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Ignition Coil Replacement How-To (2003 Astro)

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48K views 25 replies 23 participants last post by  AstroWill  
#1 ·
I don't know how to tell when your ignition coil is on the way out. It may start with power decreases as mine did. But it will eventually fail. You could be procrastinator and wait like me, then end up doing it at the most inopportune time possible. My advice would be to do it when you do the spark plugs and wires. It's a $30 dollar part, and with as much of a pain as the engine cover is to remove, you might as well do it then anyway.

Start by removing the engine cover, as shown in one of my previous posts, found here: http://www.astrosafari.com/viewtopic.php?f=9&t=4079

Once you have that off, your ignition coil is located here:

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It looks inaccessible, but it isn't. The ignition coil is kind of tucked in there, but it can be gotten out. The ignition coil is contained in a bracket that has another component attached, and is bolted to top of the motor. There may be another bracket holding it down-we'll cover that later.

Start by removing the insulated wire, as shown (note: replacement wire should be obtained from a spark plug wire kit.)

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Next remove the wire harness on the other side of the ignition coil.

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The ignition coil bracket is held on by 2 - 10 mm bolts. To remove them you'll need a deep well 3/8" drive or 1/4" drive socket with one or two short to medium sized extensions. I could not give good pictures of these bolts. They are in a straight line going from the passenger compartment toward the front of the van. Note the location of the one closest to you by the position of the socket and extensions. If you look closely, just at the edge of the ignition coil shadow you'll see the second one appearing to be under the coil-it's not, it's just on the other side, toward the front of the van...

TIP: Use a telescoping magnet at the bottom of your socket to catch the bolts as they come out-if you don't know what I'm talking about, it's something like this one: http://shop.advanceautoparts.com/we...s/stores/servlet/product_TELESCOPING-MAGNET-Ampro_9021426-P_N3499_T|GRP2083____

Alternatively, dip your socket in all purpose grease before slipping it over the bolts. If your lucky, the bolts will stick inside when you pull the socket out.

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If you're incredibly unlucky-I was-there will be a bracket still holding it. If not, scroll down to the part where it comes out.

If you are so unlucky, remove the air intake assembly, as shown in one of my previous posts, found here: http://www.astrosafari.com/viewtopic.php?f=9&t=1142

Below are photos of that bracket I was telling you about (taken from inside and outside the van. There are two 10 mm bolts on it. To get at them, you'll need a 10 mm deep well socket, extensions and a universal joint-3/8" drive worked best for me. Either dip the socket in grease or use a telescoping magnet to retain those bolts-one is actually a nut and not a bolt.

Before you do this, there is a 10 mm screw-best removed from inside the van. In the top photo, I tried to point at it with a screwdriver, but didn't get a great photo of it. To remove, you will need a 10 mm racheting wrench. You will also need a telescoping magnet to catch this.

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Front of bracket:

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Okay, you're finally ready to pull out the ignition coil. There is a wiring harness attached to another part on the ignition coil bracket-remove it.
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Unless the bracket has bolts or screws, it's riveted. Secure the whole thing in something like a vise and drill out the rivets-once you have one end out, you can tap them out with a small screwdriver or something.

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You'll need to reassemble the bracket onto the new ignition coil.

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Once done, re-install the same way it was removed.

TIP: As you've no doubt figured out, human hands don't reach many of the places you need to go to re-install bolts. You'll need to hold bolts and nuts in a socket, often connected to extensions and/or universal joints. One way to keep bolts in a socket is to dip the end of the socket in grease. Another is to try to position the nuts or bolts using a telescoping magnet. You take a chance either way. I prefer the grease method.

If anyone more experienced has other tips, or notices anything I might have missed, please reply to this post and give them.
 
#4 ·
Great post, a big help in my mission to replace the coil on my 96 ASTRO 2WD. I was lucky and didn't have a second bracket to remove. Still had the 3 main studs to secure the coil bracket to the block. However, on mine the stud closest to the front of the van had the throtle cable bracket mounted on it, which had to be removed from the stud before the stud was removed. Thanks again Chemist for your great post, really saved me some time and saved me from alot of frustration!
 
#5 ·
i did mine 2 months ago including the control module
i did the control module again last week as the part failed and needed to be replaced( thank god i bought a code reader that i keep in the truck) the problem was that the screws holding it on had rusted and become a little to brittle to be tightened without snapping after i hit a big pothole that rattled it off
as the only screws i had that fit through the icm holes were stainless steel woodscrews i had to put a wood block on the backof the bracket but its more solid then broken screws.
on the plus side my milage went from 12/ gal to 14/gal and i can accelerate uphill again.

its a great part to change if you have shitty mileage and a lack of passing power.
 
#6 ·
:ty: Will definitely help me out in the morning. i cant wait to see how much more power I'll have once finished. its like a light show down there right now. hard to start, but runs great once started. will post my news once finished. i would upload photo's but my laptop doesn't have a port to do so.
 
#7 ·
I have the extra bracket which causes a huge pain. I found I did not need to completely remove the one screw that you loosen from the front (left hand, lower one which removes vertically when looking at it from the front).
Also, I highly recommend opening the front hood to let more light in as well as removing the air intake assembly to let more light in.
 
#9 ·
Hello. I just joined this website and must say that this acticle's instructions on ignition coil replacement was extremely helpful. Other than doing brakes myself, this is the first real repair job I've attempted. My 2000 Safari now starts in damp weather and I am noticing a huge increase in acceleration power. Thanks for a great post!!
 
