Re: 91 ZR-1 Cutting Out Under Load
 

Spades wouldn't even fit up in those tiny slots. I did however use some wires.

Testing of the original GM coils got me:

Primary / Secondary
1. .6 ohms / 5.63 k-ohms
2. .6 ohms / 5.57 k-ohms
3. .6 ohms / zero
4. .6 ohms / zero

All the stock coils look fine on the primary readings. The secondary readings do look suspect.

I'll try to pull the Summit/Accel coils and get a primary reading on them today if possible.

Re: 91 ZR-1 Cutting Out Under Load
 

I bought a set of brand new GM ZR-1 D545 coils.

So.........More coils, more tests:

Summit/Accels :

Primary / Secondary
1. .7 ohms / 7.02 k-ohms
2. .6 ohms / 7.06 k-ohms
3. .6 ohms / 7.06 k-ohms
4. .7 ohms / 7.00 k-ohms

Brand New GM D545's

1. .5 ohms / 5.71 k-ohms
2. .5 ohms / 5.64 k-ohms
3. .5 ohms / 5.66 k-ohms
4. .5 ohms / 5.66 k-ohms

The one thing I did notice on the Summit Accel coils was that the slots on the bottom of each coil(that the 2 spade terminals plug into) were bigger and more loose than on the GM coils. They definitely don't make a nice tight connection. That may be the problem.

I should have the car back together tomorrow and we'll see if it's fixed.

Re: 91 ZR-1 Cutting Out Under Load
 

IT'S FIXED !!!!!!!!!!

Yes folks, my ZR-1 is running like a champ again. New GM D545 coils fixed the problem. The high rpm power is awesome. No cutting out, no miss, no falling on it's face.

For the record, let it be know that SUMMIT/ACCEL COILS SUCK !!!!!!

These are absolute JUNK !

http://www.rpmmotorsportstulsa.com/Greg/Coils1.jpg

I will be having a nice conversation with Summit tomorrow.

I would like to thank everyone out here for their help over the past 3 years and especially JeffVette.

Re: 91 ZR-1 Cutting Out Under Load
 

Congratulations Greg!!
The entire ZR-1 brotherhood applauds you!
Your perseverance, determination, and resourcefulness have finally paid off.
34 months, 173 posts, 8,600 looks later and the problem is now solved
....and at the end you got it right about the coils.
I almost picked up a set of Accels a while back for spares but went with the MSD 8224's instead. Just checked them and they meg out the same as your new set of GM D545's.

Re: 91 ZR-1 Cutting Out Under Load
 

Glad to hear Greg. Go and give summit hell.

Re: 91 ZR-1 Cutting Out Under Load
 

Is the LT5 coil a common GM part?

Re: 91 ZR-1 Cutting Out Under Load
 

Very common. GM D555 or D545. I have no idea what the difference is between the 2 part numbers. It's the same coil as used on almost every GM V6. 3 coils on the V6, 4 on the ZR-1 V8.

Re: 91 ZR-1 Cutting Out Under Load
 

I may have figured out the difference between the GM D545 vs the GM D555 coil. The D545 lists for 70 cents more than the D555. It looks like the D545 comes with a little rubber gasket a hair over an inch long that goes around the 2 pin connectors under the coil. From best I can tell, the D555 comes without the rubber gasket.

Re: 91 ZR-1 Cutting Out Under Load
 

Damn awesome !! Makes me feel better I changed out mine with GM replacements as well when I had the top end done. Damn gald to hear you chased that problem down!! I considered going the Summit route as well

Re: 91 ZR-1 Cutting Out Under Load
 

Good Job Greg!
:thumbsup:
I commend you for your perseverance.
:worship:
I personally would have given up hope after only a month or two, but you've hung in there for nearly 3 long years.
Simply Amazing.

Now, get in it and.....

DRIVE IT LIKE YOU STOLE IT!!!

Congratulations, my hat is off to you.
Long live the beast.

TomC
"Crabs"