip a tooth) would be next on the list.

gbimmer · 02-06-2004, 09:15 AM

Thanks for the help guys. I'll try your suggestions.

blkongry · 02-06-2004, 10:24 AM

Oh yeah, I was going to ask... is your car truly 'backfiring'? Meaning you drive and when you let off the gas you get a big ol' nasty KERPOW!! out of the exhaust. Or is your engine just misfiring where it is a repeated dull pop from under the hood area. Backfiring is pretty dramatic and you don't really see it that much on new vehicles. That's usually something you see with an old carburated engine with points. If it is misfiring with repeated little pops and lurches of the engine, that can be your plugs, coil packs, engine control, or even something as simple as water down in your plug area.

gbimmer · 02-06-2004, 12:51 PM

Blkongry, it's backfiring and misfiring from what your describing. When I let off the gas it makes the popping sound and even when I'm driving it will pop. On acceleration and deceleration. The car lacks power and idles really bad when I'm waiting at a light or stop sign.
I already changed the plugs and found the second cylinder with oil so I changed the valve gasket also, but no improvement so that's why I hope it's the coil packs.. hopfully not a timing issue cause that can get spendy....any other input guys...thanks in advance...

blkongry · 02-06-2004, 01:19 PM

It could also be your crank position sensor. You are on the right track... you've already replaced the spark plugs, and now on to the coil packs. After that would be checking sensors and then the DME. If all that looks good, and your vacuum lines all look good, then I would start looking to internals.

Hopefully others will give their input and insight on this topic too. Always good to have a second and third opinion/input. Good luck.

TexasBMW · 02-08-2004, 10:21 AM

Type of backfiring is important. If its a muffled pop, this is likely a backfire through the throttle body intake. This is usually a spark timing problem, firing with intake valves open. Spark jumping from one wire to another or simple mistiming, possibly crankshaft position sensor.

If it's a loud boom like a shotgun, that is an exhaust backfire caused by excess fuel/air mixture hitting hot exhaust system.

good luck

kingnine · 02-08-2004, 05:56 PM

You might want to check your fuel filter to see if it's clogged, and your fuel pressure. Sounds like you may have a lean misfire and poor performance due to lack of fuel, according to the symptoms you described. If it were a timing problem, you would experience black smoke and or carbon fouled plugs. You can easily test your coils by removing them one by one and while running the engine, lay the coil down (don't hold them in your hand), keeping the spark plug end about 1/4 to 1/2 inch away from an unpainted ground and looking for a spark. If you have spark the coil is good.