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

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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 ???/

Re: 91 ZR-1 Cutting Out Under Load

Quote:

Originally Posted by jonszr1 (Post 55508)

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.

Re: 91 ZR-1 Cutting Out Under Load

Quote:

Originally Posted by scottfab (Post 55523)

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.

Re: 91 ZR-1 Cutting Out Under Load

Quote:

Originally Posted by scottfab (Post 55502)

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.

Re: 91 ZR-1 Cutting Out Under Load

Quote:

Originally Posted by GregCrowe (Post 55526)

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

Re: 91 ZR-1 Cutting Out Under Load

Jeffvette ='s Nice guy and great American :thumbsup:

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

Re: 91 ZR-1 Cutting Out Under Load

Quote:

Originally Posted by Jeffvette (Post 55524)

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.

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?

Re: 91 ZR-1 Cutting Out Under Load

Quote:

Originally Posted by Jeffvette (Post 55906)

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