91 ZR-1 Cutting Out Under Load - Page 15 - ZR-1 Net Registry Forums

jonszr1 · 02-27-2009

when a coil goes bad does it allways effect both cylinders or can it only effect 1 cylinder ???/

scottfab · 02-27-2009

Quote:

Originally Posted by jonszr1

when a coil goes bad does it allways effect both cylinders or can it only effect 1 cylinder ???/

Both if it is the coil. My latest experience was with a single plug (#3) so I knew it was not the coil.

02-27-2009

Quote:

Originally Posted by scottfab

Both if it is the coil. My latest experience was with a single plug (#3) so I knew it was not the coil.

Not always true, sometimes the coil will fail on an individual tower. I've seen it a couple of times.

GregCrowe · 02-27-2009

Quote:

Originally Posted by scottfab

Well well well.... that was a novel. I just read all posts from the beginning to the most recent.
I had heard about this thread a couple of years ago from Jeff Flint and very sorry to see it is still active.
Let me toss out my thoughts and story.

I fought an illusive problem on my ZR1 in 1998 after having the car for about 2yrs. I drove it to the midwest and back and it developed this stumble on acceleration. As a result I ended up developing a pattern check jig for the injectors after studying the data from my scan tool.
(Diacom). No good, still stumbled so I bought RC injectors (not a mistake because of the stainless steal construction of the RC) still had the stumble. I bought a spare ECM (not a mistake as it turns out cause to pass the state inspection it is easier to replace the ECM than the chip, and safer) still had the stumble. The fuel pump #2 then failed (unrelated problem) still had stumble. I then developed an emissions problem which after much searching turned out to be the CATS. Returning to the search for the stumble I next replace the coils. Fix! It toot took several years of slowly going at it. The only difference in my case is I would drive it anyway even with the problem. That is what uncovered it since eventually the plugs told the story. I learned a LOT about the car and reading the scan data.
I hope the coils fix it !!!

PS. I am going to toss my bosh/platinums ...... I just checked the plugs as a result of reading the thread (novel) and #3 was fouled. I put in a used AC plug (since I keep spared of many many working parts) and the fouling stopped........hmmmm)

Wow, wish you had posted a long, long time ago. If you'll look back in the thread, you will see that absolutely everyone was saying fuel injectors. That delayed me for quite awhile. I'm still waiting on the Summit coils to be delivered. Your story gives me hope. Maybe by next weekend I'll have the car running perfect again.

02-27-2009

Quote:

Originally Posted by GregCrowe

Wow, wish you had posted a long, long time ago. If you'll look back in the thread, you will see that absolutely everyone was saying fuel injectors. That delayed me for quite awhile. I'm still waiting on the Summit coils to be delivered. Your story gives me hope. Maybe by next weekend I'll have the car running perfect again.

Greg, more than likely your injectors were sketchy anyways. If the coils do solve the problem, your car will run pretty sweet.

I still stand by my suggestion of pulling the plug boot off while the motor is running. A strong coil will have an audible pop to it. A weak coil will not arc at all.

http://www.zr1netregistry.com/forum/...ead.php?t=4667

GOLDCYLON · 02-27-2009

Jeffvette ='s Nice guy and great American

GrayZ · 02-27-2009

Greg, here's a thought

drive it to, M. Haibecks in chicago and fly home.

another thought, contact Corey Henderson
he will be in Oklahoma for the gathering in sept.

i'd offer to drive it to haibecks from the st louis area, going
up there to pick mine up, in a couple of weeks.
if you are pressed for time.

good luck

Keith

scottfab · 03-04-2009

Quote:

Originally Posted by Jeffvette

Not always true, sometimes the coil will fail on an individual tower. I've seen it a couple of times.

Technically impossible but I suppose ther could be something I don't understand about the failure that would have such a symptom.
I'd sure like to get a hold of one that fails on just one side.
You may have not seen the failure but I wonder if it wasn't still failing?
Or maybe one of the two ignition wires was arcing to ground.

Each of the four coils fire on two plugs at the same time.
Once on compression and once on exhaust stroke. If one plug is very fouled it may not show spark at all and the other will. Next time you see what you think is "one tower" fireing. Try unplugging both sides and place a known good plug in each and ground the outside of each plug. The spark on each should be the same even if the coil is failing. The trick is to compare a good coil to a bad one. Depending on how bad the coil is you'll see a marked difference. Best check I've seen on the net was measuring the secondary coild resistance when the coil is hot. With wires disconnected it will be about 5.7 ohms acording to my notes.

03-04-2009

I've stumbled on it twice. Spark is nice and strong on one side, and weak or non existent on the other side. Not sure if it's corrosion issues inside the tower. Next time I get one I'll save it for you to dissect.

Greg, any update?

GregCrowe · 03-04-2009

Quote:

Originally Posted by Jeffvette

I've stumbled on it twice. Spark is nice and strong on one side, and weak or non existent on the other side. Not sure if it's corrosion issues inside the tower. Next time I get one I'll save it for you to dissect.

Greg, any update?

Just got the coils in Monday. If I can find some time this weekend, I'll change them. Time is the problem though.

02-27-2009	#141
jonszr1 Join Date: Sep 2006 Location: lone pine and mammoth lakes Posts: 1,406	Re: 91 ZR-1 Cutting Out Under Load when a coil goes bad does it allways effect both cylinders or can it only effect 1 cylinder ???/

02-27-2009	#146
GOLDCYLON Join Date: May 2007 Location: Peoria, AZ Posts: 9,118	Re: 91 ZR-1 Cutting Out Under Load Jeffvette ='s Nice guy and great American __________________ GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V

02-27-2009	#147
GrayZ Join Date: Mar 2006 Location: Innsbrook, Missouri Posts: 1,720	Re: 91 ZR-1 Cutting Out Under Load Greg, here's a thought drive it to, M. Haibecks in chicago and fly home. another thought, contact Corey Henderson he will be in Oklahoma for the gathering in sept. i'd offer to drive it to haibecks from the st louis area, going up there to pick mine up, in a couple of weeks. if you are pressed for time. good luck Keith

03-04-2009	#149
Jeffvette Guest Posts: n/a	Re: 91 ZR-1 Cutting Out Under Load I've stumbled on it twice. Spark is nice and strong on one side, and weak or non existent on the other side. Not sure if it's corrosion issues inside the tower. Next time I get one I'll save it for you to dissect. Greg, any update?