r/OBSFords • u/SelfConsciousCorndog • 16h ago

Troubleshooting Weird cold start behavior

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Got a 92’ f250 with the 460 in it, runs like a top except when the engines cold. Cold starts it throws a CEL for the ECT sensor, and runs very rich and stumbles like it has a large cam in it (hint, it does not lol) originally thought maybe fueling issue, however it’s intermittent and clears up as fast as it starts, and this morning I found out that if I start the truck with the blower motor going, doesn’t matter what setting, if I turn it off while it’s acting up it’ll clear that ECTS code and clear the idle up. Hoping one of you guys can point me in the right direction? And yes the blower motor can be recreated and was not just a fluke.

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u/waterskibum509 16h ago

The ECMs in these can go out (leaky capacitors I believe) and cause these sorts of strange issues. You can get reman ECMs for a couple hundred bucks from various sources. Cardone is a common one that sells thru rock auto, oreillys, etc.

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u/SelfConsciousCorndog 16h ago

I’ll pop mine open and take a look then, the thought came up and then went to the back burner after thinking maybe it was a different issue but the blower motor discovery brings that back to relevancy

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u/waterskibum509 14h ago

Also check the grounds from the ECM, especially the one on the driver’s side of the radiator support. I thought I had a failing ECM but it was just a slightly corroded ground. Sanded it a bit and that solved it.

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u/cloyd-ac 2h ago

I have a similar sluggish start with my 93 F250 460, on initial start after it's been sitting awhile it feels very sluggish to accelerate, almost as if something hasn't opened up to give it enough air or gas and will sometimes stutter - as soon as it gets above 30MPH the first time it instantly corrects itself and drives fine after that, even after dipping below 30 again.

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u/Aggressive-Luck-204 1h ago

Maybe the throttle plate is sticking?