I say part 2 as this is a continuation from a previous thread here: https://www.ford-trucks.com/forums/9...-suddenly.html I've made a new thread as I've exhausted (I think) the usual suspects and things are actually getting worse! A summary of what is happening/been done so far:
- Starting noticing just the slightest hesitation, maybe a little RPM drop while at idle one weekend. Prior to that my '66 F100 CC/CS with a 390/C6 was purring like a kitten for the 3 to 4 weeks it finally made it on the road.
- That week, the truck started to get progressively worse with drop of idle when at a stop light, then some stumbling, then some loss of power.
- Next weekend put in a new fuel pump (already had a new Pertronix ignition, wires, plugs, and a new Edelbrock 1406 carb).
- Started right up, but after a couple of miles it started the stumbling/hesitation/power loss. Rest of week commuting to work was a progressively worse nightmare with the truck running like it was only firing on 5 or 6 cylinders.
- Following weekend was spent testing fuel tank/line - thought it was a rusty/plugged tank/line. Not the case. Then replaced the Pertronix system with original points system - no go. Reinstalled Pertronix. Pulled distributor and one valve cover to check I didn't loose a timing chain - all looks OK. Checked for jumped timing chain - nope, TDC shows rotor pointing at #1 cylinder. Pulled all plugs and noticed all very wet with gas - replace with new double platinums - no affect, and wouldn't start -> so made me think something is wrong with the new Edelbrock and it was flooding. Ordered new carb.
- Beginning of Part 2: Today I install new Summit 600 CFM carb (nice carb - based on the Ford Autolite 4100, but updated and upgradeable with Holley based parts). Everything is hooked back up, and,......won't start at all!?!?!? I check spark - got it; check fuel - got it; I'm still breathing - got air. I replaced the Pertronix coil with an original unit - no help. That's it, I've run out of options......

So I need some help here - where to go/try next? I'm getting really worried that this rebuilt 390 (by PO, but is was running very strong just a few week ago) has something going wrong inside of it? I've got gas, spark and air - how can it NOT start? Looking for guidance on what to do next.

Thanks in advance,
daggerNC

 

Did you ever put a vacume gauge on when it was running?
Is the compression good and even on all cylinders?

 

Ok, step by step.

Fuel: you have checked and say you got it.

Spark: you say you have checked that also and have it. Did you check spark for every wire?

Plugs: say they were wet with fuel. Changing them not important as for finding out why wet. Too much fuel from somewhere. You should have seen how my Cougar ran one day when 40 miles from home and the power valve blew. One could smell fuel in the exhaust while standing 10 feet behind. Ran like crap at low speeds and every light was an experience.

Timing: what is it? Just because your rotor looks to be at #1 isn't everything. Doesn't take much to be off 10 degrees and if retarded you'll have more trouble than if advanced 10. Now advance 20 or more and then hard to start. Have you ever tried to move the distributor a little each direction while the engine is running?

Vacuum: do you have a vacuum gauge? With one hooked up you can learn a lot. I tune all my engines via the vacuum gauge. If no leaks then it should be up between 18-20 and steady. If low and steady then a leak vacuum leak or late timing. If pointer floating left and right of a center point than fuel mixture too rich or too lean. I'd start your fuel mixture screws between 2-2 1/2 turns out from bottom.

Pertronix: adjusted the gap using the small clear plastic gauge in the box. Ground connected. Screws snug. Connection at coil snug. The eye hook is slightly bigger than the coil terminal and contact can be broken or sporadic especially if using the correct wire harness that uses a little boot to connect. If using a nut then no problem. I know as I have had the truck die right on the freeway due to this connection.

Engine: if none of the internals have been changed then no reason to look here. If something happened inside you would know it right away.

 

Small crack or moisture in the distributor cap?

 

Thanks guys for the quick inputs. My responses:
- Checked vacuum before and was a steady 17"; can't check now as I can't start it!
- Have not checked compression - didn't think it was necessary seeing how well it was running just a couple of weeks ago
- Did not check spark at every wire - checked at two of them and tested 4 wires for consistent resistance (these are new Pertronix 7mm wires)
- Timing - I had set it to 8* BTDC. I rotated crankshaft to point to 8* btdc on the harmonic balancer and then checked location of rotor and it was dead on (as close as eye balling it can do) to the #1 terminal. I could try moving the distributor a little each way? If the timing slipped even one or two tooth - could this be enough to mess it up like this? And if so, what could cause it to move a little like this - I have not abused/jumped on this engine at all (yet)?
- Pertronix system removed and reinstalled. All connections secured with nuts.
- New distributor cap and rotor installed.

One other thing, and it may have been just my eyes playing tricks on me amongst all the gas fumes, but when I had the coil wire off and was cranking the engine to check spark (again) yesterday it seemed like it would go 4 sparks and then a slight hesitation and then 4 more. Normal?

