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Discussion Starter #1
Hello - My mechanic currently has the front end of the motor pulled off, exposing the opti spark. I am lead to believe that it has trouble starting after it get's hot.
Bought a new MSD cap and rotor, but the current stock one does not show any signs of contamination or damage. I am going to change the coil to MSD and replace the stock ICM as well. And install the MSD cap and rotor. I hope that takes care of it. Otherwise we will be tearing it back down to replace the opti.

I am hoping the ignition coil and/or ICM are the culprit for the intermittent no start. Otherwise it runs great. Does anyone have any input?

Thanks

fairly stock 96 impala
 

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Several things are not even close to stacking up:
-Why are you "led to believe" what the problem is? Have you not personally experienced this hard starting problem yourself? Very confusing, plus unnecessarily more difficult understanding cause(s).

The "front end of the motor" does not get "pulled off" to expose an opti. The only things removed to service an opti are the serpentine belt, water pump and crank hub. The timing cover is the "front end of the motor". Has it also been removed for some reason?

Had you done a little research here first, you may have thought to use other than MSD for new parts. That brand has been lately gathering bad press for poor quality, especially opti tune-up parts. There have been recent posts recommending the best quality cap and rotor using brass posts v. cheaper built alum.

What possessed you (or your mechanic) to tear into the opti first for a 'hard start when hot' symptom? Makes no sense. A mechanic would know IC and ICM weaken with age and are much easier to test than dissecting an opti for no reason.

You've got 24 hours to edit any given post. Change/add/clarify yours for better quality replies and chances at good recommendations

And then I can edit mine to suit.
 

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I hope you are not paying your "mechanic" much. It is much easier to scope the opti outputs to the PCM than take off a water pump. It also takes little time to scope the input and output of the ICM and ignition coil and should be much cheaper than randomly replacing stuff.
 

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Discussion Starter #4
Several things are not even close to stacking up:
-Why are you "led to believe" what the problem is? Have you not personally experienced this hard starting problem yourself? Very confusing, plus unnecessarily more difficult understanding cause(s).

The "front end of the motor" does not get "pulled off" to expose an opti. The only things removed to service an opti are the serpentine belt, water pump and crank hub. The timing cover is the "front end of the motor". Has it also been removed for some reason?

Had you done a little research here first, you may have thought to use other than MSD for new parts. That brand has been lately gathering bad press for poor quality, especially opti tune-up parts. There have been recent posts recommending the best quality cap and rotor using brass posts v. cheaper built alum.

What possessed you (or your mechanic) to tear into the opti first for a 'hard start when hot' symptom? Makes no sense. A mechanic would know IC and ICM weaken with age and are much easier to test than dissecting an opti for no reason.

You've got 24 hours to edit any given post. Change/add/clarify yours for better quality replies and chances at good recommendations

And then I can edit mine to suit.

Thanks for the reply. I have experienced it myself a few times. The last time I could not get it to start, but by the time the tow truck arrived, it fired up.

I understand the front of the motor does not get pulled off. But yes, the water pump, serpentine belt and crank hub were removed. Not the timing cover. I was speaking loosely.

I did research the MSD opti parts, and I saw that people did say stay away from the MSD opti itself. But I thought the cap and rotor may be a worth while upgrade to stock. Seeing that the MSD has brass posts while the stock uses aluminum. It had mostly positive reviews online at Summit, Jegg's and Amazon.

We may have jumped the gun with the assumption that the cap and rotor was bad (which it doesn't seem like it is). It was after he had the cap and rotor off that he suggested doing the IC and ICM. We had discussed replacing the opti itself, but decided not to.

I originally though this issue was due to a faulty fuel pump. We did find the the current one was awfully burnt up. So we replaced that with a delphi unit and fixed the wiring harness.

So I plan to do the MSD cap and rotor (while it's apart), MSD IC and delco ICM with heat sink.
 

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Discussion Starter #5
I hope you are not paying your "mechanic" much. It is much easier to scope the opti outputs to the PCM than take off a water pump. It also takes little time to scope the input and output of the ICM and ignition coil and should be much cheaper than randomly replacing stuff.
We jumped the gun by assuming it was the cap and rotor. The car sat for a while and we thought that the cap and rotor most likely became corroded. But it looks fine. Please see my above response.
 

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Hopefully your mechanic used blue loc-tite on rotor screws and put a skim coat of dialectic grease on the large O rings of the cap

Needless to say more diagnostic tests should have been done before removing parts. "Disturbing" the WP drive seal while removing/installing the splined coupler is a 50/50 "seal may now leak" issue....

No start or engine shutting off once warmed up and not restarting is a common ICM fail. A failing ICM can kill a coil and vice-versa so often those are replaced as a pair.

The VERY 1st thing that should have been done, if it was not, is to check fuel pressure. If that is good than yes move on to ignition

With all this said the problem could be elsewhere like a failing wire connection within one of the Ignition systems connectors. Gently moving/tugging on wires (i.e 4 pin plug into opti, coil wires, icm) may expose such a issue if the engine is running...and suddenly shuts off when one of those wire/connections is wiggled

Replacing parts without 1st doing more diagnostics gets exspensive...especially for point & pay guys like yourself
 

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Discussion Starter #7
Lesson learned everyone. Never again will I be the “point and pay” guy.
Currently waiting for my IC and ICM. Gonna go ahead and install the MSD cap and rotor while it is apart. The brass posts seem like an upgrade over the stock cap.
This was tough to diagnose because each time my mechanic looked at it, the vehicle would start.
 

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Lesson learned .........
Glad you're sticking with us despite the gentle razzing. The thread title is generally fitting for future search, and those who happen upon this will see measurable value using more clean diagnosis v. 'tossing new parts around' with one of the all-too-common maladies of our aging model.

As offered above, you've got the perfect opportunity to find recent threads on proper 'blueprint' of the opti - which will save having to tear everything apart AGAIN in a month. And treat yourself to a new opti harness for no particular reason at all.

Be sure to close the loop and check in after hopeful fix with the new IC & ICM.


Parting thought: I've used your experience to show me just one more time that I'll take this forum and some wrench time over a mechanic any day when it comes to dealing with the quarter-century old tech in our tubs. Good Luck.
 

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Discussion Starter #10
It seems to be running well with the MSD cap and rotor, MSD IC and new ICM. I will let you know if it the no start issue comes up again.

Thanks for the help.
 

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Thanks for checking in, and good luck.
 
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