One Ignition coil or eight?

[digitalbuda]

I'm new to fixing my own vehicle and to save money, I'm going to repair some of the problems myself, except for the harder ones which I'm gonna take it to the shop instead. One of my problems is a cylinder 8 misfire according to the check engine light/autozone reader.

Instead of replacing just the one spark plug/wire/coil, I've decided to replace all 8 of them because they have not been replaced in a long time.

My vehicle is a 2001 GMC Savana G1500 SLT V8 5.7L Vortec van.

From what I read, people have said If it's a 6 cylinder then u will need 6 ignition coils, if its 8 cylinder then 8 ignition coils and so on. But when I removed the center console, I saw just one ignition coil connected to the distributor cap. Is it possible to have just one ignition coil?

https://i.imgur.com/COa7JkJ.jpg?1

 

[Railgun]

Yes, hence the distributor. Could be a bad contact on that point as well. They're relatively cheap...you could replace the distributor too.

 

[iamwiz82]

Yes, hence the distributor. Could be a bad contact on that point as well. They're relatively cheap...you could replace the distributor too.

And when you do replace it, be sure the rotor is fully seated. I nuked a brand new cap and rotor by not seating one correctly my first time. Oops.

 

[digitalbuda]

Thanks guys, that is good news. I will save about $250 buying just one ignition coil instead of 8.

 

[Wingznut]

Yes, hence the distributor. Could be a bad contact on that point as well. They're relatively cheap...you could replace the distributor too.

Do you mean replace the distributor cap and rotor? If not, why would you want to do the entire distributor?

 

[Jimzz]

I would start with the cap, rotor, plug wires, and plugs. Skip the coil if it runs well other than the cyl 8 miss fire.
Clean the throttle body and PCV valve out with some carb cleaner.

 

[boomerang]

Ignition coil does not = spark plug wire. You need to replace a spark plug wire although I am curious how a specific cylinder misfire can be diagnosed when there is a single coil.

Regardless, if the vehicle has high miles on it, it is a good idea to replace all the spark plug wires at the same time. I would also be looking to change the spark plugs themselves and it would certainly not be a bad idea to replace the distributor cap and rotor at that time. You'll have done a complete tuneup of the ignition system.

 

[digitalbuda]

Ignition coil does not = spark plug wire. You need to replace a spark plug wire although I am curious how a specific cylinder misfire can be diagnosed when there is a single coil.

Regardless, if the vehicle has high miles on it, it is a good idea to replace all the spark plug wires at the same time. I would also be looking to change the spark plugs themselves and it would certainly not be a bad idea to replace the distributor cap and rotor at that time. You'll have done a complete tuneup of the ignition system.

My van has 200,000 miles on it. I plan on replacing all 8 spark plugs/wires, the ignition coil, distributor and rotor.

Other things I have to take care of is a leaking engine coolant, I had the water pump replaced and it's still leaking engine coolant somewhere ...

 

[Railgun]

Do you mean replace the distributor cap and rotor? If not, why would you want to do the entire distributor?

Yes, cap and rotor.

 

[LTC8K6]

Is it possible to have just one ignition coil?

Cars got along just fine for a very long time with only one ignition coil.

 

[phucheneh]

Ignition coil does not = spark plug wire. You need to replace a spark plug wire although I am curious how a specific cylinder misfire can be diagnosed when there is a single coil.

Methinks you don't understand how the misfire monitor works.

Misfires are flagged as a result of variation in crankshaft acceleration. It doesn't matter what actually causes the misfire...if you have a V8, the PCM wants to see eight roughly equal bursts of accelerations for every two rotations of the crasnkshaft. If there's a dead spot when, say, cylinder eight is supposed to be firing...it sets a cylinder eight misfire code. Or, rather, it logs a misfire...strategies for actually setting a DTC vary.

You're thinking more of actual coil codes, which are far less frequent. They require a winding inside the coil to actually be shorted or broken. On the primary side. And most coils don't fail in that way- it's usually just cracked plastic and/or epoxy filling allowing the secondary (high voltage) side to arc to ground before actually travelling across the spark plug gap.

