460 won't start. Please help!
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460 won't start. Please help!
I have a 4x4 '88 f250 fuel injected 460 w/ c6 tranny.
Background: the engine already had a misfire is cylinder 6. It ran ok but had 0psi in that cylinder. The other 7 had about 145psi. Im sure I shouldn't of been driving it that way but it's a little late now haha
I was driving today, and all seemed (relatively) fine but when I started to go uphill, there was some hesitation in the throttle response and then I felt a subtle pop and smelt something kinda strange then engine died. After the engine died the smell went away.
I checked all the fuses, belts, and charged the battery and poured some gas in the tank. Spark plugs and such are fairly new also. It turns over ok but it just wont start. When i try to start it with the gas pedal down i feel like I hear a slight knock.
Any body have any ideas of what could be wrong or how to find out?
Any help would be VERY appreciated
Background: the engine already had a misfire is cylinder 6. It ran ok but had 0psi in that cylinder. The other 7 had about 145psi. Im sure I shouldn't of been driving it that way but it's a little late now haha
I was driving today, and all seemed (relatively) fine but when I started to go uphill, there was some hesitation in the throttle response and then I felt a subtle pop and smelt something kinda strange then engine died. After the engine died the smell went away.
I checked all the fuses, belts, and charged the battery and poured some gas in the tank. Spark plugs and such are fairly new also. It turns over ok but it just wont start. When i try to start it with the gas pedal down i feel like I hear a slight knock.
Any body have any ideas of what could be wrong or how to find out?
Any help would be VERY appreciated
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From: VA
That "pop" could have been your coil exploding. I've known of that happening before. Any evidence of oil leaking out of the coil? If you don't see anything there, take a spark plug out and ground it. Crank the engine over and see if you have spark jumping the gap or not (or use an inline spark tester if you have one available). If you've got spark, then it's either fuel or compression that's the issue. Check for fuel pressure, and do a compression test on all cylinders.
I doubt it's a compression issue even though you have no compression on one cylinder. I've accidentally started up my 460 (this has happened 3-4 times) without the 4 spark plug boots on the spark plugs on the passenger side bank. Once it's started up, I'll be thinking "Hmm... this is running rough," then I'll realized I didn't put the boots back on after working on it. So mine will start and run on 4 cylinders even with the other 4 fighting it (good compression on all cylinders). I think yours should still start and run (shaky & rough) even if you lost another cylinder.
Good luck!
I doubt it's a compression issue even though you have no compression on one cylinder. I've accidentally started up my 460 (this has happened 3-4 times) without the 4 spark plug boots on the spark plugs on the passenger side bank. Once it's started up, I'll be thinking "Hmm... this is running rough," then I'll realized I didn't put the boots back on after working on it. So mine will start and run on 4 cylinders even with the other 4 fighting it (good compression on all cylinders). I think yours should still start and run (shaky & rough) even if you lost another cylinder.
Good luck!
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From: VA
Yes, the ignition coil.
You've got the fuse panel under the dash, and only relays under the hood.
You've got the fuse panel under the dash, and only relays under the hood.
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Well, I did a compression test, it was about 150psi so thats ok. However I tried to ground the spark plug and nothing showed. These are fairly new and correctly gapped so I feel it might be something else. The battery and all other electrical are good. It still turns over but wont catch. Still think it might be a coil?
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I tested the coil and it seems fine, in fact I shocked myself trying to ground it haha. So spark is getting through the coil but when I tried to test a spark plug from the distributor, I got nothing. I used a brand new plug, a couple different wires, changed the cap and the rotor and I still cant get spark.
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From: VA
Okay, you've got that ruled out.
Could be the ignition control module (ICM) I guess.
If everything checks out except for the spark between the coil and plugs, than it seems like the only things that could have an issue are the distributor or ICM (or bad wiring between the ICM/distributor/coil).
Sounds like you've gone throughout the distributor and know it should be good to go. I'd try replacing the ICM. It should be about a $40 - $50 part for the replacement BWD ignition control module.
If everything checks out except for the spark between the coil and plugs, than it seems like the only things that could have an issue are the distributor or ICM (or bad wiring between the ICM/distributor/coil).
Sounds like you've gone throughout the distributor and know it should be good to go. I'd try replacing the ICM. It should be about a $40 - $50 part for the replacement BWD ignition control module.
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