Weak Coils?

[-=Jeff=-]

what are some syptoms of weak coils?

I read through RogerZR-1's thread and he ended up have weak coils..

If a coil or Coils are weak as temperature increases is it possible that the coils would get worse?

I am thinking maybe that could be an issue with mine too, as I noticed a slight stumble in Open loop tonight while driving it.. but once in closed loop and the car was warmer it was worse..

going to check fuel pressure now to see if it holds after the key is out

[tomtom72]

Yes, the symptoms of a short would get worse the hotter the windings + oil gets.

Kind of like what happens with the early OEM injector coils.

You could ohm them out after they are hot & compare that to a cold ohm reading. Or just pull a plug wire & stick a plug in the end & ground it & look at the spark intensity.


Tom

[-=Jeff=-]

just curious, trying to find the stumble issue.. as it gets warmer it gets worse.

[rogerzr1]

Is the car stumbling with the power key off? My car drove worse with the power key off. The biggest thing that my car did on a consistent basis was stumble at low rpm when I got on the gas, like being in 6th gear at 2000 rpm and accelerating. The car would always stumble. After Jeff Flint changed the coils it has been running great, no problems at all.

Hope this may help. I am still new to all of this stuff but wanted to chime in.

[-=Jeff=-]

so far, key on or off makes no difference..

[bobbyhi]

My Z is at DRM now for the same problem. I put new Accel coil packs in when I had the plenum removed. Doug told me that the Accels get too hot for our cars and that the original GM's should be installed. I got this report last week and have not heard back from Doug yet. I hope the GM's are still available. Mine would stumble with or without the key on. Usually around 4000 rpm's. Doug said that when the car was warm/hot, on the dyno, the stumble would occur. I will be talking to him early this week so I can keep everyone posted. Fuel pressure was OK - injectors were just R/R'd from RC - no vaccum leaks. ?????

[lbszr]

Autozones duralast only lasted a year and started stumbling. AC delco now for two years with no problems.

[-=Jeff=-]

well if I am going to pull the car apart to trace things.. Coils might be a good thing just to get

[lbszr]

Originally Posted by -=Jeff=-

Coils might be a good thing just to get

That's how I look at it also, and then left with spare parts to try next time, if it doesn't get fixed on the first try.


Also found the autozones and some other brands where not the same resistance values as the delco's straight off the shelf. Parts stores probably hate to see me walking in with my multimeter, forget the values but the difference was almost twice the delco value's. The US made ones seem to be the same as delco's.

Just checked, delco's seem to be in the low 5000's and some of the other's are in the mid 8000's range from post to post brand new. Might not make a difference but I didn't like it.

[GOLDCYLON]

Originally Posted by bobbyhi

My Z is at DRM now for the same problem. I put new Accel coil packs in when I had the plenum removed. Doug told me that the Accels get too hot for our cars and that the original GM's should be installed. I got this report last week and have not heard back from Doug yet. I hope the GM's are still available. Mine would stumble with or without the key on. Usually around 4000 rpm's. Doug said that when the car was warm/hot, on the dyno, the stumble would occur. I will be talking to him early this week so I can keep everyone posted. Fuel pressure was OK - injectors were just R/R'd from RC - no vaccum leaks. ?????

Bobby I replaced my coils during the last plenum pull with AC/Delcos. I picked up the set of 4 from thepartsladi on Ebay. I believe the cost for all 4 was $140. Daryll