#11 ·
In regards to the coil replacement on 2000 and up Chevy Astro that was a great description with pictures however I think I found an easier way.. Basically the coil is sandwiched in between that bracket that is a pain in the butt to get out and has to be removed from engine along with another electrical component.. If you look at the coil itself from the passenger side, there are only 2 rivets holding the coil in there where there should be BOLTS,, GRRR.. Just drill the bottom 2 rivets out and you should be able to pull the coil right up and out without disconnecting "anything else" other than the wiring harness and spark plug wire...
 
#12 ·
New member here, great website. Thanks to the chemist for this info, I never would have tried this without this blog. That being said, I still made a rookie mistake and didn't pay close enough attention to the order in which I removed the nuts & 10mm bolts holding the coil bracket & cable bracket that sits on top. Is there anyway to get an exploded schematic of this on-line? My searches haven't gotten very far. Thanks for the info.
 
#17 ·
Information, the gift that keeps on giving. ;)

This was a huge help, as I had never done one on my 2002 with the bracket on it. I did cut a corner, and only disconnected the sensor, and just took the flex hose off instead of the whole aircleaner. My trick for getting those nuts bolts etc to stay in the socket, is scotch tape. If it's a nut just put the tape over it in the socket and use a pick to punch a hole in it. For bolts & studs, put it in the socket, and wrap two pieces of tape over the edges, one on each side. It pretty much tears off without any residual tape left on the nut or bolt. Anyway, thanks for the pictures, and info, sure saved me a lot.
 
#19 ·
I was here in January 2017 and had it not been for this post & info I probably would not have made it through this job without much much more frustration. I am having to replace the coil again, and came here again for reference.

I'll ask if anyone has had a problem with the rotor tang getting too hot, and losing tension with the contact in the distributor cap? I'm on my second rotor in about six weeks, and this one actually has a little dibit (?) burned in it that at first I thought was a hole burned through it. Getting no codes notta, just losing tension in the rotor tang until it comes to a no start situation. :confused: So I am thinking it is a problem with the coil? I'm changing it, and crossing my fingers, so any help/advice about it possibly being something else would be greatly appreciated!

So back to removing it ;) I did like in th picture, so the nuts on the bracket were facing away from the engine. I'm sure that the kits probably have different size nuts & screws, mine was 7mm, so a 7mm 1/4 inch socket, swivel, short extension, ratchet, and a little wiggling & jiggling, and the coil slid right out. :banana: Sure was better than the first time. :D
 
#21 ·
Whiskeyrebel said:
@chemist, thanks for all the helpful suggestions and pictures on this thread. Without it I would have had much more difficulty changing the coil on my 03 AWD today.

Sadly, it didn't cure my misfire. I also replaced the CKP sensor - also didn't fix the misfire.
Have you checked the distributor drive gear? https://sites.google.com/site/astrosafa ... or-disease
 
#22 ·
AstroWill said:
Whiskeyrebel said:
@chemist, thanks for all the helpful suggestions and pictures on this thread. Without it I would have had much more difficulty changing the coil on my 03 AWD today.

Sadly, it didn't cure my misfire. I also replaced the CKP sensor - also didn't fix the misfire.
Have you checked the distributor drive gear? https://sites.google.com/site/astrosafa ... or-disease
I did check the rotor play while the doghouse was off, thanks to your link and thanks kindly to you for posting it. It was closer to the "OK" example.

I threw in the towel and brought it to a shop. It was damaged plug wires arcing. I had replaced the factory wires along with plugs, cap and rotor about two years ago. I wonder if I routed them poorly such that they drooped or bounced into harms' way, or if I stressed them putting them on so that a weak spot worked into it or something.

The coil needed changing anyway. Its iron core was corroded to the point that laminations were peeling, and the secondary read low ohms.
 
#23 ·
Not to necrobump, but this being the top result on google i thought I should add my 2c here: this is possible to complete, additional bracket and all, from the engine bay (no doghouse removal) by removing the full intake up to the throttle body and using a lot of extensions and a wobble. I have a 2in body lift, and i don't believe it would be possible without that however. Thanks for the great writeup!
 
#24 ·
Brian D's post above suggests drilling out the rivets to remove the coil. My thanks to Brian for the idea! I can report I did, and it was quite easy. I taped the center of the rivet (marking the location with hammer and nail), then used an undersized drill bit to drill out the center of the rivet. Followed up with successively bigger bits to remove rivet head then tapped oit the rivets. Easy to do.

I did this as part of solving the common problem of no cold start in a damp environment. I may post elsewhere the issues and solutions for no start condition and how I got past it.

Cheers
 
#26 ·
Curthb said:
Brian D's post above suggests drilling out the rivets to remove the coil. My thanks to Brian for the idea! I can report I did, and it was quite easy. I taped the center of the rivet (marking the location with hammer and nail), then used an undersized drill bit to drill out the center of the rivet. Followed up with successively bigger bits to remove rivet head then tapped oit the rivets. Easy to do.
Definitely recommend doing this while you are in there even if you aren't going to replace the coil yet. Just makes it so much easier in the future if you have to replace one outside of a shop/home environment.

Curthb said:
I did this as part of solving the common problem of no cold start in a damp environment. I may post elsewhere the issues and solutions for no start condition and how I got past it.
:thumbup:

keith92ext said:
nice write up...might as well replace the control module while you have everything out if you not sure when last changed...those cause all kind of weird problems when they start to go as well...cheap insurance.
I always recommend at least having the ICM tested while you are in there. Not always, but sometimes the OEM parts are of higher quality than what you can find these days.