lost spark in cylinder 1
 

on a drive yesterday, put my foot down a little and lost a cylinder, upon more investigation I have little/no spark at cylinder 1

I am praying its not ignition module related does anyone have any other suggestions.

Re: lost spark in cylinder 1
 

Spark plug, spark plug wire and/or coil pack.


'Crabs

Re: lost spark in cylinder 1
 

sorry I should have said the plug is good

Re: lost spark in cylinder 1
 

Start with the simple things first, you're going to have to pull the plenum if it's not the spark plug.
Coil packs do fail, if you have a DVM, compare a working coil pack to #1's coil pack.
Only a very few DIS have failed that I've heard of over the years, and it's usually associated with a whole litany of other problems that kill the DIS.

Re: lost spark in cylinder 1
 

does the other Spark plug on that same coil fire?

Re: lost spark in cylinder 1
 

yeah number 6 does fire, i am gonna do the injectors coil packs and wires all at the same time while the plenum is off and just be done with it hopefully

Re: lost spark in cylinder 1
 

I have had just one side of the coil fail on my car so don?t discount that coil pack being ok cuz the other plug fires . Jmho

Re: lost spark in cylinder 1
 

Having spark on the #6 tells me the DIS should be working..

Re: lost spark in cylinder 1
 

Just to add, the two plugs are wired in SERIES with the coil (aka "waste spark system"). So, in other words, whatever current is passing through one plug circuit is also passing through the other. Comparing the resistance across the primary and secondary sides of each of the coils is a good idea. But, too, the resistance to the #1 plug is normally greater due to the longer wire length; just to know so you don't become concerned about the difference in plug wire resistances (FYI). (However, because the plugs are wired in series, the differences in plug wire resistance would not affect the current flow.

Something else affecting coil output is the connection(s) leading to the coil pack. So, inspecting the connections to the DIS and the coil pack interface and a pulse of electronic cleaner while your at it would be worth doing "while your in there..."

I'm not trying to complicate things, but the thing about high voltage components like coils (especially), it is not uncommon for the insulation of the internal windings to breakdown over time/heat cycles. As result, shorting in the form of arching to ground OR other windings can occur, and a standard VOM will not necessarily detect an insulation failure. (A special high voltage OHM meter called a MEGGER is used to determine insulation breakdown.

Well...Not everyone has a megger handy, including many auto parts stores. And, tho I never suggest one start swapping out parts as a method of troubleshooting, in the case of suspected high voltage (coils) etc., but, when all else has been verified/eliminated, swapping coils might be the only last resort readily available (to us) to determine fault*.

* NOTE: But, keep in mind that the highest failure rate of electrical components occurs when they are first installed! (Referred to as "infant mortality" by statisticians and the reason why "changing parts out until the problem goes away" is a bad idea: often introducing new issues to the original problem which complicates the problem "exponentially!".)

OK... I'll shut up now. Just some things to stow away in the back of one's mind when troubleshooting "lectric chit". :mrgreen::cheers:

Re: lost spark in cylinder 1
 

Follow the routing of plug wire number one. Is it properly clamped behind the injector housing? Or is it lying around loose rubbing on something? Is it lying along side of the braided ground strap that is in that area? I saw this on a 1993. Looks like you have a plenum pull in your future Matt.

Re: lost spark in cylinder 1
 

I don't think the engineers originally intended for these coil packs to live in the environment that they do. There's a lot of heat under the plenum, and very little airflow. When I pulled my plenum for a bad injector and vacuum leak, I found that 3 of the 4 coils had cracked plastic housings in multiple places.

I've dealt with several other GM vehicles that used the same DIS coils and they are usually in a much better (cooler) location. However, their faiure rate is pretty regular. I doubt many older GM cars have their original DIS coil packs. Almost every older GM car I see at the junk yard with DIS has at least one new coil on it.

Re: lost spark in cylinder 1
 

This may be a little bit off the beaten track, but has anyone tried to mount the coils in a position other than under the plenum? I realize there is not a great deal of extra room under the hood, but since heat is the enemy and other GM cars do it, curious if anyone has made the attempt. Anyone? Anyone? Beuller? --Bob

Re: lost spark in cylinder 1
 

IMHO the coils and wires are cheap. Put in a new set and be good for another 20 years. R and R the starter while there. Install a new vacuum solenoid. Good to go for a long time. But this is from the perspective of my personal labor is cheap. :thumbsup:

Re: lost spark in cylinder 1
 

Great White,

I just went thru same process. These were 13 year old MSD COILS. 3 of 4 cracked.

http://www.zr1.net/forum/showpost.ph...8&postcount=16

Re: lost spark in cylinder 1
 

Paul,

I think you?ve ridden that horse a few more times. Time to let it die.

Re: lost spark in cylinder 1
 

I can't provide any links, but I recall this being discussed elseware. Probably a topic for another thread. I believe the conclusion was reached that Coil On Plug with an aftermarket stand alone ECU is the way to go. 🤑🤑🤑🤑🤑

Re: lost spark in cylinder 1
 

WELP here is an update,


changed the coil and now i have no spark anywhere so my Ignition Module is off to be tested to see if its any good. i am lost now on what to do with this thing, hopefully its not the IM cuz that will probably mean the death of the car as they are pretty much IMPOSSIBLE to find

Re: lost spark in cylinder 1
 

Hi Bob,



I remember some of the "dropped base plenum" cars remote mounted the coil pack and it's a great idea.



