got a 1980 F250 4x4 with the 300-six, holley 390 and clifford intake. my trouble is sometimes it starts, sometimes it doesnt. The main issue at hand is it stutters around 1,500-2,000 rpm, but idles great. started doing this about a month ago, and it got so bad to where it would struggle/die under acceleration, was sluggish, and had trouble driving it,and it ended up with me on the side of the road. The fuel filter looked bad, so i replaced it. didnt help, so I got a new Ignition control module,and It got me home. then shortly after I rebuilt my carb and got it tuned somewhat right, drove fine for a day or two, then wouldnt start. I then replaced the ignition switch and the ignition cylinder, didnt help much, still wouldnt run. I then looked at the cap and rotor, cleaned up the points on the cap and the rotor a bit and fired right up, drove OK. drove to school all week okay, didnt go above 2K as my secondaries are not quite adjusted right, but its not super important considering I could drive just fine, and it would idle good. It still "stuttered" around 2K, hence why I kept it below that. stuttering got worse, so I figured id replace the cap and rotor today, and it drove wonderfully. still a bit of "Stuttering" at higher rpms, but thats tuning that I havent got around to quite yet. And, sometimes while driving it will die on me completely. while driving it will stutter for a second then the RPM's will drop to zero, while still in gear (T18 4SPD) I would then push the clutch in and it would start idling again, so i would put it back in gear and it would usually get me where I needed to be. that issue happened after the new cap and rotor, and has been happening for well over a month now. Now, I go to start it shortly after I get home from my test drive with the new cap/rotor, and wont crank. I am not getting spark, and am puzzled. Everything in the ignition system has been replaced within a year ago, besides the distributor (plug wires and plugs about a year ago, coil in november, and the module/switch/cylinder/cap/rotor very recently. The only thing I can think of is to replace the distributor, but I would rather not throw more money than neccesary into it (broke *** high school kid, LOL) anny info would be appreciated.

 

Well you do have a year on the plugs. You did not say what plugs you got in it? If you have them fancy million mile ones scrap them and put in what the IGN system was made to use, Good old copper plugs.
Some have had issues with them fancy plugs.

I think you may have 2 or 3 things going on here. Thing is to find just what 1 or 2 it is? Note new parts can be bad out of the box.
The ICM (box) I take it was the cheapest one the store had and that can be an problem. Do you still have the old one (I hope) maybe put that back in.
I would like to know what the fuel pressure you have going to the carb and what fuel pump you are using, motor driven or electric?
When you rebuilt the carb did you find dirt in the float bowls? When was the last time you checked the float levels, both should be just below the hole and when you shake the truck it should just dribble out.
When it dose not start you need to check for spark and fuel. Fuel is easy remove the air filter, open the choke and when looking down the carb move the throttle you should see fuel squirt. Spark pull the coil wire from the dist. cap and hold about 1/8 to 1/4 inch from the motor and crank the motor. If it is good you should hear a snap from the spark.
Do you have a after market tach? If so disconnect it and see if it changes anything. Maybe leave it disconnected till you have it fixed.
That should keep you busy for a bit.
Dave ----

 

Check for wear marks on the face of the distributor pickup coil, as seen here:

https://www.ford-trucks.com/forums/1...tator-gap.html

Probably not what you have, but the symptoms are similar. Quick and easy to rule out.


Please define "won't crank". Does the starter engage normally and get the crankshaft spinning properly, even if the engine won't run on its own? I think that is what you mean, but wanted to be sure.

 

OK a few things... Im guessing you bought it with the upgraded carb/intake right? Im wondering if some of your stumbling might be that the carb was never tuned right from the start. Now onto the not running/stalling/starting issue. What do the plugs look like? Are they wet? carboned up? Pale white in color? ALl look about the same, or some different then others? Get yourself a inline spark tester. They are cheap, and real handy for this kind of diag. When it acts up you need to do your diag.. As was said in previous posts.. check for fuel. If thats good, check for spark from the coil. If thats good check for spark at each plug. Also make sure your discription is right.. No crank is when the engine doesnt turn over at all. No start is just that... also it can fire without starting..hearing the popping, or trying to start... all handy to know when your asking for info.

 

sorry, yes I meant it will turn over, just not run. And as far as i can tell it’s not firing. The 2 plugs I checked were kinda red in color, and yes I bought it with the carb and intake on it. I am getting fuel

 

Sounds like the pick up coil in the distributor.
it can be bought seperatly from the distributor and is easy to replace.
it will give you all the symptoms you have listed .
Buy a motorcraft unit as most orher brands are of poor quality.

