Timing off... any suggestions?

[dragonfly4]

Newbie to the list. Just got my first Cruiser, '87 FJ60... having an issue with the timing. Basically, the rundown is...

Can see the bb when the vacuum hoses to the Vac Adv Ass are disconnected. When you reconnect them, it advances beyond the window.

Taking the Dis cap off and applying vaccum to the ports causes the rotor to spin quite a bit, more so than we've seen on other Dis.

When the vac hoses to the Vac Adv Ass are disconnected, it idles much lower (about 200 rpm) than when they are connected.

So, any guesses? It's pulling a vacuum from somewhere... The Vac Adv Ass is bad? (ouch! $152 I don't want to spend if I don't have to...)

Any help would be MUCH appreciated...

 

[NocalFJ60]

Welcome to the forum.. Where in CA are you located?

If I remember correctly the smaller outer diaphram is controled by the High altitude compensation valve when the altitude changes to control timing. The inner bigger diaphram is controled by a port off the carb which varies vacuum as you open the throttle. Check where the vacuum line goes on the inner bigger diaphram. It sounds like you are getting a constant high vacuum instead of the ported vac from the carb. If you have a vacuum guage hook it up to the line going to the main diaphram and see what it is... the guage should change from low vacuum to high as you open the throttle more or give it gas.


Goodluck

 

[Cruisergreg]

Check where the vacuum line goes on the inner bigger diaphram...

While you're at it you might want to check ALL the vacuum lines for leaks/correct connections. They are almost always mis-routed after 20 years of mechanics monkeying around under the hood.

 

[Mr. Toad]

Sounds like your distributor is working fine, but your distributor advancer is getting vacuum when it shouldn't.

Time to: 1) figure out when (or under what conditions) the dizzy is supposed to get vacuum; 2) what kind of vacuum it's supposed to get (e.g. ported, manifold . . . ); and 3) what sensor input causes vacuum to be applied to the distributor advancer.

You can't really expect a precise, on-line diagnosis, but once you understand the system, you can figure out what's not right about it.

 

[djawahir]

I've got a penny and a half to add. I've been working with dragonfly4 on the vacuum hoses. All of the 3mm vacuum hoses have been replaced by us about 3 days ago. We went through the hoses and made sure they were on correctly. But we haven't checked to see the amount of vacuum on the entire system yet.

On a side note, when testing the primary and secondary vacuum advance ports with a vacuum pump, the advancer on dragonfly4's rig seems to advance quite a bit before stopping. When I did the same test on my rig, my advancer didn't move nearly that far. (And I think that part of my cruiser is operating correctly...)

Does any of this sound familiar to anyone??

Anyone? Bueller??

 

[NocalFJ60]

The travel of how much it advances depends on how much vacuum it receives. At idle you should be measuring hardly any vacuum. Check the hoses at the base of the carb on the inside next to valve cover. It should be connected to the bottom connection closest the firewall. It sounds like your are getting max intake vacuum at idle.

 

[djawahir]

Hey NocalFJ60, I guess I should clarify a little. I think something may be wrong with dragonfly4's distributor, because when I manually pull 20mmHg on her primary, it advances farther than when I pull 20mmHg on my distributor's primary.

Does anyone know what could be the issue? Does she need a new distributor?

 

[NocalFJ60]

The only thing I can guess is there might be some mechanical stop inside that limits the travel and has fallin off which lets it travel more. I don't have mine or I would go look at it now. Maybe someone has a picture or you can compare the inside on the 2.

 

[FJ40Jim]

Hey NocalFJ60, I guess I should clarify a little. I think something may be wrong with dragonfly4's distributor, because when I manually pull 20mmHg on her primary, it advances farther than when I pull 20mmHg on my distributor's primary.

Does anyone know what could be the issue? Does she need a new distributor?

The FJ60 dissy has a bunch of vac advance available. IIRC, something like 20 degrees when it's all in (hello knocking and pinging!).

You might measure the available vacuum advance in degrees on both dissys and I can compare to new reference parts here.

If the one dissy doesn't have much vac advance, somebody may have modded it to decrease vac advance. there are ways to do that.

 

[jwest]

It seems the degree of advance relative to vacuum HG's, rather, the particular spring/weight combo in the distributor may be matched and mated to a particular corresponding color coded VTV valve as called out on the VECI.

Does the main diaphram have a working inline VTV? Is it the same color as in the other vehicle. Is the orientation right, color side toward the diaphragm? It's supposed to cause a delay to advance by restricting vacuum (towards manifold) but release quickly (back towards distributor).

But what is the issue? Is there a driveability problem or you just don't like the timing characteristics?

 

[dragonfly4]

It seems the degree of advance relative to vacuum HG's, rather, the particular spring/weight combo in the distributor may be matched and mated to a particular corresponding color coded VTV valve as called out on the VECI.

Does the main diaphram have a working inline VTV? Is it the same color as in the other vehicle. Is the orientation right, color side toward the diaphragm? It's supposed to cause a delay to advance by restricting vacuum (towards manifold) but release quickly (back towards distributor).

But what is the issue? Is there a driveability problem or you just don't like the timing characteristics?

Main issue would be performance... as I'm not sure if it is attributing to the other problems, I'm assuming that the timing being off is causing the rough idle and the occasional knocking of the engine at lower rpm. Not sure...

Another factor is that at higher speeds/rpm (anything above ~60 mph) the engine sounds great.