Won't idle after timing set?

[metalmonkey47]

On my A-series 210. Electronic dizzy, MSD ignition, Weber 32/36

 

 

 

I noticed when helping my friend set the timing on his Chevy that my timing light was off, which meant my car was off. Went and picked up a new inductive timing light, and found my timing was about 16 degrees btdc, and re-adjusted to the FSM spec of 5 degrees. Made a shit ton more power, but now has trouble idling. I've re-adjusted it now to about 900RPM idle, and it still won't idle. If I turn on my headlights, it will drop to 400RPM and stall at idle.

 

All this was done with the engine warm @ 180degrees after an hour of driving. I can't imagine how bad it's gonna be after cooling off

 

I really don't wanna advance the timing again, because it seemed like with advanced timing it ran like shit compared to now.

 

 

 

 

 

I've already pulled the idle jet and cleaned it, replaced all the ign components recently (cap, rotor, plugs, wires, etc) and can't seem to figure out why it won't idle where it should be.

[Laecaon]

Timed with vacuum advance disconnected?

[metalmonkey47]

Timed with vacuum advance disconnected?

 

That's correct. Vac advance would only effect it under throttle anyways.

[Laecaon]

pull the plugs and see what they are telling you. Could be too rich... Sounds like timing/fuel related.

[ggzilla]

Idle-cut solenoid is disconnected perhaps. It will cause those symptoms.

[banzai510(hainz)]

adjust carb mixture and

adjust speed screw on carb to get idle up do these in conjuction with the timming light.

[datzenmike]

5 degrees seems a little low for an A series engine. I would expect no less than 8-10 degrees. Anyone know the spec for sure?

 

Get the timing on for sure and make sure the idle cut solenoid is working or you won't have fuel for the idle circuit. Without starting the motor, turn the ignition on/off/on/off and listen for a click sound on the carb... then:

 

Turn the idle speed screw as low or close to 600 as you can and turn the idle mixture screw in and out to get the fastest smooth idle, turn idle speed down and repeat the idle mixture screw adjustments as many times as needed to get the idle down around 650-750 and smooth.

 

The mixture screw will turn in until it is too lean and the idle gets bad. Turn back out until too rich and idle gets bad... select a position roughly halfway between.

[ggzilla]

Timing spec for the later engines is 5 degrees, for early 70s it is 7-10.

 

I never heard of a timing light being off, unless it is one of the fancy ones with adjustable timing. Light works at the speed of light after all. Electricity too.

[metalmonkey47]

Thanks guys for the advice! Deffinitly not the solenoid, as I can hear it click on after turning the ignition on, and it will idle if I advance the timing 1 degree. (I loose massive power at 1 degree!)

 

Mike, according to the tag under my hood with the emissions info on it, idle on the 5 speed is 700RPM @ 5 degrees. I'm gonna go tinker with the thing as soon as I have time. I really need to re-jet the carb, so maybe now would be a good time eh?

 

Mixture screw is on the base of the carb, correct?

 

 

GGzilla, I'm not sure what's up with that light. It's about 40 years old, the magnet was falling out of it, and it was kinda finicky to start.

[banzai510(hainz)]

Mixture screw is on the base of the carb, correct?

 

YES

[ggzilla]

A lot of guys have had trouble with the 32/36 adapter plates working loose. I used lock-washers on mine, never had a problem.

[metalmonkey47]

A lot of guys have had trouble with the 32/36 adapter plates working loose. I used lock-washers on mine, never had a problem.

 

I've encountered that problem 4 times now. I loc-tite'd it on there and it's been good since then

[metalmonkey47]

SO I spent the last hour tinkering, and I have the idle mixture set and adjusted, but it still won't idle for shit. It's rough and stalls easy. Especially under any load (Wipers, headlights, etc)

 

 

I pulled the idle jet again and blew a ton of pressure through it,and it's 100% clear.

 

 

 

 

 

I'll try to get a video after the rain stops.

[racerx]

timing for L18 can also be 12 degrees. Yeh, when I changed out my engine from L16 to L18, there were 2 timings one for 5 and the other for 12 see which one works best. I nver did get an answer and 12 worked better. Did not knock at 12.

[metalmonkey47]

http://www.youtube.com/watch?v=TCtj1yAQW-w

[metalmonkey47]

bump

[metalmonkey47]

Any other ideas?

[hogboy52]

My 210 is advanced 10 deg. which is what the under-hood tag says. The idle jet operates at part throttle which runs smoothly so is not a problem. Does the idle mix screw actually go over rich? Often it won't if it's clogged. Otherwise if it's an on/off situation except for the unlikely event of water in the fuel, I would think air leak air leak. Does the vacuum advance can leak?

