Alright. Mom's Grand Marquis won't start again!!!

[fordman]

Hi guys,

Some of you may remember a few weeks back I posted that my mothers 1999 Grand Marquis wouldn't fire up in below zero weather. After the weather warmed up it fires up. Put a bottle of heet in the tank thinking the fuel lines froze.

Well, here we are in wonderful Chicago. We just had temps that with the windchill hit almost -40 degrees! coldest in some 15 to 20 years here. Same thing happened. it wants to turn over,but as soon as it does it doesn't stay alive. It runs for 2 seconds and in those 2 seconds it hisses and dies.

The thing making me nervous is after it dies it lets out a LOUD HISSING noise from under the car. It goes on for a good 10 seconds or so. It sounds like compressed air being released. What in the world is that?

It has a brand new battery and plugs. One coil pack (cylinder 8) was replaced a few weeks ago. My mother doesn't drive to often so it does have the same tank of gas in it from a few weeks back when we had this problem before.

Could it be bad gas? it has heet in it. Im stumped. PLEASE, any advise would be great. Thanks Again.

[scruff]

how many miles are on the car? it could be a fuel pump issue check for fuel pressure at the intake manifold fuel rail valve also did you change the distributor cap and rotor? it could also be the ignition module that is attached to the distributor,
Good luck

[Fourth Horseman]

how many miles are on the car? it could be a fuel pump issue check for fuel pressure at the intake manifold fuel rail valve also did you change the distributor cap and rotor? it could also be the ignition module that is attached to the distributor,
Good luck

A 99 Grand Marquis won't have a distributor, but I agree about checking fuel delivery and ignition. Fordman, if you give it some throttle right after it starts can you keep it running?

[scruff]

opps sorry i thought it was a 1990 for some reason lol

[Aren Jay]

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[RF Overlord]

Unlikely to be bad gas or it would run poorly when warmed up, too.

Do as Fourth Horseman suggested above^^^...give it a little throttle after it catches
and see if it will stay running. If it does, then you have a bad IAC.

Also, don't waste your money on HEET. Half a bottle of isopropyl alcohol from the local pharmacy will do the exact same thing.

[Marauderjack]

Unlikely to be bad gas or it would run poorly when warmed up, too.

Do as Fourth Horseman suggested above^^^...give it a little throttle after it catches
and see if it will stay running. If it does, then you have a bad IAC.

Also, don't waste your money on HEET. Half a bottle of isopropyl alcohol from the local pharmacy will do the exact same thing.

I wouldn't use IPA as I think you can only get it 70% and 90%...the rest is water!!!:shake: 90% is better than nothing but you are still adding water to your gas!!:confused:

You can get methanol from hardware stores and it will be close to 99%...that would be better than IPA and cheaper than any of the gas driers sold!!:beer:

[RF Overlord]

'jack is correct. I only use the 91% stuff and forgot that the common stuff is 70%.

The only saving grace is that since the water is already bonded to the alcohol, it will burn through, just like the water that gets picked up by the various "dry-gas" products (like HEET), and the 91% stuff will absorb more water from the tank (if any is present).

[Fourth Horseman]

If you suspect IAC valve they're easy to pull and clean up with some throttle body cleaner. If that doesn't help you could consider replacing it, as they're not very expensive. Another thing to look at is oxygen sensors. My father's '93 Crown Vic LX was recently exhibiting similar symptoms to the ones you describe. After a little troubleshooting I replaced the O2 sensors and the car runs perfectly now. My father reports the engine is snappier and has more pep than it has in years.

[grampaws]

If the IAC is faulty holding the throttle down slightly
should keep it running.It could be freezing up.
If it still doesn't run leave the key on find the schrader valve
on the fuel rail and press it in like letting air out of a tire.
if it just trickles then fuel filter or fuel pump or relay could be the
fault.Fuel filter probably has frozen water in it?
Isopropyl alcohol is beter methanol becomes acidic when mixed with water.
if it's water change the filter.

[fordman]

Update:

When I was trying to start it for the last 2 days in below zero temps, it would turn over for 2 seconds. I would then hit the gas to try and help it along in those 2 seconds. It did no good. It would not respond to my throttle demands and die out and a huge hissing noise would come fro underneath the car. No air suspension on her car, so it is not a air compressor letting air out.

Anyways, todays temp. is 20 degrees above zero and my mother calls me today and says she tried to start it a few times and on the 3rd try it caught, it was putting so she floored it, and it ran fine. I was there this evening and the things perfect. I give up. Im going to clean the IAC valve as some of you have said to do.Im also going to change fuel filter. Any other ideas would be wonderful. Thanks again everyone.

P.S. - Is fuel filter in same spot as Marauder? I believe it is.