[channingjames]

I recently bought a 1997 GT. It runs fine, but when I try to start it in the mornings it is very hard. After I get it started and let it idle for a few minutes, it's good to go. I don't have any trouble starting it the rest of the day. When I try to start it when it's cold, it turns over just fine. I'm wondering if it has and air or fuel problem? I'm going to run sea foam in it in a couple of days and see what that does.

 

[1996mustang]

Does it turn on the windshield wipers automatically when u have a cold start? Just asking mine does it only in cold weather lol. Plus i have a similar issue mine runs a bit rough on cold but warm no problems......might be the fact i need a tune though with all the mods i added.

 

[cliffyk]

Check the battery voltage while cranking it over when cold--if it is dropping below 10.5V the PCM will be affected, it could be a weak cell in the battery...

 

[taylor98gt]

Mine does the same thing, I know I have a bad battery so I'd say that's most of it, plus their fairly cold natured anyway lol

 

[channingjames]

I checked the battery today, is running 100%. Also the alternator is working great too. I'm thinking maybe the throttle position sensor could be bad. I also got sea foam for the in tank fuel filter, possibly it's not getting enough fuel. But it doesn't make sense for a fuel problem because once I get it started in the morning, it would start right up hours later. I got MAF sensor cleaner and throttle body cleaner, I'm hoping that will help along with an oil change tomorrow. I know a little bit about cars, I've worked on them some and have common knowledge of everything. I just don't know a whole lot. All advice and suggestions are appreciated!

 

[cliffyk]

I checked the battery today, is running 100%. Also the alternator is working great too. I'm thinking maybe the throttle position sensor could be bad. I also got sea foam for the in tank fuel filter, possibly it's not getting enough fuel. But it doesn't make sense for a fuel problem because once I get it started in the morning, it would start right up hours later. I got MAF sensor cleaner and throttle body cleaner, I'm hoping that will help along with an oil change tomorrow. I know a little bit about cars, I've worked on them some and have common knowledge of everything. I just don't know a whole lot. All advice and suggestions are appreciated!

I am curious as to how your checked the battery and determined it to be 100%?

How was the generator tested?

With EFI systems a great many starting problems are battery related...

 

[channingjames]

I took it to auto zone and they tested my battery and alternator for me

 

[cliffyk]

I took it to auto zone and they tested my battery and alternator for me

The handheld testers they use are just go/no go devices, and will often "pass" a marginal battery. To properly test a starting duty battery's capacity you need to do a high current (at least 1/2 of the CCA rating) load test that applies that load for 10 to 15 seconds. The least expensive such tool of which I am aware is this one from Harbor Freight, which is currently on sales for $55.

The handheld testers apply a small load (10 to 15 A) and use software algorithms to interpolate (I.e. "guess") the battery's actual high current performance. The 500 A carbon pile tester actually tests the battery's high current performance.

If I had a nickel for every battery that has passed a FLAPS test, and then failed a real high-load test, I'd have 25¢ or 30¢.

The generator (generator, not alternator--see below) tests performed by the handheld devices are better.

from the 2003 shop manual:

 

[Mathew r Wright]

I take my Fluke16 and check voltage if it is not 13 1/2 to the least or greater then it a sad day...

 

[channingjames]

My battery light is on, also. Like I said, I don't know a whole lot. The guy at auto zone said the battery light didn't matter, since it passed that test. So should I just buy a new battery? I first thought it was a battery problem but my co-workers know a bit about vehicles and they convinced me it wasn't. But one time my car was already warm and I had driven to work. I turned it off and then immediately tried to start it. It wouldn't start, so I got a friend to jump it and it started right up. I cleaned the throttle body and mass air flow sensor, that seemed to help some with the time it takes to start in the morning. Tomorrow I'm putting sea foam in the gas tank and changing the oil.

 

[cliffyk]

"The guy at auto zone said the battery light didn't matter, since it passed that test."

Huh? This is why everything the "technicians" at any FLAPS tell you be taken with a grain of salt, and largely ignored.

I would get the battery properly tested before I just ran out and bought a new one--it is of course also possible that the generator is bad instead/also. Find a real mechanic or auto-electric shop and have them test it...

 

[Mathew r Wright]

"The guy at auto zone said the battery light didn't matter, since it passed that test."

Huh? This is why everything the "technicians" at any FLAPS tell you be taken with a grain of salt, and largely ignored.

I would get the battery properly tested before I just ran out and bought a new one--it is of course also possible that the generator is bad instead/also. Find a real mechanic or auto-electric shop and have them test it...

Can't agree more... I would listen to CliffyK he knows what he's talking about he's helped me more than anyone and is smarter than most I know also... Smart people like him are a few and far between...

 

[1996mustang]

Can't agree more... I would listen to CliffyK he knows what he's talking about he's helped me more than anyone and is smarter than most I know also... Smart people like him are a few and far between...

+1 i would definitely get the battery checked first as for testing the alternator....little mechanic trick is to disconnect the positive side while the car is running. If car stays alive atleast for the moment u can rule out the alternator

 

[Mathew r Wright]

+1 i would definitely get the battery checked first as for testing the alternator....little mechanic trick is to disconnect the positive side while the car is running. If car stays alive atleast for the moment u can rule out the alternator

Really? I didn't know you could still do that cool.

 

[Xtrosity]

Really? I didn't know you could still do that cool.

I had and older car where the alternator died and ran the whole car off the battery. Didn't find out until a few days later when it was hard to start, of course it didn't have all the technology the mustangs have. As for testing batteries, I've always used the old sun machines. Always work great never found a reason to switch.

 

[Fastfive_ogt]

+1 for checking the battery. But the charging light is probably on do to the diode in the alternator. It could still be charging with that light on. As far as hard start when cold. If its not the battery I would suggest checking ECT when the engine is cold. Possible that its reading incorrectly causing a lean or rich condition when it's cold. Test your battery and charging system first of course.