I recently upgraded my 1967 F-250 4.9l 300 i6. I replaced the intake manifold with an Offy "C" series, updated to EFI dual exhaust manifold then to top it all off threw on a little Holley 2 bbl 2300 carb (part # 0-7448). Now after getting all this put on and plugged up, compression checks out, fuel pressure checks out the damn thing wont start. It turns over freely, sounds like it wants to fire up every time but simply won't stay running after I bring the key back. Has any one tried this combination with better luck? Is this common? Should I be looking to upgrade my ignition system?? Also, I changed the plugs yesterday and spaced them to approximately .05

 

Hi S.S. Clarence, welcome to the forums.
That's a nice setup you have and it should fire right up. If it's not, you still have an issue somewhere.

An engine always needs 3 things to run: Air, Fuel, Spark

Air:
Make sure that the choke isn't completely closed. I've had this happen before and it wouldn't start for anything. The choke plate should be open about 1/8" to 1/16" when cold.

On the flip side, too much air is an issue as well. Double check that there aren't any major vacuum leaks, such as an uncapped PCV or brake booster port on the intake, etc.

Fuel:
You're certain that gas is getting to the engine? Does fuel squirt into the carb when you work the throttle?

Spark:

Did you touch the timing/ignition/distributor at all?


You still have something not set right if it's not running.

 

Thank you AB, it is a nice a lil set up and it adds to the frustration to why it won't fire up for me. The carb is getting fuel, all lines have been plugged and everything is torqued to spec. Everything seems to pointing to ignition, do I need to advance my timing? I haven't touched the distributor or ignition since it was parked a few months back.

 

The ignition coil tested bad, going to replace that asap. Is there anything else that a bad ignition coil and fouled plugs could effect?

 

Nice find on that. I was going to say, if everything's buttoned up nice and tight, you probably have something wrong with your ignition. The stock ignition should work just fine with that setup. My first thought was the plugs, since I recently got a bad plug brand new out of the box. Granted, my engine ran, but not very well.

I'd try just the ignition coil and see what that does. If it fires, it should also clean up those fouled plugs in short order, as long as they're not damaged.

 

Summit should have it to me sooner than later. I replaced the plugs yesterday so they should be nice and fresh still, unless they were bad out of the box. Did these motors have a ballast resistor? I know my 1963 Valiant with a 225 slant 6 had a ballast that gave me a hell of time until I got to know her better.

 

I'm not sure on that one, since I've never worked with the points ignition (they went to the DuraSpark II setup in the 70s). Hopefully someone'll chime in who knows.

I hope that coil takes care of your issue and it fires right up.

 

Yes, they had a big ugly resistor on the firewall. The points got 8 v.

https://www.google.com/search?q=1974...fuArf-G7rXtZM:

OMGosh, if you don't want to be fiddling with the points every six months, convert to Petronix module, or a DS2 distributor with a GM 4 pin. (Although I do kinda miss the days when I could clean the points with the gf's emery board and set the points with a matchbook cover).

 

"(...could clean the points with the gf's emery board and set the points with a matchbook cover)"

Those were the days!

 

I can't find the ugly ******* on my '67 F250. I read some where that certain modules had a pink wire in the dash that took the place of the resistor.

 

I think only the really old Fords (50"s and older I think) had a resistor on the firewall if needed.


That pink wire that is in the main wiring harness is the resistor.
So if you need to run a full 12 volts to the coil you have to bypass that wire by either removing it from the main harness or running a new wire from switch to coil.


That is why in your other post I say run a relay that is triggered by the stock resistor wire that sends 12 volts to the system you want to run.
Dave ----

 

New ignition coil, gapped the plugs to .04 and it is still the same. Starts when it turns over but won't stay running. I held it to start the other day and the truck came to life but then it started to surge and revved up really high. I turned the key to shut it off and it kept revving up as if I were flooring it. Took the key out of the ignition and it still did not shut off, ran out and pulled the negative wire from the the battery. Saw that I had the wires on my coil switched so I fixed it and had to replace the starter. Has any dealt with something similar?

 

The coil wires switched should only make it hard to start and run not have anything to do with it revving high or not shutting off.


I just went over the first post. New offy intake & EFI exh manifolds.
IIRC abandedbronco had issues with breaking tabs because the manifolds were not on the same plane on the washer side.
Also IIRC there are tabs on the EFI manifolds that hits the stock intake so the intake will not sit flat on the head causing a vacuum leak and revving.


Here is my post on EFI exh manifolds and stock intake and what I ran across.
https://www.ford-trucks.com/forums/1...questions.html


Now lets look at revving first because if it does start you don't want to blow the motor up.
Remove the throttle cable/linkage so it cant keep the throttle open.
Make sure the fast idle cam is not holding the throttle plates open. Maybe even back off the choke so you know the fast idle cam is out of the picture.
Also check the idle speed screw and maybe back it off as well.


Check all vacuum hoses/lines to make sure none fell off and are cracked.
PCV line hooked up or plugged?
Brake booster line hooked up or plugged?


If that is all done and if it still revved up when started you have a vacuum leak some place and you will have to find out where.
Look up finding vacuum leaks using smoke on youtube as that is what I would do.


Or you need to pull everything back apart and look at gaskets to see if they are sealing right. I see you are using a v4 intake and a v2 carb so you MUST be using an adaptor.
I have heard of some adaptors not sealing as they should and you need to LOOK REAL CLOSE at the gaskets to see the leak.
It would be at the adaptor recessed bolts to the edge of the opening to the inside. This just bearly seals if looked at closely.


Now as for starting you had to do something if it all worked before the intake/carb/exh swap.
What wires did you touch? Why was the coil wires switched as you should not have to touch anything on that side of the motor to do the manifold swap.
Add any wires for the choke and if so where did this power come from?


Why did the truck stay running with key off? The coil wires on wrong would not cause this so look else where.
Again you did something with the wiring to cause this.
If it is not getting spark after you let go of the key you could run a hot wire from batt + to coil + to get it to run. to stop remove this wire and it should stop if everything else is good.
Dave ----

 

Oh plug gap shod be somewhere around .036" not .05 you have.
This could also be why it is hard to start/run?


You still running points and if so did you do anything to them?
What is the gap on them? A match book cover used as a feeler gauge works in a pinch.
Dave ----

 

thanks for the response fuzzface!

Yes, I brought the plug gap back down to .04. The points are still there and I have not touched the distributor during this.

I swapped out my ignition coil because it tested low and was careless when putting it back on. During the upgrades I noticed my starter solenoid needed some attention and so did my voltage regulator. I ordered new ones and plugged them in the same way they came out.

I have backed off the idle screws. It is a manual choke so no new wires there. I can check the points when I get home but they were set using a feeler gauge before it was parked.

Could a faulty voltage regulator cause the surge? Or the same careless mistake of switching the wires on the starter solenoid. I did double check that after I discovered my mistake with the ignition coil.