As you may have read in an earlier thread, my '86 F250 4x4 I-6 300 quit on me Friday night. Let me start a little further back. ... Sunday night I parked my truck after pulling my toy hauler over the pass from eastern Washington. I noticed a bit of fluid under the truck when I walked by a little later and attributed it to water from the A/C which I had been running all the way back. Ok, now back to Friday night. I was able to get the truck started but as soon as it idled down from the choked fast idle, it died. It sounded like it loaded up. From then on, it would not start. I noticed a heavy gas smell and guessed it was flooded. I walked back to the tail pipe and sniffed there and noticed a faint gas smell. I noticed a puddle under the truck and found it to be gas. I traced the leak down to a punctured carb float and replaced it, set the float height and then reinstalled the carb. It would not start.

I've checked spark (nice & bright blue in the sunlight) and timing (right on 10 degrees). I changed the plugs and fuel fouled oil and oil filter. It still would not start so I said screw it with that carb and went ahead and replaced the full exhast system and intake with parts I'd been accumulating. I now have EFI exhaust manifolds going to a 2 1/2" pipe through a 13" Flowmaster knockoff and exiting ahead of the passenger side rear wheel. Also installed are a 2bbl carb off a 1976 V6 Mustang. I rebuilt the carb before installation. The carb is marked with "1.08" on the side and also has a tag with the label: "D6ZE VA" and then below that in smaller writing is "C 68 3". The carb is bolted to a Clifford Performance intake manifold. Everything was torqued to spec. I installed a manual choke on the carb.

My friend suggested that gas might have washed down the cylinder walls and caused the rings to seal poorly, not giving me enough compression to start. I checked compression and the lowest cylinder was 143psi and the highest was 155psi.

So, I've got good spark, I've got fuel, and I've got good ring seal. (The carb is squirting gas from the acc pump when I work the throttle, so I know I have fuel) I've tried starting it with full choke, 1/2 choke and no choke. My ignition timing is good. I even squirted a 2 second shot of starting fluid down the carb throat a couple of times and it still would not start? I'm about to give up at this point?

Any ideas of what i can try next?

 

In doing all the work, are you sure you have the spark plug wires on the correct plug?

Does it fire at all?

 

It doesn't even try to fire. Nada, nothing, not even a hiccup. Very frustrating. I have checked and double-checked that I have the right plug wire going to the correct cylinder.

 

maybe clean and gap the plugs

 

Plugs are brand new and gapped to spec.

Keep the ideas and feedback comin' I do appreciate it!

 

Well - if you have gas, compression & spark - timing is the only thing left - are you sure the rotor is turning? Did you remove the distributor? Could it be 180 deg. out of time?

 

I'm going to pull the rotor cap tonight and see what I can see. Ignition-wise all I've checked for is good spark and that the timing is correct. Tonight I'm going to pull the rotor cap and see what's going on. Somebody mentioned in the 80-86 forum to check the pin on the bottom of the distributor, so I'm gonna check that out tonight. I don't think it could be 180 off because the distributor has not been pulled since it was at the dealership down in CA in April when it was installed.

Thx for the replies! - DORN

 

I didn't mention the pin due to you mentioning you had spark - usually, you won't get spark if the pin is sheared. I would check anyway - at this stage you have nothing to lose.

Good Luck

 

Ok, I checked the distributor and the rotor turns as I crank the motor. I went to check spark again and now there is zero spark? WTF???! So, here's where I'm at now. I've got power to the coil when I turn on the ignition, but still no spark. I have a spare, new ignition module (I've had two go out on me in the last 4 months.) so I went ahead and swapped them out. Still no spark. This is a mystery.

 

I don't know really what I did, but I have spark again. I checked at all 6 plugs just to verify. Timing is at 10 degrees.

I hate to say it, but I think I'm gonna have to step away, work on my dirt bikes and maybe have a mechanic look at this thing. I'm at a loss.

 

Out of curiosity, if the truck wont run, how do you know timing is at 10? I would look hard at that because you wont get a backfire or anything if the timing isnt close to right on or 180 out. Take a breather and start over with the distributor. Make sure that when #1 is at TDC, the rotor is pointing at the #1 spark plug tower on the cap. That will put you close or at about 180 out. You should get some activity there. Is this a computer controlled beast?

 

It turns out my problem, or at least the most pressing one is that I have an intermittent spark. It works sometimes and doesn't at other times. When I have had spark, I was able to verify that my timing was indeed set at 10 degrees.

It's looking like the distributor. I have power to the coil and good spark out of the coil, but no spark at the plugs. I've changed the ignition module. If it is the distributor, I'm just gonna buy a spare and carry it behind the seat, along with an spare ignition module. This will be the 3rd distributor in 4 months.

Is there a distributor that I can buy that takes the whole ignition module out of the picture, maybe somethhing with simple mechanical or vacuum advance?