I'm fixated on Coil on Plug and going megasquirt as the DIS boxes are at a premium and I have a good one. The waste spark stuff is old school (I had them on my turbo buick) and the MS3 pro is down around $1100 bucks now.


Don't need no stinkin DIS

Re: lost spark in cylinder 1
 

DIS boxes are still around. Post up that you need one. they are expensive, but cheaper than dumping the car.


if you want to sell the car not running, you will take a bath. Reach out to the brothers, or go MS as it's definitely a workable path and will make the car easier to service with coil on plug like the LS (no spark plug wires) and no issues with the DIS as it's no longer in the mix. The MS gives much better tuning and full wide band learn fuel trim which is light years ahead of the old factor ECM. Integration is not trivial, but it's been done. Raptor has the "plug and play" wiring harness for about 2k and they only real sacrifice is that the "security" system and gas mileage interface doesn't exist and become inoperative.



I'd like to do my implementation a bit different as the raptor stuff retains the DIS. It's not needed and coil on plug is way better! for the big bucks the DIS is costing us, seems like a no brainer to spend less and get better at the same time!!

Re: lost spark in cylinder 1
 

:notworthy

Re: lost spark in cylinder 1
 

NOT to beat a dead horse but ill revive this a bit, its been over a year without a running driving ZR1

IM was tested by MH and came back good, Coils changed, Plugs and wires changed, Injectors are done.

Still nothing from Cylinder 1

anyone have any other suggestions cuz the cars turned into a very large poster sitting in my drive way that i love looking at and sometimes remember driving.

Re: lost spark in cylinder 1
 

How does the crank sensor physically look?

Re: lost spark in cylinder 1
 

Fine, nothing staring me in the face as messed with or wrong.

Re: lost spark in cylinder 1
 

so we believe we have good DIS, coils, wires, spark plugs, but still no joy?? So within the electrical system likely we don't have a trigger for the coil to fire on the dead hole. This indeed takes a deeper approach to the "root cause" analysis to determine the source of the problem.


It's really hard to help remotely, can you get the car down to VA or up to Chicago?? I'm thinking that either wiring or something maybe in the ECM has gone south but indeed it takes a very methodical approach and testing to trace this type of problem. Parts swapping can be expensive and frustrating even when they are cheap.


Having lots of LT5 trouble shooting experience and spare parts lying around is a big help to pinpoint the problem. This one sounds like a tough one like a bad pin or wiring harness issue. Bet the old coil is fine too. Most times when they go both sides of the coil fail to spark and you lose 2 cyl. I have seen the corrosion on top of the coil towers get really bad too (*mostly on turbo buicks) which causes a weak spark to that cyl.


You've already tackled the "basics" so grab that Factory Service Manual!!! It's also a great help and has some nice trouble shooting trees. You can also reach out to Gordon K. for remote support.




I'd start with Mark H. and see what he advises as next step if you want to work this yourself. Consider compensating him for his remote trouble shooting time as it will save you several handfuls of hair and scuffed knuckles and is the right thing to do.



All else fails, drag it to a pro to get er dun.




Hope to help u!!!

Re: lost spark in cylinder 1
 

I just want to go over some basic ideas again.

1) new parts do not mean that they are positively good. I know someone said that already.

2) The spark has to go from one tower thru the wire, jump the plug gap (from the center electrode to the ground electrode), travel thru the block to the other plug, jump the gap (from the ground electrode to the center electrode), thru the other plug wire, back to the other mating tower. this is the complete path that the spark needs to travel.

it fires BOTH plugs every rotation. one on the compression stroke and the other on the exhaust stroke.
knowing this, can you swap the #1 and #6 wires on the towers and see if the spark moves from the #6 plug to the #1 plug? not swapping wires, swapping towers #6 to #1- this will send the spark the opposite direction thru the same path. swapping the towers moves starting point of the spark from #6 to #1,



if #1 fires and #6 dies, this would indicate that the spark travel thru the block is poor/not getting to the other plug. the spark will ground to the nearest possible ground and not completing the whole circuit. for example: sparks starts in tower #6, it travels down the #6 plug wire and sparks the #6 plug, then somewhere that spark ground to the block/something else before it gets to the #1 plug, the #1 plug will never fire and you will have the symptoms you describe. If this is truly happening, swapping towers and sending the #6 spark to the #1 cylinder should spark the #1 plug and kill the #6 spark..... It is a weird scenario but what you have is weird so it might worth a try.

If the above starts firing the #1 and kills the #6, then looks for a bad block ground or a short of a plug wire somewhere along the entire path..

John


If that does not work take the #1 plug out and ensure that there is only ONE washer on the plug, and none down in the hole. if there are 2 washers in there, the grounding is compromised and the escaping cylinder pressure can push the plug wire off the plug as well... = dead cylinder/poor spark. ask me how I know that one...

Re: lost spark in cylinder 1
 

I didn't see this addressed previously in the thread, but I am assuming you have pulled plug #1 out and tried starting the motor to see if there is spark at the #1 plug. Is that correct? Or how do u know its not firing? Use an old style inductive timing light on #1?

Re: lost spark in cylinder 1
 

Matt, you are not that far from me.
Maybe we can get together some weekend and I can help you sort this problem out.
Paul

Re: lost spark in cylinder 1
 

yes tried to see if there was spark at #1


I really appreciate everyones responses and sharing of knowledge.

I am inching closer and closer hopefully to having a running driving ZR1 again soon