What ignition coil should I use?

[Catbox_95]

At 142,000 miles, I'm having minor issues that are leading me to believe that my coil(s) are not up to par. So I was thinking of replacing them. I know that the stock coils are pretty good, but is there anything else out there that may provide a stronger spark? 4G63.

 

[bryanwheat]

The stock coils are more than what 99 percent of people need. They should be fine with 30+ psi from a big turbo. What issues are you having?

 

[Catbox_95]

Yeah, that's what I thought. Just wanted to be sure. The issue I'm having is, under normal acceleration there is a surging of a sort, an inconsistency, lack of smoothness. And under full acceleration it is also evident, and up top it feels as if it's lacking in power. The car is all stock with the exception of an air filer, full 3" exhaust (no cat), boost gauge and removed bcs restrictor. Before I did all that and while the car was 100% stock it did the same surge thing under acceleration, no different. What I've checked so far:

Boost leak - passed
Vacuum leak - passed
No codes
ALL cam & crank timing marks - correct

So I'm about to replace the plug wires and was thinking of replacing the coils as well. Any ideas?

 

[bryanwheat]

How many psi did it hold during the boost leak test, and for how long. What plugs are you running and what gap? You can test the plug wires and ignition coil with a multimeter before replacing them.

 

[vinnio]

Yeah, like said above. Test em out before you replace them. Let me know if you need the spec"s I can look them up on all data if needed.

 

[Catbox_95]

Yes, the specs would be very helpful, thanks. We need a good thread on this anyway because I've been searching and it hasn't been easy to find.

We held 10-12 psi during the boost leak test. I am running NGK BPR6ES plugs, gapped to the recommended spacing (I can't remember what it is, I looked it up when I installed them. .030ish)

Thanks for the help...

 

[bryanwheat]

Yes, the specs would be very helpful, thanks. We need a good thread on this anyway because I've been searching and it hasn't been easy to find.

We held 10-12 psi during the boost leak test. I am running NGK BPR6ES plugs, gapped to the recommended spacing (I can't remember what it is, I looked it up when I installed them. .030ish)

Thanks for the help...

You need to go higher than 10-12 psi on a boost leak test. Go at least 25 and verify that it isn't leaking anywhere. Even small leaks will make the car run bad.

 

[92AWDHX40]

The stock one should do just fine.

 

[Catbox_95]

Dang, do you have to pull the intake manifold off to get the coils out?

 

[bryanwheat]

No, just unbolt it from the intake manifold.

 

[Calan]

Keep in mind that testing the coils for DC continuity (or measuring resistance) as per the FSM will only tell you if the coil is bad; it won't tell you if it's good.

Ignition coils are inductive and can break down and degrade at high operating voltages. The problem may not show up with a simple low-voltage resistance check.

 

[Catbox_95]

According to the manual, the coils are out of spec in resistance on the low voltage side. I am reading 1.2 ohms, instead of the .5 - .7 range they should read. Either way, I just picked up a couple new coil packs and will get them installed as soon as it cools off a bit. I'll post my results.

Well, that didn't fix the problem. Is it running better though? I don't know because apparently I've opened up a whole new can of worms. Normal driving is fine. Go more than 3/4 throttle, or full throttle, and it bogs down horribly, pops, and acts as if there's a stutter box on it or something. Uggghhhh.....

 

[talontd92tsi]

Did you check the plugs/wires? Sounds like the spark is getting blown out under boost. I personally gap my plugs at .027-.028, but I run a bit more boost than you do.

 

[Catbox_95]

Brand new plugs, another set of NGK BPR6ES. Gapped .028. New coils. Yes, it does feel like spark is getting blown out, because it only does it at full boost and full throttle. But it didn't do it at all before I replaced the coils, and now it does it. I've checked and re-checked everything that I messed with when changing out the coils and all looks fine. The wires are old, there's a new set in the mail on their way here. But still, it didn't do it with the old coils, and now it does it. I just think that maybe I disrupted something else in the process of replacing the coils.

 

[fosforito95]

if you checked everything you might want to try checking your power transistor next

 

[Catbox_95]

If my wires are not-so-good, and I put new coils on, is it possible that the coils are now producing the energy they should have been, and the bad wires are now more prevailant?

Also, at idle, I sprayed some carb cleaner on the injectors where they enter the intake, and the idle dropped significantly indicating a leak. Could this small leak cause such a pronounced stutter problem?

 

[vinnio]

Sorry for the wait. Here's the exact specs. You need to test the primary side and the secondary side. Primary being the side that is plugged into the engine harness. And secondary being the side that goes to the plug wires.

For primary side un plug the 3 pin that connects to the coil packs. Use your dvom to test resistance from the point of the triangle connector (common) to each of the two other pins. Resistance should be between .70 to .86 ohms.

For the secondary side you test between the two plug wire connectors on both coils. Resistance should between 11,300 and 15,300 ohms.

Keep in mind that testing the coils for DC continuity (or measuring resistance) as per the FSM will only tell you if the coil is bad; it won't tell you if it's good.

Ignition coils are inductive and can break down and degrade at high operating voltages. The problem may not show up with a simple low-voltage resistance check.

100% true. And sadly the equipment needed to test this further cost more than a 2g sells for!!!

OP: My last ignition issue that I had was so dumb I figure ill share it with you. My plug wires were finding ground through the metal hood liner. I love the free fixies! so worth a look ehh?

 

[007jimmy]

Also, at idle, I sprayed some carb cleaner on the injectors where they enter the intake, and the idle dropped significantly indicating a leak. Could this small leak cause such a pronounced stutter problem?

Yes, pulling un-metered air at idle and leaking already metered air during boost. Make sure to change all 4 seals. Also check your spark plug wires to see if they are broken inside of the boots that plug into the coil pack.. The outside is fine looking but its the insides that matter. Seen it many times.

 

[Catbox_95]

Thanks for all the help, guys. I will continue to work on it and update pertinent information.

I'm onto a different lead now - you know those 3 black plastic spacer/gaskets that go in between the fuel rail and the engine? I lost one when I removed the fuel rail, so I made one out of a piece of metal tubing and some washers. I thought this was just a spacer, but at the dealership it's listed as a "gasket". This could be the problem, no? I ordered one and it will be in tomorrow so I'll know for sure then.

 

[turboglenn]

The 3 black things holding the fuel rail up are just spacers. I've turned custom ones from 6061 AL for use on a few cars with no issues.. After having dealt with dropping a few and having to fish them back from "no where land" just because i was working on the injectors i sat and made a dozen of them from white delrin on the lathe one day just so if i lost them i wouldn't have to worry about fishing them out if i dropped them and i've used them without any issues in place of the factory black astic pieces

My friends car has an AEM rail and FIC 1600;s and for some reason (i think it's the rail) i had to turn a custom set that were extra long..anyway i doubt those are causing you any running issues unless you have the wrong length and they are lettung the injectors leak at the 4 little rubber seals you mentioned earlier