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92 Fleetwood 2dr cpe - FWD, 96 Seville SLS, 02 Seville
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847 Posts
Discussion Starter #1
Have a 92 Fleetwood (FWD 4.9l), that usually works fine, but on occasion, it'll crank but won't start. With a lot of research, I've found the following:

- never a problem if it is restarted within a few minutes of shutting off.
- usually not a problem in the morning
- problem most frequent after 20 minute of shut off our sitting in the Sun
- if it won't start street a number of cranks, waiting 20-30 minutes will enable a start
- have gotten it started with starter fluid
- have replaced fuel tank, pump, filter, pressure regulator.
- tps, throttle all checked, tuneup done with plugs, wires, distributor
- fuel pressure at 43psi, regulator wool pull it down to 39

I suspect it's starved for fuel when trying to start a partially earn engine.
If the block is hot, it will start, if the block cools down but water temp is warm+, then it won't start.
It's likely a card start choke is helping to start the car under all but the warm coolant temp scenario. However, I'm not sure if this explains the waiting 20-30 minutes approach from above.

Ideas
 

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1992 Fleetwood S&S Hearse, 1993 Buick Roadmaster
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567 Posts
Coolant temperature sensor or ignition control module come to mind. Either could be responsible for a weak start. However, the "started it with starter fluid" part wouldn't match, so....

Sometimes I wonder if I'm helpful.
 

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92 Fleetwood 2dr cpe - FWD, 96 Seville SLS, 02 Seville
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847 Posts
Discussion Starter #3
Coolant temperature sensor and MAT sensor both checked out. Tried bypassing them with a resistor to force a cold start - no change.

Control module replaced with distributor. No change.

Tried adjusting the idle position (via FDC) to totally open or totally closed (i.e. cold start choke) - No change.

Disconnected Pressure Regulator vacuum hose thinking the starting process might have have created extreme vacuum - No Change.
 

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1985 Sedan DeVille
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1,883 Posts
Have a 92 Fleetwood (FWD 4.9l), that usually works fine, but on occasion, it'll crank but won't start. With a lot of research, I've found the following:

- never a problem if it is restarted within a few minutes of shutting off.
- usually not a problem in the morning
- problem most frequent after 20 minute of shut off our sitting in the Sun
- if it won't start street a number of cranks, waiting 20-30 minutes will enable a start
These are symptoms of a leaking injector flooding the intake and/or wetting a plug. Eventually it will depressurize the fuel rail and the gasoline will evaporate, then it starts fine.
 

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'93 Sixty Special 4.9l V8, '01 Sebring Convertible, '13 300C
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354 Posts
Had similar issues. My fix was a new fuel cap. the valve on the old had gone bad. easy to test out too: open up the gas tank when it happens. If the car starts: new cap for 3 bucks.
 
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