CDI Timing advance. By royldoc (Read 1,914 times)

[royldoc]

I recently purchased a cdi from tvnacman that advances the ignition spark at higher revs of the engine. I am going to try to plot a graph of the timing. First I need to mark a degree scale on the flywheel. The use of an adjustable timing light is also possible but must be mounted in a fixed position, because I only have two hands. I will also use my o- scope with one channel connected to the pick-up wire and the other channel connected to the output . I should be able to see on the scope the difference in time from when the pickup coil sends a voltage to the cdi and the output voltage to the coil.

Roy

[tvnacman]

Glad to see the weather cleared up , interesting cdi isn't it ?


John

[royldoc]

Yes it is. So far I haven't had a chance to give it a test ride. Just been playing around with it in the garage. In the meantime I need to chase down a non charging issue on my truck so won't get to play with this for a little while.

Roy

[tvnacman]

what year make and engine size , I have alldata .

[royldoc]

This a 94 ford explorer. with a 4.0 engine. But not to worry I have a chiltons shop program. I'm thinking it's a bad ground. This is just my luck though My 96 explorer is in the shop getting new heads put on it. Normally I don't pay for mechanic work, but I am getting to lazy lately. and just don't have the time.

Roy

[tvnacman]

Jan 29, 2013 11:56:51 GMT -6 royldoc said:

This a 94 ford explorer. with a 4.0 engine. But not to worry I have a chiltons shop program. I'm thinking it's a bad ground. This is just my luck though My 96 explorer is in the shop getting new heads put on it. Normally I don't pay for mechanic work, but I am getting to lazy lately. and just don't have the time.

Roy

Are you still chasing the short ?

I'm sitting at the edge of my seat to see what the ampltude and frequency is of the discharge . I was thinking it would be a sawtooth . Seeing the the discharge in relation to pulse .

Raise your hand if your going to or did a google search!!!!!!!!!

John

[royldoc]

John I haven't really had time to work on the explorer. I did clean up several ground connections. I am now thinking it has more than one electrical problem. It has been getting down to about 10 degrees at nite here and with the rain and Ice we had earlier this week. I got busy fixing a lot of frozen locks and broken keys. Now I got some family events I have to attend, So probably won't get to the scooter till next week..

I do many google searches. Just not on the cdi yet.

[tvnacman]

I was teasing about the google searches .

John

[Alleyoop]

Roy, I think you will like the Advancing CDI, I have one on mine. Mine used to Kickback all the time starting it, I tried a bunch of CDIs I have about 5 CDIs and found that when I put on the standarrd CDI I found it would not Kickback. So I googled and found what they call an Advancing CDI, Retarded at low RPMS and advances as the RPMS get higher. So I talked to John because he was going to order some CDIs and asked him to order one of those for me. And it works just beautifull no more kickbacks at startup and a little more power as the rpms climb.
Alleyoop

[tvnacman]

Feb 2, 2013 10:40:19 GMT -6 Alleyoop said:

Roy, I think you will like the Advancing CDI, I have one on mine. Mine used to Kickback all the time starting it, I tried a bunch of CDIs I have about 5 CDIs and found that when I put on the standarrd CDI I found it would not Kickback. So I googled and found what they call an Advancing CDI, Retarded at low RPMS and advances as the RPMS get higher. So I talked to John because he was going to order some CDIs and asked him to order one of those for me. And it works just beautifull no more kickbacks at startup and a little more power as the rpms climb.
Alleyoop

Al Roy has a piece of equipment that I don't . I'm interested in what it will show .

John

[royldoc]

John, I finally got time this morning to try to test that cdi. So I go to the shop to get one of the oscilloscopes and notice that the beckman is gone, no problem Ill just grab the tektronix. So I lug it up to the garage, set it up and reach into the pouch to get the leads. Then I notice there is only one and the tip is missing. Now I'm Thinking out loud That D@?$ boy of mine. So I grab the phone and call him. I Get the classic "Oh ya I forget to tell ya I needed to borrow it" He said he was working on a pulse width modulator for a hydrogen generator and ran out of time at my place. I said I don't mind but what the 7734 happened to the leads? Apparently my grandson was with him and he don't really know what happened. So now he is going to bring them back when he has time. Darn kids.
life would be almost boring without them.

Roy

[tvnacman]

Roy I got all excited when I saw you post on this thread . Very disapointed , the scope thing is a big plus !!!!!! Did you go for a ride with the new cdi ? Are you installing it in the 72cc ? Does it start easer ?

John

[Alleyoop]

Some of the new timing lights will also do the job they have settings to display the RPMS and timing degrees, I have one of those. Heck they even have Volt Meters now that include RPMS display, Technology is just moving along.
Alleyoop

[royldoc]

John, I did install it on the 72cc. It started smother and idled about 200 rpm slower. I took it for a ride to qt about 2 mile. I bought this so when I put the stroker crank in it won't buck when started.
Alley my timing light has a knob with a scale on it to advance or retard the light, but won't tell rpm. I use it mostly for checking plug wires. I want to put the scope on it so I can see the phase shift between the trigger coil and the output, also it will show what kind of wave it produces. The boy is supposed to drop by Saturday.

Roy

[tvnacman]

Missing LCP , its like a gun and no bullets .


John