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tach goes crazy, engine misses

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Old 08-27-2019, 01:07 AM
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tach goes crazy, engine misses

Hello Thirdgen… haven't been in awhile but of course now I need a bit of help.. and here I am... so .. 84 S/E v6 just started missing and stumbling about 2000 rpm and above, some at below … the tach goes crazy when this happens and it seems the higher the rpm the worse it gets... I replaced the electronic ign. module w/ no results although it did seem to help for a few minutes... damn... any thoughts.. I have done some wire checking looking for loose connections etc... and put a jumper wire direct from the bat to the coil after removing the stock hot wire from the coil and no good... yikes... please advise.... love this site... Doug
Old 08-27-2019, 03:27 AM
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Re: tach goes crazy, engine misses

Did you check or clean any grounds?
Old 08-27-2019, 09:01 PM
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Car: 84 s/e, 94 must conv, 66 must
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Re: tach goes crazy, engine misses

yes I have and replaced the electronic ignition inside the dist as well as the cap and rotor... not as bad now but still the tach freaks out at about thirty five and misses a bit about four thousand... does this car have a computer and would the coil do this sometimes???
Old 09-01-2019, 06:49 PM
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Re: tach goes crazy, engine misses

Did you properly grease the ignition control module before installing it on the distributor? If not there could be your problem. There’s a special white lithium grease and you have to grease the metal surface of the ignition control module before installing it against the distributor. this helps with heat dissipation. It Has to be a dielectric white lithium grease, it usually comes with the ignition control module. I have been able to use the clear dielectric grease to rejuvenate the white grease on my ignition control module periodically when it gives me trouble.

Are your spark plug wires touching metal somewhere and arcing through the jacketing?

Have you followed all the vacuum lines to make sure there’s no dry rot cracks split tubes or disconnected lines?

While cold have you manually cycled the EGR valve?
Old 09-05-2019, 04:08 PM
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Re: tach goes crazy, engine misses

I DID Not grease it and thanks as I wondered about that... I turner out to be the pick up coil... It was pretty done for and now it works very well... although what a gas.. u have to take the distributor apart to get it in there and that's not easy to do.. but what the heck it works great now and the wife is happy... Ya.... so once again... Thirdgen comes through in a pinch... thanks guys for all the help... Doug
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Old 09-05-2019, 08:07 PM
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Re: tach goes crazy, engine misses

monitoring the forums one thing is for sure most if not all the car was running now its not has been pick up coils or injectors, it seems that the life span has been reached on these items, especially if you do something that requires removal and install of that part, seems any jolts basically finishes them off...
Old 09-06-2019, 09:38 AM
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Re: tach goes crazy, engine misses

Originally Posted by Camarillo
Did you properly grease the ignition control module before installing it on the distributor? If not there could be your problem. There’s a special white lithium grease and you have to grease the metal surface of the ignition control module before installing it against the distributor. this helps with heat dissipation. It Has to be a dielectric white lithium grease, it usually comes with the ignition control module. I have been able to use the clear dielectric grease to rejuvenate the white grease on my ignition control module periodically when it gives me trouble.

Are your spark plug wires touching metal somewhere and arcing through the jacketing?

Have you followed all the vacuum lines to make sure there’s no dry rot cracks split tubes or disconnected lines?

While cold have you manually cycled the EGR valve?
You absolutely do NOT want to use a grease on the ignition control module. The stuff that is usually included with a new one is a thermal paste, NOT GREASE. The module transfers heat through the metal on the bottom side of the module, to the distributor base. You want a CONDUCTOR of heat, NOT AN INSULATOR. A thermal paste, like what is used on computer heat sinks, is the correct paste to use for this. I prefer Arctic MX4. It's inexpensive, and a cheap way to give the ICM the best chance at not dying a molten heat death.
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Old 09-06-2019, 10:14 AM
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Re: tach goes crazy, engine misses

Originally Posted by RJ IROC
You absolutely do NOT want to use a grease on the ignition control module. The stuff that is usually included with a new one is a thermal paste, NOT GREASE. The module transfers heat through the metal on the bottom side of the module, to the distributor base. You want a CONDUCTOR of heat, NOT AN INSULATOR. A thermal paste, like what is used on computer heat sinks, is the correct paste to use for this. I prefer Arctic MX4. It's inexpensive, and a cheap way to give the ICM the best chance at not dying a molten heat death.
White lithium grease is commonly used as a thermal conductor. Actually most greases are a thermal conductor not insulator. The issue is when grease dries out it looses some ability to conduct heat because it srinks leaving small gaps. Even artic silver dries up over time but it's designed so that dried it also conducts heat better.. It's why mass production computers use thermal pads that will not dry out, not paste. All a thermal grease or paste does is fill the microscopic imperfections so you have more surface area in contact. It just has to conduct heat better than air to be effective, though better is better. The struggle with artic silver is it a conductor of electricity where as white lithium is dialectic. Back in the 80s and 90s most of us called the CPU to heatsink goop thermal grease.

Back in 99 I use to push and chips to above 1ghz (first production 1ghz CPU was March 2000) using home made water cooled cases and white thermal grease because the and chips had exposed connections and you couldn't use electrical conductive paste.
Old 09-06-2019, 11:19 AM
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Re: tach goes crazy, engine misses

Originally Posted by RJ IROC
You absolutely do NOT want to use a grease on the ignition control module. The stuff that is usually included with a new one is a thermal paste, NOT GREASE. The module transfers heat through the metal on the bottom side of the module, to the distributor base. You want a CONDUCTOR of heat, NOT AN INSULATOR. A thermal paste, like what is used on computer heat sinks, is the correct paste to use for this. I prefer Arctic MX4. It's inexpensive, and a cheap way to give the ICM the best chance at not dying a molten heat death.
Thank you for the correction. I have been unable to find the white paste provided with new modules, outside of coming with a new one. I tried the di electric stuff when my white paste dried out.
Old 09-10-2019, 10:02 AM
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Re: tach goes crazy, engine misses

Best Buy has the thermal grease
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