Fixing Eddie

[firefire]

The 1986 EVTM (Documentation/Electrical/EVTM/1986 EVTM/Carburetor Circuits) has info on this, but it is CONFUSING! The first page, shown below, says it is for Broncos sold in Canada. The second page says it is for 5.8L engines in F150s and F250s sold in the 49 states. But doesn't include Broncos.

So your question of "what triggers the throttle kicker" is hard to answer. So let's first make sure we are talking about the same piece of gear. There are two solenoids, the Throttle Position Solenoid, which has one wire to it and that wire is black, and the Decel Throttle Kicker Solenoid, which has red/yellow and a tan/white wires to it. Which one(s) do you have? And which one are you asking about?

Hi. Gary. This is the decel throttle kicker. Jim is right. His description of the TK function is correct. The TK is activated by vacuum at a certain level when driving/ cruising. I guess that this vacuum level happened when I tried to start the cold engine.Function 2: When the Ac compressor runs it sends 12v to an electrically controlled vacuum valve, which then activates the TK to raise rpm.

Today I checked the fast idle screw. I had backed it out to much earlier. Therefore no extra throttle/ gas when the choke engaged. Turned it in a little and engine starts easily. Around 1200 - 1400 rpm. May try to take it down a little. Dont like high rpm with cold engine. Outdoors its still refrigerator temperatures.

 

[Gary Lewis]

Hi. Gary. This is the decel throttle kicker. Jim is right. His description of the TK function is correct. The TK is activated by vacuum at a certain level when driving/ cruising. I guess that this vacuum level happened when I tried to start the cold engine.Function 2: When the Ac compressor runs it sends 12v to an electrically controlled vacuum valve, which then activates the TK to raise rpm.

Today I checked the fast idle screw. I had backed it out to much earlier. Therefore no extra throttle/ gas when the choke engaged. Turned it in a little and engine starts easily. Around 1200 - 1400 rpm. May try to take it down a little. Dont like high rpm with cold engine. Outdoors its still refrigerator temperatures.

Ok, seems like you are getting a handle on it.

As for the temps, what do you expect waaaaaaay up there?

[firefire]

Ok, seems like you are getting a handle on it.

As for the temps, what do you expect waaaaaaay up there?

Hi again. At last we are in for better weather this week. No snow or rain. Around 9`C at daytime and some SUN :). In the last days I have tried some more timing and carburator work. First I found TDC (, at compression). Spark plug hole test. Corresponded with timing mark, 0 tdc. Used a wrench to turn engine to 10BTDC mark. Took top off distributor. Rotor points at contact for cylinder 1. Disconnects vacuum advance from distributor. Adjusted idle speed needles till I got -17 HG . After connecting everything back on again engine would back fire. Twisted distributor to more advanced, and engine ran better. Even adjusted the accelerator pump to squirt earlier.

On a testdrive engine stopped three times when driving at very low speed.Started right up afterwards. Its no fuel delivery problem. So today I loaned a test light at work. Now I turned the distributor to ignite at 8BTDC. At 750 rpm I got -17 hg. vacuum in carburator. Checked with light, 8BTDC ok. Tried Static timing, got blinking at TDC. When I connect vacuum advance to distributor, RPM increases up to 850. Then I found something interesting. Removed top of distributor. With vacuum pump vacuum advance starts moving at -1HG and reaches max movement at -5HG. Checked the hose for the vacuum advance. From the carburator I got -8HG at idle and -15 HG at max when rising RPMs. That suggests that vacuum advance is always at max ? With vacuum advance connected I tested ignition again with the light. Blinking constantly at 30BTDC regardless off RPMs. What do you experts think ?

[Gary Lewis]

Hi again. At last we are in for better weather this week. No snow or rain. Around 9`C at daytime and some SUN :). In the last days I have tried some more timing and carburator work. First I found TDC (, at compression). Spark plug hole test. Corresponded with timing mark, 0 tdc. Used a wrench to turn engine to 10BTDC mark. Took top off distributor. Rotor points at contact for cylinder 1. Disconnects vacuum advance from distributor. Adjusted idle speed needles till I got -17 HG . After connecting everything back on again engine would back fire. Twisted distributor to more advanced, and engine ran better. Even adjusted the accelerator pump to squirt earlier.

