302 FI hard start when Hot
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302 FI hard start when Hot
My '86 302 FI has developed a problem with hard starting when hot.
It starts up when cold in about 3 seconds and idles and runs great - good power. When it warmes up to temperature and I shut it off for about 20 to 30 minutes, when I try to restart it - it may take 30 to 40 seconds of cranking to start and it sounds like it may only be hitting on one or two cylinders; then it will take off and runs good again until I shut it off.
I replaced the ignition module and the coil is only about a year old. I did extend the wiring and relocate the iginition module to the fender to keep it cool. I replaced the high pressure gas pump went out last summer and I replaced it - the fuel pressure is about 50 psig.
Any ideas?
Thanks,
Oscar
It starts up when cold in about 3 seconds and idles and runs great - good power. When it warmes up to temperature and I shut it off for about 20 to 30 minutes, when I try to restart it - it may take 30 to 40 seconds of cranking to start and it sounds like it may only be hitting on one or two cylinders; then it will take off and runs good again until I shut it off.
I replaced the ignition module and the coil is only about a year old. I did extend the wiring and relocate the iginition module to the fender to keep it cool. I replaced the high pressure gas pump went out last summer and I replaced it - the fuel pressure is about 50 psig.
Any ideas?
Thanks,
Oscar
Mountain Pass
Joined: Nov 2003
Posts: 137
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Two things come to mind...
First, clean your IAC valve (Idle Air Control valve) and your throttle body with throttle body spray. I would remove the valve and spray it out really well. You would be surprised how much gunk builds up in there.
Try "priming" your fuel pump a few times next time you start it hot. Do this by turning the key "on" for a second or two without turning to the "start" position. You may even hear the pump running and the sound changes once it builds up pressure. If this helps it to start better, then you may have the following problem:
Second possibility, watch the fuel pressure gauge once you shut the engine off. If it drops off sharply in a few seconds, you may have dirty injectors that leak out fuel instead of holding it in. This effectively floods the engine (and loses fuel pressure). Once the engine sits long enough, the fuel evaporates, or worse, gets past your rings into the oil. Then it will start fine as its not so rich.
Hope this helps.
Ryan.
Try "priming" your fuel pump a few times next time you start it hot. Do this by turning the key "on" for a second or two without turning to the "start" position. You may even hear the pump running and the sound changes once it builds up pressure. If this helps it to start better, then you may have the following problem:
Second possibility, watch the fuel pressure gauge once you shut the engine off. If it drops off sharply in a few seconds, you may have dirty injectors that leak out fuel instead of holding it in. This effectively floods the engine (and loses fuel pressure). Once the engine sits long enough, the fuel evaporates, or worse, gets past your rings into the oil. Then it will start fine as its not so rich.
Hope this helps.
Ryan.
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From: Virginia
Try holding the pedal to the floor while cranking and see if it starts quicker. This will turn the injectors off till you let up on the pedal. If it starts quicker, this might also confirm the leaky injector theory stated above.
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Guy's - Thanks,
I'll clean the IAC and see if that helps - The injectors are rebuilt ones I installed last fall - I'll check that too.
Usually, I do let the fuel pump pressure up before I hit start - I'll try holing it to the floor.
Oscar
I'll clean the IAC and see if that helps - The injectors are rebuilt ones I installed last fall - I'll check that too.
Usually, I do let the fuel pump pressure up before I hit start - I'll try holing it to the floor.
Oscar
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