Diagnosis

[frogmn666]

Yeah, I saw that after I bought mine.

The closest thing to a function generator is the calibration ouput on my scope. What has always
confused me is how to figure frequency by the display.

This is the 2 volt p-p 1K output at 50us.

And at .1ms. How do I figure frequency?

 

[60s Refugee]

I believe you guys. Just like you, I wonder why a 12v coil would need 8v. and no resistor in the OEM duraspark applications. I just wanted to be sure before I bypass the pink wire.

Harry

 

[Bort62]

If that is .1ms, or .0001 seconds per division, then your period is ~ 10 (divisions) x .0001 or


.....

.001 seconds. 1/.001 is 1000 hz

 

[frogmn666]

Recap: 66 Mustang 200cid, 3.3L I6.

Worked fine with stock dizzy and rebuilt 1100 carb. With the new Duraspark dizzy and GM HEI mocdule, it won't idle below 1050. Wires, cap, rotor are all new as is the dizzy.

Bypassed the ballast resistor wire by unplugging the bullet connector about 3" from ignition switch. Ran a wire from the engine side of the fireewall to the ignition switch and crimped on a new male bullet connector.

Cut the Red/Green wire at the firewall side of the main disconnect and crimped in my new wire that goes to the coil on the Red/Green wire. This give me a full 12 volts all the time to the coil and module. Installed DSII dizzy and GM module. Won't idle down below 1050 rpm.

Timing is irrevelant as it dies abruptly when the rpm drops below 1050 no matter what the timing is set at.

Tried 3 coils and they all do the same thing. The spark dies right before it stops running.

Will replace the dizzy today and if that doesn't work, I will replace the HEI module.

Before I installed the dizzy, I put my ohm meter across the orange and violet leads and when spun with my fingers, I could see a change in the reading, so it is putting out something, whether it is right, I don't know.

Waveforms with my scope appear to be correct, but it doesn't fire the coil all the time during cranking.

Will update after I get a new dizzy installed.

Thanks all for the help. I know I won't be embarassed with the resolution.

If you could see my forhead, you would see F... me.....

 

[frogmn666]

Getter, peel back the corrugated cover and look for a splice. Today, I got another one from Autozone and it looked like all new from the pick-up coil to the end of the connector, but it was spliced just outside of the grommet. I have no idea why there is a splice, as everything looks new.

I took the Checker dizzy back and got a refund after being interrogated as to why I'm returning it. I then went to AZ and bought the one I saw Friday but didn't buy because it didn't look like pictures I've seen.

I had AZ check the GM HEI module and even after heating it up with mutiple tests, it passed.

I then bought the dizzy I saw last Friday that the guy cross-referenced to what should have been a 78 Fairmont(302690) but when I went to install it today, the gear would not go into the block.

The gear on this one is .18" larger than the stock dizzy. It is .35" longer and the gear is also .35" further from the base.

Remember in my last post about having F... Me tattood on my forehead? Well, it strikes again.

So here is the plan. I called Checker and told them to put a hold on the dizzy I returned. I will buy it back and exchange the base plate/pick-up coil with the one from AZ, then return the AZ one. They gotta give me a refund as they sold me the wrong part and it was never installed. Couldn't do it today as I had a beer or two and do not drive if I have only had one beer all day.

AZ said I could not return this dizzy after installing it. Well ha, ha, ha, I couldn't install it. They also hit me with a $30.00 core charge. Checker was $2.00 and the Fairmont one from AZ was $10.00 per their web site. I don't want to give up my stock dizzy as a core if I don't have to. I also noticed that the stock dizzy has some nice looking springs in it.

When I worked for AT&T, I had access to spring tension gauges that were never used. At the time, I had no use for them. Shoulda taken them home as I could now use them to test different springs.

From what I have read, the Mr Gasket spring is softer. When I installed the dizzy from Checker, it appeared to advance way to soon with the stock light spring. Which spring should be changed? It would be nice if dizzys were sold with no springs and you could then pick from a handfull of supplied springs to set your curve then way you want it.

 

[BIGREDRASA]

BIGREDRASA, other than the carb, you have the same ignition I have. If you remove the vacuum line, can you idle down to 500-700 rpm?

Yes, that's how I checked the initial timing. Disconnected and plugged the ported vacuum line from the carb to the DSII.

 

[frogmn666]

That is exactly right and what I plan to do if I can get it to idle right.

 

[grocery getter]

yeah, mine is spliced.

is the part number 302690 ? if it is, that is the correct number. maybe it was boxed wrong.
if I was you. i'd wait for the correct distributor, then install it and go from there. wait on the recurve until you get this idle deal solved. I think you're asking for more problems swapping parts.

 

[60s Refugee]

Frogmn,

I don't know if you guys have Advanced Auto Parts out there, but the dizzy I got from them slid right into the hole and there were no spliced wires. 78 Fairmont.

Go back to the DSII sticky. It tells you which spring to change. The lighter of the two. It also said to bend the post on the heavy spring 3/32. The idea IS to get the advance quicker, but maybe you are getting it a bit too fast.

I don't know if I'll be able to try to start mine tomorrow or not, but I might get lucky and have everything go right for once! I'm going to set initial as close to 8* as I can (I'll go to 10* after the engine is running OK) and try to get a hookup to a manifold vacuum source for the advance. Perhaps off the carb base plate next to the PCV nipple or maybe to the modulator line fitting. I have a fitting with two hose nipples that will screw into the base plate hole. I'll plug the ported vac advance hole in the 1100 and also the auto choke vac hole to prevent a vac leak (I converted to a hand choke).

Harry

 

[frogmn666]

302690 is the correct #. AZ somehow cross referenced it to a 302669 which has the bigger gear and longer shaft.