On a testdrive engine stopped three times when driving at very low speed.Started right up afterwards. Its no fuel delivery problem. So today I loaned a test light at work. Now I turned the distributor to ignite at 8BTDC. At 750 rpm I got -17 hg. vacuum in carburator. Checked with light, 8BTDC ok. Tried Static timing, got blinking at TDC. When I connect vacuum advance to distributor, RPM increases up to 850. Then I found something interesting. Removed top of distributor. With vacuum pump vacuum advance starts moving at -1HG and reaches max movement at -5HG. Checked the hose for the vacuum advance. From the carburator I got -8HG at idle and -15 HG at max when rising RPMs. That suggests that vacuum advance is always at max ? With vacuum advance connected I tested ignition again with the light. Blinking constantly at 30BTDC regardless off RPMs. What do you experts think ?

That’s a strange vacuum advance unit. I would expect it to come in between 5 and 10 and be all in between 15 and 20. But this one could easily cause pinging if not detonation with that much advance.

Unless I’m missing something I think you need to replace it. And I’d use something like an adjustable one from Crane Cams.

[ArdWrknTrk]

Hi again. At last we are in for better weather this week. No snow or rain. Around 9`C at daytime and some SUN :). In the last days I have tried some more timing and carburator work. First I found TDC (, at compression). Spark plug hole test. Corresponded with timing mark, 0 tdc. Used a wrench to turn engine to 10BTDC mark. Took top off distributor. Rotor points at contact for cylinder 1. Disconnects vacuum advance from distributor. Adjusted idle speed needles till I got -17 HG . After connecting everything back on again engine would back fire. Twisted distributor to more advanced, and engine ran better. Even adjusted the accelerator pump to squirt earlier.

On a testdrive engine stopped three times when driving at very low speed.Started right up afterwards. Its no fuel delivery problem. So today I loaned a test light at work. Now I turned the distributor to ignite at 8BTDC. At 750 rpm I got -17 hg. vacuum in carburator. Checked with light, 8BTDC ok. Tried Static timing, got blinking at TDC. When I connect vacuum advance to distributor, RPM increases up to 850. Then I found something interesting. Removed top of distributor. With vacuum pump vacuum advance starts moving at -1HG and reaches max movement at -5HG. Checked the hose for the vacuum advance. From the carburator I got -8HG at idle and -15 HG at max when rising RPMs. That suggests that vacuum advance is always at max ? With vacuum advance connected I tested ignition again with the light. Blinking constantly at 30BTDC regardless off RPMs. What do you experts think ?

Does your vacuum diagram not show a thermal vacuum switch selecting between full manifold vacuum and (V-REST) a vacuum restriction usually in the form of a tiny colored plastic splice or elbow?

My truck counts on that restriction to limit vacuum at idle and slow response to closed throttle.

[Gary Lewis]

Does your vacuum diagram not show a thermal vacuum switch selecting between full manifold vacuum and (V-REST) a vacuum restriction usually in the form of a tiny colored plastic splice or elbow?

My truck counts on that restriction to limit vacuum at idle and slow response to closed throttle.

Jim - Does your vacuum advance work like his on such small amounts of vacuum?

Even with a restriction after a bit of time you'll get the full vacuum. In my class on parallel systems where we modeled electrical systems in pneumatics we learned that a restriction is the equivalent to a resistor. So unless there's a vacuum leak on the other side of the restriction causing the equivalent of a current, eventually the vacuum on either side of the restriction will be equal.

So, is there a controlled vacuum leak?

[ArdWrknTrk]

Jim - Does your vacuum advance work like his on such small amounts of vacuum?

Even with a restriction after a bit of time you'll get the full vacuum. In my class on parallel systems where we modeled electrical systems in pneumatics we learned that a restriction is the equivalent to a resistor. So unless there's a vacuum leak on the other side of the restriction causing the equivalent of a current, eventually the vacuum on either side of the restriction will be equal.

So, is there a controlled vacuum leak?

I can't confirm.

My original advance unit is probably 30 ,years gone.

[Gary Lewis]

I can't confirm.

My original advance unit is probably 30 ,years gone.

Ok.

So we need to determine if the original vacuum system is intact, or if he's going to have to go back to a simple system w/o the thermal switch and restrictions. Right?

[firefire]

Does your vacuum diagram not show a thermal vacuum switch selecting between full manifold vacuum and (V-REST) a vacuum restriction usually in the form of a tiny colored plastic splice or elbow?

My truck counts on that restriction to limit vacuum at idle and slow response to closed throttle.

Hi. Here is a picture of the diagram. Take a look. I cant see anything connected to the vacuum line.

Do you think the amount of vacuum from the carberator is normal ?

[ArdWrknTrk]

Hi. Here is a picture of the diagram. Take a look. I cant see anything connected to the vacuum line.

Do you think the amount of vacuum from the carberator is normal ?

No.

Your advance seems to use timed vacuum, directly from the carburetor port.

It is impossible for me to know all the variants.

So we need to understand why your distributor sees so much vacuum.(or why it is pulling in so much timing)