 

[LTC8K6]

http://www.magnaflow.com/07techtips/TechBulletin/TB80011.pdf

Misfire detection paper as phucheneh said.

I didn't know that, either. You learn something new every day...

 

[WoodButcher]

My van has 200,000 miles on it. I plan on replacing all 8 spark plugs/wires, the ignition coil, distributor and rotor.

Other things I have to take care of is a leaking engine coolant, I had the water pump replaced and it's still leaking engine coolant somewhere ...

Didn't by any chance overheat at one point?
If you can't find the leaking coolant you could have a cracked head or bad intake gasket. Either one could cause a misfire. You need to pull the #8 plug and diagnose before throwing money at parts.

 

[SparkyJJO]

I'm scratching my head... I'm pretty sure GM stopped using distributor caps long before 2001

 

[LTC8K6]

I'm scratching my head... I'm pretty sure GM stopped using distributor caps long before 2001

Nope. Still had them.

 

[Wingznut]

I'm scratching my head... I'm pretty sure GM stopped using distributor caps long before 2001

Check out the pic that the OP linked, it's right there.

 

[digitalbuda]

Didn't by any chance overheat at one point?
If you can't find the leaking coolant you could have a cracked head or bad intake gasket. Either one could cause a misfire. You need to pull the #8 plug and diagnose before throwing money at parts.

From what I've read, GM Vortec engines are notorious for their original cheap plastic intake gaskets. Over time, the dexcool coolant eats away at the plastic gaskets and starts to leak inside. Whenever I look underneath the van, I only see 1 or 2 drops of it. Sometimes I don't see the leaks on the floor at all. I do smell the burning coolant. I have to replace the coolant to normal levels every month or so.

Sears Auto said it would cost around $1500 to replace the upper/lower and valve gaskets? Does that price seem reasonable?

 

[WoodButcher]

$1500 sounds reasonable if your pulling the heads as well but I don't know that you need to. Did they diagnose or just give you a ball park figure? If it is a cracked head a new set will run about $500 for the parts. I bought a pair last month for a 350 that is going into my '93 safari. The donor motor had been overheated and cracked the heads.
http://www.astrosafari.com/viewtopic.php?f=127&t=17922&start=60
Page 3 and 4 I began on the engine. Got some good pics.

I did the intake gaskets in my '97 safari It took me about 16 hrs over two weekends. I didn't pull the heads my issue was obvious. While I had it apart and the intake on my bench I wish I had opened the plenum and replaced the spider. I don't know what sort of injection you have but in my case the spider is often a problem after 150,000 which was about where I was at the time. It has always run rich and I think this may be the issue but now at 280,000 miles plus I'm not fixin' it!
The intake gaskets cost about $40, the Haynes manual I had cost $20, today I use that and the factory service manuals, ($50 -150 depending on year and make) misc hoses, new thermostat, clamps, fluids, permatex, wd40, duct tape and band aids, I spent maybe $300 and my truck was parked for 10 days. Do it yourself if you have a place to.

My biggest issue is the fact I need to have a lot of faith in the guy doing the work, in a van most often there is more disassembly to get to the problem then to fix the problem itself. I'd rather do what I can myself so I can clean, inspect and repair everything else on my way in and out.

 

[digitalbuda]

Yeah I'm thinking about doing myself. I know how to do it, just need to get the proper tools. I don't think I have a blown head gasket but will check it. Fuel injector is kinda expensive. Gonna try and clean them

 

[Throckmorton]

Does a 2001 GM really have a spinning distributor? I thought every car since the 90s has had electronic distribution

 

[WoodButcher]

There is not that much needed as far as specialty tools needed, basic toolbox, metric and SAE wrenches and sockets. Torx sockets and some flare nut wrenches. With a van extensions, swivels and wobbles are key along with thinking it through. My intake only weighed a few pounds but I had my kid help with the install, w/ four hands on it and eyes front and back it was a piece of cake.

I looked up a thread I saw recently on this
http://www.astrosafari.com/viewtopic.php?f=43&t=52362&p=444562&hilit=intake+manifold#p444562
good pics.
The 4.3 and 5.7 are very similar and share many of the same issues.