Doesnt wanna idle when timing is set to 10-12. Only idles happy when advanced.

[MadMax_636]

So, I recently got my Ranger back up and running. I fixed all of the issues that I knew about (EGR block off and why my intake was getting flooded. It was a blown power valve gasket.) but now, I cant get the idle right. When I set my timing to 10-12 it idles but very very rough. It only idles smooth when I put it to around 15+ degrees of timing. The dizzy makes a rattling sound which Ive never heard until I started getting it run again. Ive been thinking about removing the dizzy to check it over but I cant until Thursday.

I dont really know where to start. I need help with getting everything back to normal. I talked to a tech at the dealership (Hes a Toyota and Ford master tech) and hes said he stopped using the timing light and just went by sound and vacuum. Mainly on older high mileage motors like mine.

 

[tw205]

Have you made any adjustments to the idle mixture?

 

[MadMax_636]

Have you made any adjustments to the idle mixture?

Yeah, When I get the idle to go up. So does the timing. When I revert the timing to 10-12 it does the same thing.

 

[tw205]

I am referring to the idle mixture screws on the front of the carb. Not the idle speed on the throttle

 

[MadMax_636]

I am referring to the idle mixture screws on the front of the carb. Not the idle speed on the throttle

Thats what I mean. When I adjust them to see if its lean or rich.

 

[tw205]

Ok. are you running factory ignition or does it have a duraspark conversion ?

 

[MadMax_636]

Ok. are you running factory ignition or does it have a duraspark conversion ?

duraspark dizzy and GM HEI

 

[tw205]

Good. So set your base timing at 10 degrees with vacuum disconnected to the dizzy. Plug the vac port on the carb so you have no leak. Hook up a vac gauge to manifold vacuum. Turn your idle screws in to gentle seat and back them out 1 1/2 turns. Fire it up. Turn up the idle at the throttle a little if you need to just to keep it running. Watch your vacuum gauge and turn the mix screws out 1/4 turns at a time alternating between them both until you reach the highest vacuum. You should be between 15 and 20 lbs. then adjust your idle speed to 950 for automatic 850 for manual. Oh and hook the vacuum advance back up.

 

[MadMax_636]

Good. So set your base timing at 10 degrees with vacuum disconnected to the dizzy. Plug the vac port on the carb so you have no leak. Hook up a vac gauge to manifold vacuum. Turn your idle screws in to gentle seat and back them out 1 1/2 turns. Fire it up. Turn up the idle at the throttle a little if you need to just to keep it running. Watch your vacuum gauge and turn the mix screws out 1/4 turns at a time alternating between them both until you reach the highest vacuum. You should be between 15 and 20 lbs. then adjust your idle speed to 950 for automatic 850 for manual. Oh and hook the vacuum advance back up.

Thanks, I know all of that but the hardest part to do what you said is the idle rpm. I dont have a tach and in the past when ive tried to install/wire one it. It kills the ignition/spark. Ive learned about the carb transfer slots and having zero or very little vacuum on the ported vac port helps with setting curb idle speed screws.

Also, the dizzy I have is the second one Ive had (They are out of stock everywhere) and when I got my second/current one. The vacuum advanced port didnt work. I attached my vacuum pump to it and barley moved if at all. So I never hooked it up since the vacuum from the ported vacuum never could make it do anything nor could sucking on the hose.

 

[tw205]

Thanks, I know all of that but the hardest part to do what you said is the idle rpm. I dont have a tach and in the past when ive tried to install/wire one it. It kills the ignition/spark. Ive learned about the carb transfer slots and having zero or very little vacuum on the ported vac port helps with setting curb idle speed screws.

Also, the dizzy I have is the second one Ive had (They are out of stock everywhere) and when I got my second/current one. The vacuum advanced port didnt work. I attached my vacuum pump to it and barley moved if at all. So I never hooked it up since the vacuum from the ported vacuum never could make it do anything nor could sucking on the hose.

I seen people searching for those dizzys on TRS. Seems they are unavailable everywhere. I have read a few threads where people have been getting the duel vacuum distributor and just leaving the retard port open. It works.
The idle speed is not so important so I wouldn’t worry about it too much.
What carb are you using?
I have two 2.8 BIIs both running duraspark. One has motorcraft 2150 the other still has the factory computer feed back model.
So if your dizzy vac advance module isn’t working have you tried finding a new module?
I won’t speak of advance if you have no way of achieving it.
My timing light has a built in tach. Neither of my 2.8 rigs have a tach so the timing light is handy.
If you have a vacuum gauge it would be beneficial to at least check what your getting. It could help indicate if you have vacuum leaks elsewhere.

 

[MadMax_636]

I seen people searching for those dizzys on TRS. Seems they are unavailable everywhere. I have read a few threads where people have been getting the duel vacuum distributor and just leaving the retard port open. It works.
The idle speed is not so important so I wouldn’t worry about it too much.
What carb are you using?
I have two 2.8 BIIs both running duraspark. One has motorcraft 2150 the other still has the factory computer feed back model.
So if your dizzy vac advance module isn’t working have you tried finding a new module?
I won’t speak of advance if you have no way of achieving it.
My timing light has a built in tach. Neither of my 2.8 rigs have a tach so the timing light is handy.
If you have a vacuum gauge it would be beneficial to at least check what your getting. It could help indicate if you have vaccine leaks elsewhere.

Im running a 2150 non feedback. Ive been thinking about getting a multimeter that has a tach feature on it. (I also work within the computer and car field) so I can use that for my rpm readings.
For the finding a new module. You mean the vac can? Thats how I killed my last dizzy. I was trying to replace the non-adjustable one with one that could be adjusted. So no. Im have not since idk if I can find one that will fit right in since my last one didnt.
Ive got mech advance thats all. No vacuum advance.

Ive used my timing light and vacuum gauge for helping me set timing. Ive also replaced my PCV valve since it was sticking even after cleaning it and I recently replaced my EGR gasked (Blocked off)

 

[tw205]

Have you checked for vacuum leaks around the intake and carb and blocked off egr port? My 2150 leaks at the right side of the rod. She still pulls 17 lbs vac so I let it be. Some day I’ll invest in a new Holly.
Done any valve adjustments. They can throw off you vacuum as well

 

[MadMax_636]

Have you checked for vacuum leaks around the intake and carb and blocked off egr port? My 2150 leaks at the right side of the rod. She still pulls 17 lbs vac so I let it be. Some day I’ll invest in a new Holly.
Done any valve adjustments. They can throw off you vacuum as well

Ive checked around for leaks and I cant find any but I might be pulling the intake manifold and replacing the gasket since its original.
Ive tightened the carb bolts/nuts since its always good to check them incase they have loosed. I have ones loosed which caused a massive leak.

 

[tw205]

I use starting fluid to look for leaks. Spray at suspect locations and you will hear the engine try to stall if there is a leak.
What amount vacuum are you pulling ?

 

[MadMax_636]

I use starting fluid to look for leaks. Spray at suspect locations and you will hear the engine try to stall if there is a leak.
What amount vacuum are you pulling ?

When its running rough its around 15 when its running happy. Its 20+ inchs.