03 not starting when warm
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03 not starting when warm
My 03 explorer is having symptoms similar to vapour lock. It starts fine when its cold but ocassionally will not even fire once it is warm. This happens when I shut it off for a short period of time, usually to check my mail or quickly run into a store. I could crank the engine over all day and it wont even fire. I can usually smell gas at this time, so I assume that it is not getting any spark. If I wait one or two minutes it will start fine. This is getting very frustrating because every time I take it to the dealer or try to troubleshoot it myself it won't do it. It displays no fault codes as well. Any ides would be greatly appreciated.
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The computer is probably getting carried away with cold start enrichment, and the engine is flooding. With the ambient temperature very cold, and the engine warm, the sensors are conspiring to tell the computer to dump in lots more fuel than is actually needed. The too-rich mixture won't light, and the engine won't start.
Next time it happens, try flooring the accellerator during crank. This puts the computer into "clear flood" mode, and it will shut off the injectors. It should fire on the residual fuel, and you can then release the gas pedal. If it doesn't even pop during "clear flood", try releasing the gas pedal and crank for 10 seconds more. If that doesn't work, try carrying around a timing light so that you can check for spark (or non-spark) the next time this happens. You might have a temperature sensitivity problem with the ignition system. Usually, the computer will not supply fuel if it is not getting spark.
To attempt to cure the problem, you might try replacing the ACT or ECT sensors, or both.
Next time it happens, try flooring the accellerator during crank. This puts the computer into "clear flood" mode, and it will shut off the injectors. It should fire on the residual fuel, and you can then release the gas pedal. If it doesn't even pop during "clear flood", try releasing the gas pedal and crank for 10 seconds more. If that doesn't work, try carrying around a timing light so that you can check for spark (or non-spark) the next time this happens. You might have a temperature sensitivity problem with the ignition system. Usually, the computer will not supply fuel if it is not getting spark.
To attempt to cure the problem, you might try replacing the ACT or ECT sensors, or both.
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Thank you for the reply Fefarms! This evening it wouldn't start again, so I tried what you suggested and held the gas pedal all the way down. It worked perfectly and my explorer fired up imediately! I had no idea that this would cause the computer to go into flood clearing mode, but it makes sense. It will be alot easier to solve this problem now that I have a direction to go in.
Thanks Again!
Thanks Again!
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The "pedal to the floor" thing is left over from the era of carburetors. I think the designers figured at least some drivers would remember this technique from the bad old days when flooding happened all the time. Plus it opens the throttle to let plenty of extra air into the system to dry things out.
One other possibility is that you have a failed fuel pressure regulator that is piddling extra fuel into the intake plenum through the vacuum line. This is of little consequence during a cold start, but is enough to cause flooding on the first warm start attempt after a brief stop. You can check this by checking your fuel pressure and observing the rate of fuel pressure bleed-down when the in-tankn pump shuts off, or by pulling off the vacuum hose and looking for fuel or vapor smell coming from the regulator.
One other possibility is that you have a failed fuel pressure regulator that is piddling extra fuel into the intake plenum through the vacuum line. This is of little consequence during a cold start, but is enough to cause flooding on the first warm start attempt after a brief stop. You can check this by checking your fuel pressure and observing the rate of fuel pressure bleed-down when the in-tankn pump shuts off, or by pulling off the vacuum hose and looking for fuel or vapor smell coming from the regulator.
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fefarms,
I'm not sure "trans threading" is allowed in FTE but you may be able to help me with my issue (see thread "94 Explorer will not start" January 16, 2005).
I'm trying to get this 94 running and I considered the FPR as a potential issue. The plugs get very wet on cranking. When you say "bleed-down" I assume you mean that the pump KOEO produces ~40psi and if there is an issue with the FPR you will see a reduction in pressure when the pump shuts off (and/or fuel in the vac line)?
Also, if the engine is flooding would a "clear flood" condition a.k.a. foot to the floor help this engine catch?
Any ideas would be appreciated before I pull off the intake and heads!!
I'm not sure "trans threading" is allowed in FTE but you may be able to help me with my issue (see thread "94 Explorer will not start" January 16, 2005).
I'm trying to get this 94 running and I considered the FPR as a potential issue. The plugs get very wet on cranking. When you say "bleed-down" I assume you mean that the pump KOEO produces ~40psi and if there is an issue with the FPR you will see a reduction in pressure when the pump shuts off (and/or fuel in the vac line)?
Also, if the engine is flooding would a "clear flood" condition a.k.a. foot to the floor help this engine catch?
Any ideas would be appreciated before I pull off the intake and heads!!
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