My 96 Grand Marquis with slightly over 140,000 miles has suddenly been difficult to start. It idles very rough before it does run and will usually stall a few times. I leave it set for a few minutes and it fires right up and runs fine. I am planning a trip to Florida soon but don't want it to not start on a vacation. Any thoughts what it might be?
Grand Marquis difficult to start
- Thread starter spk2000
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IAC valve is a common problem on these. That would be my guess:
http://www.autoclinix.com/Ford/Ford_IAC.html
http://www.autoclinix.com/Ford/Ford_IAC.html
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I did put new plugs in a few months back. They were Autolite Iridium's and it ran great after pulling out the E3's that were in it from when I bought it. I did put premium gas in it on the last tank as it seems to run better on premium. It was from CountryMark that is top tier gas.
Interesting on the IAC valve. It does not stall or idle rough except at start up. Once it is running it runs very smooth. At start up it almost seems starved for fuel but once going it is fine.
Might be the mass airflow sensor(maf). It can be cleaned with MAF cleaner, brake pad/rotor cleaner or electronic parts cleaner. It is located between the air filter and the throttle plate. There are two tamper proof torx screws holding it down. Unplugging the maf will generate a check engine light when you start the car. But if the car idles, with the maf sensor disconnected, that would pretty much point to the maf. To get rid of the check engine light use of obd reader or disconnect the negative terminal of the battery.
Originally Posted By: beast3300
Unplug the maf sensor and see if it starts easier. Try running it without the MAF for a few miles. Common failure on those is MAF.
Never seen the MAF cause a issue in cold start then OK when warm... Sure electronics sometimes have cold failure issues, but compared to a likely dirty/gummy IAC, isn't very likely... Still if MAF has never been cleaned, it's past time, though cleaning one on my 175K mi F-150 made no difference(I was doing it as maintenance no doubt never cleaned)...
I'm voting IAC... That should be easy enough to tell, if bringing up idle slightly with throttle smooths it out, that's probably the issue...
Unplug the maf sensor and see if it starts easier. Try running it without the MAF for a few miles. Common failure on those is MAF.
Never seen the MAF cause a issue in cold start then OK when warm... Sure electronics sometimes have cold failure issues, but compared to a likely dirty/gummy IAC, isn't very likely... Still if MAF has never been cleaned, it's past time, though cleaning one on my 175K mi F-150 made no difference(I was doing it as maintenance no doubt never cleaned)...
I'm voting IAC... That should be easy enough to tell, if bringing up idle slightly with throttle smooths it out, that's probably the issue...
I vote IAC also. Pull the IAC off and see if dirty inside. I've fixed the issues that you have by cleaning them out really well with some brake cleaner. The get junk built up in them and the valve won't move. When it's cold it's in open loop and will run pretty rich and being cold it will want to raise the idle. I've seen them stall by basically being flooded in open loop if the IAC doesn't open up to let the extra air in. But then when it warms up and goes into open loop the IAC is probably sitting right where it needs to be so then it runs and idles fine.
One other way to check to make sure the IAC is working. Once the engine is warm and running like normal turn on the AC. If the rpm drops and doesn't correct itself them the IAC valve isn't moving.
One other way to check to make sure the IAC is working. Once the engine is warm and running like normal turn on the AC. If the rpm drops and doesn't correct itself them the IAC valve isn't moving.
I try to start it and it dies. No matter how much I try it won't start just keeps dying. I let it set for 30 seconds and it fires right up and runs perfect even when cold. I will check both MAF and IAC as I have done nothing to these and have owned the car since ~82,000 miles.
First, unplug the MAF and start it as suggested above....its free, and it will quickly eliminate it as a cause. Always suspect a fuel pressure concern. Always. Cycle the key four-five times before start up to prime the fuel rail, and see if that improves the situation. Once again.....its free.
Not saying it isn't an IAC, but I replaced very few of them on Fords over the years. People seem to suspect them for wayyy too often.
Not saying it isn't an IAC, but I replaced very few of them on Fords over the years. People seem to suspect them for wayyy too often.
Do you have access to a scan code to check cylinder head temperature and engine coolant temperature, as well as check for codes? Could be an issue with either sensor.
Also, when was the fuel filter last replaced? When the engine fires up and idles rough, does it smooth out if you raise the revs a bit?
Also, when was the fuel filter last replaced? When the engine fires up and idles rough, does it smooth out if you raise the revs a bit?
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