I'm impatient and want stuff now. That is why I wanted to swap parts with the 669 to the 690. The best deal would be to go to Checker and get another 690 and not mess with swapping base plates. Checker is just around the corner from my house, but don't carry as many parts as the depot that is 3 miles away does. AZ is about 1/2 mile away. I don't know if the Checker depot has any more 690s

AZ may bitch if they see scratch marks from when I popped off the reluctor to check/change the springs. My response would be: "I know nothing"

 

[Bort62]

302690 is the correct #. AZ somehow cross referenced it to a 302669 which has the bigger gear and longer shaft.

I'm impatient and want stuff now. That is why I wanted to swap parts with the 669 to the 690. The best deal would be to go to Checker and get another 690 and not mess with swapping base plates. Checker is just around the corner from my house, but don't carry as many parts as the depot that is 3 miles away does. AZ is about 1/2 mile away. I don't know if the Checker depot has any more 690s

AZ may bitch if they see scratch marks from when I popped off the reluctor to check/change the springs. My response would be: "I know nothing"

Screw AZ. You scratched it trying to install it before you discovered that THEY GAVE YOU THE WRONG PART.

Their fault, not yours.

 

[frogmn666]

Ian, Autozone tested my module several times and heated it up and it passed. Is there any way the module could test good, but still be bad?

The scratches, if any, are on the base plate from using two screwdrivers to remove the reluctor and check/change the springs?

As far as returning my AZ dizzy, when I bring in my stock dizzy and put the two together, they will agree they sold me the wrong one. I give them credit for trying to help me.

60s Refugee, let us know asap how it works for you. Peel back the corrugated cover and look again for a splice. I have no idea why there is a splice, but it shouldn't hinder operation.

From what I have read, you don't want the mechanical advance coming in before around 1300, yet vacuum advance to ~40° total comes in from manifold vacuum. Granted, it drops off when you gas it, but it is still there before that.

All of my previous GM engines used manifold vacuum and that is what I'm going to use once I get this thing running right.

Checker/Shucks/Kragen have that price match policy of cost minus 10%, meaning if you find it for less, they will sell the item to you at the lower price -10%. That is great if you know the price is lower at a different store. If you don't kow it is lower, you will pay more at CSK. And they wonder why CSK is on the market for lack luster profits.

I'm not making this up. A K&N filter recharge kit is $9.99 at Autozone. The same part number is $14.99 at Checker.

Locking lug nuts at AZ are $9.99. At Checker, the same brand and part number is $19.99

The 302690 dizzy I got from Checker was 54.99. At AZ it was $50.99.

You be the judge. The only time I buy from Checker is when AZ doesn't have it in stock.

 

[BIGREDRASA]

I don't know about GM, but the Fords I've worked on had a vacuum valve that switched from ported vacuum to full manifold vacuum when the coolant got too hot. They used manifold vacuum only to increase idle speed in case of overheating.

 

[Bort62]

I don't know about GM, but the Fords I've worked on had a vacuum valve that switched from ported vacuum to full manifold vacuum when the coolant got too hot. They used manifold vacuum only to increase idle speed in case of overheating.

That is for emissions.

 

[frogmn666]

Can we have a drum roll please...

TA-DA-TA-TA-DA-TA-TA-DA-TA...............

With the Checker body and the AZ pick-up coil, it does the same thing. Timing light goes off right before it dies.

AZ tested the module, and their test box said it was good, but I'm not convinced the box tests it at low rpm.
He did test it several times to heat it up.

I got my $51.99 dizzy and $30 core charge back from AZ. The guy at AZ I bought it from didn't hassel
me at all other than saying Checker could have priced matched to $50.99 from $54.99. The guy at Checker
felt it necessary to inform me of the $2.00 core charge. Pocket change.

I ran a wire from the + post on the battery to the coil. Sam Ting!

The only thing I can do now is replace the module for $19.00 and somehow convince AZ that I have a bad one.

Think people. What else could cause it to die if the rpm goes below 1050. It ran perfect with the stock dizzy.
Fuel pump is new, carb is rebuilt. The spark just dies below 1050. It runs great above 1050. No miss or anything
abby. You remember Abby... Abby Normal from Young Frankenstein (1974)

 

[60s Refugee]

I remember it well! "What a pair of knockers!" "Thanks".

Harry

 

[frogmn666]

That is one of the few movies I will watch more than once. Another is Top Gun.

Now, fix my problem.....

You get yours running yet?

Ref, admit it. If you pull back the foreskin, there is a splice.

I wonder if there is a difference in HEI modules. I asked for and bought one for a 1979 Chevy.

 

[Bort62]

All of the 4 pin HEI modules are the same in design.

So frog, if I came over to your place to help you with this, the first thing I would insist we do is verify TDC and check initial timing.

I forget, have you done so ?

Since you have replaced everything else, it is either a bad module (certainly possible) or your timing is SO screwed up that it wont idle right.

When you say it runs great over 1050, can you drive it or is that just in neutral ?

 

[frogmn666]

I will check TDC with a dummy spark plug and go from stop to stop and split the difference.

How could you check initial timing with an electronic dizzy?

As far as driving it, I can't do that now. I'm playing lawyer and am working on a case.

 

[Bort62]

Check initial timing by looking at where the rotor is in relation to the #1 spark plug terminal on the cap w/ the engine @ TDC. Just make sure it is approximately where you think it is, and not 30* off.

If you can't drive the car, it is entirely possible the timing is WAY wrong. If the timing is way too far advanced or retarded, the engine will act obviously screwed up under load. However, unloaded it may appear to run "fine"

I'm starting to think it is going to be a timing issue.