[metalmonkey47]

I have no vac advance. Only centripetal in the dizzy since I'm running weber with ZERO emissions.

 

My underhood tag says 5 degrees. Is yours A14 or A15? Odd that theres a variance.

 

 

 

I have decided that I need to re-jet the carb, however I'm unsure of the jet sizes I need. I'm sure the idle jet is probably oversized.

[hogboy52]

Well had to go check and actually it says 8 deg. It's a late `79 A14 engine. In the owner's manual it says 8+/-2 and for Canada 10+/-2 so felt 10 was good to go and I have never had any "pinging".

Why would you want to not have any vacuum advance? Since I replaced the leaky can on my dist. I have been getting a solid 29 mpg with almost entirely stop & go town driving. It had been 22 mpg or less.

Really with a no smog setup I would try running manifold vacuum to the dizzy since motors do like more advance at idle and run more smoothly that way.

[banzai510(hainz)]

A weber DGV has a port at the base of the carb. Since your not running the vac adv I assume this port is plugged?

 

 

No idle means a leak somewhere.

 

By chance dizzy shaft is tight? no side to side wiggle? this is a long shot on this one.

 

 

 

HOGBOY

You never want to run manifold vac to the dizzy. Just the from the carb.

[hogboy52]

For fifty years manifold vacuum was nearly the only method of timing control. It's single purpose was to avoid "pinging" while climbing steep grades or at full throttle with the reduced vacuum drawing the timing back. Carburetors in this period had no vac fittings.

The main purpose of the later "standard" system is by means of late timing to send flames far into the exhaust manifold to burn off HC's and CO. With simple engines the older system still works fine.

[metalmonkey47]

Well had to go check and actually it says 8 deg. It's a late `79 A14 engine. In the owner's manual it says 8+/-2 and for Canada 10+/-2 so felt 10 was good to go and I have never had any "pinging".

Why would you want to not have any vacuum advance? Since I replaced the leaky can on my dist. I have been getting a solid 29 mpg with almost entirely stop & go town driving. It had been 22 mpg or less.

Really with a no smog setup I would try running manifold vacuum to the dizzy since motors do like more advance at idle and run more smoothly that way.

 

I don't run vac advance because of several reasons.

 

A: My advance diaphragm leaks at both ports.

 

B: I'm running zero emissions, and with a centripetal advance, there's no reason to further advance any timing.

 

 

 

If I was to run straight from manifold to dizzy for vac advance, then at idle I'd no longer be at 5/6 degrees of timing because the vac advance would advance the timing at idle, therefore forcing me to further retard the timing. It would be a never ending loop wouldn't it?

[metalmonkey47]

A weber DGV has a port at the base of the carb. Since your not running the vac adv I assume this port is plugged?

 

 

No idle means a leak somewhere.

 

By chance dizzy shaft is tight? no side to side wiggle? this is a long shot on this one.

 

A: Yes, dizzy vacuum port is capped with a nice new tight vacuum cap.

 

B: Where all is there for a leak? I have quadruple checked everything. The only vacuum ports I have is from the manifold to brake booster. I've replaced the hose and used hose clamps to keep it tight. My adapter is tight 100% with no cracks.

 

C: Dizzy shaft is super tight. I've had it apart once in the last few months to inspect and I was very satisfied with it. Advance plate was 100% complete and operating.

[datzenmike]

I don't run vac advance because of several reasons.

 

A: My advance diaphragm leaks at both ports.

 

B: I'm running zero emissions, and with a centripetal advance, there's no reason to further advance any timing.

 

 

 

If I was to run straight from manifold to dizzy for vac advance, then at idle I'd no longer be at 5/6 degrees of timing because the vac advance would advance the timing at idle, therefore forcing me to further retard the timing. It would be a never ending loop wouldn't it?

 

A... replace or fix.

 

B.. Oh yes there is. If you never run less than full throttle you don't need vacuum advance. Remember the rule: the less the cylinder is filled the more timing you need to get the most out of it. Any part or light throttle will benefit from more advance.

 

Al carbs after the mid/late 60s has a vacuum advance port on it. This port has zero vacuum at idle but provides vacuum as you step on the gas. So in effect it is way retarded at idle (for emission reasons) but as soon as you come off idle the vacuum advance kicks in and adds advance in proportion to the intake vacuum. Heavy throttle has low vacuum so there is very little advance because the cylinder is filled. Vacuum advance makes the car more efficient at part throttle driving like around town and at light throttle at highway cruise speeds.