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prostreet69camaro
10-05-2003, 04:36 PM
I have a msd 6A hooked to a HEI distrubutor with a autometer tach. When the car is idling the tach needle bounces. When you rev it the tach is steady. With the msd 6a disconnected and the tach hooked to the HEI the tach doesnt bounce. The distrubutor is wired for a mag pickup. I went ahead a ran another mag pickup cable from the dist. to the msd to bypass the wires that I ran thru the inside of the car for the install. It did not make a difference.

prostreet69camaro
10-07-2003, 05:04 AM
Is there some kind of adapter that I need to add. I have been reading other posts and it was suggested.

Dazed and Confused

msdtech1
10-07-2003, 09:58 PM
What model Autometer tach are you using?

MSD Tech1

prostreet69camaro
10-13-2003, 04:49 AM
The tach is a Autometer # ATM 5897

msdtech4
10-13-2003, 09:14 AM
prostreet69camaro,

Make sure that you have the tach hooked to the tach output of the MSD box and not to the tach terminal on the HEI. If this is how it is hooked up, the first thing I would recommend trying is to use some dielectric grease on each terminal inside the cap. Put just a minimal amount of this on the terminal and this will settle this down. You are getting some noise from the spark jumping from the rotor to the terminal in the cap. This should take care of the jumping.

Thanks,

MSD tech4

prostreet69camaro
10-13-2003, 09:26 AM
Thanks for the reply, The tach is hooked to the msd6a tach output. I tried hooking the tach to the dist. and the tach would not work. I will try the dieltric grease on the cap terminals.

msdtech4
10-13-2003, 10:13 AM
prostreet69camaro,

Let me know how it turns out.

Thanks,

MSD tech4

prostreet69camaro
10-14-2003, 07:54 PM
The dieletric grease did not help.

msdtech4
10-15-2003, 10:20 AM
prostreet69camaro,

I have to believe it is a noise problem due to phasing in the distributor. It happens once in a while with the stock distributors. What kind of plug wires are you running? Is the battery in the trunk or in the engine compartment? Check the battery to engine ground, make sure this is OK, this can create some problems to. It is a noise problem and since the dielectric grease did not help we need to look at some of the other common issues.

Thanks,

MSD tech

prostreet69camaro
10-15-2003, 02:42 PM
Just a little back ground on the car. I just got the car running. It is actually a friend of mines car. It has a new BRE 383 motor complete from them carb to pan. I will have to find out what the make of the spark plug wires are. I know they have the plastic heat shrink cover over the whole length of the wires. I wired it with a painless wiring kit. All new wiring and the battery is in the front. It has 2/0 ground wires from the motor to the frame and the neg. from battery to block with paint removed on all connections. The msd6a is hooked directly to the battery which is mounted on the pass. fenderwell. All the guages and tach are new. The ground for the inside is a buss bar type from painless with a #10 hooked to the battery and all wiring inside for grounds are tied to the buss bar. The tach is also mounted in a DSE metal dash.

prostreet69camaro
10-16-2003, 08:27 AM
The spark plug wires are Moroso blue max spiral core 11 mm #71073700

msdtech4
10-16-2003, 11:50 AM
prostreet69camaro,

I still think the problem lies in the distributor. You can check the plug wires for resistance. You need to get an average per foot on the plug wires and look for a wire that is out of range compared to the rest of the wires. I don't think this is the case due to the fact the system operates off idle. The problem sounds like a phasing problem in the distributor, the rotor not pointing at the terminal like it should be. This creates a lot of noise and causes this type of problem. Do you have an old spare cap you can drill a hole in? If you do e-mail me or send me a personal message with a fax number and I will send you the diagram on how to check rotor phasing. Is there a vacuum advance canister on this distributor? If so is it hooked up?

Thanks,

MSD tech4

prostreet69camaro
10-16-2003, 07:55 PM
I will see about getting another dist. cap and then pm you.

prostreet69camaro
10-16-2003, 07:57 PM
There is a vacuum advance and it is not hooked up. Should it be hooked up ?

msdtech4
10-17-2003, 10:46 AM
No the vacuum advance causes a change in rotor phasing and could aggravate the situation.

Thanks,

MSD tech4

prostreet69camaro
11-13-2003, 12:50 PM
Well we finally found the problem. It was the alternator. It was new but was making a whining noise. You could only hear the noise when it was idling. We disconnected the alternator and the tach is fine now.

mike

msdtech4
11-13-2003, 02:42 PM
prostreet69camaro,

Glad to hear you figured it out. That is strange it cause that problem but caulk that up lessoned leaned for the next time. Thanks for letting us know what happened so we can point other people in other direction when this happens.

Thanks,

MSD tech4