Question - engine sputters but doesn't fire
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Question - engine sputters but doesn't fire
I just put a new 351m crate motor in a 1989 F250.
Set the timing to top dead center, turn distributor, but only one spot has a spark. Engine sputters like it's going to start, but doesn't fire over.
I'm stuck - do you think it's a timing problem or maybe computer? Relays? Any suggestions?
Set the timing to top dead center, turn distributor, but only one spot has a spark. Engine sputters like it's going to start, but doesn't fire over.
I'm stuck - do you think it's a timing problem or maybe computer? Relays? Any suggestions?
Posting Guru
Joined: Aug 2000
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From: (near) Denver USA
Are you sure the crate engine is a 351M?
What was the original engine in your truck?
If the crate engine is a direct replacement for your original engine, it is a 351W, and you should check in this forum for more info:
https://www.ford-trucks.com/forums/f...?s=&forumid=55
What was the original engine in your truck?
If the crate engine is a direct replacement for your original engine, it is a 351W, and you should check in this forum for more info:
https://www.ford-trucks.com/forums/f...?s=&forumid=55
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You're right, it could be a 351W -- I was told it was a modified. I know it's the same as the original was.
Any idea what the problem could be? It fired over for a minute, but hasn't started since. It sounds like it's gonna turn over, but just doesn't.
Any idea what the problem could be? It fired over for a minute, but hasn't started since. It sounds like it's gonna turn over, but just doesn't.
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Checked & rechecked. Checked everything I could think of and I'm stumped!
What are the chances it's something to do with the catalytic converter?
It had a rough idle when I bought it and needed a new motor, so I didn't get to check too many things out on it.
What are the chances it's something to do with the catalytic converter?
It had a rough idle when I bought it and needed a new motor, so I didn't get to check too many things out on it.
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From: peoria, az
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Spark & fuel both ok. I replaced lots of things, so did the guy I got it from, so most parts are new. Maybe vacuum lines or the computer is screwing things up? I don't know. Thanks for your suggestions.
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stepman
good to hear because as you can tell by my recent post count I have too much time to kill and this is where my energy is going. Quite frankly if someone thinks like me that tends to scare me. Just kidding, later
89f250
I know little about efi so my initial question of do you smell gas was intended more to a carbed motor when I saw 351m I first thought carbed. Sorry about that. Let us know if the tps was the problem. later
good to hear because as you can tell by my recent post count I have too much time to kill and this is where my energy is going. Quite frankly if someone thinks like me that tends to scare me. Just kidding, later
89f250
I know little about efi so my initial question of do you smell gas was intended more to a carbed motor when I saw 351m I first thought carbed. Sorry about that. Let us know if the tps was the problem. later
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Joined: Aug 2003
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From: kansas
If TPS voltage is too high the ECM thinks you,re holding the throttle wide open. The ECM then decides you,ve flooded the engine somehow and it will not fire the injectors. This is called CLEAR FLOOD MODE. It will not begin to fire injectors until a certain rpm is reached which cannot be reached just by cranking. Using a volt meter see what the green wire from the TPS reads. It should be 1. volt or less and vary to about 4.5 volts at wide open throttle . Other two wires are 5.volts with key on, the other is ground.
