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Ask Someone: 1988 Ford F-150 #1575943919

(excuse the long post) Hey y’all I’m new to the forum and had a problem that no mechanic has been able to figure out yet. I just picked up a 1988 F-150 5.0L/ 302 (Non-HO) 4x4 5spd with around 220k miles on it a few months back. Truck ran like a charm for weeks with no problems except an oil leak and missing window. I found the oil leak coming from the O-ring on the distributor, and decided to replace it. Took out the distributor, marked the timing, and reinstalled with the new O-ring. Crank, but no start. I had a few extra bucks lying around and I went to preventative maintenance and decided maybe the distributor died on me. So put on a new one. Still no luck. Here’s what’s been done since:
Found TDC and did the normal procedure to set the ignition timing about 11 times now with no luck.
New motorcraft spark plugs
New Accel spark plug wires
New battery
New starter and solenoid
For those going to ask, heres what I’ve done/ found. Spark plugs are all getting great spark, checked them all twice. SPOUT connector is out. Fuel pump and relay click with key on, and fuel rail is keeping a consistent 44psi for a few mins after key is off. Inertia switch is not active. Fuel injectors are working, and even tried starter fluid with no luck. Compression is good. Air intake is good. Mechanical timing is good. Distributor turns when cranking. Have tried all the above with old and new distributor. Checked the ignition switch, grounds, and all the wires from the ECU and solenoid with all getting proper resistance/ voltage. Battery is getting proper voltage and amperage. Fuel is new, as just filled up before it wouldn’t start. Only been sitting for about 2 weeks.

Again, please excuse the long post, I am just super stumped here. Between me, my buddies, and mechanics, I’ve had 15 eyes on it with no luck. Any and all help is greatly appreciated.

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Make absolutely sure that shaft is lined up right. I haven’t seen it overly often, but every once in awhile someone gets it 180 degrees off. Shouldn’t, theoretically, be possible on most if not all dizzys because the key slot is offset, but it happens. I even did it on an old Honda once.

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I have an early 70’s Ford truck, same engine, but mine is carb/points-condenser-coil ignition. Since you have spark and fuel, and the distributor is rotating ok, my guess is the tdc you are using is the exhaust stroke tdc. There’s two tdc’s for a 4-stroke engine. One on the compression stroke, and the other on the exhaust stroke. If using the exhaust stroke one, the spark plugs will be firing on the exhaust stroke so you’ll be able to confirm fuel and spark, but it won’t go. when the distributor is installed correctly the rotor will point to the wire that goes to cylinder number 1 when number 1 is at the top of the compression stroke. double check tht. Cylinder number 1 on my 302 V8 is on the passenger side, front. Number one on Fords of that era is always the cylinder positioned most forward (towards the front of the vehicle) of the 8.

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yessir, will check. i’ve played with that shaft a few times to make sure it’s lines up alright but i’ll double check.

yes, i’ve done it on the compression stroke each time and if it won’t start, i’ll flip it 180 out for good measure and still nothing. will triple check though, thank you

I’ve never worked on a ford with an electronic ignition distributor.

Can you static time it ?
Engine TDC compression stoke, #1 spark plug out and grounded hooked to spark plug wire, turn distributor housing until you get spark.

never heard of it, but definitely worth a try. i’m away from the truck for a little but i’ll let you know after some trial and research, thank you

I don’t know if you can with your truck, I was asking the forum.

I had a difficult to diagnose cranks but won’t start problem one time w/ my VW Rabbit. Good healthy visible spark, good compression, dizzy doing its thing, fuel system ok. But no matter what I did it just would never catch and run. Very puzzling. It turned out the cause was the engine was flooded with gasoline from prior fuel system testing. OP, one idea, remove the spark plugs and if there’s signs of excess fuel, let the cylinders air out overnight. Worth a shot anyway.

good idea, thank you sir

Are you absolutely certain you installed all the plug wires to the proper position on the disty? If that is good and you are sure you aren’t 180 degrees out on the disty then I suggest you try rotating the disty slightly in either direction to see if you can get any reaction while cranking the engine.

yessir, ive wired them up exactly like Ford states and ive tested for 180 out multiple times. i’ve gave the dizzy timing each way (retarded and advanced) up to 30 degrees each way and all it’ll do is backfire when i go too far. really throws me off. but thank you sir, much appreciated

Another idea: I had a problem once on my 70’s Ford truck where I had both spark and fuel, cranked robustly, but it wouldn’t start. If I sprayed starter fluid into the air intake & it would cough a little, like it was trying to start. But never would. That made me think I had some kind of weird fuel-system problem. But everything checked out ok in the fuel system. The only clue I got from the ignition system testing, the color of the spark was more orange-ish than I’d expect. That turned out to be the reason it wouldn’t start. Spark was there, but not strong enough. The color of the spark should be blue-white.

I expect you already know most any Ford knowledgeable mechanic could get to the bottom of this problem quickly.

that’s another thing that threw me for a whirl, the spark is a strong blue spark from brand new (properly gapped) plugs. Clear as day. but that’s a great suggestion, thank you sir

You mentioned the fuel injectors are working, have you looked at the spray pattern and compared them to one another? Just an idea.

I have not, and it’s actually a great idea. The previous owner told me they are relatively new injectors, so that’s the closest thing I got. just curious how it would run so well before and all the sudden not start. I will take a look into doing so, do you have any recommendations how?

I have to assume that between the time you removed the disty and put it back in place, the crankshaft wasn’t moved AT ALL while the disty was removed and, you put it back in the exact same tooth position it was originally in. If that is case here then the only other thing that I can think you could have done wrong is somehow put the plug wires on the wrong cylinders. The backfiring is an indication of that.

at first, yes the crank wasn’t moved. but after a few tries and no start, i started the process of resetting TDC and the dizzy so that it is all lined up. after doing this process with no success (many many times) i’m pretty much out of ideas. the wires are all labeled in 3 places to triple check they’re all wired up right

Well assuming that the plug wires are in the correct position and the ignition timing is at least close to where it should be then you basically have only one other possibility left, valve timing. Since you stated that the engine was running great before the change was done it seems the valve timing should be okay. Checking the compression should confirm that. If compression is good and the wires are truly going to the correct cylinders then the disty rotor position has to be off slightly from where you think it should be. You may be a couple of teeth off the correct position.

that’s a good idea, i’ll be sure to do a compression check soon. the closest thing i have to that so far is when i put my thumb over the spark plug hole and feel air coming out. thank you sir