setting timing as per the FSM

[sr5luv]

I was checking for time on two of my tercels. I plug the hose specified in the fsm and set to 5degrees. then reset the hose. but I don't get a jump back up to 13degrees like the fsm says it should. but there is nothing that says what is up when it doesn't. my 83 has only two hoses on the dizzy. and my 85 has three. but on both i will plug the upper diaphragm. and on the 85 the one closest to the driver side fender. Help?

[dlb]

if the timing doesn't advance when you reconnect the vac advance hose to the upper diaphragm, it could be one of a few things.

1) the diaphragm is broken. put a clean hose on the port and suck (if there is a second port with a smaller hole on the upper diaphragm, plug it while you suck on a hose connected to the other upper diaphragm port). if you can suck air through, the diaphragm is broken. in that case, plug the vac hoses that normally go to that diaphragm until you can replace the advance unit. it's a good idea to test the lower diaphragm as well while you're at it. broken diaphragms are vacuum leaks.

2) the vac advance hoses are mixed up. trace the vac lines and confirm that the hose for the upper port with the normal opening runs to the pronged thing on the intake manifold just in front of the carb. the hose for the upper port with the small opening should run to the HAC. the hose for the lower port should run to a port on the carb.

your '83 must not have HAC, which is why it only has 2 advance unit ports.

[4wdchico]

if the timing doesn't advance when you reconnect the vac advance hose to the upper diaphragm, it could be one of a few things.

1) the diaphragm is broken. put a clean hose on the port and suck (if there is a second port with a smaller hole on the upper diaphragm, plug it while you suck on a hose connected to the other upper diaphragm port). if you can suck air through, the diaphragm is broken. in that case, plug the vac hoses that normally go to that diaphragm until you can replace the advance unit. it's a good idea to test the lower diaphragm as well while you're at it. broken diaphragms are vacuum leaks.

2) the vac advance hoses are mixed up. trace the vac lines and confirm that the hose for the upper port with the normal opening runs to the pronged thing on the intake manifold just in front of the carb. the hose for the upper port with the small opening should run to the HAC. the hose for the lower port should run to a port on the carb.

your '83 must not have HAC, which is why it only has 2 advance unit ports.

A third possibility: The vac system could be ok, including the vac advance assy, and the grease in the vac advance system inside the dist. could be dried out and sticky so as not to allow the timing to be changed by the vac advance assy. On our old cars this is a possibility.

[dlb]

that's a good point. there is an easy test for a stuck advance: remove the distributor cap and try to turn the rotor counter clockwise. there should be a small amount of spring-loaded play. if there is not, you will need to disassemble the dizzy follow the FSM instructions, clean out the old grease, re-grease it, and reassemble it. it's not very hard but might take a few hours your first time.

[sr5luv]

tested the diaphragm. And its shot. i plugged both lines. Until i can get a new one, what do i set my timing to? i set it back to 5 degrees now it wont idle. just set it back up to 13 degrees?

[dlb]

it should idle and run fine at 5* BTDC without the upper vac diaphragm hooked up. you will just have to adjust the idle speed on the carb to compensate for the lack of advance at idle. i would set the base timing to 10* BTDC and the idle at around 850 rpm.