Cant set timing properly

[mercwoody87]

car -87 MGM Colony Park
engine-'88 5.0 HO converted from EFI to Carb, msd all round, new wires, plugs, cap, rotor, etc. Spark Plug firing order/wiring is correct.

So my problem is I cannot seem to set the timing correctly. When I set the timing to 10o BTDC (where the book says it should be) the engine stalls at Idle and seems to be bogged down completely, however under hard throttle/high load it pulls strongly and smoothly. When I advance the timing further, the Idle increases to a maintainable speed but the engine pings and rattles under hard throttle/high load. I thought I would solve the problem by setting the timing to somewhere in between, but it is still stalling.

[BGoins12]

Did you unplug the spout connector by the distributor before timing it? It looks sorta like a fuel injector plug with a cap in it. Pull the cap and then check the timing. If you did unplug it, the harmonic balancer could have slipped and will need replacing.

[88grandmarq]

Did you unplug the spout connector by the distributor before timing it? It looks sorta like a fuel injector plug with a cap in it. Pull the cap and then check the timing. If you did unplug it, the harmonic balancer could have slipped and will need replacing.

did you bother to read that he has removed the EFI and is running a carb?

[88grandmarq]

car -87 MGM Colony Park
engine-'88 5.0 HO converted from EFI to Carb, msd all round, new wires, plugs, cap, rotor, etc. Spark Plug firing order/wiring is correct.

So my problem is I cannot seem to set the timing correctly. When I set the timing to 10o BTDC (where the book says it should be) the engine stalls at Idle and seems to be bogged down completely, however under hard throttle/high load it pulls strongly and smoothly. When I advance the timing further, the Idle increases to a maintainable speed but the engine pings and rattles under hard throttle/high load. I thought I would solve the problem by setting the timing to somewhere in between, but it is still stalling.

First, make sure you are using the timing pointer and not the round hole, next to the pointer.

also, make sure the distributor is installed correctly. being a tooth off will cause similar problems to what you are describing.

if you are using a vacuum advance distributor, make sure the vacuum hose is connected to a ported vacuum port on the carb

[sly]

you may also need to adjust the idle set screw on the carb.

I'd poke the idle set screw up some to dial in the timing, then set the idle... then double check the timing. once the stock settings are dialed in, then I'd play with it to get it really happy.

[cld783]

you may also need to adjust the idle set screw on the carb.

I'd poke the idle set screw up some to dial in the timing, then set the idle... then double check the timing. once the stock settings are dialed in, then I'd play with it to get it really happy.

try to set both when warm..

[86VickyLX]

did you bother to read that he has removed the EFI and is running a carb?

Just because you're running a carb doesn't mean you can't run a TFI distributor...

What RPM is the engine idling at? Is the balancer new or old? (they can get screwed up and start to read inaccurately) What kind of vacuum do you got on the motor in idle?

[gadget73]

The spout connector would do exactly nothing with a TFI distributor on a carb engine. Its input from the computer. No computer means no input which means no spark advance. Running a TFI distributor with a carb is a pretty horrible option anyway for something thats street driven.

Sounds like you need to adjust the carb, likely the idle needs to be raised and probably the fuel mix screws played with. Set the timing where it belongs to start with, and adjust the carb so it idles.

[mercwoody87]

It Is not a TFI distributor, I had to change the distributor when I made the efi -carb swap. It is a vacuum/centrifugal distributor. also the carb is brand spanking new direct from holley.

[gadget73]

Are you setting the timing with the vacuum line disconnected or no? It should be unhooked to set base timing. Lean fuel mix will also make things ping, as will an improper timing curve. You can always pull timing to make it stop pinging, but you might be costing yourself a lot of power if the real reason is a too-small main jet. If all the stuff is new out of the box, I'd pretty well guarantee none of it is perfectly optimized for your setup. It may be close enough, or it may not be. Hard to say without knowing exactly what jets are in the carb, what distributor is in use, and how the timing curve is set up.

[import convert]

with the proform HEI style distributor and a ford E cam on my last carb motor it pinged a lot even at like 7* base and a rich holley 600 and 93 octane. with a stock dizzy and a explorer cam on this motor at like 9* base i have yet to have a problem on 89 octane and i havent tried to get a performacne tune on the dizzy yet

[1987cp]

Things that come to mind:

- Is your "0" mark really true TDC?
- What is your total spark advance?
- What distributor are you using and what advance springs and limiter are installed?
- What carburetor MODEL are you using and what, if anything, has been done to it?
- How are you approaching the task of carb calibration?

You've given people precious little information to go on.

Personally, I'd start by checking TDC, setting base timing to something very conservative like 4 or 6 degrees, make sure you have light advance springs and usually a 20-degree (marked "10") limiter slot, leave the vacuum advance disconnected entirely, and then turn your attention to the carb.