Thanks again,
dagger

 

Nothing lost by tweaking the distributor a little clockwise and counter-clockwise to see what the result is. Maybe the engine catches or gets close to let you know you are on track. There been more than a few times where I have removed a distributor on the big Merc, thought it was in the right place, and it wouldn't start. So can't hurt to try since when you have fuel and good spark then something must be out of phase.

 

Some progress! Pulled all the plugs and they were all covered with intake runner deposits (my best guess - lots of gas washing out the intake). Cranked the engine over a few times to listen for compression puffs and watching the rotor action. Stuck my finger in #1 and have lots of compression there! Aligned the distributor to 8* BTDC on the compression stroke. Cleaned off all the plugs and reinstalled. Turned the ignition and it hit immediately and ran - but it wouldn't idle at all and I could hear and feel that it wasn't running on all 8 cylinders and had to keep my foot on the gas pedal. Glad to see it run though.

OK - so I must have enough spark, fuel, air and timing to get the engine to run. But it has no power and is missing on one or more cylinders. My next thought is perhaps I have a defective spark plug wire or two? I'm going to buy some new wires and new rotor and cap for the fun of it. What the heck else could it be??

Thanks!
dagger

 

You need to be able to start the engine fron under the hood. Short hand held jumper wire on the solinoid will work. With Pertronix (DO NOT LEAVE THE KEY ON) while you are working on the engine and if you forget to turn off the key you will burn out the Pertronix. I use a jumper wire from the + on the battery for a ignition key and a short jumper on the solinoid to spin it over. You should have a snapping blue spark from the coil and each of the plug wires. You need to be able to move the dist and rev the engine at the same time. Careful of the fan. Pertronix likes nice steady 12 + volts. If you still have the pink resistor wire in the ignition circuit you do not have adequate voltage for the Pertronix. Slapping on new parts is not the solution here. You need to figure out what is causing the problem.

 

It sounds more like a distributor timing type issue to me. Maybe your coil is acting up.

Can you even check the fuel line for pressure see how much your getting but it sounds like the fuel is good.

 

Ignitor I: operates with original ignition system wiring intact and any coil (Mustang)

Ignitor II: Can operate with resistance wire in place as I have done it. If you are running a simple street engine with a healthy resistance wire you should be good to go as my big Merc was. However, if you are a racer or have a pretty modified engine then you want the full 12 Volts. I went 12V as the Merc 410 is a 10.5 compression engine. Also best with 45,000V coil and 0.6 ohm resistance. (Parklane and F100-anything for some mpg)


Ignitor III: MUST operate with 12 volts. No if's and's or but's. Same 45,000 coil but has 0.35 ohm resistance I believe. (soon to go into Cougar)

 

Am running a switched +12v line to the Pertronix Flame Thrower (1.5 ohm) and then into the Ignitor I module. This is what the factory tech person told me to do (confirmed a second time - I disconnected my factory pink resistor cable).

I can recheck my switched 12v lead, though I wonder if for some reason it's not providing enough current could it be an issue (vohm meter will still show 12v)? William, I could hook a temp direct 12v lead from the batter terminal to the + coil terminal it the above scenario could be a factor? Thanks!

 

I use 12v direct from the battery all the time but just for a short time if the coil needs a resistor. Yours may or may not. I connect battery direct because I usually work alone and need to do everything from under the hood. Be sure you are in neutral!!!!! After it starts turn the dist 1/8th on an inch at a time clockwise (advancing a few degrees at a time) The engine should smooth out and runn. Let it run like this for 5 minutes or so. Then time it according to whatever specifications the factory recommends. Also take some WD-40 and look for a vacuum leak by spraying around the intake and carb gasket area with the engine running at a fast idle. If you have even a small leak WD will find it. Again look for that blue snapping spark, not yellow.

 

The factory tech seems confused. Enough auto web sites out there confirming standard wire for the Ignitor I and that is what Pertronix said when they first came out with the I. The major confusion was always with the Ignitor II as their instructions were ambivalent. As far as disconnecting the pink wire completely that is something I wouldn't do and didn't on mine. No side effect as electricity will take the path of least resistance anyway.

 

FWIW you may have a coupla wires crossed. jsut a thought

 

Flyn - I probably have a few crossed inside my head, but this truck was running smooth as butter for a number of weeks and then started acting up without me changing anything!

Mike - I agree with the confusion with Pertronix, that's why I called them again just a couple of weeks ago. I also read that the factory resistor wire was used based on early coil designs plus too hot meant burning out points quicker. With this new coil design plus magnetic field effect sensor it can handle the higher voltage and current...? I'll do some research and maybe a third call!

William - I'll try the direct 12v on start up (and hot spark check). Maybe I need to look for a better switched 12v?

Thanks all!