 

Ooh, I missed this important clue on first read. If the distributor is still turning (in this case, mechanically back-driven via the rear axle, etc.) and the ignition system has power, the tach should still show actual RPM even if the engine is not producing power. So there's a possibility the ignition switch is intermittent or misadjusted. If you can duplicate the fault, try wiggling the key to see if that helps.

If no improvement, I'd be willing to gamble your time and money on a distributor pickup coil.
Here's a good video explaining the replacement process on an earlier model, but the basic details should be applicable:




This part has me perplexed. If the engine was being back-driven, depressing the clutch pedal would cause the actual RPM to drop. I'm not sure how lower RPM would regain engine operation.

 

Ooh, just remembered an important thing to check. Remove the distributor cap and carefully inspect the two flexible wires for the pickup coil. When the vacuum advance mechanism rotates, those wires flex. Over time, they rub against the housing and develop a bare spot in the insulation and can short out, killing the ignition. The frustrating part is the fault is only active at certain combinations of RPM and throttle position, so it can be hard to duplicate for troubleshooting.

 

Maybe the answer lies is what he's not telling us.
Everyone is assuming this is still a stock DS2 ingition system.

Any chance you installed a "hot coil" with a primary coil resistant around .6 ohms.

Jim

 

Just had a thought which might explain this bizarre behavior. See my previous comments about the pickup wires flexing and shorting to the distributor body under certain conditions. When the engine is being back-driven, vacuum is still being created and the vacuum advance system is responding as designed.

But when RPM drops, less vacuum is created and the vacuum advance system starts to relax. The wires are no longer shorted, the ignition system fires again, and the engine is still spinning just fast enough for it to run again on its own.

 

yes it is the stock duraspark system. I said screw it and decided to replace the entire distributor today, and it’s being a total bitch to get it adjusted right. It’s at around 16BTDC, but now there is a new issue. It is running horribly. It takes forever to start(I crank and crank it, and eventually it starts to run, then it finally idles) and it’s stumbling at whatever rpm it is at, and I’m pretty sure it is running rich as now the spark plugs are black. Also, when I shut it off, lots of smoke is sitting in the carburetor. The carb(Holley 390, Vaccuum secondaries) is adjusted right (I think?) with the idle mixture screws turned out 1 turn from all the way in, and the float bowl adjusted properly. I am stuck here and have no idea what I should do.


UPDATE
this may sound stupid but now my thought is I thought I set TDC to the compression stroke, but maybe I accidentally set it to the exhaust stroke (don’t know how I would accidentally do this, but maybe I did) and it would explain why it’s running like garbage, and maybe it would explain why there is smoke in the carburetor. But I’m not sure if it would even be able to run if the timing is set to the wrong stroke.

 

If that number is right… that is a problem. There is no way a DS2 base timing is supposed 16° but I be wrong.

 

It will run at 16* BTDC but I was getting way too much pinging and backed it down to 12* to 14* I think I am at now.
I replaced the pickup coil in the dist. and it ran like crap and I had to turn the dist. a lot to get it to run good. I dont remember why it was like that but I did fix it so it runs great now.

You may want to pull #1 plug and with a finger over the plug hole tap the key, starter button on the solenoid works, till you r finger get pushed off.
Check the timing mark and turn by hand till at TDC. Pop the dist. cap and see if the rotor is pointing to #1 plug wire. If not pull the dist. and drop it back in so it dose point to #1 plug wire.
Dose it run better so you can get the timing to say 12* BTDC vacuum off and plugged?

If you find the rotor is not pointing to #1 or 180* off then I would pull the dist. and see if the roll pin sheered and the gear turned and then caught and spinning the shaft but way out of timing.
Dave -----

 

Oh as for the carb running rich once you get the timing under control look into the power valve (PV)
If this is an older Holley when they back fire up thru the carb it can blow the PV and it can then leak fuel and run rich.

You want to take a vacuum reading with motor up to temp at idle and in gear if auto.
Whatever that reading is you want to start at half that. So if you are getting 20 HG you want a 10 HG power PV as a starting point and adjust up / down from there.
If driving at steady speed and it surges you need to go up 1 number as the valve is opening & closing at that vacuum level.
When the vacuum drops the PV should open to richen the mixture then as the vacuum comes back up close to lean up the mix.
Dave ----

 

Reading between the lines, the symptoms changed with the replacement distributor, right? If so, this would imply the old one probably had some sort of issue. Furthermore, the new one has some problem, but likely a different one. Or this new one may be fine but there was a new problem induced during the installation, such as a connector not fully seated or the timing set wrong.

I'd suggest rechecking all connectors that were disturbed. If no improvement, try tweaking the timing by ear in one direction and then the other. I'd also inspect the roll pin, as previously suggested.