Really bad Tach Flutter

QWERTYphoon

QWERTYphoon

Motley Driver Award 2009
I was driving the phoon on the highway yesterday and it started to misfire. I could hear the engine just barely missing every five seconds or so. Then I noticed my tach was jumping all over the place. Really bad Tach Flutter. I have never had this problem until then. Then I decided to drive the phoon to work today and it did the same thing. Only on the highway. I have MSD 6al, delco plugs gapped .028 (meth). My guess is the dist or wires are on there way out. the plugs have only 2k miles on them. Any advice? :banghead: :banghead: :banghead:
 
SY2932

SY2932

Administrator
Re: Really bad Tach Flutter

Tach flutter = ignition, ignition, ignition. You can check the ignition coil without having to remove it from the truck:


"This is a brand new MSD coil #8226. The coil does NOT have to be removed from the vehicle to perform these checks. Any connections on the terminals will have to be done with a paperclip or other small object as the test leads won't be able to reach the pins inside. This value should be infinite resistance (open). If not, replace the coil."

"From here on out, the resistive values are not "carved in stone" and are approximate. Here, the value should be very low or zero. If not, replace the coil."

"Here, the resistance should be high but, not infinity (open). If not, replace the coil. *These checks will work on a stock coil as well*."

Usually when an ignition module goes out, you are dead in the water. It either works or it don't. Mine went out this past weekend and it was a $120 tow bill to get it home. I would have worked on it along the roadside but I was broke down at the bottom of an off ramp for the highway... Be sure to check if any of your plug wires have touched the downpipe too.
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: Really bad Tach Flutter

I would check/replace the wires first. Also check and connection of the 2 wire harness going from the coil to distributor.
 
QWERTYphoon

QWERTYphoon

Motley Driver Award 2009
Re: Really bad Tach Flutter

Thank you thanks you thank you thank you I will start there! An thank you!
 
QWERTYphoon

QWERTYphoon

Motley Driver Award 2009
Re: Really bad Tach Flutter

I got a code for an ignition module, were is it located at? Is it on the dist. I also will be checking my MSD Coil tonight. I have no wires touching, and my cap and rotor have less than 2000 miles. I will keep you guys posted.
 
jjorgensen52

jjorgensen52

NHSTE - I'm the only one!
Re: Really bad Tach Flutter

The module itself is underneath the cap of the distributor, at the back. Has a 2 pin and 4 pin connector plugged into it, screwed into the dist and has some heat sink glue on it.
 
Big Dave

Big Dave

New member
Re: Really bad Tach Flutter

No, you do not have to remove the distributor just the cap and rotor. module is bolted to top of distributor. Probably got some corrosion inside if they havent been changed for a while.
 
Last edited:
Big Dave

Big Dave

New member
Re: Really bad Tach Flutter

Did you already check out the coil? sometimes the wire from distributor to coil has corrosion built on it to. The post above about the coil with pictures is very good to check.
 
SY2932

SY2932

Administrator
Re: Really bad Tach Flutter

QWERTYphoon said:
Do I have to remove the distributor?
Click to expand...

No, all you have to do is remove the distributor cap. I would mark each wire before you pull it so that it will be easier to get everything back together later. I write the cylinder number on wire near the distributor and on top of the distributor cap on my truck... You won't have to remove the rotor. If it is is a "bad" position, bump the starter to rotate it out of your way.

There is a two wire connector for the pick up coil below the rotor. It is held in place with a plastic clip. I small flat blade screwdriver works good for getting it disconnected.

I know that Autozone can test the ignition module it to see if it's bad or not. The GM part number for it is 1048-2827. Duralast brand from Autozone with lifetime warranty is part number #DR140. If you need a new one, it's going to be around $30-$40.
 
Last edited:
cloneman315

cloneman315

Active member
Re: Really bad Tach Flutter

go to a dark place ,parking lot open the hood give it some gas and watch for sparks on wires etc,im guessing wires,just watch out for the fan.
 
MIGHTYMOUSE

MIGHTYMOUSE

Turbo F body guy
Re: Really bad Tach Flutter

SY2932 said:
I know that Autozone can test the ignition module it to see if it's bad or not. The GM part number for it is 1048-2827. Duralast brand from Autozone with lifetime warranty is part number #DR140. If you need a new one, it's going to be around $30-$40.
Click to expand...


good info, does msd or ect have a part number for these?
 
QWERTYphoon

QWERTYphoon

Motley Driver Award 2009
Re: Really bad Tach Flutter

Coil checked out fine. Ignition module checked out fine. I have not had any problems since my last post. weird intermittent problem. I am rebuilding this winter and the truck is in storage now. Thanks for all the help guys.
 
2fast4u

2fast4u

PUMPING THAT IRON!
Re: Really bad Tach Flutter

QWERTYphoon said:
Coil checked out fine. Ignition module checked out fine. I have not had any problems since my last post. weird intermittent problem. I am rebuilding this winter and the truck is in storage now. Thanks for all the help guys.
Click to expand...

Dont EVER believe the ignition module tests/results at the Auto parts store!! This is an accurate statement. Always replace em when doing a full meal tune up. Them modules go out all the time. And when you do replace it, always buy the heavy duty version, or better yet a GM module. :tup:
 
QWERTYphoon

QWERTYphoon

Motley Driver Award 2009
Re: Really bad Tach Flutter

I plan on buying a MSD Distributor when I do the heads this winter. New plug wires, new coil. Every thing I have mentioned I replaced about 20,000 miles ago. I think I read somewhere that our ignition system is junk and only lasts like 20k before you have to do a full meal tune up. I have also replaced plugs twice (mainly because I was injecting methanol) but all the plugs look good (even #3). You all should also know that I have mounted my 6AL in my trunk (in the location the jack was located). I talked to MSD and they said that there was no limit to how far away I needed to mount it but they did say to run the trigger wire through the firewall in a different location than the rest of the wires. Also, if any body is still reading my post at this point I have found that my after market radiator flex-a-fan w/ spacer is causing false knock. Must have something to do with harmonics or something because the truck pulls hard now with the knock is gone.(well, maybe a little knock is still there)
 
cloneman315

cloneman315

Active member
Re: Really bad Tach Flutter

this is true keep the wires away from the main harness i had mine there and it made mine go wacky to.put the iridium plugs in also
 
You must log in or register to reply here.
Top