Coil Pack resistance

[boost97gst]

I searched a bit but couldnt find what im looking for.

Ive been getting break up at first in the higher rpms but it rapidly got worse and even cruise was bucking and reading super rich afrs(i.e. was definitely no sparking on atleast 1 cylinder).
Wires are good, boots good. Rang 1-4 on secondaries got 14.5k ohms. Thats out of spec and i ordered a replacement. You think im chasing the right part? I had to compensate by gapping all the way down to .016 which is just to small for even the 25 psi im running. I went ahead and got a new power transistor just in case too(thanks to the classifieds they rock!)

I think my spark has been weak since i bought this car, it DOES have 204k miles on most parts and the PT and coils look original. I just hope im not barkin up the wrong tree. On e85 at 30 psi i shouldnt have to gap my br8es's lower than .022 if i had sufficient coil voltage/current right?
Thanks y''all

* primary was a .9 and 1.0 so im good there and PT (without battery attached) reads about 3.5M ohms 3-7. Should be open, i know, but thats very very high and i dont believe its causing it

 

[c2ypt1c]

How old are the plug wires? EDIT: nvm, I see the wires are good...

A misfire should read lean due to the remaining unburnt oxygen molecules (o2 sensor reads oxygen, not fuel).

 

[boost97gst]

Well, at idle its fine so if it were say, a stuck open injector id see and feel it then. I just had my injectors cleaned and flow tested too.
Yes, since ive owned the car at times it will suddenly go lean and a misfire cel will come on. Normally a cycle of the keyswitch remedies that. But this is a whole 'nother can of worms. Much more severe.

 

[c2ypt1c]

Have you done a boost leak test? (I know it's an obvious question, but you don't mention it).

Also, how is your fuel feed/filter set up? 6an filter to rail? Tank to rail? OEM filter? SS filter?

 

[boost97gst]

At cruise under vacuum a leak would cause a very lean condition. To answer though: no. I have not done a BLT in few months. Nothing has changed in my setup though and i gotta say, im hitting my target afrs in boost, i dont think im pushing air out. Thats besides the point. Vacuum causes lean conditions, even at idle. Not super rich cruise afrs and breaking up bad in the higher revs.

This feels like when my plug wires shot shit last year. Im more interested in getting feedback on secondary resistance on the coils. Thank you though.

And i have to differ on something: If you dump fuel into a cylinder and dont ignite it, the afrs WILL go rich, not lean.

 

[c2ypt1c]

At cruise under vacuum a leak would cause a very lean condition.

Not necessarily, if the system is running in closed loop (which it should be at idle/cruise)...fuel trims would be screwed up, not your afr. Question is - why are you getting kicked out of closed loop? The o2 hasn't cycled for 128 secs because it's too rich...sounds like a fuel issue (regulator?).

And i have to differ on something: If you dump fuel into a cylinder and dont ignite it, the afrs WILL go rich, not lean.

Here's Wes' explanation:

Yes, misfires can cause any O2 sensor to report a leaner mix.

Combustion (in our case) is the reaction between Oxygen and fuel. Of course the O2 molecule is used up in the reaction, so the amount of O2 left over directly relates to the amount fuel burned. The wideband displays this as leftover Air per unit of Fuel, aka the Air/Fuel Ratio.

When a misfire occurs, the Air that should have been used up enters the exhaust and the wideband reads a higher concentration of Air. The gauge will then display an AFR that is leaner than accurate.

 

[luv2rallye]

2g secondary coil resistance spec is 11.3-15.3k. Try heating the coil and PT with a hair dryer to see if it causes missfires. If so replace it.

 

[boost97gst]

Thanks. Will do

 

[gsxdragger]

The hair dryer was the secret to finding my coil issue!

 

[boost97gst]

Well, i have a feeling thats it cause the further i drove the worse it got. Now that could be the plugs fouling more and more, true, but it very well could be caused by heat in the coil pack or PT. Got em both coming. Should be here mid next week so ill post up if it fixes it or not. Im gonna throw in a new set of plugs too. Ive got 3500 miles on these. New set of 8s wouldnt hurt

 

[gsxdragger]

Exactly, I change plugs like i change underwear... daily!

 

[boost97gst]

Coil pack fixed it. Just to update. Pulls hard at 25psi no breaking up at all to redline